Robust estimation for FOG signal based on median method

In the strap-down gyro north seeker, gyro drift are primary factors to degrade orientation accuracy. On the basis of eliminating high frequency periodic noises, a new algorithm based on robust estimation is presented to degrade the influence of abnormal noises on the accuracy of FOG north seeker. The robust estimation formula of FOG and its influence function are deduced. Robust estimation serves the median of observations for the robust initial value and applies the median of the residuals of the first epoch robust estimation to obtain stable standard deviation factor. The mixed iterative algorithm based on high breakdown point initial value and assisted by IGG III scheme is described. The calculations show that robust estimation based on reliable initial value and standard deviation factor can effectively degrade abnormal disturbances, and in turn, can improve the accuracy of FOG north seeker.