MASTERS IN TELECOMMUNICATION ENGINEERING. OPTICAL NETWORK AS EARTHQUAKES EARLY WARNING. SYSTEM. (R.O.S.A.T.S). Author: Eng.
MASTERS IN TELECOMMUNICATION ENGINEERING OPTICAL NETWORK AS EARTHQUAKES EARLY WARNING SYSTEM (R.O.S.A.T.S)
Author: Eng. MIGUEL ANGEL IBAÑEZ
Thesis Director: Dr. RICARDO DUCHOWICZ (CIOp – U.N.L.P.) Version 10.
2012
ACKNOWLEDGMENTS: To the authorities of Argentine Republic, President Cristina Fernández de Kirchner for approving the deployment the Optical Fiber Network plan that enabled to elaborate this thesis as a blueprint and simple contribution that surely will add another and allow in expand the project "Argentina Conectada" irreversibly improving telecommunications in the Argentine Republic, with social impact in actual times and for future argentine generations of XXI century. Authorities and staff of the National Institute of Seismic Prevention (INPRES) ARSAT SA, University of La Plata (UNLP), Optical Research Center (CIOp) and National Telecommunications Commission (CNC), for the provision of information. A different important actor of optical / education area in Latin America such as; FTTH Council G. Guitarte and E. Jedruck, Telcon-Prysmian Group, Mr. S. Ragusa, GIKO Group, Mr. J. Sanchis, IDETEL C. Marín, FOETRA O. Iadarola, UTN BA Ing. G. Oliveto and OIC SA D. Hereñú for their interest and continued support for research and development of new telecommunications technologies.
To my teachers in different universities for listening and guiding my "infinite" inquiries, proving that curiosity are the first thing that a teacher has to encourage. My appreciation and ensure that I practice their example and I am confident that my students also will do it. All students, friends and colleagues of Argentina and Latin America who provided support for some time in the different optical networks projects I took part. My appreciation and thanks for being there, and always shared a passion for telecommunications, which have participated directly or indirectly in the implementation of this proposal. To my parents, José and “Pepa” for their infinite love and patience. To my children, Florencia, Javier and Alejo, daily love, no words just a feeling of gratitude for the happiness of seeing them well grow leaning on each project with interest and curiosity. Eng. Miguel Angel Ibañez. Mat Copitec Nro. 2693 August 2012.
SUMMARY
Optical telecommunications networks were developed in thousands of kilometers in Argentina by dominant firms in the business between 1993 and 2003, mainly oriented as transport links between cities of high GDP, economically attractive. In 2010 the national government launched the project "Argentina Conectada” which includes the construction of the "Optical Fiber Federal Network" will cover over 40,000 km covering most of the territory and provide a high speed link, low latency and have high safety from design with redundant physical paths in optical fiber and radio systems used in this "National Optical Backbone".
In parallel with the telecommunications development in Argentina described above earthquakes and natural disasters in various parts of the world of high impact in terms of loss of human lives and material destruction happen. Just remember the last event in the region on February 27th 2010 that hit Chile, that violence and speed caused a major disaster. In Argentine Republic we remember San Juan earthquakes on 1944 and Caucete 1980 without prior warning to the population of that province and that, if this would be repeated in the area today would be possible to have an "early warning alert system ", automatic and massive in communication systems such as, cellular, TDA, TV would provide greater opportunity to survive the inhabitants of the affected area and reduce damage to take actions to emergency services such as, gas, electricity, fuel, etc.
In the above context, this work presents, analyzes and proposes innovative way to use-with minimal additional cost-optical transport networks telecommunications currently being built across the country (REFEFO), as an earthquakes early warning network, thus adding value to the initial project "Argentina Conectada", as UIT suggested in its document "Trends in Telecommunication Reform 2012", (1), incorporating environmental sensors also optical and local manufacture (UNLP-CIOP) and integrating current seismic systems managed by INPRES (National Institute of Seismology Study) that are distributed (150 approx.) radio connected sensors by radio to potentially have more than 1500 measurement of optical links REFEFO (lower installation cost and maintenance that actual by radio) coinciding with the areas described in the current seismicity map of Argentina, establishing a high security optical modern network of early warning for natural disasters to interact / warn the inhabitants of the
territory by different telecommunications terminals, such as: cell / SMS /TDA / TV / CCTV / radio / specific terminals as sky alert etc. and also with neighboring nations connection, forming staged a "mesh of earthquakes early warning in South America."
(1) Chapter 2, "Creation of nac Broadband Plans", Table 1, item 2 Goals and Objectives / Developing countries / "Goals and most sophisticated …
INDEX 1. - INTRODUCTION ...............................................................................................................9
2. -TECHNOLOGY STATUS ................................................................................................19 2.1 OPTICAL TRANSPORT NETWORK AND ACCESS: OPERATING PRINCIPLE, CONSTRUCTIVES TOPOLOGIES AND ASSOCIATED MATERIALS ...........................................................................................20 2.2 OPTICAL TRANSPORT NETWORK: OPTICAL FIBER FEDERAL NETWORK PROJECT.............................................................................................................40 2.3 NATIONAL NETWORK OF SEISMIC ARGENTINE STATIONS.......................51 2.4 SCADA SURVEY AND CONTROL OF MULTIVARIABLE OPTICAL NETWORK SYSTEM……………..…………………………………….......................................67 2.5 OPTICAL ENVIRONMENTAL SENSORS AND ITS APPLICATIONS........................................................................................................................72
3. – WORKING HYPOTHESIS.............................................................................................77 3.1 GENERAL OBJECTIVE..................................................................................................79 3.2 SPECIFIC OBJECTIVES..................................................................................................79 3.3 SCOPE……………………………………………………………………………………………..80
4. -PROPOSED SOLUTION...................................................................................................81 4.1 COMPARISON OF ARGENTINE SEISMOGRAPHIC NATIONAL NETWORK AND OPTICAL FIBER FEDERAL NETWORK PROJECTED FOR TELECOMMUNICATIONS .................................................................................83 4.2 TECHNOLOGICAL CONVERGENCE BETWEEN REFEFO, AND EXISTING NETWORK OF SEISMIC STATIONS (REFEFO) AS
DETECTOR AND TRANSPORT WORKING IN SEISMIC RISK AREAS (PRIORITIES).……………………………………………………………………………………..87 4.3 TECHNOLOGICAL CONVERGENCE CREATING EARLY WARNING NETWORK DIRECT TO RESIDENTS (INTERNET, MOBILE PHONE SMS, TDA, CATV, RADIOS,) ……………………………………………………………………………...... 87 4.4 CONVERGENCE MODEL –OPTICAL NETWORK INTEGRATION PROPOSAL-BASIC ASSEMBLY DETAIL...................................................................... 92 4.4.1 Graphic of the proposed scheme "ROSATS" from the op. detector -Tx FO-to node……………………………………………………………………………..………........ 93 4.5 SOCIO-ECONOMIC IMPACT ANALYSIS OF THE PROPOSAL IMPLEMENTATION……………………………………………………………………………….94
5. - OPTICAL SENSORS ....................................................................................................... 95 5.1 INTRODUCTION………………………………………………………………………………96 5.2 MAIN PARAMETERS…………….................................................................................. 97 5.3 SENSORS DESIGN. ANALYSIS …..……..................................................................... 98 5.4 VIBRATION SENSOR DEVELOPMENT FOR EARTHQUAKE MONITORING. ……………………………………………….…………………………………………………………115 CASE 1: FIZEAU SENSOR…...……………………………..……………………………….116 CASE 2: BRAGG GRATING (FBG) ….......................................................................... 120 BRAGG GRATING ENGRAVING ................................................................................ 122 5.5 LABORATORY TESTING (CIOp) 5.5.1 SENSOR CONSTRUCTION.................................................................................... 126 5.5.2 SENSITIVITY DETERMINATION....................................................................... 128 5.5.3 WORKING RANGE SENSOR DETERMINATION ......................................... 129 5.6 RESULTS OF OPTICAL SENSORS TEST............................................................. 129
6. - CONCLUSIONS ............................................................................................................. 131
7. – FUTURE RESEARCH………………………................................................................. 135
8. – BIBLIOGRAPHY…………………………………………………………………………..…139
9. - APPENDIX I .................................................................................................................. 143 9.1 SEISMIC PHENOMENON.......................................................................................... 144 9.2 SEISMOLOGY STUDIO MEDIA……........................................................................ 146 9.3 MAGNITUDE SCALES - INTENSITY …................................................................ 147 9.4 EARTHQUAKE PREDICTION…….......................................................................... 150
10. – ANNEXES II……………………………………………………………..…………………..153 1.1 RING OF FIRE ……………............................................................................................ 154 10.2 TECTONIC PLATES………....................................................................................... 156 10.3 GEOGRAPHICAL LOCATION JAPAN CASE..................................................... 158 10.4 GEOGRAPHICAL LOCATION CHILE CASE...................................................... 159 10.5 EARLY WARNING SYSTEMS ENVIRONMENT IN THE RISK REDUCTION PROCEDURE………………………………………………………............................................. 159 10.6 WARNING DISSEMINATION................................................................................ 161 10.7 EARLY WARNING SYSTEMS IN THE WORLD ............................................. 166
11. - APPENDIX III ............................................................................................................. 177 11.1 GENERAL DESCRIPTION OF TRANSMISSION PRINCIPLES ABOUT OPTICAL FIBER……………………...................................................................................... 178
1. INTRODUCTION
1. INTRODUCTION In recent years and throughout the timeline of our time, there have been a series of events linked to multiple natural disasters that have ample evidence of the power of nature and when these happen, remind us the low reactive power that human has against that.
Man's life since ancient times, has experienced flooding, the strength of hurricanes and tornadoes, violence of volcanic eruptions and earthquakes, year after year, natural disasters, bring about a greater number of loss of life and materials. The causes of this increase of the losses are related to the largest number of world population, increasing urbanization, the type of economic activities, population settlement in hazardous locations and lack of early warning networks that demand natural disasters interconnected using new technologies in computing telecommunications.
Each year there are millions earthquakes in the world, a large percentage takes place in unpopulated areas, several thousand are recorded by seismographs throughout the world, some hundreds are perceived by the general population, causing some damage to cities (population or constructions), less than a dozen are of such a magnitude to be considered of magnitude greater than 8 on the Richter scale, most occur within the "Fire Ring" (see Annex 9.1) and there is no place on the planet that can be considered completely free of earthquakes although Antarctica registered a few and low magnitude.
Next, as the context of the thesis, we present a brief narration of the earthquakes, which marked their passage in recent times, cases: • Japan 2011, • Chile 2010 and • Argentina 1944:
JAPAN. • The Great East Japan Earthquake of 2011 (see Annex 10.3), in Tohoku region, was of magnitude 9.0 MW [1], reaching an intensity of IX [2] on the Mercalli scale, which triggered waves tsunami of up to 40.5 meters and this happened at 14:46:23 local time (5:46:23 UTC [3]) on March 11th of this year. The epicenter of the quake was in the sea, off the coast of Honshu, 130 km east of Sendai. At first we calculated the magnitude at 7.9 MW which was subsequently increased to 8.8 MW8.9 MW then according to the records of the Geological Survey (USGS). Finally reaching 9.0 MW confirmed by the Japan Meteorological Agency and the USGS and lasted about 6 minutes. U.S. Geological Survey explained the earthquake occurred because of a shift in the area near the interface between subduction plates [4] between the Pacific Plate and the North American plate. Two days ago, this earthquake was preceded by another major quake, but of minor magnitude, occurred on Wednesday, March 9th, 2011, at 2:45:18 UTC on the same area of the east coast of Honshu, and had a magnitude of 7.2 MW, at a depth of 14.1 km Also that day the authorities of the Japan Meteorological Agency gave a tsunami warning, but only local to the east coast of the country. On February 1st the volcano became active in Shinmoe, Miyazaki province, this indicates a tectonic reactivation pre-earthquake.
The magnitude of 9.0 MW made it the most powerful earthquake suffered on Japan's history to date and the fourth most powerful in the world.
Picture 1. Japan Hearthquake and tsunami Data March 11th 2011 Inverse interplate fault Pacific, North American) 9,0 M L (Richter seismological scale ) 9,0 Mw (Seismological scale moment magnitude) INTENSITY IX Mercalli DEPTH 32 Km LENGTH 6 min. AFECTED AREAS Japan and Pacific basin VICTIMS 15.836 death 3.650 missing and 5.948 injured
DATE TYPE MAGNITUDE
Source: Author's calculations based on data from the U.S. Geological Survey (USGS) [1] Seismic scale moment magnitude is a logarithmic scale used to measure and compare earthquakes, based on the measurement of the total energy, which is released in an earthquake. [2] Mercalli Earthquake Scale is 12-degree scale developed to assess the intensity of earthquakes through the effects and damage to various structures.
[3] Coordinated Universal Time is the time zone of reference to calculate all other areas of the world. [4] Plates subduction is a process of sinking of a lithospheric plate under another at a convergent boundary, according to the theory of tectonics plate. Source: Author's calculations based on data from the U.S. Geological Survey (USGS)
CHILE. • The 2010 Chile earthquake happened at 3:34:14 pm (UTC-3), on Saturday February 27th, 2010, which reached a magnitude of 8.8 MW. The epicenter was located in the Chilean sea, opposite the towns of Curanipe and Cobquecura 150km northwest of Concepción (see Annex 9.4), at a depth of 30.1 km below the earth's crust. The quake lasted 3 minutes 25 seconds, at least in Santiago. It was felt across much of the Southern Cone with different intensities, in places like Buenos Aires and São Paulo in the east. In the regions of Maule and Bio Bio, the earthquake reached an intensity of IX on the Mercalli scale, wiping out much of the cities and Constitution, Concepción, Cobquecura and Talcahuano port. In the regions of La Araucanía, O'Higgins and Metropolitan, the quake reached an intensity of VIII causing major destruction in the capital, Santiago de Chile, Rancagua and rural localities. A strong tsunami struck the coast of Chile as a result of the earthquake, destroying several villages already devastated by the earthquake impact. Total victims 525, nearly 500 thousand homes are severely damaged and are estimated to total 2 million homeless, the worst natural disaster in Chile Picture 2. Chile earthquake and tsuname date DATE February 27th 2010 TYPE Interplates inverse fault (Nazca, South America ) MAGNITUDE 8,8 MW (Seismologic scale moment magnitude) INTENSITY IX Mercalli DEPTH 30,1 Km DURATION 3 min 25 seg. AFECTED AREAS Valparaíso, Metropolitana, O'Higgins and Maule areas Biobío and La Araucanía, Chile VICTIMS 525 death and 25 missing
Source: Author's calculations based on data from the U.S. Geological Survey (USGS)
ARGENTINA. • The San Juan earthquake happened on January 15th, 1944 at 20:50 local time, reaching a magnitude 7.8 degrees on the Richter scale, with a surface wave magnitude of 7.4 Ms [5] and a maximum intensity of IX on the Mercalli scale. The epicenter was located 20 km north of the city of San Juan, La Laja town, Albardón department, at 30 km depth.
Peak area was spread and covered approximately 200 km ². Mendoza was also damaged, especially in the department of Las Heras. The quake was felt in the cities of Cordoba and Buenos Aires.
The earthquake destroyed almost the entire city of San Juan, where we can say that the disastrous effects of the earthquake were due, not only to the violence of the quake, but also the precarious buildings that existed years ago. While early estimates spoke of 12,000 victims, subsequent studies indicated that total death in this earthquake may have reached 20,000. Picture 3. San Juan - Argentina earthquake data DATE January 15th 1944 TYPE Liquefaction phenomena associated with earthquakes MAGNITUDE 7,8 ML ( Richter seismologic scale) 7,4 Ms (Seismologic scale of superficial waves magnitude) INTENSITY IX Mercalli DEPTH 30 Km DURATION Ro records AFECTED AREAS San Juan and Mendoza areas VICTIMS 10.000 deaths
Source: Author's calculations based on data obtained from INPRES
[5] Seismic magnitude scale of surface waves, is a scale based on the maximum amplitude caused by the Rayleigh surface wave period in the range 18 to 22 seconds ________
EARLY WARNING SYSTEMS. Introduction
The national civil protection institutions currently operate national warning systems in case of large-scale phenomena, such as earthquakes. In these systems, the national weather agency carries out the monitoring of the evolution of the phenomenon and recommends national institution issuing alerts for regions that follow. With this information, the national institution issues a press release alerting the public, which calls mass media, radio and television.
The main aspects to consider different types of early warning systems are: • Systems must be integrated into better way to national and/or civil protection institutions and must consolidate an interaction between the national monitoring system and local systems to achieve an integral development of mutual benefit. • Local systems are barely known by national scientific monitoring, so should encourage interaction and plan with integral national and continental vision depending on how is it defined: local / national / regional. • It is necessary to introduce the various communications media the dissemination of information regarding such systems to raise awareness and reach most of the population to protect.
Operating principles. Early warning systems (EWS) have as aim to alert the public in case of a natural disaster of such proportions that can cause damage. It is detailed more properly and extension in Annex 10.7. Any system of this kind must satisfy the operating criteria to provide an advance alert so that people can take the minimum precautions needed in approaching the phenomenon. These are integrated systems based on three components:
• Monitoring of conditions related to the related phenomenon. • Events forecast and daily and historical backup record • Alert to different terminals and response of the national entity
Major technological advances made during the last twenty years in communications, can generate high capacity links, which are transmitted by telephone, video signals and data at the speed of light through optical networks with propagation velocity of 150.000km/sec against propagation of mechanical waves of an earthquake in the order of meters / second so if the detection is efficient, with very detailed geographic network could lead early warning signals of communication terminals to local inhabitants with seconds in advance to the effect that gets rougher and thus provide greater chance of survival not to receive any notice.
Simultaneously with the advance in optical transport networks, important developments were generated at different sensor technologies for determining various interest parameters: vibration, pressure, etc. The confluence of both industries (communications and sensors) can generate an early warning system in case of an earthquake but it is perfectly applicable to other variable of interest you want to achieve network monitor protecting people, reducing loss of life to quickly seek protection and material, to be able to make emergency action such as closing circuit gas, electric, etc.
The value of the obtained information by the optical sensors backbone allows, for example: • Early detection of earthquakes or volcanic movements. • Generation of alarm signals and systems for mitigating effects (power failure, stop or slow moving vehicles speed, lift scheduled scan, etc.). • Control of damage due to weather events on structures such as buildings or bridges. • Generation of information and predictive models. • Planning of agricultural systems and land use. • Crop selection, determination of planting and harvest.
• Programming and irrigation control. • Etc. Early warning systems are key in disasters like earthquakes in our case to alert and prevent further possible losses. The Federal Network of Optical Fiber will provide predictive information in real time through the early warning system for earthquakes interacting with meteorological agencies, regional governments and institutions for the civilian’s protection.
The early warning system for earthquakes implemented a minimum resource of the Federal Network of Optical Fiber will integrate the entire Argentine Republic, reduce human and material losses of great magnitude, because the vision of this thesis is to create a modern first pillar civil protection throughout the country, creating the Earthquake Early Warning (Earthquakes Early Warning, EEW) and adding a number of mandatory alerts media, generated automatically, no matter what is being broadcast in the media.
2. STATE OF TECHNOLOGY
2. STATE OF TECHNOLOGY INTRODUCTION:
Individually the following describes the principle of operation and status of each technology and then in the next item 3 develop these elements based on the proposed integration of optical networks, detection, transport and automatic alerts sent to local centers / national and regional (Latin America). Technologies are described below: 2.1 - Optical transport networks and access. Operating principle. 2.2 - Optical Network "REFEFO" project "Argentina Conectada". 2.3 - seismology networks of Argentina Republic, operated by INPRES. 2.4 - SCADA networks, monitoring & remote control. 2.1 OPTICAL TRANSPORT NETWORK AND ACCESS: OPERATING PRINCIPLE, CONSTRUCTIVE TOPOLOGIES AND ASSOCIATED MATERIALS.
A telecommunications system consists of a physical infrastructure or not (wireless) called Link through which information is conveyed emitted from a source (Node A), to the final destination (Node B or "client"). On this basic infrastructure carry telecommunications services received by the customer (Pic. 1). This infrastructure is also called the "Telecommunications Network".
Text picture 1: Nodes-links, terminal equipment
Picture 1: Network and Terminal Equipment.
The generic definition of previous telecommunications network has two specific segments either transporting information between network nodes, called "transmission" and the transport of information between a node and clients (Terminal) known here as " Access Network ".
To receive a telecommunications service, user uses a computer "Terminal" by which get wired or wireless connection to the telecommunications network.
Each telecommunication service has different characteristics, may use different access networks and transport, therefore, may require different user terminals. For example, to access to the telephone network, the required terminal equipment is a telephone set; for receiving the cell phone service, the terminal equipment consists of cellular phones, to receive TV service air, etc.
2.1.1 Network Element: Link. - The set of links and nodes form a communication network and it shows two segments linking physical or intangible clearly differentiated dedicated to transport links and links access-dedicated.
2.1.1.1 Definition of Transport and Access Network. - For illustrative INPRES, we can establish an analogy between telecommunications and transport. In transport, network consists of all the roads of a country and what where vehicles run, which in turn serve to transport persons or goods. In telecommunications data is transported via data transmission networks. When a communications network: • Connect nodes together is called: Transport Network. • Connect nodes with customers, is called: Access Network.
The main reason to developed telecommunications networks is the cost of establishing a unique link or "dedicated" between any two users on a network would be very high, especially considering that not all the time all users communicate to each other. It is better to have a dedicated connection for each user to have access to the network through their computer terminal, but once inside the "transmission network” information / messages will use links that are shared with other communications by other users. Comparing again to transport, in all houses there is a street where a car can run and in turn lead to a road, but not all homes are located on a road dedicated to exclusively servicing a single vehicle. Streets play the role of the access channels and highways the shared channel (transport). In general it can be said that a telecommunications network consists of three elements: • A set of nodes in which information is processed
• A set of links or channels that connect the nodes to each other and through which information is sent to and from the nodes • Terminals where customer receives and sends his/her information. From the point of view of its architecture and the way in which information is conveyed, telecommunications networks can be classified as switching networks. These networks consist of alternating succession of nodes and communication channels, i.e., after being transmitted through the information channel, arrives at a node, the node in turn, processes the necessary to transmit it for the next channel to reach the next node, and so on (Picture 2).
Text picture 2: dedicated link/ shared links
Picture 2: Switched Network.
Switching networks, as described above can be subdivided into two switching types: circuit or packet. In packet switching, the message is divided into small independent packages; each one adds control information (e.g., the source and destination addresses), and circulating packets from node to node, possibly via different routes.
When arriving at the node to which destination the user is connected, the message is delivered (Figure 3). This technique can be explained by means of an analogy with the postal service. We suppose that it is desired to send a complete book from a point to geographically separated to other. The commutation of packages is equivalent to separate the book in its leaves, put each of them in on an envelope, put to each on the origin address/destiny and later to leave all the envelopes in a postal mailbox. Each envelope receives an independent treatment, following, probably, “different physical routes” to arrive at its destiny; but once all of them have arrived at their destiny, the complete book can be reassembly.
Text figure 3: Message consistent on three packages Origin=node 1, destination=node 3 Message – Destination Figure 3: Package Switching.
Moreover, in circuit switching is seeks a trajectory between users, a communication is established and maintained this path for as long as you are transmitting the information or not, with permanent occupation of the bond until it produces disconnecting the circuit (Picture 4).
Text 4: Information-Node 1/2/4 Figure 4: Circuit Switching.
To establish communication with this technique a signal is required to reserve different segments of the route between both users, and during communication channel will be reserved exclusively for this pair of users.
2.1.1.2 Transmission Means. - Transmission means are physical or intangible means through which information travels from one point to another within the communications network. The characteristics of a medium are critical for effective communication because of them depends largely on the quality of the signals received at the destination or intermediate nodes in a route. The transmission means are divided into two classes:
a) Guided Transmission Means. E.g. copper cables, coaxial cables and optical fibers. For these types of channels can be transmitted the following data rates:
Physical Media
Referential Transmission Speed
Copper Cable (braiding pair)
Up to 10/100 Mbps
Cable Coaxial
500/1000 Mbps
Optical Fiber
>20 Tbsp.
Copper cables are, doubtlessly, the most used means in analogical transmissions as much as digitals. They continue being the base of the urban wire networks. Materials that are made (copper) produces attenuation in the signals, in such a way that a distances among 2 and 6 km a relay station must be placed. Coaxial cables have a shield that in the transmission isolates the central conductor of the noise. They have been used in communications of long distance and in distribution of television signals and one is also used in data communications network. The distance between relay stations is similar to the one of copper cables, because a greater transmission band is used, which allows to majors rates in the digital communications (Picture 5).
Text Figure 5: Metallic cable- isolation-Metallic netting-Isolation- Wire Figure 5: Types of wire ropes.
Optical fibers also transmit optical signals (photons) instead of the electrical ones (electrons) on two previous cases. They are lighter that those of metallic cords and allows to transmit higher rates
than the first. In addition, although signals are affected by noise, they are not altered by noise of the electromagnetic type and can support longer distances between relay station (about 100/1000/5000 km). Their main applications are the long distance connections, metropolitan connections and local networks. In progressive form, optics fibers will be releasing traditional services on copper overturned optician, or optician plus copper cable of reduced length (topology FTT” X”), that allows maintaining the high speed of transmission and minimum operating expenses. The fundamental difference between the transmissions that use optics fibers and those of purely electrical nature is in the fact that, in first, the information controls to optics signals, that is to say, information modulates some characteristic of an optics signal. The advantages of this type of transmissions are multiple: they are less sensible to the noise of the electrical type, and by the space that the optics signals occupy in the phantom, the capacity is greater than the one that offer systems based on metallic cables. Optics fibers have been of extraordinary importance in the transoceanic transmissions. The demand of this type of transmissions has grown to rates of about 24% a year in the Atlantic, with also expansion to the Pacific, Caribbean and Mediterranean. The cable for this class of applications consists of having devices of high trustworthiness, great bandwidths and few losses. This originated that, around 1980, came up the first proposal from a transoceanic system based on optics fibers, that, as well, allowed in 1988 install the first system of this type.
b) Unguided transmission means. - They are radio waves that also include microwaves and satellite links. The microwaves use transmitting antennas and reception of parabolic type to transmit with narrow beams and have major concentration of broadcast energy. Of fundamental way, they are used in long distance connections, of course with relay stations, but lately they have been used also for point-to-point short connections.
Satellite links work of a very similar way to the microwaves: a satellite receives in a band the signals of an earth station, amplify and transmits them in another frequency band. The principle of the satellites operation is simple, although with the course of the years it has become more complex: radio signals are sent from an antenna towards a satellite parked in a fixed point around the Earth (called “geostationary”). Satellites have a reflector oriented towards the sites where are wanted to make arrive the reflected signal; and in those points, also had antennas whose function is, indeed, to catch the signal reflected by the satellite. Of this point in future, the signal can be processed so that, finally, it is given to its destination. The advantages of the via satellite communications are evident: great distances without concerning the topography or the orography of the land, and antennas that have ample geographic covers, of way like many earth receiving stations can be used simultaneously to receive and distribute the same signal that was transmitted at the time. Also, the communications via satellite have been used for multiple applications: from the transmission of telephone conversations, the transmission of television and the videophone conferences to the data transmission. The transmission rates of can be from very small (32 Kbps) to about Mbps. Requirements about the multiple access, handling of diverse types of traffic, establishment of networks, integrity of the data and security are satisfied with the possibilities offered by technology VSAT (very small opening terminals).
Among the services that may be offered through VSAT technology are: radio broadcasting and distribution services, databases, weather and stock market, stocks, facsimile, news and music programming, advertising, air traffic control, TV entertainment, education, data collection and monitoring, weather, maps and images, telemetry, two-way interactive service, credit card authorizations, financial transactions, database services, reservation service, library service, interconnection of local
networking, email, emergency messages, compressed videoconferences , etc.
In order to understand the operation of the systems based on via satellite transmissions, and its association with satellite antennas, next the principle of this type of antennas is based: the geometry of a parabola is like an emission that arrives at the parallel parabola to its axis is reflected happening through its center, and an emission that leaves its center, when affecting the parabolic surface, is reflected parallel to its axis (Picture 6).
Text: Satellite signal Axis pointing to the satellite Focus-reflected signal Parabola Figure 6: Operation of a satellite dish.
Applying these ideas to the telecommunications, it can be observed that if the axis of the satellite dish is oriented towards the satellite, the originating emissions of this one will arrive at the parallel antenna to its axis, and those originating emissions of the center of the parabola will follow a parallel trajectory to the axis of the parabola until arriving at the satellite. Consequently, in the center of the parabola an energy collector must be placed that catches everything what comes from the satellite, that was reflected by the parabola, and sends and it to the processing
circuits. In that same point, transmitter must be located, whose function consists of getting the information towards the satellite so that this one, as well relays, it retransmit until its final destiny. It will have been possible to observe that there are in many points of a city antennas of parabolic type, whose directions are more horizontal than those than they aim towards a satellite. One is a microwave antenna, in which the same principle of directionality already described is used. It is possible to emphasize that the main difference between microwave and radio transmissions consists of which first they are omnidirectional (in all the directions), whereas second they are unidirectional (in a unique direction); therefore, the radio does not require antennas of parabolic type. Although, strictly speaking, the term `radio' includes all the electromagnetic transmissions, the applications of the radio are assigned in agreement with the bands of the phantom in which the transmissions are realized. As the wavelength of a signal depends on its frequency, to speak of a spectral segment specifically is equivalent to speak of the rank in which is the length of the waves in that segment. For example, to frequencies between 1GHz and 300 GHz (1 GHZ= 1000 MHz) are called microwaves: the wavelengths are contained in a rank of 100 cm1 mm10 mm even though the segment between 30 GHZ and 300 GHZ (corresponding to wave longitudes between 10mm and 1 mm) also are known as millimetric waves. In the following picture, the applications of the different ranks from the phantom appear. Band 30-300 KHz
Name LF Low frequency
300-3000 KHz
MF –medium frequency
3-30 MHz
HF high frequency
Applications Aerial and maritime navigation Navigation, radio, commercial AM, privates link, fixed and mobile Broadcasting, short
30-300 MHz 300-3000 MHz
VHF very high frequency UHF ultra high frequency
3-30 Ghz
SHF super high frequency
30-300 Ghz
EHF extra high frequency
wave, fixed and mobile links Television, FM radio, fixed and mobile links Television and microwave, meteorological navigation Microwaves and satellite radio navigation Experimental
Finally, it is important to emphasize that a modern telecommunications network normally uses different types of channels to obtain the best solution to the different problems from telecommunications of the users: frequently, there are networks that use radio channels in some segments; via satellite channels in others; microwaves in some routes; radio in others and, in many of its links, the telephone public network. 2.1.2 Network Element: Node. - Nodes, fundamental part in any telecommunications network, responsible to realize the diverse functions of processing required by each one of the signals or messages that circulate or go through the network connections. From a topological point of view, nodes provide the completion with the physical links that connect the diverse nodes to each other and conform as a whole the network. Nodes of a telecommunications network are electronics active or optician equipment that can be installed Indoor/Outdoor and conform a marshaling area in a communications network. In
networks they are called POTS “Centrals”, to be associate to the classic commutation, also known as “Internal Plant” in a traditional network scheme. Their functions are:
a) Establishment and protocol verification. The telecommunications network nodes realize the different processes from communication in agreement with a set of rules that allow them to communicate to each other. This set of rules is known with the name of communication protocols, and they are executed in the nodes to guarantee successful transmissions to each other, using the channels that connect them. b) Transmission. It is necessary to make an efficient use of the channels, thus, the nodes of the network adapt the information to the channel, or the messages in which is contained, for their effective transport through the network.
c) Interfaces. In this function, the node is in charge to provide the channel the signals that will be transmitted, in agreement with the means of which is formed the channel. If the channel is a radio, signals will have when coming out to be electromagnetic of the node, independent of the form that they have had to its entrance and, also, of which the processing in the node has been by means of electrical signals.
d) Recovery. If during a transmission is interrupted the possibility of successful finishing the transference of information from a node to another, the system, through its nodes, must be able to recover and resume as soon as possible the transmission of those parts of the message that were not transmitted successfully. e) Format. When a message travels throughout a network, but mainly when an interconnection between networks exists that handle different protocols, it can be necessary that in the nodes the format of the messages modifies, so that all the network nodes (or the networking) can successful work with this message. This is known as format or reformat if the format is due to modify with the format it arrives to a node. (Picture 7).
Text: Start signal Address Control Information Error detection End Picture 7. Typical package format
f) Routing. When a message arrives at a node of the telecommunications network, necessarily it must have information about the origin users (emitting) and destiny (receiving). Nevertheless, whenever the message travels by a node - and considering that in each node there are several connections linked, by which, at least in theory, the message
could be sent to anyone of them, in each node must make the decision from which must be the following node to whom must be sent the message, to guarantee that it arrives quickly at its destiny. This process is denominated routing through the network. The selection of the route in each node depends, among others factors, of the instantaneous situation of congestion of the network, that is to say, the number of messages that at every moment are in process to be transmitted through the different connections from the network. g) Repetition. Protocols exist that, among its rules, have a forecast by means of which the receiving node detects if there has been some error in the transmission. This allows the destiny node to ask for the previous node that relays the message until it arrives without errors, and the receiving node can, simultaneously, relay it to the following node. h) Address. A node requires the capacity to identify directions to make arrive a message at its destiny, mainly, when the end user is connected to another telecommunications network. i) Flow control. All communication channel has a certain capacity to handle messages, and when a channel is saturated, no messages must be send by means of that channel until the messages previously sent have been delivered to their destinies. j) Depending on the complexity of the network, the number of users whom it has connected and to those whom the service is provided, it is not indispensable that all the telecommunications networks have orchestrated all the preceding functions in their nodes. For example, if a network only consists of two nodes each of as diverse users are connected, it is evident that functions are not required both such as address or routing in nodes that form the network.
k) Once exhibited the components of a network of telecommunications, it is possible to emphasize that what really gives value to the telecommunications is the set of services that are offered by means of the networks and that are put at the disposal of the users. That value depends on the type of communication that can establish a user and on the type of information that can send through the network For example, through the telephone network to provide telephone services and business people. Among these services for oral communication are local telephone service (both residential and commercial and industrial), phone service and long distance phone service for international long distance, but in recent years may also be made by the network fax transmissions and data. Through a cable television network can provide distribution of television signals to homes in general, but lately have started services restricted to certain types of users, such as services such as "pay per view". It is possible that, thanks to technological advances in various fields, in a near future are interconnected telephone networks with cable television, and through this interface users can simultaneously exploit the vast processing power with the telephone networks.
2.1.3 Network Element: Terminal. - Terminals, a key part in any telecommunications network, are the teams receive / send information from the client to the communications network and vice versa must be appropriate to the various processing functions that require each of the signals or messages circulating or passing through the network links.
Text: Terminals Evolution towards next network generation
Picture 8: Terminals - evolution towards next generation networks.
This and other elements of a communications network has evolved over time from the first telegraph terminal, via the phone, reaching far with multiservice terminals (telephony, data, TV) and denominating broadly Network Terminal or "NT" active device termination of the communication network in the customer's home and it connects the terminal end that would provide the required service to the customer (e.g. POTS analog telephone network, ISDN digital phone, IP phone packet network).
Text: Individual network for each service- PSTN Cell Networks, Data Network (IP, ATM, FR)- Broadcast Network. Voice, data, TV, early alert
Picture 9: convergence of networks and services - Evolution used by the "Early Warning System Earthquake" on REFEFO.
2.1.4 Analysis: Light as information medium in Communications. It can be admitted that in the communications an energy exchange is put into play that can be classified of different ways. One of them is the spectral one. In this concept, two parameters are related: space and temporal.
Spatial parameter we will relate to the “wavelength” since this reflected space propagation (periodic) and the other parameter which is the temporal frequency are called.
Text: Spectral of electromagnetic waves Infrared-Ultraviolet-X rays Gamma Rays-Cosmic Rays Extremely low frequencies- Radio electric waves-Microwaves-Visible spectrum RED-ORANGE-YELLOW-GREEN-BLUE-VIOLET Non- ionizing radiation-Ionizing radiation –Thermic effects Thermic Effects Frequencies-Frequency bands- Wavelength Figure 1.9 Electro magnetics waves spectrum
Figure 9: Electro magnetics waves spectrum.
If we were placed in the temporary parameter (frequency), and analyze its propagation in the metallic conductors of pairs we can transmit energies around 1000MHz in theoretical form, which differs from the practice, where are reached 100MHz (UTP STD). In the case of the radio links, it is reached not more than 20/40GHz in the practice (the theoretical value is until 1011Hz).
If both previous signals are used like “transport” to apply on them frequency modulation techniques (useful information), these will be the “carriers”, and if these are used on transmission channels of a determined bandwidth, an optimization of this one will be obtained, which will allow transmitting a greater amount of signals than without this technique. In systems on which optics fibers like transmission means are used, optics spectral zone, frequency is around 1014Hz, and if techniques of frequency modulation were used, it could get a transmission capacity of 107 times greater than of a metallic conductor, about of 104 times the one of a radio link. About the expressed in the previous paragraph, the physical justification of the increasing use of optics fibers in all the systems of loss telecommunication resides low/middle and high transmission capacity, where no “ceiling” or speed limit of the side of “means of transmission or connects optician” is observed, being only limited by the optics active equipment used at the ends of the connection and that evolves year after year.
Text: Transmission –Transmission media –Copper-Optical Fiber-Radio (air-emptiness) Receptor Based on this canonical model forms the basic communication model:
Text: Node-link-terminal
Making a comparison between the canonical model and the basic one, we can say that the means of transmission of one happen to be the connection of the other, and the transmitter and the receiver migrate to which node and terminal are called, respectively. But following in what location are the transmitter and the receiver, they will vary the importance and the capacity of information that they issue. For example, in a node, they will be communications equipment of high capacity, and in a terminal, a telephone or modem, in agreement with the service. If we put together several basic models, a real communications network forms, as it shows the following figure:
SERVICE SEIO EQUIPMENT PHYSICAL
Generic Telecommunications network
A
SERVICE EQUIPMENT PHYSICAL B
Basic layers
Figure 10: Telecommunications Network. Basic block diagram
2.1.6 Why Optical Fiber? - One of the objectives in the telecommunications world was looking for a physical transmission medium capable of carrying large amounts of information and that it may suffer less deterioration over long distances. In that search were found as copper conductors (coax, twisted pair), the optical fiber and the same air (radio links, satellite), obtaining all these different strengths and weaknesses for application in the field of telecommunications. Physical media
capable of delivering information mentioned stands out: the optical fiber, either by the cost of implementation, cheaper than a link or satellite link, as the information-carrying capacity, higher bandwidth than Radio and copper links to great lengths to link. The advantages of optical fiber as the transmission medium are:
a) Low Attenuation: Optical fibers are the physical transmission medium with lower attenuation, since it can establish direct links, i.e. without repeaters, about 100 to 200 km, thereby increasing the reliability and reducing the cost of electronic equipment.
b) High Bandwidth: The transmission capacity is very high transmission systems on a single wavelength. This capacity can be increased by methods multiplexed wavelengths, such as WDM systems (Wavelength Division Multiplexing). For example two optical fibers can carry all the telephone conversations of a country, provided that the transmission equipment to be able to handle so much information (between 100Mhz/Km to 10Ghz/Km).
c) Reduced weight and size: The diameter of an optical fiber is similar that a human hair. A cable of 60 optical fiber has a total diameter of 15 to 20 mm and an average weight of 250 Kg / Km, instead of copper wire pairs 900 0.4 gauge has a diameter ranging between 40 and 50 mm and a average weight of 4.000 Kg / Km, if we compare these values can be deduced that the fiber optic cable increases the ease and cost of installation.
d) High flexibility and available resources: optical fiber cables can be constructed totally with dielectric materials and the raw material is implemented in the manufacture of silicon dioxide (SiO2), which is one of the most abundant resource in the surface Earth.
e) Electrical insulation: the absence of metal conductors can not induce currents in the cable (valid for optical fiber cables without armor), can therefore be installed in places where there are dangers of power cuts.
f) Absence of radiation: optical fibers carry light and emit electromagnetic radiation that may interfere with electronic equipment is not affected by radiation emitted by other means surrounding it, by the thus constitutes a secure transmission means for transporting information high quality to be implemented at sites where the emission of electromagnetic radiation is not accepted.
g) Cost and Maintenance: Optical fiber cables and the technology associated with the manufacture and installation has fallen sharply in recent years, which is why today the cost of building a plant fiber is comparable plant copper. Another important point is the maintenance of the plant, which in one fiber plant requires almost no maintenance or are significantly lower compared with copper. Therefore, it can be concluded that the optical fiber, depending on the requirements of the particular communication may constitute the best physical medium for transporting large amounts of information without suffering damage it by external agents.
2.2 OPTICAL TRANSPORT NETWORK: OPTICAL FIBER FEDERAL NETWORK PROJECT.
Broadband is the essential infrastructure of XXI century as it was created dirt roads first and then the railroad a century ago is a platform of opportunities to stimulate economic growth, innovation and equal opportunities.
In today's world we live in the new developments in electronic communications are evolving continuously adapting to the demands of human permanent, changing the way we educate our children, provide health care, manage energy, compromising the government, to ensure public safety and civil protection by providing new ways to ask for help and receive emergency information quickly and efficiently.
As part of the national telecommunications Argentina Conectada, Federal Network of Optical fiber, is born, a project of national infrastructure whose primary purpose connectivity throughout the territory of the Argentine Republic, covering regions not currently have this type of infrastructure and reaching areas that incumbents do not cover by commercial decisions.
Argentina Conectada, defines the state a leading role in the field of telecommunications, promoting the creation of a national telecommunications operator, ARSAT SA Argentina satellite solutions company to administer the Federal Network Optical Fiber from its central node built in Benavidez, Province of Buenos Aires, where remotely will be coordinated and controlled all primary and secondary nodes of the network.
In the wholesale market, the role of ARSAT S.A. involves the management and marketing of services to provide cooperatives, SMEs and local operators the bandwidth necessary to ensure the provision of quality services to users around the country.
The Federal Network Optical Fiber is divided into nine regions, this network of 18,000 km in a first stage, will allow the interconnection of individual provincial operations centers and provincial access points to the network with the national operations center and the national point of network access that is located in Benavidez as mentioned above, this run is complemented with12, 000 km belonging to other suppliers, which added to the provincial networks will total one ultimate goal of more than 60,000 km long, and together with satellite services also provided by ARSAT SA will ensure the inclusion of all the inhabitants of the territory. Among the implications presented by this network, there is the contribution of technological change that this project will generate transformer across our land, ranking this as a strategic pillar for continuous improvement of governance and regional connectivity.
Federal Network Optical Fiber. Provincial Network Optical Fiber Source:http://www.argentinaconectada.gob.ar/contenidos/red_federal_de_fibra_optica. html
The Federal Network of Optical Fiber has two stages: Stage I: Using existing optical fiber networks in Argentina. Stage II: Building backbone and Provincial o Federal Backbone: Building in 9 regions. o Networks and provincial rings
2.2.1 Stage I: Using existing optical fiber networks IRU `s 12,000 km. approx. (Contracts of Irrevocable Right of Use). Distribucion de IRU´s por operador A
B
C
D
KM Parcial 447 560 532 477 381 352 322 351 208 231 537 326 100 425 402 217 231 566 611
437
239 E F
Localidades Bs As - M del Plata Tres Arroyos - 9 de Julio BB Neuquen M del Plata BB Usuhaia Pampa del rincon Posadas Pasos de los libres Posadas Corrientes Zarate Concordia Cordoba Serrezuela Catamarca Tucuman Cordoba Tucuman Tucuman Salta Salta Jujuy V Mercedes (SL) Lincoln Catrilo Chivilcoy Bariloche P del Aguila Bariloche V la Angostura Bs As - M del Plata S Tome P de los Libres S Tome Rafaela S Fransisco Rafaela S Fransisco Arroyito Arroyito Rio Primero Rio Primero Cordoba Cordoba Rio Cuarto Benavidez Resistencia Abasto Malargue
Text: IRU´s operator Distribution-Partial KM-Localities-Total KM
KM totales 2016
1845
2804
1287
1125 2060 11137
2.2.2 Phase II: Construction in 9 regions, 17,100Km Main.
Text: Number. Region-Main Km per region-Provinces- Main stretches km per province- Provincial stretches per province. Derivations Km. Region: East Centre-West Centre-Misiones Region-NWA South-NEA North-NEA South-North Patagonia-South Patagonia
New stretches to be built, which are defined regions of Federal Network Optical Fiber Project:
a) Central East Region. DATOS RELEVANTES Nro Provincias: 5 Troncal: 2.410 Km Derivaciones: 748 Km Provincial: 5373 Km
Texto: Important Data. Number of provinces. Stretch-DerivationsProvincial
SOURCE: http://www.prensario.net/1691-El-gobierno-argentino-presenta-la-red-federal-de-fibra-optica.note.aspx
Picture 11: East Centre Region. b) East Centre Region
DATOS RELEVANTES Nro Provincias: 4 Troncal: 2.823 Km Derivaciones: 321 Km Provincial: A definir
Texto: Important Data. Number of Provinces. Stretch-DerivationsProvincial SOURCE: http://www.prensario.net/1691-El-gobierno-argentino-presenta-la-red-federal-de-fibraoptica.note.aspx
Picture 12: Central Region. Note: This fiber optic network is especially important for use two hair fiber for remote measurement of earthquakes and covering an
area of high seismic potential (see Argentina earthquake map on page 50 Figure No. 3).
DATOS RELEVANTES Nro Provincias: 1 Troncal: 694 Km Derivaciones: 196 Km Provincial: A definir
SOURCE: http://www.prensario.net/1691-Elgobierno-argentino-presenta-la-red-federal-de-fibraoptica.note.aspx
Texto: Important Data. Number of provinces. Stretch-DerivationsProvincial
Picture 13: Misiones Region. a) NWA North region.
DATOS RELEVANTES Nro Provincias: 3 Troncal: 2.168 Km Derivaciones: 430 Km Provincial: A definir SOURCE: http://www.prensario.net/1691-Elgobierno-argentino-presenta-la-red-federal-de-fibraoptica.note.aspx
Texto: Important Data. Number of provinces. Stretch-DerivationsProvincial
Picture 14: NWA North Region. Note: This fiber optic network is especially important for use two hair fiber for remote measurement of earthquakes and covering an area of high seismic potential (see Argentina earthquake map on page 50 Figure No. 3).
e) NEA South Region
DATOS RELEVANTES Nro Provincias: 5 Troncal: 2.520 Km Derivaciones: 720 Km Provincial: 1.078 Km
SOURCE: http://www.prensario.net/1691-El-gobierno-argentinopresenta-la-red-federal-de-fibra-optica.note.aspx
Texto: Important Data. Number of provinces. Stretch-DerivationsProvincial-to define
Picture 15: NWA South Region.
Note: This fiber optic network is especially important for use two hair fiber for remote measurement of earthquakes and covering an area of high seismic potential (see Argentina earthquake map on page 50 Figure No. 3).
f) NEA North Region.
DATOS RELEVANTES Nro Provincias: 6 Troncal: 2.731 Km Derivaciones: 492 Km Provincial: 2.517 Km SOURCE: http://www.prensario.net/1691-El-gobierno-argentino-presentala-red-federal-de-fibra-optica.note.aspx
Texto: Important Data. Number of provinces. Stretch-DerivationsProvincial Picture 16: NEA North Region
g) NEA South Region
DATOS RELEVANTES Nro Provincias: 6 Troncal: 2.731 Km Derivaciones: 492 Km Provincial: 2.517 Km
SOURCE: http://www.prensario.net/1691-El-gobiernoargentino-presenta-la-red-federal-de-fibra-optica.note.aspx
Texto: Important Data. Number of Provinces. Stretch-Derivations-Provincial Picture 17: NEA South Region. h) North Patagonia Region DATOS RELEVANTES Nro Provincias: 6 Troncal: 2.731 Km Derivaciones: 492 Km Provincial: 2.517 Km SOURCE: http://www.prensario.net/1691-El-gobierno-argentinopresenta-la-red-federal-de-fibra-optica.note.aspx
Texto: Important Data. Number of provinces. Stretch-Derivations-Provincial Picture 18: North Patagonia Region
i) South Patagonia Sur and Tierra del Fuego Region
DATOS RELEVANTES Nro Provincias: 2 Troncal: 2.193 Km Derivaciones: 100 Km Provincial: 763 Km SOURCE: http://www.prensario.net/1691-El-gobiernoargentino-presenta-la-red-federal-de-fibra-optica.note.aspx
Texto: Important Data. Number of provinces. Stretch-Derivations-Provincial Picture 19: South Patagonia region.
DATOS RELEVANTES Troncal FO Submarino: 40 Km
Texto: Important Data-Stretch- Submarine FO
Picture 20: South Patagonia and Tierra de Fuego Region (Strait of Magellan crossing). General scheme of the Federal Network Optical Fiber
Texto: International connections- Argentine Republic-NAP National (Access network point) –Regional NAP-Locality – Province- International Network-Provincial Network- Stretch Network-Metropolitan Network –Last mile Network
Remote Measurement of Federal Network Optical Fiber to ensure minimum repair time
The lack of early detection to a degradation / fiber optic backbone cut is the main reason for non-compliance with SLA in optical transport networks of high level. Federal Network Optical Fiber will use as a constitutive part a remote network of optical measurement in real time with GPS positioning so that before a degradation of this optical link is detected, recorded in a database and a ticket issued so NOC automatically from the Master of Benavidez, with replies to the region of the country where the problem has occurred. The above definition will: - Act ASAP, fulfilling the contracted SLA by ARSAT with different agencies / provinces / entities in the country, using their services. - Generate quality record of the optical parameters of the Federal Network as "historic" and thus preventive actions to keep the Federal Network in optimal conditions of information transport.
-Reduce investment in optical instruments maintenance in both federal and provincial network, to make the determination of faults remotely without the need for optical instruments or transported in bulk. Is illustrated as example in the picture below the basic scheme of remote measurement "Federal Network of Optical Fiber", based on OTDR in each node connected to a data network to a dedicated server.
Picture 21: Basic Remote Measurement Scheme for Federal and Provincial Network of Optical Fiber.
Summary: - There is an optical network with a range of thousands of miles and high capillarity (2500 cities) covering a high percentage of the Argentine Republic thus fulfilled its goal of generating highquality national connectivity (low latency and minimum BER 10E12) combined with high security by having multiple routing paths for traffic in each node (4-9 degrees of freedom per node) makes it a suitable infrastructure for use in optical networks for early warning of earthquakes or other natural disaster, for example. -The main connection nodes by region (number 7) makes possible the connection of local sensors and local activation of early warning messages in the event, with direct outputs to cellular terminals or regional TV also directly through an alarm management system with access unified communications service to each intended to be used as a link with the inhabitants (e.g. phone / TV) 2.3 NATIONAL NETWORK OF SEISMIC ARGENTINE STATIONS
National Institute of Seismic Prevention (INPRES.) - INPRES has primary responsibility conducting studies and basic applied research in seismology and seismic engineering, for the prevention of earthquake risk by issuing regulations to make optimal stability and permanence existing civil structures in seismic areas of the country.
National Network of seismic stations is composed by fifty (50) stations distributed throughout the country. For topographical reasons and interconnectivity, distribution is integrated forming five areas of seismic risk and grouped into three zones namely North Zone network, Central Zone network and South Zone network.
Picture 1: Zoning of Argentina according to the degree of seismic hazard. SOURCE: INPRES
Argentina is divided into five zones according to the degree of seismic hazard, in agreement to the following table:
ZONAS ZONA 4
ZONA 3
ZONA 2
PROVINCIAS
LOCALIDADES
Calingasta - Ullún - Albardón - Angaco -Zonda - Rivadavia Chimbas - Capital -Santa Lucía - San Martín - Pocito SAN JUAN Parte de Caucete - Rawson - 9 de Julio - Sarmiento 25 de Mayo MENDOZA Las Heras -Parte de Lavalle - Godoy Cruz - Luján de Cuyo Capital - Guaymallén - Maipú - San Martín - Junín Parte de Orán - La Caldera - Gral. Güemes - Capital SALTA Parte de Rosario de Lerma Chicoana - Cerrillos - Metán Parte de Anta - Parte de Guachipas Parte de Tumbaya - Tilcara - Valle Grande JUJUY Capital - Ledesma - San Antonio - El Carmen San Pedro - Santa Bárbara Parte de Independencia - Gral. Sarmiento - Gral. La Madrid LA RIOJA Parte de Gral. Juan Facundo Quiroga - Gral. Lavalle Parte de Rosario Vera Peñaloza Parte de Lavalle - Tupungato - Rivadavia - Tunuyán MENDOZA Santa Rosa - Parte de La Paz - San Carlos Parte de San Rafael SAN JUAN Parte de Caucete - Iglesia - Jáchal - Valle Fértil SAN LUIS Parte de Ayacucho - Parte de Belgrano TIERRA DE FUEGO Parte de Río Grande - Parte de Ushuaia Famatina - San Blas de los Sauces - Chilecito - Arauco Castro Barros - Sanagasta - Capital - Gobernador Gordillo LA RIOJA Parte de Independencia - Gral. Belgrano - Gral. Ocampo Gral. Angel V. Peñaloza - Parte de Rosario Vera Peñaloza Parte de Gral. Juan Facundo Quiroga - Gral. San Martín CATAMARCA En su totalidad CORDOBA Cruz del Eje - Minas - Pocho - San Alberto - San Javier MENDOZA Parte de La Paz - Gral. Alvear - Parte de San Rafael Parte de Malargüe NEOQUEN Minas - Chos Malal - Ñorquín - Loncopué - Picunches Aluminé - Huiliches - Lácar - Los Lagos RIO NEGRO Parte de Pilcaniyeu - Bariloche -Parte de Ñorquinco Santa Victoria - Iruya - Parte de Orán - Parte de Rivadavia Gral. José de San Martín - Los Andes - La Poma - Cachi SALTA Parte de Rosario de Lerma - Molinos - SanCarlos - Cafayate Parte de La Viña - Candelaria - Rosario de la Frontera Parte de Anta - Parte de Guachipas CHUBUT Parte de Cushamen - Parte de Futaleufú JUJUY Santa Catarina - Yavi - Rinconada - Cochinoca Susques - Humahuaca - Parte de Tumbaya STGO DEL ESTERO Parte de Pellegrini - Parte de Copo Parte de Ayacucho - Junín - Parte de Belgrano - Capital SAN LUIS Coronel Pringles - Libertador Gral. San Martín - Chacabuco Parte de Gral. Pedernera TIERRA DE FUEGO Parte de Río Grande - Parte de Ushuaia
Text: Zones-Provinces-Localities
Source: Authors based on INPRES (Regulation INPRES - CIRSOC 103)
ZONES ZONE 4
PROVINCES SAN JUAN MENDOZA
SALTA JUJUY LA RIOJA ZONE 3 MENDOZA SAN JUAN SAN LUIS TIERRA DE FUEGO
LA RIOJA
CATAMARCA CORDOBA MENDOZA NEOQUEN RIO NEGRO
ZONE 2 SALTA
CHUBUT JUJUY
LOCALITIES Calingasta - Ullún - Albardón - Angaco -Zonda - Rivadavia Chimbas - Capital -Santa Lucía - San Martín - Pocito Part of Caucete - Rawson - 9 de Julio - Sarmiento 25 de Mayo Las Heras -Parte de Lavalle - Godoy Cruz - Luján de Cuyo Capital - Guaymallén - Maipú - San Martín - Junín Part of Orán - La Caldera - Gral. Güemes - Capital Part of Rosario de Lerma Chicoana - Cerrillos - Metán Part of Anta - Parte de Guachipas Part ofTumbaya - Tilcara - Valle Grande Capital - Ledesma - San Antonio - El Carmen San Pedro - Santa Bárbara Part of Independencia - Gral. Sarmiento - Gral. La Madrid Part of Gral. Juan Facundo Quiroga - Gral. Lavalle Part of Rosario Vera Peñaloza Part of Lavalle - Tupungato - Rivadavia - Tunuyán Santa Rosa - Parte de La Paz - San Carlos Part of San Rafael Part of Caucete - Iglesia - Jáchal - Valle Fértil Part ofAyacucho - Parte de Belgrano Part of Río Grande -Part of Ushuaia Famatina - San Blas de los Sauces - Chilecito - Arauco Castro Barros - Sanagasta - Capital - Gobernador Gordillo Part of Independencia - Gral. Belgrano - Gral. Ocampo Gral. Angel V. Peñaloza -Part of Rosario Vera Peñaloza Part of Gral. Juan Facundo Quiroga - Gral. San Martín Totaly Cruz del Eje - Minas - Pocho - San Alberto - San Javier Part of La Paz - Gral. Alvear - Part of San Rafael Part of Malargüe Minas - Chos Malal - Ñorquín - Loncopué - Picunches Aluminé - Huiliches - Lácar - Los Lagos Part of Pilcaniyeu - Bariloche -Part of Ñorquinco Santa Victoria - Iruya - Part of Orán - Part of Rivadavia Gral. José de San Martín - Los Andes - La Poma - Cachi Part of Rosario de Lerma - Molinos - San Carlos - Cafayate Part of La Viña - Candelaria - Rosario de la Frontera Part of Anta - Part of Guachipas Part of Cushamen - Part of Futaleufú Santa Catarina - Yavi - Rinconada - Cochinoca Susques - Humahuaca - Part of Tumbaya
STGO DEL ESTERO
Part of Pellegrini - Part of Copo Part of Ayacucho - Junín - Part of Belgrano - Capital
SAN LUIS
Coronel Pringles - Libertador Gral. San Martín - Chacabuco Part of Gral. Pedernera Part of Río Grande -Part of Ushuaia
TIERRA DE FUEGO
Source: Authors based on INPRES (Regulation INPRES - CIRSOC 103)
ZONES
PROVINCES CORDOBA
CHACO CHUBUT MENDOZA NEOQUEN ZONE 1 RIO NEGRO SALTA SAN LUIS SANTA CRUZ FORMOZA LA PAMPA STGO DEL ESTERO TIERRA DEL FUEGO ANTARTIDA ISLAS DEL ATLANTICO SUR
CORDOBA BUENOS AIRES CORRIENTES
CHACO ZONE 0
CHUBUT ENTRE RIOS FORMOZA LA PAMPA
LOCALITIES Sobremonte - Ischilín - Part of Tulumba - Punilla - Colón Totoral - Part of Río Primero - Capital - Santa María Part of Río Segundo - Calamuchita - Río Cuarto Part of Gral. San Martín - Juárez Celman Part of Tercero Arriba - Part of Gral. Roca Part of Presidente Roque Sáenz Peña Part of Almirante Brown - Part of Gral. Güemes Part of Cushamen - Languiñeo - Tehuelches - Río Senguer Part of Futaleufú Part of Malargüe Pehuenches - Añelo - Zapala - Confluence Catán Lil Picún Leufú - Collón Curá Part of Gral. Roca - Part of El Cuy -Part of Pilcaniyeu Part of 25 de Mayo - Part of Ñorquinco Part of Rivadavia Part of Gral. Pedernera - Gobernador Dupuy Lago Buenos Aires - Río Chico - Lago Argentino - Güer Aike Ramón Lista - Matacos Rancul - Chical Co - Part of Chalileo - Puelén Part of Pellegrini -Part of Copo - Part of Alberdi Jiménez - Río Hondo - Banda - Figueroa - Guasayán Capital - Robles - Silípica - San Martín - Choya Loreto - Atamisqui - Part of Ojo de Agua Part of Río Grande - Part of Ushuaia
Río Seco - Parte de Tulumba - Part of Río Primero San Justo - Part of Río Segundo - Part of Tercero Arriba Part of Gral. San Martín - Unión - Marcos Juárez Part of Presidente R. Sáenz Peña -Part of Gral. Roca Totally Totally Part of Almirante Brown - Part of Gral. Güemes - Maipú Libertador Gral. San Martín - Chacabuco - 9 de Julio Gral. Belgrano - Independencia - Comandante Fernández Quitilipi - 25 de Mayo - Presidente de la Plaza Sargento CabraL - Gral. Donovan - 1° de Mayo - Bermejo 12 de Octubre - O'Higgins - San Lorenzo - Libertad Fray Justo Sta. María de Oro - Mayor Luis J. Fontana Tapenagá - San Fernando Gastre - Telsen - Biedma - Paso de los Indios - Mártires Gaiman - Rawson - Florentino Ameghino - Sarmiento Escalante Totally Bermejo - Patiño - Pilagás - Pilcomayo - Pirané - Formosa Laishi Relaicó - Chapaleufú - Trenel - Maracó - Conhelo Quemú-Quemú
Picture 2: Map of Maximum currents in Argentina
SOURCE: INPRES
Picture 3: Map of Seismicity of Argentina SOURCE: INPRES
2.3.1 Seismic Network. - Seismic networks are composed of field and central registration stations. The instruments are at different stations can detect speed (traditional network) or acceleration (called strong motion network) on the ground before a seismic event.
a) Field Stations: houses the sensor or geophone that detects and amplifies the ground motion, equipment needed to convert the mechanical signal ground in an electromagnetic signal that can be transmitted to the central recording station, the antenna that emits the signal, the batteries that provide power to the other elements and a solar panel accompanied by a regulator that keeps the batteries charged. Modern sensors are basically pendulum-damped oscillations, which can be converted into an electrical signal. The pendulum swings can work in a vertical plane or in a horizontal depending on how the pendulum mass is subjected, in the first case would have a vertical sensor (normally called component Z), the second case we have two freedom degrees, giving sensor in a North-South (NS component) and finally a sensor East-West (EW component).
Picture 4: geophones or modern sensors, horizontal sensors
(Components NS - EW) and Vertical Sensor (Component Z)
Besides sensors can detect the speed and acceleration of the ground, the first ones (NS – EW components) are designed to detect moderate seismic activity are basic requirements for seismic monitoring of an area, the second (Z component) receive the special name of "accelerometers", and are prepared to detect strong seismic activity, being almost insensitive to moderate and small scale.
Seismometers are characterized by the “characteristic response” (Alguacil, 1986; Payo, 1986; Kulhanek, 1991), it reflects the overall behavior of the seismometer and therefore the appearance of the seismogram. The characteristic response is not more than a graph, which depicts the amplification of the seismometer, detects movement versus frequency of oscillation, which disrupts the instrument.
The field stations are deployed in an area of interest for its seismic activity. They are located in remote parts of the "seismic noise", i.e. towns, roads, lush vegetation, and coastal enclaves that are not sheltered from adverse weather events, such as the wind. Besides field stations may be fixed or mobile, in the first case, computers that run continuously from the same point and with little technical maintenance and in the second case, it is ad hoc teams displaced in a zone eventual interest itself (for example, in the case of swarm which is the occurrence of a seismic event set in a specific area during a period of time).
b) Registry Central Station receives and records information detected and sent by the field stations. The electrical signal reaches the central recording station suffers two treatments:
• Again it is converted into a mechanical signal and is recorded by a tape print medium web (analog recording) • It is digitized and recorded on a computer means (digital recording)
The records are called, respectively, analog or digital seismograms are fundamental data that the researcher can extract information about the seismic event, and treatment and the same process are crucial part of any seismologist information.
2.3.2 Analog stations with IN-SITU. - This group consists of the first stations were installed in the country and its configuration can record one, three or six components of ground motion. They are equipped with analog seismic systems, typical of the technology of the time; the seismic signal is amplified and plotted on a strip of paper during 24 hours. The record obtained is called "seismogram". These records, in addition to capturing seismic waves have a timestamp, indispensable for analysis, the time signal is incorporated into the record from a high-precision clock, located in the station, which is daily corrected by radiofrequency from Central INPRES.
2.3.3 Telemetric stations. - This type of stations are classified into two main classes: a) Analogic telemetry stations. - These stations, which are also known as "remote stations" analog seismic signals, from sensors deployed in the same, are amplified and conditioned to be transmitted by radio links, with continuously without interruption, either directly or via relay stations, to a distant receiving station, where it is incorporated and the time signal is digitized and transferred to a test system. Remote
stations can register, one or three components as applicable, to which have an analogue amplification and transmission of information in real time to enable such alternatives. In radio links are used radio equipment in the VHF or UHF frequency modulation (FM), to ensure good fidelity to that information. See Figure No. 5 with drive system "dial up".
Text: Remote Station- Public telephonic line-Digital Registry for the seismic activity INPRES Central- Central Station of registry-Place City of San Juan Analysis System References: GPS-Seismometer triaxial of Broad Band-Data acquisition System (Digital) with DIAL-UP Telephonic modem (2 wire/28800 bps)
Available analysis system in INPRES
Picture 5: Telemetric Instrumentation Station
Remote Monitoring of seismic activity DIAL-UP Source: INPRES.
b) Digital telemetry stations. - In this System of digital data acquisition are used. These are programmable computers, microprocessors using latest generation ultra low power and high reliability. They have enough memory drive for storing programs and operational control instructions allow for the incorporation of additional operational commands that allow you to work as intelligent remote station transmitting the information acquired in real time via two-way radio links VHF or UHF frequency modulation (FM).
The registration information of the hour, minutes and seconds to the identification of events, from a very high stability built-in clock, with a precision of about one part per million (PPM) / ° C for temperatures from -20 to + 60 ° C, with a displacement of less than 10msec per month, which is synchronized, to others in a time signal of universal time, through a system of automatic adjustment schedule satellite (GPS). This watch delivers a coded signal of year, day, and hour, minute and second, which is setting the time and automatically adjusted. It is like a clock pattern used in optical transmission systems SDH technologies. To avoid loss of information acquired, before an interruption of communications, data acquisition equipment digital storage medium used as a magnetic carrier, the capacity of the order of 3Gb. This configuration allows the team to gain further information for a sufficient period, until the link is restored or the
inconvenience that caused the stoppage of the transfer of information.
2.3.3 Sub-centers. – Sub-centers, as the name implies, are the sites where records are obtained from the remote stations that make up a Network Zone, communication from these stations to the sub-center is done by two-way radio links in electric VHF or UHF bands and down towards the telephone Central (Dial-Up). The equipment installed consists of a data acquisition system with high-capacity storage, RF modem, a telephone modem and communications programs for two routes. 2.3.4 Collection Center, Processing and information Analysis. - This center is located in the Institute's headquarters, where all the information is stored, sorted, processed and analyzed.
2.3.5 Mobile Team. - As its name implies, is made up of a number of portable seismic stations, which are installed, for a period of time, in strategic locations to obtain records of seismic activity in a specific area for perform special studies, such as: • Replicas detection: Determining accurately, seismic activity after the occurrence of an earthquake of great proportions, by installing several teams in the affected area. This action complements the information obtained from the National Network of Seismic Stations. • Studies of seismicity in certain areas. • Determination of seismic activity induced by the filling of dams. • Determination of the seismic activity of a geological fault. • Determination of the seismic noise, for site selection and location of sensitive vibration equipment.
Portable stations, available in the Institute, are classified into two types:
a) Portable stations with analogue technology: These stations are made with: o o o o o
a seismometer. a continuous recording channel. a high stability clock. an amplifier with gain and selectable filter. a drum or paper registration, the registration may be made of ink on smoked paper. The recording chart speed is selectable.
A battery system incorporated, independently of about 72 hours.
b) Portable stations with digital technology: These stations are made with: o A data acquisition system programmable to record six channels with corresponding seismometers. o Broadband amplifiers and filters programmable of high dynamic range. o 24-bit digitizers. o High stability clock controlled by GPS. o Magnetic media for storing registers. o Incorporated batteries, with range of up to a month, depending on the recording mode. o Radio transmission systems, if include remote sensors for greater coverage area are required.
2.3.6 National Institute of Seismic Prevention (INPRES) Among its main features we can mention the following:
• Plan and conduct the seismicity study of the national territory, assessing the seismic risk in every zone of the country. • Operate throughout the country the National Network of Seismological Stations, National Network of accelerometers and, at the headquarters of the National Institute, the Laboratory of Earthquake Resistant Structures. • Plan and provide regulations that rule the construction of each seismic zones of the country. • Project and make technological studies and provide technical assistance regarding construction materials and seismic systems. • Conduct awareness campaigns at all levels, to create an awareness of the seismic problem and its solutions and conduct technical extension publications. • Provide technical assistance in specific disaster caused by earthquakes, in order to solve the problems arising from the destruction of buildings and civil infrastructures. • Act as local validation authority, from the seismic point of view, in large infrastructure projects such as hydroelectric plants, mining facilities, power plants, etc. Installed or being installed in the country. • Implement the National Seismic Prevention Policy. INPRES, is responsible for the installation and maintenance of the National Network accelerometer (RNA) Actually has 143 devices distributed nationwide. With the last 70 installed, have joined the greatest technological advances in the field, such as digital recording, data acquisition directly through a personal computer (PC), obtaining high definition records, and the possibility of remote operation, via modem (communication with the device installed anywhere in the country by telephone from headquarters INPRES through a computer). Cuadro Texto: Telephonic communication (Modem)-Personal Computer
Accelerometer-accelerometer
Picture 6: RNA Components Source: own elaboration
Picture 7: Map of the National Network accelerometer (143 Points) SOURCE: INPRES.
Table: Location accelerometer sites in Argentina PROVINCES SAN JUAN MENDOZA
SALTA
CORDOBA
TUCUMAN
LA RIOJA
CATAMARCA
JUJUY SAN LUIS NEOQUEN STGO DEL ESTERO LA PAMPA CORRIENTES RIO GRANDE CHUBUT
LOCALITIES Calingasta - Ullún - Albardón - Barreal -Zonda - Rivadavia - Caucete Chimbas - Encon - Jachal - Las Flores - Media Agua - Pie de Palo Pocito - Rawson - Rode - San Juan - San Martin - Santa Lucia Tamberias - Valle Fertil El Carrizal - Gnral. Alvear - La Paz - Las Heras - Malargue - Mendoza Lavalle - Godoy Cruz - Luján de Cuyo - Guaymallén - Maipú - Tunuyan San Rafael - San Martín - Uspallata Cafayate - Chachapoya - San Ramon de la Nueva Orán - El Tunal Guemes - La Merced - Laviña - Metán - Rosario de la Frontera - Salta Salvador Maza - San Lorenzo - Tartagal - Cnel. Moldes Carlos Paz - Cordoba - Cosquin - Dean Funes Rio Cuarto - Rio Tercero - Salsacate Sampacho - Villa Dolores Burruyacu - Concepcion - El Cadillal J.B. Alberdi - Tucuman - Tafi del Valle San Pedro de Colalao Anillado - Capial - Chilecito Chamical - Chepes La Rioja - Patquia Belen - Catamarca Choya - Santa Maria Tinogasta Humahuaca - Jujuy La Quiaca - San Martin San Pedro Merlo - Quines San Luis - Villa Mercedes Alta Barda - Buta Ranquil Piedra de Aguila - Zapala Frias - Santiago del Estero - Termas de Rio Hondo Colonia 25 de Mayo - Santa Isabel Ituzaingo - Yacyreta Bariloche Esquel
Source: Compilation based INPRES
Summary:
- Shows an INPRES network of sensors distributed in seismic quakes, more than 100, connected to a central node by radio (VHF) or copper telephone lines exist through dial up.
- Have more measurement points gives more information collected by the system and ensures INPRES best record seismic events, thus having more number of sensors is useful but its connection from the ground instead of the node sampling remains a complex point as it registers isolated areas and to date (2012) INPRES had no other networks to reach the central node and acquire data. Today it is possible to improve this information collection network using REFEFO as we will see later.
2.4 SCADA SURVEY SYSTEMS AND MULTIVARIATE CONTROL APPLIED TO OPTICAL NETWORKS. Supervisory Control Systems and Data Acquisition (SCADA) are applications designed to control and monitor geographically dispersed data as environmental sensors. These systems are based on the acquisition and transmission between a host computer and a number of SCADA remote terminal units (RTUs) and / or programmable logic controllers (PLC), the central operator terminals and improving the efficiency of the monitoring process and Control.
These systems can be relatively simple, such as monitoring of environmental conditions of a small office building (Picture 1) or too complex monitoring a nuclear plant or seismic activity of a sectored country.
Picture 1: Environmental sensors. Source: DPS TELECOM.
Traditionally, SCADA systems have made use of the public switched network (PSTN) for control purposes or radio systems, typically VHF. Today many systems are monitored using the infrastructure of local area network (LAN) and wide area networks (WAN). Wireless technologies are being widely deployed for monitoring purposes.
A SCADA application has two elements: a) The process / system / machinery to monitor or control is required, this can be a power plant, a water system, a network, a system of traffic lights or anything that you want monitor. b) A network of intelligent devices, which are connected with the first system via sensors and control outputs.
A SCADA system execute four functions: • Data Acquisition. • Network Data Communications. • Data presentation. • Control. The four SCADA functions are performed by four kinds of SCADA components: a) Sensors (digital or analog) and control relays that interact directly with the managed system.
b) Remote Telemetry Units (Remote Telemetry Units, RTUs). These electronic devices which interconnect microprocessor controlled physical world objects via data transmission, these devices are deployed in specific sites, where acquisition points of local data receive sensors status and deliver commands to control relays.
c) SCADA Master Units (Master Units, MTU). They are large computer servers that serve as the central processor in the SCADA system. Master units provide a human interface (Human Machine Interface, HMI) to support the communications system, monitor and remotely control located field data in the interface devices.
d) The communications network is which connects the SCADA master unit to remote telemetry units (RTUs).
Picture 2: Schematic SCADA. Source: GLOBALSCADA. Texto: A typical SCADA scheme Remote sensors and RTUs- Communication channel- Master Station
2.4.1 Discrete versus analog alarms. - Some sensors detect on / off conditions which are reported as on and off, as in the case of a building access system as shown in picture 4, which is accessed by fingering a single card or personal authentication code, which can be represented as an analogue value that crosses a threshold, other sensors measure more complex situations, where accurate measurement is very important and precision as in the case of seismic thresholds for classification of alarms.
Picture 3: Building Access System (BAS) Source: DPS TELECOM.
For most analog measurements, the ideal is to keep the desired value between a medium and higher level. For example, you may want the temperature in a server room remains continuous values between 16 and 22 Celsius degrees, or also may want to monitor an industrial plant variables driving voltage, temperature, pressure, gas emanation, etc. Immediately notifying if sensors detect conditions outside that range.
Picture 4: Thresholds values. Source: DPS TELECOM.
In more advanced systems, there are four threshold detectors see figure 4 or more user-defined values to help you distinguish the " alarms severity ", indicating when certain value had exceeded another, such as an alert minimum seismicity and province, outside the threshold range that threatens the population, set by INPRES. One of the main advantages of using "analog sensors" for environmental monitoring is the ability to control the change of analog values in real time. This helps to take quick decisions and prioritized for any eventuality previously located the critical measurement points of distributed centralized seismicity of the affected area.
2.4.2 Sensors power. - Main options for the sensor supply SCADA system:
a) Commercial Energy. - This is a simple implementation of SCADA sensors energy. However, when the remote sites experience a power outage, so do their sensors and are unprotected from a power surge.
b) RTU Energy. - The ideal way to provide power to the sensors is through a secure supply redundant power. Using SCADA and power supply, sensors are protected from commercial power failures because they are running on the same battery protection.
5.2 ENVIRONMENTAL OPTICAL SENSORS AND APPLICATIONS.
Optical fibers have strongly contributed to the development of the telecommunications industry and in the sensors area for over three decades. Because you need to keep getting better use of the special features that fiber has, optical devices have been built as DWDM couplers (Dense Wavelength Division Multiplexing), amplifiers and environmental sensors that have contributed the ongoing development of our networks because they are inherently low loss and can be interconnected networks that transport different complex signals. With these systems, called "All Fiber" has dropped one of the constraints for any system of long-distance communication, which is the loss of signal attenuation.
Photonics covers a broad spectrum of activities related to the phenomena study of light interaction with pure or doped materials with atoms or molecules, which act as optically active centers, examines the light emission processes, propagation, deflection transmission, amplification and detection. Photonics has dramatically boosted the search for materials that may have application in optical communication technologies, radiation detectors, fluorescent color screens, optical filters, optical drives, as active media for lasers coordinated frequency in devices optoelectronics, information transmitting means, routers and optical radiation controllers, optical memories, etc.
Sensors based on this technology can be used to measure many different parameters, such as temperature, pressure, displacement, electric field, refractive index, rotation, position, vibration, volcanic emissions, etc. The design includes various multiplexed types (WDM, TDM, etc.) and signal coding methods similar to those used in electronic devices, which reduces substantially the cost of the systems. Different variants enable the development of discrete sensors e.g... Twenty sensors in a fiber (in certain applications up to thousand sensors per fiber) or continuous (Picture. 5)
Picture 5: Distribution of optical sensing with a continuous cable. Source: ESANDS.com
Among discrete sensors can mention interferometry’s fiber optic sensors and particularly to those generated by refractive index variations of periodic type generated in the core of a
photosensitive fiber (Bragg grating, long period networks), which have many advantages over other optical fiber sensors. One of the main advantages of the sensors based on Bragg grating is attributed to the identification by wavelength of the external parameter information transmitted by the network. Since the wavelength is an absolute standard, signals reflected by the FBG (Fiber Bragg Grating) can be processed so the information remains immune to power fluctuations along the optical path. This inherent characteristic of FBG sensors makes it very attractive for applications in harsh environments, smart structures and in situ measurements. They are widely used in the development of optical sensing techniques, acting as precise monitoring sensors in real time, thanks to the multiple advantages including unlimited bandwidth and noise immunity.
As mentioned sensing types can be classified as:
a) PRECISE SENSING: A single sensor for each fiber strand, located at a particular interest point.
b) ALMOST DISTRIBUTED SENSING: Various sensors on a single fiber strand, interrogated by multiplexing (e.g. FBG technology)
c) DISTRIBUTED SENSING: Measuring system in which the same fiber acts as a distributed sensor capable of sensing at all points along the link based on non-linear effects (Raman or Brillouin effect).
The general advantages presented by the fiber optic sensors are the following:
Immunity to electromagnetic interference, applicable: • Electromagnetic fields or high voltage environments. • explosive, corrosive or chemically aggressive. • High and low temperatures. • Environments exposed to nuclear radiation / ionizing. Lightweight, small size, flexible, low thermal conductivity. Electrical insulation, low-loss transmission of signals over long distances without repeaters (remote sensing). Electrically liabilities. Chemically inert. Easy to install. Ability to remote interrogation, fiber working as transducer element and transmission medium. Big wavelength
Fiber optic sensors accelerate the transition of the entire telecommunications industry in its transition from the world of digital electronics digital photon. 2.5.1 Particular advantages of sensors based on FBG.
We can mention the following: Multiplexing Capability (Sensor Networks) of several transducers to share expensive terminal equipment and reduce the amount of required wiring. Embedded Installation ("smart structures") Wavelengths coding. Mass production at reasonable cost. High strains resistant.
High and low temperatures resistant (from 4 degrees Kelvin to 1000 degrees Celsius). Ability to achieve long distances between sensors and data acquisition devices.
FBG technology provides higher multiplexing capacity, compared with higher precision technology and distributed measurement encoded as absolute parameter signals wavelength are (selfreferencing). It can be implemented with FBG: • Temperature sensors • Strain gauges • Accelerometers • Pressure sensors • Inclinometers • Displacement sensors
2.5.2 Industrial applications. - FBG technology can be used in the following areas:
• Monitoring of civil structures: Bridges, Tunnels, Dams, and Highways. Important variables such as deformation, displacement, pressure, temperature and beams vibration, columns, platforms, bridges, retaining walls and other structural elements. The most important requirement, which must be, met deformation sensors is the long-term stability of the system output data, which can be achieved by a measurement system calibration almost as free of FBG technology.
• Oil wells monitoring: located both on land and the bottom of the sea. Important variables such as: temperature, pressure and fluid.
• Pipelines transportation monitoring: one of the most critical structures in the world, since most are in places difficult to access and require close monitoring to prevent environmental disasters. If any damage occurs, the real-time monitoring of FBG sensors can help to reduce the time and repair costs, since it is possible to know the exact location of the damage. Variables such as strain and temperature.
• Oil storage tanks monitoring: to identify leaks and fluids that can contaminate soil or water because of possible oil spills. Variables such as leak detection.
• Hydroelectric plant monitoring: Variables such as vibration and temperature.
• Power cables monitoring. Variables such as vibration.
• Power transformers monitoring. Insulating material degradation between windings, calculation mistake of electric thermal behavior, the effect of power surges generate temperature increases, which in turn can lead to malfunction of the processor, or if it is located in a substation, generate blackouts over wide geographical areas. Variables such as vibration and temperature.
3. WORKING HYPOTHESIS 3.1. GOAL. – Its proposal is interconnect telecommunication network of the project "Argentina Conectada" with the national network of seismology INPRES and add to this the use of new optical sensors developed by CIOP, Universidad de la Plata, to create a "Early Warning Alert system" with automatic alarm outputs via: SMS / AD / CATV / Radio / etc. creating a new application for the "Federal Network Optical Fiber " wide coverage and territorial / regional capillarity with minimal additional cost and contributing to improving INPRES network to expand the amount of monitoring points.
This hypothesis can be later extended to other risk variables that define its monitoring convenient national and interconnected with other regional countries / Latin American creating on stages a network of early warning of earthquakes or other natural risks.
3.2. Specific objectives. - To achieve the general hypothesis of previous work the following objectives are set: • Use Federal Network Optical Fiber as the fundamental basis of the system. • Add to the existing network of new INPRES accelerometer most (1500) points monitors in critical areas (Northeast and Cuyo) for its high potential for earthquakes and install sensors at critical points. • Develop and use the above proposed network new optical sensors to detect ground vibrations, transmitting information through optical communications links to processing centers,
receiving, recording and analyzing data through a permanent centralized datacenter. • Detecting and Managing Information Risk with backup datacenter. • Manage alarms in a concentrated and avoiding false alerts by priority or make announcements before confirmed detection.
3.3. SCOPE. - The following paper describes the main features to create an early warning system in general, and it focuses on developing sensors that require specific for operational test and evaluation by INPRES, so limit is set as the this document the following aspects:
• Analyze and confirm or not the feasibility of using optical telecommunications networks of the "Argentina Conectada" as new support and integration with existing networks INPRES accelerometers. No interconnections costs are assessed to each company until define the final model integrated network.
• Analyze, select and propose suitable optical detector sensitivity but not only for operational ease to integrate with REFEFO. Field tests exceed this first study but are recommended in "future research",
• Generate an open and modular proposal for further critical analysis of each actor and later generation of specific work plans that analyze Hw and SW: specific project requirements, milestones, cost, time being of interest realization. The previous points were treated on this ground in this document.
4 – PROPOSED SOLUTION
4 – PROPOSED SOLUTION INTRODUCTION
Described below networks and elements to be integrated produce the innovation proposed. Finally a comparison table of the main definitions will be make are then presented as conclusions and future research, focusing on the practical part of the lab performed for the case of optical sensors listed in item 5 separately to present in more detail the benefits of working with next-generation sensors to be manufactured locally and multiple applications in the industrial field, surpassing its timely implementation as accelerometers in a network of earthquake detection and early warning
The topics are described below:
4.1 - Comparison of seismographic network and optical fiber network (REFEFO). 4.2 - convergence of telecommunications networks and seismic measurements. 4.3 - proposed integration model and basic mounting detail 4.4 - social and economic impact analysis of the proposal.
4.1 COMPARISON OF ARGENTINE SEISMOGRAPHIC NATIONAL NETWORK AND OPTICAL FIBER FEDERAL NETWORK PROJECTED FOR TELECOMMUNICATIONS
The National Network accelerometer 44 seismic stations installed in:
PROVINCIA
NUMERO DE ESTACIONES SISMOLOGICAS
SAN JUAN MENDOZA LA RIOJA JUJUY SALTA SAN LUIS CORDOBA TUCUMAN CATAMARCA SANTA FE - PARANA CORRIENTES POSADAS BUENOS AIRES - LA PLATA NEOQUEN VIEDMA USHUAIA TOTAL INSTALADAS
12 6 5 4 4 2 2 1 1 1 1 1 1 1 1 1 44
SOURCE AUTHOR IMPRES BASED
Today the National Network of Seismic Stations is composed of 50 (fifty) stations distributed throughout the country,
Now we analyze the Federal Network Fiber Optic. Adding the above concepts and forming a single structure: integrated by: • 54 federal optical network segments, (grouped into five rings). • 8 main nodes • 485 nodes • 8 international outputs (7 Terrestrial and 1 Submarine cable). • North South of the entire Los Andes coverage. • 1000 junction boxes on NW seismic zone and Cuyo that can contain optical vibration sensors (Bragg grating) on 10,000 junction boxes of optical fiber to a total of 40,000 km optical network of the country. • 3 or more freedom degrees or physical connection on each node, with high security by optical path redundancy. • Convergent optical physical network into two traffic concentration points and thus national alarm handling in/out to
"validate alarm center" with registration datacenter security level and where it will connect to the national management system INPRES, responsible for managing the national network of accelerometers Argentina, obtaining: detectors concentration and alarms in single node (two node one east and one west side of the country), better data security and reduced operating and maintenance costs. • use the same optical fiber network transport-REFEFO-as optical detector + optical transport to the node on a single pair of hairs to allow optical sensors and connection in series without losing its unique identification to be "recorded Bragg grating with a specified lambda ", that identifies the entire optical network, with lower installation costs and maintenance that a sensor connected VHF radio. • use DWDM transport transmission channels and forwarding measurement since the earthquake wave travels approx. 5km/sec and detection and transmission to the master node and from there to the areas where the seismic impact through optical fiber network (REFEFO) and associated equipment- 200.000km/sec (v = 2E8 m / s L = 2,000km t = 1 m sec) where notice anticipatory, seconds before reaching the hazardous event.
OPTICAL STRUCTURE OF THE "FEDERAL NETWORK OPTICAL FIBRE "REFEFO-
Source: REFEFO Project presentation ARSAT -SA 23/09/11
In the previous map are shown 54 stretches grouped in five (V) rings, which connect the Argentinian territory as follows: ANILLO I
II
III
IV
V
TRAMO NUMERO 1,2,3 4,5,6 7,8 8,9,34,35,36 41,42,47,48 49,50,5354 27,28,35,36,37,38 39,40,41,43,44,47 50,51,52,54 16,17,18,19,20 21,22,23,24,25,26 27,29,30,32,33,39,46 10,11,12 13,14,15 37,38,45
PROVINCIA TIERRA DE FUEGO SANTA CRUZ CHUBUT - PARTE DE RIO NEGRO RIO NEGRO - NEOQUEN PARTE DE LA PAMPA - PARTE DE BUENOS AIRES PARTE DE MENDOZA PARTE DE LA PAMPA - PARTE DE BUENOS AIRES PARTE DE MENDOZA - SAN LUIS - CORDOBA - PARTE DE SAN JUAN PARTE DE LA RIOJA - PARTE DE SANTA FE PARTE DE :CORDOBA - LA RIOJA -SAN JUAN - CATAMARCA SANTIAGO DEL ESTERO - PATE DE SALTA - PARTE DE JUJUY PARTE DE SNATA FE - PARTE DE CHACO - PARTE DE FORMOSA MISIONES CORRIENTES ENTRE RIOS
SOURCE: PREPARED ON THE BASEIS OF PREVIOUS REFEFO PROJECT
4.2 TECHNOLOGICAL CONVERGENTE "REFEFO-SEISMIC NETWORK." DEFINITION OF OPTICAL TRANSPORT NETWORK (REFEFO) USE DEPENDING ON SEISMIC RISK AREAS. In the Federal Fiber Optic Network about the zoning by the degree of seismic hazard and the National Network of Seismic Stations, can focus as critical to take into account the facilities of our optical sensors in the first instance, the following distribution:
Ring III, covers the area of locations zone: 4 - 3 - 2 - 1 - 0, as seismic zoning map, and can be connected and work together with the seismic stations: San Luis - Cordoba Mendoza - San Juan - La Rioja Buenos Aires. Ring IV covers the area of locations zone: 4 - 3 - 2 1 as seismic zoning map, and can be connected and work together with the seismic stations: Tucumán- Catamarca Salta - Jujuy - La Rioja - San Juan. Ring II, covers the area of locations zone: 4 - 3 - 2 1 - 0, as seismic zoning map, and can be connected and work together with the seismic stations: Rio Neuquén Black - La Pampa (Santa Rosa) - Mendoza and new stations being installed. Ring I, covers the area of locations zone: 0 - 1 -2 - 3 as seismic zoning map, and can be connected and work together with the seismic stations: Tierra de Fuego (Ushuaia) - Santa Cruz (Rio Gallegos) - Chubut (Rawson) and new stations being installed. Finally ring V, covers the area of locations zone: 0 1-2 as seismic zoning map, and can be connected and work together with the seismic stations: Corrientes - Misiones (Posadas) - Santa Fe and Catamarca and new stations being installed
4.3 TECHNOLOGICAL CONVERGENCE CREATING EARLY WARNING NETWORKS DIRECT TO THE RESIDENTS (INTERNET, CELL BY SMS AND TELEVISION AD, CATV, RADIOS).
Introduction. It is noted that the hypothesis of the thesis presents three settings of network integration described above: . - Integration of existing sensor network INPRES added or converted to optical connection (today VHF radio connection) and connected to REFEFO. Also be available to connect from junction boxes (quantity 1500 in NWA and Cuyo) Federal Network Optical Fiber as possible points detector of fiber placement and welded to transport fiber cable that would connect the main optical vibration sensor with nearest node either ARSAT SA or IMPRES, whichever is convenient for distance, node-detector.
- Integration of transport network: using Federal Network Optical Fiber as transmission of data collected on a secondary node, remote or current IMPRES network working with more than 100 accelerometers.
-Integration of alarm management and alarm notice to other networks such as: mobile (SMS Priority), Digital Television Broadcasting (TDA), closed Community Television (CCTV), radios, etc., which will be present all the above services on Benavidez Master node, facilitating connection with the destination network of earthquake alert signaling.
A further possibility is to concentrate on Benavidez Master node and then out- by optical transmission - retransmitting detection/alarms- to IMPRES building in San Juan province,
whichever is convenient at the detection time, and alarm triggering.
As for the alarms reception in the terminals of the inhabitants, we note that it is immediately application is possible in cellular networks for its wide dissemination in the country and worldwide. Its significant development is known that has taken the market of mobile phone in the world, according to the International Telecommunication Union in 2011 was estimated about 6,000 million subscribers, representing a penetration rate of 86.7% worldwide, In our country there are approximately 57.87 million subscribers (1.44 per habitant, INDEC) reaching a penetration of 117%, on the other hand, the needs of mobile data communications have enabled cellular networks that were originally designed for voice transport, provide a higher rate of data transfer, providing new services to the user, which is proposed as a channel to send earthquake early warning via SMS or through a government application installed on all 2G, 3G or LTE next generation terminals.
Another automatic communication alarm channel is Open Digital Television. Currently the deployment of Open Digital Television continues to increase with the installation of new transmission of digital terrestrial television in different parts of the country as shown in Picture 1 and relevant description on Table 1.
Picture 1: TDT Coverage map SOURCE: tda.tvdigitalargentina.gob.ar
TRANSMITTING PLANNED Buenos Aires city (MOP) Fronteer Sta. Fe province Buenos Aires city (Edificio ALAS) Río Turbio, Sta. Cruz province Villa Martelli, Buenos Aires province Cte. Piedrabuena, Sta. Cruz province La Plata, Buenos Aires province Comodoro Rivadavia, Chubut province Campana, Buenos Aires Province Santo Tomé, Prov. de Corrientes Baradero, Buenos Aires Province Lago Puelo, Chubut province Cañuelas, Buenos Aires Province Ushuaia, Tierra del Fuego province Pinamar, Buenos Aires Province Neuquén, Neuquén province San Clemente del Tuyú,Buenos Aires Province Viedma, Río Negro province Coronel Suárez, Buenos Aires Province Jachal,San Juan province Mar del Plata, Buenos Aires Province Villa Angela, Chaco province Luján, Buenos Aires Province Caleta Olivia, Sta. Cruz province San Nicolás, Buenos Aires Province Quimili, Santiago del Estero province Dolores,Buenos Aires Province Puerto Deseado, Sta.Cruz province Necochea, Buenos Aires Province Pico Truncado, Sta. Cruz province Olavarría, Buenos Aires Province Salta, Salta Province Resistencia, Chaco Province San Salvador de Jujuy, Jujuy Province Formosa, Formosa Province Córdoba, Córdoba Province Villa María, Córdoba Province Leones, Córdoba Province La Rioja, La Rioja Province San Juan, San Juan Province San Carlos de Bariloche, Río Negro Province San Miguel de Tucumán, Tucumán Province Paraná, Entre Ríos Province Posadas, Misiones Province Río Gallegos, Santa Cruz Province Villa Gobernador Galvez, Santa Fe Province Santo Tomé,Santa Fé Province Santiago del Estero, Santiago del Estero Province Santa Rosa, La Pampa Province San Luis,San Luis Province Mendoza (Cerro Arco), Mendoza Province Chascomús, Buenos Aires Province Las Flores, Buenos Aires Province Navarro, Buenos Aires Province Brandsen, Province Buenos Aires Azul, Buenos Aires Province Arrecifes, Buenos Aires Province Cañada De Gómez, Santa Fe Province Trenque Lauquen, Buenos Aires Province Rafaela, Santa Fe Province Catamarca, Catamarca Province Añatuya,Santiago del Estero Province Viedma, Río Negro Province Villa Dolores, Córdoba Province La Matanza, Buenos Aires province reinforcement of 2,000,000 inhabitants coverage
Picture 1: City with Transmission coverage and TDA Source: tda.tvdigitalargentina.gob.ar
Technological convergence between different technologies described as Federal Network Optical Fiber will obtained data from optical sensors and INPRES from Benavidez, will be responsible for data distribution to the inhabitants of the country in sectors requiring guidance on how to proceed through different types of audible and text alarms, activating contingency plans, interacting with cellular networks of interconnectivity agreement, generating data from these networks via SMS or mobile broadband by state applications for users with smart terminals and information transmission from digital terrestrial TV networks / mobile systems to take control and direct television transmission ARSAT could interrupt programming processes enabling interactive information of what is happening, thus establishing a national converged network natural disaster emergency that integrates new generation features (NG911) and multimedia communications to support emergency personnel throughout the country.
4.4 CONVERGENCE MODEL –OPTICAL NETWORK INTEGRATION -PROPOSAL-BASIC ASSEMBLY DETAIL Based on the concepts earlier proposed: - Gather and integrate from the optical sensor and accelerometer that records vibrations from the ground where it is installed by the Federal Network Optical Fiber by using an optical fiber dedicated to the measurement and recording of earthquakes in a series circuit of optical detectors recorded by Bragg grating by providing unique identification to each "hair fiber" and - A mechanical assembly to allow work this "pig tail recorded fiber " from each junction box REFEFO on INPRES indicated as the most convenient for its location on the ground and
- Distances to nodes of about 50km by the required power of the light source detector to coincide with the REFEFO transmission scheme having optical jumps of approximately 100km so, sensor would link the intermediate positions to ensure transmission to the secondary or regional node and from there by a DWDM channel transmission system to achieve overall seismic target nodes: a) Master node Benavidez b) connection node for INPRES current network. - Then nodes transmission signal would drop to a management system with dual function: a) recording of measurements collected as total country 7x 24 x 365 days and b) input of the alarm system that would perform the functions of notice, sent areas / entities / linked communications networks (Internet / phone / AD) according to the instructions "stored" in the appropriate program and level earthquake such as PTO prioritizing actions, Example: warning to energy companies, gas, electricity, etc. to emergency closing its facilities in areas that will be affected in the next seconds.
Text: REFEFO Node Light source-Detector- coupler
OF Network REFEFO (cable+sensor+Bragg) Two FO hair of network TX Picture 13: Scheme of a measurement system with Bragg grating in optical fiber.
The sensors are analyzed, base choice and detailed design in chapter 5, p. 122
Chart 4.4.1 proposed scheme "ROSATS".
4.5 ANALYSIS SOCIO-ECONOMIC IMPACT OF THE PROPOSAL IMPLEMENTATION The seismic alert system for a country, region or locality may inform people about impending danger; reduce death, injury and property
damage. Here are some aspects considered in relation to the socioeconomic impact of the proposal: • Reducing loss of life. • Integrate telecommunications networks nationwide with seismic sensing networks and obtain synergy between both, added early warning to society, facilitated by the use of new technologies and contributing concretely to the care and safety of the inhabitants of a country by the state. • Availability of immediate real-time information for the prevention and mitigation in case of earthquakes or other natural events. • Integration between meteorological agency, INPRES, state and entities involved in cases of earthquakes, which will inform the media, through a validation alarm center, for example, Benavidez (NOC Master of ARSAT SA) all media for civil alert. • Vital protection for civil society that provides a modern state. • Lower costs for repair and damage nationwide. • Actively contribute to seismic risk localities. • Effectively distribute messages and alerts and ensure continual development of the most risky towns because of its location on the INPRES seismic map and earthquake statistics. Example: San Juan province. • Perform technological upgrade of existing accelerometers developed new optical generation in the country.
5 – OPTICAL FIBER SENSORS 5.1 Introduction Advances in photonic technology as a result of telecommunications and the characteristics of fiber technology have enabled the development of multiple devices of interest in this area [1-3]. Many of these devices were generated for the optical fiber sensors field in sectors or "application niches" where traditional sensors are not working properly or not functioning. So is being used in environments with high electromagnetic fields (e.g. power generation stations), or in the environment where the generation of electrical signals is dangerous. (E.g. pipelines, biogas plants, airplanes), or in applications that require small size systems and compatible with the object or body to be measured (e.g. biomedical sensors) or in places where the temperature is so high that traditional sensors do not work properly due to multiple factors (e.g., steel mills, foundries, welding).
The general configuration of a sensor of this type is shown in Picture 1 and as shown in the diagram, comprises a light source, a sensing system and an optical detector interconnected with optical fiber.
Picture 1: Basic scheme of an optical fiber sensor. Text: Optical fibers – Light source-sensing system-detector
Depending on how the measurement of the external disturbance is made is usually classified in two main classes: extrinsic and intrinsic. In the diagrams in Picture 2 are simply shown their fundamental difference.
a) Extrinsic sensors. - Includes those applications in which the fiber acts as a waveguide only bringing light to a "black box", which modulates the beam in response to the parameter being measured. Under this approach, modulated or prints information by any particular method the fiber and is used to drive only the radiation from the source and to the sensor device. This information may be encoded in intensity, phase, frequency, polarization, spectral content, etc. (Picture 2D)
b) Intrinsic sensors. - Also called "all-fiber sensors", use the optical fiber as waveguide where the interest magnitude is to be measured, but unlike the previous case, external disturbance acts directly on the fiber. Light remains in the fiber at any time (Picture. 2b).
Text: Optical fiber -perturbation -sensor module- optical fiberperturbation- optical fiber
Figure 2: Basic types of optical fiber sensors: a) extrinsic b) intrinsic
Since light provides a means for measuring an external disturbance into the optical fiber sensor may be many types of sensors as wave properties are possible to modulate.
5.2 MAIN PARAMETERS The equation with which usually represents the electric field vector of an electromagnetic wave, shows all properties that can be modulated by an external shock:
E E0 sen(t kx )
(5.1)
where E0 is the wave amplitude
is the angular frequency k is the wave number equal to 2π / λ (wavelength λ) φ is the phase constant
The simplest type of sensor which can be built is one in which the perturbation directly modify the light amplitude, resulting in a change of intensity at the detector (related to its square). The major challenge in this type of design and its major limitation is to separate the fluctuation in intensity due to the external disturbance from other causes fluctuation generated spurious (light variation from the source, power supply variation, etc.).
Interferometry sensors are instead disaffected to this limitation as external perturbation generates a phase difference between two light waves. Thus the encoded information is insensitive to variations in intensity, an example in which a measurement can be performed from the phase modulation. Designs are considerably more complex, but provide very high resolutions.
The frequency or light wavelength has a decisive role in the above two cases, because they have a functional relationship with both the absorption and reflection due to the interferometry phase shift dependent on the wavelength.
The vector nature of the light is used very efficiently with polarimetric type sensors where the state of polarization of the wave is affected by the external disturbance [3]
5.3 SENSOR DESIGNS Different types of sensors are adaptable design of the structural vibration monitoring, and particularly position and interferometric. We will focus particularly on these.
5.3.1 intensity sensors. - In some cases, the simplest type of sensor construction is that based on the intensity modulation. Sensors are inherently simple, requiring a few elements and electronic components. In Picture 3 shows a sensor consisting of two optical fibers arranged close to each other, in this case forms a vibration sensor. The light propagating along the fiber forms a light cone angle, which depends on the difference of the refractive indices of the core and the covering or cladding.
Light can be captured by the other end of the fiber will also depend own acceptance angle and distance "d" of separation between the two fibers. When this distance changes, either a vibration or a
displacement, the intensity of light varies accordingly. The foreign agent is well represented by modulating a light intensity proportional, in certain ranges easy to recognize.
Picture 3: Intensity optical fiber sensor. The light from the first fiber is coupled to the second cone from opening characteristic of the second fiber.
Often, many applications do not allow an arrangement as shown, so a frequently used variation is shown below in Picture 4.
Text: Optical fibers-Mirror located in a flexible surface-Perturbation
Picture 4: Alternative of fiber optic sensor utilizing flexible mirror intensity or mounted on a sensitive surface to the disturbance to be measured.
This configuration uses a mirror, or simply a mirrored surface or polished enough that can respond to an external shock, such as the pressure of a sound wave. In this scheme the light injected by one of the fibers is expanded and reflected from the mirror then being coupled to the second part. The degree of coupling depends on the distance of separation between the fibers and the mirror, and the acceptance angle of the fiber output.
As the mirror or reflector varies its relative position because of the disturbance, effective separation is amended, generating intensity modulation in the second fiber. This type of sensor is especially useful in applications where you want to know a binary type of information (on / off, lock doors, interlocks, etc.). However, depending on the quality of the mechanical design, can be used, and is suitable for detecting similar measurements as vibrations and sound waves, pressure, displacement and distance.
5.3.2 intensity by bending sensors. - A more complex way in which light passing through the fiber module is by a decreased intensity due to losses in the core by bending or "bending". If an optical fiber is subjected to a curvature greater than the allowed (known as bending radius parameter), degrades the essential condition for transmission via total internal reflection between the core and the coating, causing light loss. The best practical results have been achieved with microfolds, locally generating controlled and convenient useful for pressure measurement, vibration and other environmental effects [47].
Picture 5 shows the typical scheme consisting of a light source, a fiber optic line within a section of a device with a profile such that it can conveniently modular external disturbance from micro curvatures controlled not to destroy the fiber.
Text: Light source-Detector Inductor system of micro distortion
Picture 5: Fiber Optic Sensor modulated in intensity by micro bending. This is an example of intrinsic fiber optic sensor, because the fiber that modifies the way in which light is transmitted. Such sensors have a very good performance in the linear region, one in which the curvatures are approximated along the core as a sinusoid. Special care should be taken in the design to avoid irreversible damage to the guide. Corke et al. [8] have made a review of this technique, while Giles et al. [9, 10] reported 1% linearity improvements using optical switching techniques.
5.3.3 Interferometric Optical Fiber Sensors. - Interferometric sensors occupy much of the attention of scientists and engineers for decades. Its properties and versatility have positioned in the varied types of applications ranging from simple temperature measurements, to the intelligent control of large structures such as bridges and buildings and the aerospace industry. Since require a very stable assembly, are highly sensitive to vibrations.
In this type of sensor, fiber is closely related to the measuring mechanism, since the light can remain within the nucleus to interact with the field to be measured. The optical phase of light propagating is modulated by the parameter to be detected, and then being
detected inters ferometrically compared with the phase of a reference light.
Besides the inherited advantages of fiber optics, have additionally: the geometric versatility as a sensor, large dynamic range, low loss and extremely high sensitivity.
Interferometric based in optical fibers can be divided into two broad categories: those in which two interfering beams, as Michelson type configurations, Sagnac and Mach-Zehnder, and the multiple beam interferometer, mainly represented by Fabry –Perot cavity.
5.3.3.1 Mach-Zehnder and Michelson inter ferometric sensors. - The bender-beam interferometers allow the measurement of changes in the extremely small phase difference generated by the disturbance. To a first approximation, the optical phase delay that light undergoes when passing through an optical fiber is:
nkL
(5.2)
where n is the refractive index of the fiber core, k is the wave vector in the vacuum (k = 2π / λ, λ being the wavelength), and L is the length of the fiber span. "nL" magnitude is therefore the "optical path".
Picture 6 shows the basic elements, which form a Mach-Zehnder Interferometer: a light source, usually an isolated laser diode, large enough coherence length. A first single mode directional coupler which divides the incident radiation, generating two light beams of equal intensity in general that are coupled to the two arms of the
sensor, one of which is the sensor itself, and the other is used as reference.
The transducer located in the sensing arm is suitably designed for measuring an environmental effect of isolating the reference arm of the external disturbance, thereby generating one optical path difference between the two beams.
Text: Light source- coupler- Sensed fiber reel- Reference fiber reel- couplerDetectors Picture 6: Mach-Zehnder interferometer.
These two signals are recombined by a second coupler, to form an interference signal that is detected by respective photodiodes.
Assuming coupling coefficients of k1 and k2, couplers, and optical fibers α1 and α2 in each of the fiber sections, can be written the equations of the electric field as each arm as: E1 E0 1k1k2 cos 0t 1 E2 E0 2 1 k1 1 k2 cos 0t 2
(5.3)
Taking into account that the optical intensity averaged temporarily for periods bigger than 2π/ω0, can be expressed as:
(5.4)
I E12 E22 2 E1 E2
and further that the coefficients of coupling should choose them are such that k1 = k2 = 0.5, while the losses in the fiber may approximate as α1 = α2 = α, (pp. 274-277, [1]), then Eq. (5.4) takes the following expression: I 0 2 I I ´ 0 2 I
1 cos 1 cos
(5.5)
Where l and l ' represent the outputs of both arms of the interferometer, with l' complementary output (replacing k2 by 1- k2, and vice versa), I0 is the average intensity of the light beam, and Δφ = φ1 - φ2 is the phase delay suffered between the two roads. Finally, considering that the phase variation can be separated into two members, that is:
d d s sen(t )
(5.6)
and it is assumed that the differential phase shift dφ has some amplitude φs and frequency ω, while φd represents a slow variation, then Eqs. (5.5) can be re-written as:
I 0 1 cos d s sen(t ) 2 I I ´ 0 1 cos d s sen(t ) 2 I
(5.7)
These signals can be converted to electrical signals by the photodiodes and detectors combined with differential amplifiers: i ( I I´) I 0 cos d s sen(t ) (5.8)
where ε is the photo detectors responsibility. By simple mathematical treatment, as shown in Chap. 10 of reference [11], we conclude: di I 0 sen d s sen(t )
(5.9)
The eq. is significant and shows a limiting factor because it amplitude depends on the sen (φd) occurs that φd is dependent on many factors of the environment, e.g. temperature, if it approximates a multiple of π tend to fade the signal, whereas for odd multiples of π / 2 will be high.
Picture 7: Transfer generated in-fiber interferometers.
Picture 7 graphically explains the problem, from a curve of intensity as a function of the relative phase of the light beams in each arm of the device. It is noted that for a given phase difference, the output of the device may be reduced because of the sensitivity degradation (φ d → nπ, fading effect).
A usual way of overcoming this drawback is to introduce one of the arms in a piezoelectric device that stretches the fiber, thus inducing an increase in the optical path to compensate the effects of spurious measurements.
For the demodulation of the interfering signals are basically two homodyne techniques: active and passive. In which the reference is derived from the same original source before being modulated, however numerous schemes have been used in which the heterodyne demodulation technique is thus makes a shake signal with another self-test commonly known as " local [12].
a) active homodyne detection. – Consists on generating the drift compensation systems to bring the square before collecting data. In the early years of interferometry with fibers investigators added constructed compensating fiber windings piezoelectric rings, so that by applying a voltage around the fiber is subjected to an increasing stretching the effective length of the reference arm. In its beginning this control was performed manually, and then enhanced by an electronic feedback system. This approach was then supplemented by other routes, such as the variation of the supply current of the LED laser, since in some cases these sources of near-infrared semiconductor exhibit a drift of the center wavelength with respect
to the power supply (only a few GHz / mA) [13], which allows a variation ΔL of a few centimeters.
A significant improvement to this method is that no simplifications and approximations, and the output are linear phase, providing better dynamic range [14]. Nevertheless, active detection has two major questions that almost necessarily limit its application to laboratory limiting the dynamic range of the feedback elements need restoration or "reset" that complicates the system's ability to detect phase changes in order micro-radians.
The second reason is that the complicated scheme implementation in multiplexed systems, since the source can only maintain a balanced interferometer, compromising the stability of the rest. Because of all this is that the passive homodyne detection, but uses certain simplifications and approximations, has a wider application and acceptance.
b) Passive homodyne detection. - The basic approach and one of the first used involves the generation of two signals optically phased by 90º [15], so that now the signals are: I 0
1 cos 2 I i´´ 0 1 sen 2 i
(5.10)
And its response to small changes in the phase will therefore I 0
d sen 2 I di´´ 0 d cos 2 di
(5.11)
From these equations and Picture 8, can be seen that when one signal is at a minimum, the complement is maximal and vice versa. The results used in this technique results in a direct measure of the phase difference.
Picture 8: Two signals generated with a 90 ° difference in phase, for quadrature detection.
As can be seen in either situation, it is always possible to rescue one of the signals. There are several ways to handle these two outputs to avoid the problem of fading, one of the first and simplest is to sum the squared differential and then take the square root
i di 2 di´´2
I 0 2
d
(5.12)
Should be noted that in all these procedures is assumed dφ
