Fiber-optic Gyro Compass Study

Fiber Optic Gyroscope (FOG) is applied broadly in military and civil fields, because its performances precede that of laser gyro and mechanism gyro. The SINS presents the future track to develop in INS. Then, FOG-SINS will be a emphasis to be studied with FOG applied broadly. Fiber Optic Gyrocompass studied in the paper is a special SINS. It can realize independent initial alignment on the anchored ship rocking with rather big amplitude.The main efforts done in the thesis are as follows:1. Because the output data of the most the inertial sensors in SINS are incremental forms, the fundamental theory of SINS based on the output data forms is described in this thesis. The theory includes quaternion and rotation vector, coning error, sculling error and scrolling error and the compensating methods of these errors. The SINS navigation errors caused only by strapdown algorithms are simulated.2. Independent initial alignment of the marine strapdown inertial system on the big rocking base is studied especially, and it is the core algorithm of The Fiber Optic Gyrocompass. Two useable means are mentioned: ① the means of the precision alignment with least square methods in inertial frame is studied. ②the means of the alignment with the Kalman filter in inertial frame is studied. The coarse alignment is realized by combining of the earth inertial frame, the origin of which is at the earth's center and the base inertial frame, the origin of which is at ship's gravity center, and the attitude matrix is calculated according to the gyro and accelerator measurements.3. The marine-borne integrated navigation system is studied. The paper presents the form of SINS/DVS/GPS integrated navigation system based on SINS. State and observation equations are established for Kalman filter. The simulation result shows that the integrated navigation system can reduce navigation error when the part-feedback calibration method is used.The main innovations done in the thesis are as follows:1. The initial alignment is done based on g2. Due to inertial frame is as reference frame in the initial alignment, then the information of the earth rotation about its axis is translated as the information of the g's vector, so the north information can been distilled from it. The disturbance of the base rock is controlled.