Navigation system for determining position of road vehicle evaluates signals giving momentary speed of vehicle or stretch of road covered and signals may be compared with navigation marks

摘要

The road vehicle navigation system incorporates a GPS, and the speed and direction (33) of the vehicle is determined at frequent intervals. The distance moved during a given time interval may be recorded. There may be two calculated entry points (54,64). Points where the vehicle stops (32) are recorded. The path along streets (21-23) on a map may be traced.