Abstract:

In the ultratight coupled structure of GPS and strapdown inertial navigation system (SINS), the value of carrier Doppler estimated by inertial measurement unit (IMU), satellite ephemeris and other information is the main factor to affect the performance of carrier tracking loop. So an accurate carrier Doppler estimation method using auto regressive moving average (ARMA) model is proposed. The time series analysis method is applied to establish a mathematical model by means of determining the stationariness of stochastic Doppler error sequence. The model type and order number are selected by studying the autocorrelation function and the partial correlation function of the stochastic error sequence. The YuleWalker method is applied to estimate the model parameters and an appropriate model is obtained. Simulation results indicate that the model is suitable for application, which could fit the stochastic Doppler error accurately and provide precise estimates for aided carrier tracking loop in ultra tight system.