Angle random walk error propagation and suppression methods in long-term inertial navigation system

The angle random walk (ARW) error is a significant limitation of the navigation performance in long-term inertial navigation system (INS). To weaken the impact of ARW on the system accuracy, its error propagation law and suppression methods are studied in two aspects: initial alignment and long-term navigation. Simulation results show that ARW directly affects the azimuth alignment accuracy, and during long-term navigation, the oscillation amplitude of velocity produced by ARW coefficient N is approximately equivalent to the constant drift of 60N. The error by 24 h cycle is the key to the oscillation error of attitude, and the variance of the oscillation term in position error grows with the square root of time, meanwhile, the improvement to the ARW alignment error by Kalman filter is validated, and level damp has an effect on weakening the oscillation term of the system position error.