Laser Gyro North System Modeling And Parameter Identification

Since coming into being in the 1970' s, the technology of laser gyroscope has been developed rapidly and used widely in the field of medium-high precision technology. Compared to traditional mechanical or electronic gyroscope inertial system, strapdown inertial system using laser gyroscope has many advantages such as small volume, rapid starting, low cost, fine dynamic performance. So in the recent years, many countries invest in the research of land position, direction and navigation system with the laser gyroscope technology. In this paper, the laser gyroscope North-seeking system is specialized as a subsystem which is associated with the North-seeking function. Its precision is one of the key performance measure of the whole system, so the research work of laser gyroscope North-seeking system model building and parameter recognition is of much theoretical and engineering significance.First, the paper provides detailed description of various North-seeking methods and analysis of their peculiarity and application range respectively. Then, the paper points out that the multi-position North-seeking method is the superior method of them. In the 3"' chapter, analysis of error factors and features of the sensors in the system are provided. According to the fact that laser gyroscope has many error factors which cannot be separated easily, Allan variance analysis method is introduced to establish corresponding estimating method in the time domain . Based on the analysis of error, appropriate polynomial error model of the laser gyroscope is built to satisfy the error processing of the system. Recognition methods of model parameter and experiment results are given out as well. In the 4"' chapter, according to the author' s deep research in the working procedure of North-seeking system, several algorithms are provided such as static correction, data filtering and attitude computing method. At the same time, these algorithms are tested and perfected according to the experiment data. In the 5"' chapter, first the paper adopts the simulation analysis method to analyze the ideal North-seeking performance measure of the laser gyroscope based on the real data. Then, experiments of the sample time length and stability of the all-attitude North-seeking precision are taken in the real North-seeking system.