Patent ID: 6236357
Filing Date: 2001-05-22
Classification: G01S

Abstract:
An automatic vehicle location method for monitoring by a Dispatch Center, the position of at least one vehicle comprising the steps of:via the Dispatch Center, tracking the changes in the position of a vehicle with respect to an electronic map, said map having predefined decision points;via a mobile unit in a vehicle, receiving position signals from the transmitter of a position system;storing in said mobile unit, an identical map;via an automatic vehicle location (AVL) box in the mobile unit, monitoring vehicle movement change indicia;upon reaching a decision point, transmitting position and movement update messages to the Dispatch Center only when one or more vehicle change indicia cross a predetermined threshold; andin both the Dispatch Center and said vehicle, extrapolating the position and movement of said vehicle between decision points by following a projected path on said map according to the same algorithm.