Angular Velocity Algorithm And Error Analysis For GFSINS

Gyroscope Free Strapdown Inertial Navigation System(GFSINS) is a kind of SINS which only uses accelerometers but gyro. Because of no gyroscope, a series of difficulties caused by the narrow dynamic operating range of gyroscopes can be avoided; GFSINS has the characteristics of low cost, low power consumption, fast response, high reliability, long lifecycle, and so on. Especially, it applys to the inertial navigation with large angular velocity and acceleration. Because of the above advantages of GFSINS, its research and application are emphasized by domestic and overseas experts.In the thesis, the fundamental theory of the GFSINS is introduced first, including the specific output equations of each accelerometer, the configuration method of accelerometers and the calculation of the angular velocity. Based on the above analysis, the following main investigations have been done:1. Refering to configuration schemes in domestic and overseas documents, the thesis puts forward a new nine-accelerometers configuration scheme and uses the output equations to calculate angular velocity. Nowadays, angular velocity algorithms including integral and extraction, consist in quickly cumulative error and sign estimation error, so an new angular velocity algorithm for this nine-accelerometers configuration is presented to overcome the drawbacks.2. The iterative errors of angular velocity and navigation parameter are caused by measuration error from the accelerometers, so that GFSINS can't work in a long time, as well as its application is limited. In order to solve this problem, this thesis establishs error model of the accelerometer through its redundant configuration, to compensate the accelerometer error. Simulation results show that the angular velocity calculation precision is obviously improved.3. An extended Kalman filter has been designed and applied to the angular velocity calculation, and the simulation analysises show that the extended Kalman filter can reduce the angular velocity errors resulted from the accelerometer bias.