| 摘要 |
PURPOSE:To correct an azimuth error at the time of abrupt azimuth variation of magnetic compass azimuth data from measured azimuth data by a satellite by comparing azimuth signals obtained from a magnetic compass sensor and satellite data with each other. CONSTITUTION:Assuming that a moving body passes through an external magnetic field generation point at the time of running at a speed where abrupt azimuth variation never occurs, an error detection part 6 operates by automatic or manual switching if a running speed fed from a satellite data receiver 2 exceeds a set value and also compares pieces of azimuth information corresponding to the outputs of the receiver 2 and an estimated azimuth and position arithmetic part 5 with each other; when the difference increases abruptly, it is judged that the difference is caused by an external magnetic field, and the difference is inputted as an error signal to the arithmetic part 5, which varies the level of the azimuth signal from the magnetic compass 3 and forms a loop based on the azimuth signal of the receiver 2 so that the error signal is zero, thereby correcting the azimuth signal. Thus the moving body runs without deviating from a target course at any time. |
