A ZERO MOTION DETECTION SYSTEM FOR IMPROVED VEHICLE NAVIGATION SYSTEM

摘要

The improved vehicle navigation system and method uses information from a Global Positioning System (GPS) to obtain velocity vectors, which include speed and heading components, for propagating or "dead reckoning" the vehicle position from a previous position to a current position. The improved vehicle navigation system has a GPS receiver which provides the GPS velocity information which is calculated from a full set of GPS delta range measurements. GPS position data alone is not accurate enough for certain applications, such as turn-by-turn route guidance in automobile applications, because its error may be 100 m and there is considerable position drift, even when stationary. GPS velocities are much more accurate than the position data, 1 m/s or thereabouts, and can be used to propagate a known position forward and be more accurate over time than the GPS position solution. These velocities are instantaneous and not those computed from differencing two positions. The current position is calculated by adding displacements obtained from the GPS velocities to the previous position.