Accessible Global Positioning System (GPS)

8 and Related Orientation Technologies

Learning Objectives

Orientation has taken a significant technological leap forward in the last decade. Data of increasing accuracy from global positioning system (GPS) became available for non-military applications; computer hardware and software became more robust, portable and lightweight; WiFi and Bluetooth technology removed the need for unsightly constraining connecting wires and leads. The new generation of portable GPS orientation systems has built on these key technological developments to give visually impaired and blind people the potential tools to navigate journeys over much longer distances. For the visually impaired or blind person, even the running commentaries that these new GPS devices can give an enhanced travel experience whilst on bus-rides or a train journey. This chapter provides a personal perspective from two US engineers who were involved in creating these new systems. Various issues like the potential of the emergent technology, commercialisation issues and the use of these systems within the visually impaired and blind community are discussed. The learning objectives for the chapter include:

•Understanding the main principles of the orientation data generated by the GPS system.

•Gaining an appreciation of the issues involved in developing available advanced technology into a commercial assistive technology system.

•Understanding the different aspects of user interface design, test procedures and eventual commercialisation.

8.1 Defining the Navigation Problem

The cities we live in were not designed with visually impaired people in mind, especially when it comes to navigation. When a person who can see looks for an unfamiliar place how do they do it? They look at a map, look for visual cues like street signs, ask someone for directions, or log onto an Internet map web site. If a sighted person now puts on a blindfold and tries the same things, they will find that printed maps are useless as is looking around for street signs or

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other landmarks. Asking for verbal directions can be useful if someone is available but in general people do not give adequate navigational directions, because their navigational skills are visually based. For example: “Where is Big Mama’s Pizza?” – “Go down five or six blocks until you come to Main Street turn left and follow this until you reach the fork in the road and take the street on the left. Then continue for about five minutes until you see the big pizza box on the side of the building. You can’t miss it.” Try and follow these instructions if you are blind or if you are sighted with a blindfold on.

From the illustration above, you can see that access to location information is an essential part of navigating independently. Location information is another way to describe all the environmental cues that one uses to understand one’s surroundings and to navigate. Some examples are street signs, businesses and landmarks.

8.1.1 What is the Importance of Location Information?

Sighted people know when they are lost and when they are in their “comfort zone” based upon familiar landmarks assimilated through experience. They have mental map images based upon this information.

Consider what sighted people have to work with when they are getting around. One can easily see street signs, building names, distinct landmarks, familiar and unfamiliar settings. They can take or leave this information if and when they need it and it is a huge part of what helps them in getting around. It is not just that they can see where they are going, it is the fact that they have all this location information to guide them and to give them feedback and choices. The blind individual has a considerable disadvantage because they do not have access to location information (Loomis et al. 1994).

Until recently, almost all location information was print and visual and therefore not accessible to people who are blind and to most that are visually impaired. Most people who are blind or visually impaired are used to not having location information so they literally and figuratively do not usually know what they are missing. At the same time, it is fundamental to independent navigation that one uses the available tools. When detailed information is not available, blind people still make the most of the situation, however, increased location information will enhance the quality of the travel experience and will give the user more with which to work.

Another aspect of navigation for the blind, which has been under-played, is travel in vehicles. We live in an age of motor vehicles and although blind people may walk more than the average person, more than half their travel time is probably spent in a vehicle. When a blind person is in a vehicle, there is little to no contact with the signs and landmarks one is passing. It is analogous to riding in a vehicular cocoon, deprived of information even more than when walking.