Study on Initial Alignment Technology of Onboard SINS Based on Azimuth Setting

The initial alignment technology of onboard SINS based on azimuth setting was researched.First,the relationship between azimuth error and misalignment error was deduced.The observation equation by adding azimuth error as observable variable was introduced.The Kalman filter equation based on azimuth setting was designed.The observability and unobservable variables equation of the system were analyzed with the method of singular value decomposition.The result shows that all gyro drift is observable,all accelerometer bias is unobservable.Simulation results show that the initial alignment method has an advantage of high precision and fast convergent speed.