International Global Navigation Satellite Systems Society IGNSS Symposium 2009 Holiday Inn, Surfers Paradise, Qld, Australia 1 - 3 December, 2009
More freedom for the Blind and Vision Impaired – A Proposed Navigation and Information System Binghao Li School of Surveying and Spatial information Systems, UNSW, Australia Phone 93854189, Fax 93137493 Email:
[email protected]
Euan Ramsey-Stewart Ramsey Stewart Industrial Design Email:
[email protected]
Kenny Johar Vision Australia Email:
[email protected]
Daniel Woo School of Computer Science and Engineering, UNSW, Australia Email:
[email protected]
Chris Rizos School of Surveying and Spatial information Systems, UNSW, Australia Phone 93854205, Fax 93137493 Email:
[email protected]
ABSTRACT There are over 1.2 million Australians registered as having vision impairment. There are many more cases that go unrecognised and untreated in our society. Welfare for this group costs AUS$12 billion a year with lost business opportunity costs of AUS$42 billion. In the UK, the welfare cost is estimated at £49 billion per annum just for those Blind and Vision Impaired (BVI) that suffer from Glaucoma and Cataracts, indicating that the overall welfare costs of blindness are much higher. Any system which could increase the mobility and independence of the vision impaired has the potential to save significant taxpayer dollars. University of New South Wales, Vision Australia and Ramsey-Stewart Industry Design have secured a four-year ARC Linkage project to develop a Mobility and Location Information system for the BVI. The prototype is a system comprising a handheld/mobile device, Information and Communications Technologies (ICT), indoor and outdoor positioning technologies and Server Software that gives a BVI person information about where they are and how to get to where they want to go. Furthermore, a lot of location related information can be provided by such a proposed system. This is an excellent example of a “location-based service”, which has been slated as the largest area of growth for ICT in the coming decade. This product will not replace the traditional white cane or guide dog, but is an additional device to enable the BVI to enjoy mobility and have an improved sense of confidence and self assurance. This paper presents some background to the project and discusses the challenges of this research.
KEYWORDS: BVI, Navigation, Positioning, Information
1. INTRODUCTION It is obvious that our societies are increasingly more mobile. In the developed world the miniaturisation and proliferation of ICT such as mobile phones, personal wireless laptop computers, wireless home automation and security, increased personal car usage and personal GPS systems are rapidly and constantly evolving. We are a society constantly on the move, in a world that is becoming smaller by the day, wanting access to all forms of information wherever we are. It is assumed that this freedom of access is enjoyed by everyone. Sadly this is not the case. The aged and disabled are in danger of being left behind and isolation from society can result. This is surprising, as approximately 15% of the world’s population, around 1 billion people, are moderately or severely disabled, and disability prevalence rises with age (World Health Organization, 2004). Furthermore the ageing population is on the increase and by 2050 23.8% (6.8 million) of the Australian population will be over the age of 65 (United Nations, 2008). There are over 1.2 million Australians registered as having vision impairment. There are many more cases that go unrecognised and untreated in our society. Welfare for this group costs AUS$12 billion a year, with lost business opportunity costs of AUS$42 billion (ABS: 6523.0, 2003-04). In the UK, the welfare cost is £49 billion per annum just for those Blind and Vision Impaired (BVI) that suffer from Glaucoma and Cataracts (BBC, 2003), indicating that the overall welfare costs of blindness are much higher. More significantly, an IBMcommissioned study by Deakin University in 1999 found that there is a more than US$1 Trillion worldwide market for technology designed for the disabled (Bagshaw, 1999). Equality is a fundamental principle of human rights. Guaranteed in article 1 of the United Nations Universal Declaration of Human Rights, the right to equality underpins all international human rights law. For many, our community and its environment creates barriers to equal access and participation, effectively denying people their human rights. Activities of daily living such as walking down the street, catching public transport or shopping can often become an overwhelming task. This can lead to harrowing and frightening experiences, making it more likely that the disabled, especially the BVI, will not venture into the public again, further disenfranchising that person from society and creating greater societal isolation. This creates a culture of dependence on social welfare and Non Profit Organisations (NPO). In July 2008, Australia ratified the Convention on the Rights of Persons with Disabilities (CRPD). Article 8 of the convention requires states to ensure people with disability can access all aspects of the community, and article 20 enshrines the right to personal mobility with the greatest possible independence. Providing facility, environmental information and real time navigation to those who require it creates independence and greater self esteem for the individual. This reduces the strain on, and constant need for, family/carers and relieves pressure from an often over-stretched social welfare system. University of New South Wales (UNSW), Vision Australia (VA) and Ramsey-Stewart Industry Design have secured a four-year ARC Linkage project to develop a Mobility and Location Information system for the BVI. The proposed system comprises a handheld device, several Information and Communications Technologies (ICT), indoor and outdoor positioning technologies, and Server Software that gives a BVI person information about where they are and how to get to where they want to go.
2. SYSTEM DESIGN Any all-purpose navigation system for the BVI must incorporate a variety of technologies in order for it to be useful – usable and location relevant information, a viable user interface, a comfortable method of carriage, and an accurate location system, especially in an indoor environment. The proposed system can be seen as enabling a very specific application of location-based services (LBS). In general, LBS are services that exploit knowledge of where the user is located or where the query for information is directed in a geographic sense. These applications cover nearly every aspect related to human mobility (Williams, 2003). Industry forecasts for LBS have predicted huge market growth (Analysys, 2001; ABI Research, 2004). However, the growth of the LBS market has been slower than many of these forecasts. There is currently no product on the market that can provide the complete navigation service, both outdoors and indoors, with the appropriate HUI, and with location-based information delivery targetted for the BVI. A critical component of LBS is the positioning technique(s) required to provide the location of the mobile user at an acceptable accuracy level (Li, 2006). In general, GPS (or more generally the Global Navigation Satellite System - GNSS) is usable everywhere where there is clear sky. However it fails to operate where it's impossible or difficult to receive the satellite signals, such as inside most buildings, in ‘urban canyon’ environments, and underground. Assisted GPS (A-GPS) has been developed to enable fast time-to-first-fix (TTFF) and high sensitivity (weak signal) acquisition. There are several specifications for commercial control plane-based A-GPS systems (3GPP, 2008; 3GPP2, 2004) and Secure User Plane Location (SUPL) (Li et al., 2009). The development of the Open Source GNSS Reference Server (OSGRS) provides an alternative to commercial A-GPS reference data solutions (Yan et al., 2007). Tests in urban environments have demonstrated that A-GPS can significantly reduce the waiting time for a positioning solution (from more than 40s in the case of standalone high sensitivity GPS to about 11s when using A-GPS) and increases the number of tracked satellites. In environments where GPS completely fails alternative positioning technologies should be used. For example, ultrasound and infrared positioning system have been developed (Priyantha et al., 2000; Want et al., 1992). These systems require the deployment of new infrastructure, hence they are very costly. Utilising deployed infrastructure for wireless communications for positioning purposes is more attractive as it is much cheaper and it can be deployed much faster. Mobile phone network and WiFi are examples. WiFi is a very attractive alternative positioning technology due to the widely deployed WiFi access points (APs) (Li et al., 2005). Currently there are several companies that provide WiFi-based indoor positioning systems (http://www.ekahau.com/; http://www.innerwireless.com/visionover.asp); however the accuracy is not very high (Gallegha et al., 2009). None is designed with BVI users in mind, and none is truly integrated with GPS (for outdoors) although implementations in smartphones such as the iPhone provide GPS and WiFi as alternative location determination technologies. Traditional mobility aids for the BVI are the white cane and/or guide dog. In the last decade there has been an increase in Assistive Technology to aid in BVI mobility. Research has led to the development of many ultrasonic mobility aids (Miniguide, Sonic Pathfinder, and KASPA), which detect obstacles using a similar sonic method to that used by bats (http://www.gdp-research.com.au/minig_1.htm; http://web.aanet.com.au/tonyheyes/pa/pf_
blerb.html). HumanWare’s Trekker system is based on standalone GPS (http://www.humanware.com/en-australia/products/gps/trekker/_details/id_88/trekker.html). As we mentioned previously, GPS has difficulties indoors – it is estimated that approximately 80% of the time people are working or living indoors. In general, if people go outside, the urban area is more likely to be the environment where they spend most of their time. A device that can deliver location specific information under all urban/suburban environments is needed. The second major problem with HumanWare’s Trekker system is its complex user interface. The third problem is the limited information provided. Many researchers have focussed on the development of positioning technologies for indoors and outdoors. For example, Microsoft’s Place Lab software (http://www.placelab.org/) allows devices such as notebooks, PDAs and mobile phones to locate themselves using radio beacons such as WiFi APs or GSM mobile phone towers (CellID) (Lamarca et al., 2005). Navizon (http://www.navizon.com/) in the U.S. claims to be the first positioning system that combines GPS, WiFi and mobile phone positioning. However, it trilaterates signals from WiFi APs and mobile phone towers to find position; and GPS is used to map the WiFi and cellular landscape. The combination of GPS, WiFi and mobile phones remains a challenge. Mok and Xia (2005) proposed a general integrated mathematical model that can be used for integrating GPS/GNSS with other positioning technologies. The integration of WiFi and GPS based on signal strength (to derive distance) is discussed in, e.g., Mok et al. (2006). However, reliably converting received signal strength to range has difficulties. ‘Fingerprinting’ has emerged as perhaps the most attractive method for WiFi positioning (Li et al., 2005; Salter et al., 2008; Li et al., 2006). The integration of WiFi and GPS has been investigated by, e.g., Cheong et al. (2008) and Gallagher et al. (2009). Algorithms developed for the integration of other systems could be borrowed – for instance those by Evennou & Marx (2006) and Sirola et al. (2003).
Figure 1. Integrate several positioning technologies to provide location for BVI.
All current positioning technologies have their own pros and cons. No technology appears to be a clear “winner” for ubiquitous positioning and navigation. Integrating several technologies mentioned previously, and others such as Radio Frequency Identification (RFID), Inertial Navigation System (INS), etc., can go some way to addressing the ubiquitous positioning problem. In this research project positioning technology integration is one of the challenging tasks (Figure 1). The proposed system consists of three parts: 1) positioning technology, 2) BVI user interface, and 3) dynamic information provision (including information database structure). Figure 2 illustrates the structure of the proposed system.
Figure 2. The structure of the proposed system. Location information would be delivered by combining A-GPS, ICT technologies, as well as integrating other sensors such as a digital compass. In an outdoor environment A-GPS will be used, while in an indoor environment other technologies will be used. During the transition from one of these environments to the other a combination of all the methods may be used. BVI people require an easy-to-use Human User Interface (HUI) to submit requests and connect to a server through the cellular network or WiFi. For a person who is not vision-impaired, visualisation is an ideal way to display where facilities are, how to access them, and other location based information. However for the BVI the HUI intended for sighted people can not be used. For instance, if the BVI person still has a little vision, an enlarged map and text would be preferred. For a completely blind person, voice is an ideal means of delivering information. Keyboard entry (obviously different from the one used for sighted people), vibro-tactile, etc., are all possible interfaces. In this project the dynamic information provision will take advantage of VA’s MPower project. MPower makes available not only newspapers, magazines and journals, but VA’s entire library, along with a raft of services available on the world wide web, available to the vision impaired community in an accessible format on a mobile phone. MPower is still under development by VA. MPower will enable the BVI community to receive and use
information when and where it is required. The BVI will be able to use this system to navigate to a destination, obtaining the information about their location or destination. The system can also be used as an emergency aid for the BVI. 3. RESEARCH CHALLENGES Integrating different positioning technologies is a research field in itself. Often the integration is rather simple (e.g. “loosely-coupled”), and the system components do not need to interact at a deep level. It is all very well to have A-GPS working outdoors and WiFi/RFID working indoors, however the integrated system must also work during transition from one of these environments to the other, an area which so far has not been adequately researched. Integration of A-GPS, WiFi, cellular networks, RFID and near-field communications positioning is a core research challenge of this project. In all likelihood there may well be the need for additional sensors, e.g. compass for heading, barometer for indoor height determination, and inertial systems for dead-reckoning. Integration of such a large number of sensors requires careful algorithm design. There are two ‘schools of thought’ on the final integration platform (Figure 3). One is to use products already available in the market (the ‘general purpose platform’), e.g. PDA or mobile phone. The other approach is to develop a dedicated platform (Ramsey-Stewart, 2006). Both approaches have advantages and disadvantages. However, at this stage, the general purpose platform is preferred. The latest generation of the PDA/smartphone is WiFi-enabled, has built-in GPS chipset, and may even have a digital compass and accelerometer (e.g. iPhone 3GS).
Figure 3. Dedicated platform vs. general purpose platforms (N95, Gphone and iPhone, from left to right). The requirements of BVI users are very different from sighted people. For example, what kind of HUI will be best? Some research has been carried out to address such questions (Ramsey-Stewart, 2006). However, current research remains more or less on a conceptual level. When developing the prototype it is very likely many problems will arise which have not even been identified apriori. Hence a major challenge will be the detailed system design and the HUI which can best meet the BVI user requirements within the constraints of the available capabilities of the general purpose platform.
As the wireless signal environment is designed principally for communications, it may need to be modified in some ways to make it also suitable for positioning (for instance, deploy RFID tags). There is therefore considerable work to be done in database design and implementation, communications, sensor integration, and so on. Connecting all of these elements within a small general purpose platform is a tremendous engineering challenge. 4. PROJECT APPROACH The project has been broken down into several tasks. Firstly, the system design must be carried out before any other task is started. Based on a user requirements analysis, the system design commence, and the equipment will be selected and tested. Engagement with the BVI community will be necessary in order to clearly define the type of information they most seek from such a system, and which cannot currently be accessed using other devices/technologies. There are many technical details to be worked out, partly based on what the BVI community requires from the location sub-system, but constrained by the device capabilities. The system design will generate the initial guidelines for the development of the user interface, the positioning algorithm and platform, and the way to introduce location information into Mpower. The system design will be iterated as the project progresses. Then the three technology-related tasks will commence: positioning algorithm development, BVI user interface development, and dynamic information provision system development. The positioning technologies/algorithms are the core of this system. A-GPS will be used outdoors where GPS satellites can be tracked. WiFi and RFID will mainly be used indoors. But other techniques may be incorporated as the need arises. There are research challenges associated with positioning, such as the WiFi database creation and maintenance, improving the WiFi positioning accuracy, and so on. The user interface of current PDAs/smartphones is not suitable for this project and considerable work will focus on the ergonomic design requirements of the BVI. The interface of the dedicated platform shown in Figure 3 could be borrowed. The dynamic information provision is under the umbrella of Mpower, which has been developed by VA. The information maintained by VA will be linked to location (such as timetables of trains or buses), other location-related data will be classified, and the server can be accessed via the cellular network or WiFi. The major output of this project will be the prototype system. Obviously extensive testing will be necessary. This will be an iterative process: test, find problem, modify, and test again … until the requirements are met as best as they can be given the constraints of the device capabilities. BVI volunteers will be involved in the testing. 5. CONCLUDING REMARKS The proposed navigation and information system will create a prototype device that improves the mobility and independence of the BVI. The system will assist in social equality and workforce participation for the BVI and other persons with disabilities. It is expected that the project will also lead to an innovative design for the BVI-machine interface. A simple, easyto-use interface can also be used in other products for the BVI. Furthermore, the project will generate an innovative design for an indoor/outdoor positioning and information delivery system. This design can then be used for many other applications, from personal navigation to location-based services for tourism, etc.
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