“…Recently, the structures of different gyros have been comprehensively analyzed to constrain the gyros’ bias error, scale-factor error and random error, e.g., MEMS gyros [ 6 , 7 , 8 , 9 ], ring laser gyros [ 10 , 11 ], fiber optic gyros [ 10 , 12 ], resonant optical gyros [ 13 , 14 , 15 , 16 ] and dynamically tuned gyros [ 17 , 18 , 19 ]. Other very active areas include constraining the gyro bias error and modeling of temperature drift through different kinds of filter methods [ 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. However, only few works present the details of building a complete gyro north finder system that provides high precision azimuth reference information.…”