Direction sensor having an earth magnetism sensor and a rate gyro sensor and navigation system having this direction sensor.

摘要

The direction sensor has an earth magnetism sensor (1) and a rate gyro sensor (2) that calculates a compensated direction by weighted mean process of outputs from the earth magnetism sensor and the rate gyro sensor. The compensated direction has a high detection accuracy similar to the rate gyro sensor in a short time, but does not have an error accumulation of the rate gyro sensor in a long time because the rate gyro sensor is subsantially calibrated with the accurate direction obtained by averaging outputs of the earth magnetism sensor. The navigation system has distribution information of the magnetic disturbances to earth magnetism on a map (5) and it reduces the weighted mean ratio to the earth magnetism sensor (1) when the magnetic disturbance at locating position is large. The accuracy of the compensated direction is further improved by excluding inaccurate outputs of the earth magnetism sensor (1).