PONTES - Positioning and navigation of visually impaired pedestrians in an urban environment
For outdoor applicability in an urban environment, an overall concept of navigation is adapted to the special needs of blind and visually impaired pedestrians. The development aims at a prototype of a navigation system which covers the total spectrum of specific components.
This comprises an appropriate modeling and mapping of the navigational environment, a complete acquisition and efficient storage of relevant geodata, effective routing algorithms generating lists of maneuvers, accurate positioning methods, a reliable map matching of the trajectory for route checking, an adequate generation of guidance instructions, and suitable man-machine communication devices.
Initial specification of the geodata, especially thematic ones, is performed by the assistance of blind persons. This is to gsuarantee that the system is able to compensate parts of the user’s handicap by imitating spatial cognition and reasoning of the visually impaired human being. In the same sense the routing algorithm will compute the safest route from the starting point to the desired destination, rather than the shortest or fastest.
Position determination uses an integrated concept of satellite- based positioning (GPS or DGPS) and dead reckoning (compass, step detection) accomplished by a position processing software using Kalman filtering. Dead reckoning bridges GPS data gaps typically occurring in an urban environment. In opposition to sighted pedestrians, the visually impaired is strictly stuck to a line-based movement.
Therefore the map-matching procedure transforms the position to a location relative to the elements of the modelled path on the digital map. Along this route, the user is acoustically supplied with adequate maneuver instructions including warnings of obstacles and off-route situations.
Institute of Navigation and Satellite Geodesy, TU Graz - Manfred Wieser
Styrian Association of the Blind and Visually Impaired People - Mario Kowald
Institute of Navigation and Satellite Geodesy, TU Graz