Modified Dynamic North-Finding Scheme With a Fiber Optic Gyroscope

Abstract

With the development of laser and optical fiber, the north finding system (NFS) with fiber optic gyroscopes (FOGs) has become an active trend in inertial technology research. This paper demonstrates the error analysis of dynamic north-finding with a fiber optic gyroscope and a new way for the FOGs noise measurement in the dynamic implementation. Moreover, in order to suppress the north-finding error caused by FOG bias drift, especially for the small azimuth angle, we propose a modified dynamic north-finding scheme by taking advantage of the dynamic method. The experiments verify the validity of the proposed error analysis for the dynamic implementation. Experimental results show that for a FOG with bias instability of 0.005°/hr, the average (Avg) north-finding bias error is less than 0.03° (0.5 mrad) around 2° azimuth angle by the proposed modified scheme. And compared with the conventional dynamic north-finding, this scheme reduces the estimated error (1σ) of azimuth angle and the bias error (Avg) by 22% and 23.8%, respectively, at the small azimuth angle. For a poorer-performance FOG with 0.0262°/hr bias instability, the proposed method is more effective and reduces 32.4% estimated error (1σ) of azimuth angle.