| 摘要 |
PURPOSE:To enhance the detection accuracy of the position of an own vehicle immediately after an apparatus has been attached to the vehicle by a method wherein every distance computation factor which differs at every kind of vehicle is computed quickly and with good accuracy after the apparatus has been attached to the vehicle. CONSTITUTION:When a GPS is received effectively, a vehicle-speed-conversion- factor computation means 104 computes the ratio of a GPS Doppler speed computed by a GPS-speed computation means 101 to a speed signal which is output from a speed sensor 102, and a vehicle-speed conversion factor is computed. In addition, filtering means 105 to 108 which average the vehicle-speed conversion factor are selected by a filter selection means 109, and an optimum vehicle-speed conversion factor is found. In addition, an abnormality-detection and initialization means 110 by which, when the definite number of higher of vehicle-speed conversion factors before a filter input is continuously different by a definite ratio or higher, a vehicle-speed conversion factor adopted at present is regarded as abnormal and which initializes a computation and processing operation is provided. |
