APPLICATION OF GPS POSITIONING TO MANAGEMENT OF MOBILE OPERATION

NavTrax is a dispatch-type automatic vehicle location and navigation ( AVLN) system targeted for the specialized fleet-management market. Dis cussed in the paper are its positioning, communications, digital mappi ng, and host (dispatch) components. Its positioning component is a rob ust GPS-based system integrated with dead-reckoning sensors via a spec ialized class of filtering techniques similar but not equivalent to a Kalman filter. The communication module presently employs cellular or UHF ratio-type technology. The digital-mapping component is an intelli gent digital single-line road-network data base stored in vector form with full connectivity. A limited form of map matching (MM) is perform ed for integrated navigation, but the main purpose of MM is for the de finition of location. This approach allows Nav/Trax to employ less-exp ensive digital maps as compared to AVLN systems that are purely terres trial-based and use the map for positioning. The paper concludes with a discussion of a demonstration project with the Calgary Police Depart ment.