8.7 Test Procedures and Results

284 8 Accessible Global Positioning System and Related Orientation Technologies

When an intersection is described in terms of the clock face or right-left-front- back, the user may not initially have the mental imaging skills to understand the intersection description. It takes practice hearing these descriptions before the user can automatically assimilate the information. Users improve their cognitive imaging skills after becoming proficient with the GPS and digital maps.

Although accessible GPS has begun to be used, there is some lack of awareness and understanding of the empowering value of location information. If you have never had something, how can you appreciate its value?

Some people feel that there is no need for advanced technological devices that tell you where you are in space; listening and walking with a long cane or guide dog are sufficient. However, way-finding orientation technology is not designed to replace the long cane or the guide dog. Wayfinding orientation technology provides a blind traveller with more options. These electronic tools will be used primarily to gather detailed and accurate information about the outdoor environment. With these new technologies, the blind traveller can become safer, more efficient and more independent especially in the complex modern world.

8.8.2 Limitations of the Technology

It is fair to say that the current GPS technology offers users many benefits but there are also limitations, issues like accuracy and seamless availability.

On average, commercial GPS receivers are accurate within 9.15 m (30 feet). This accuracy will not guide a blind traveller straight in the front door of a restaurant without exploration by the user when near the destination. Instead of being a system that pinpoints the location, it is a system that gives access to location information that was previously not available to people with visual impairments. It creates a general description of the surroundings and helps in the cognitive mapping process that is necessary for travelling successfully and independently. Cognitive mapping is a process in which an individual acquires, stores, recalls, and decodes information about the surrounding environment (Downs and Stea 1973). It is best to start integrating location information training into the lives of blind people rather than waiting for perfect worldwide GPS with centimetre accuracy.

One of the greatest weaknesses for GPS-based navigation systems has been in areas where the GPS signals are not available, for example inside buildings and subways. A friend recently asked “When the boat was first introduced, what if people had said, but it doesn’t travel on land?” What is now available on the BrailleNote GPS is very beneficial; it is the beginning of emerging GPS technologies for blind and visually impaired individuals. Those who wait for the perfect solution and do not start learning how to utilize location information now to further their orientation and understanding of the environment will be missing the boat.

8.8.3 Ongoing Development

As new technologies evolve, there is a critical point when that technology passes from fringe to mainstream. Key to development in a niche market, especially a small one like assistive technology for visually impaired and blind people, is adapting a mainstream technology and not a fringe one. Since cost is such a huge barrier for a relatively low-income population, piggybacking mainstream technology is fundamental to reducing the cost barrier and to ensuring that the adaptive technology will keep pace.

Once a GPS system was released for sale in the assistive technology market, improvements in the functionality, accuracy and convenience was then the focus.

It is important to cultivate communication between end-users and developers. Gathering user testimonies on how the technology did and did not work in certain situations drives the need for improvement in future versions.

As GPS receivers become wireless, smaller and more accurate, these commercial devices must be integrated into the adaptive technology. This is best done by keeping the GPS hardware separate from the adaptive technology as opposed to building it into a dedicated Braille or speech unit. There are always trade-offs, which influence the decision whether to go with separate components versus integration but it is ideal to minimize the adapted part of the solution, while maximizing the commercial components. This will be balanced by the priorities of functions blind users require.

Also, in the near future, augmented GPS systems with enhanced positional accuracy will become available. Coupled with more accurate street maps, we will be able to pinpoint more reliably the location of a target destination. There are both satellite and ground-based systems, which correct for the GPS errors. Sub-meter and even centimeter accuracy is currently available but the costs and size restricts it to commercial applications.

Indoor navigation is another important area for improvement. Sendero Group has been working to integrate an indoor navigation module with GPS to enhance navigation in urban canyons and indoor environments. Motion detectors in a personal navigation module (PNM) including a compass, keep track of where the user is walking. Waypoints and points of interest can be triggered by this indoor system in the same way that the GPS system does for outdoor environments.

Talking Signs™ using infrared transmitters are used to announce doorways and other key indoor locations through a hand-held audio receiver. An infrared beacon system has been developed in the Czech Republic and is being tested in some European cities. Talking Lights™ is another indoor technology under development. In this technology, a modified ballast can be inserted in a florescent light fixture to give it a unique position identification. These sensors can theoretically be connected to a PDA, which has a database of a building, to trigger indoor location information.

For this indoor technology to be effective databases of indoor information must be developed and occasional “known” positions must be part of the indoor environment. These known indoor locations can work in conjunction with the