Error analysis and test study of fiber optic gyroscope north-finder

摘要

North-finder system is an important application of the inertial technology. It provides true north azimuth information to all kinds of ground-based equipment. This paper designed a dynamic automatic north-finder based on the modulation output of fiber optic gyroscope (FOG). In this scheme, the sine output signal of the FOG was sampled and disposed, and then the real north of surveyed point on the surface of earth was calculated. The deviation caused by the base tilt was compensated by an accelerator. The output signals of FOG and accelerator were computed combined with the position sampled from increasing encoder by digital signal processor. Successive rotating technique was adopted to modulate the FOG signal periodically. Most of the low frequency part of random gyro drift errors was compensated. The north-finder accuracy was improved compared with the traditional static measuring method. The test result shows the FOG automatic north-finder obtains 2′ true north angle accuracies within not more than three minutes, can meet the orientation need of artillery, terrain measurement vehicle, armored car, unmanned drive vehicle, geodetic survey and tunnel exploration.