Research On Parameter Error Analysis And Compensation Of FOG North-seeker

With the continuous development of Fiber optic gyroscope, Fiber optic gyroscope will be applied more widely, but there are some disadvantages in the application of FOG north seeker, such as temperature effect, non-linearity of scale factory and disturbance, they decrease the precision and speed of North seeking.This paper established compensated model of the nonlinearity error. For the parameter's instability of nonlinearity model, a two-position detecting arithmetic based on symmetry measure method is presented, which transforms the non-linearity error to equivalent gyro bias error. Two-position Kalman filter can estimate and compensate the bias error, eliminate the influence of the parameter's instability of nonlinearity model, To incline drift after FOG start-up, according to the coefficient incline drift and the slope of outcome is same approximately, convert incline drift into constant drifts of FOG, Two-position Kalman filter can estimate and compensate the constant drift error. To disturbance, the Kalman filter was applied to improve the precision of North seeker.Based on the above ideas, this paper research on the following aspects.1.Two-position and one-position sampling scheme based on FOG has been proposed, quantificational analyzed the effect of gyro bias,scale factor and accelerometer's bias, scale factor to the precision of North seeker.2.A two-position detecting arithmetic based on symmetry measure method has been presented, eliminated the influence of the parameter's instability of nonlinearity model. The experimental results indicate that this method can effectively improve the accuracy.3.In accordance with the dynamic restriction of vehicle, the output expression of virtual gyroscope and virtual accelerometer has been presented. In accordance with the error equation of initial alignment on static base, a Kalman filter has been designed for initial alignment, the initial alignment algorithm has been test through simulation on two virtual gyroscope and virtual accelerometer.4.This paper established a FOG output model, based on the fiber optic gyroscope characteristics, presented a method of scale factor'calibration.5.To incline drift after FOG start-up, a new method that can eliminate the incline drift been applied, which can shorten the time and improve speed of North seeker.