Application of GPS Positioning to Management of Mobile Operation

Abstract

NavTrax is a dispatch‐type automatic vehicle location and navigation (AVLN) system targeted for the specialized fleet‐management market. Discussed in the paper are its positioning, communications, digital mapping, and host (dispatch) components. Its positioning component is a robust GPS‐based system integrated with dead‐reckoning sensors via a specialized 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 intelligent digital single‐line road‐network data base stored in vector form with full connectivity. A limited form of map matching (MM) is performed for integrated navigation, but the main purpose of MM is for the definition of location. This approach allows Nav/Trax to employ less‐expensive digital maps as compared to AVLN systems that are purely terrestrial‐based and use the map for positioning. The paper concludes with a discussion of a demonstration project with the Calgary Police Department.