Evaluation of Spatial Displays for Navigation without Sight

We report on two route guidance tasks using a highly accurate GPS receiver. Eight participants who were visually impaired or blind traveled two routes, one on a city sidewalk, and one in a city park. We tested and compared two types of spatial output devices that give route guidance information. One output display used a hand-held pointer, using a standard Talking Signs receiver that integrated the GPS signal information with the Talking Signs® signal information. This device gave travel instructions and on-course confirmation when pointed in the proper direction. The other spatial display used auditory virtual reality that presented the audible spatial information (waypoint direction and distance) through small air-tubes inserted into the ear. Travel times, distance, and errors were recorded. In addition, we tested users' ability to find precise locations, such as the intersections of small paths and a bus stop pole. Various subjective ratings were collected about blind participants' needs and perception of the various display and output options that they used. All subjects completed the tasks with both output displays, found all the waypoints and locations, and rated the two displays highly. The virtual sound display produced superior times overall and received slightly higher favorable ratings.