VEHICLE POSITION DETECTOR

摘要

PURPOSE:To improve the azimuth detection accuracy by using absolute azimuth data when the exception state of the absolute azimuth data continues for a specific distance or time and it is decided that the absolute azimuth data is reliable. CONSTITUTION:When a state wherein the data of an earth magnetism sensor 12 is not used at all and only the data of a relative azimuth sensor such as a wheel speed sensor 11, an optical fiber gyro 13, or a vibration gyro 14 is used for azimuth estimation continues for the constant travel distance or time and it is decided from the output data of the earth magnetism sensor 12 that the reliability of the earth magnetism sensor data recovers, a locator 1 fetches the data of the earth magnetism sensor 12 and the azimuth of the vehicle which is found so far is reset and replaced with the mean value of the data of the earth magnetism sensor 12 to detect the position of the vehicle. Consequently, the accumulation of an error due to the continuous use of only the relative azimuth data is precluded and the azimuth detection accuracy can be improved.