A Novel Carrier Loop Based on Unscented Kalman Filter Methods for Tracking High Dynamic GPS Signals

Optimal Kalman filtering theory has developed for many years. With the characteristics of unscented transformation, the unscented Kalman filtering (UKF) makes it possible to maintain locking with large Doppler frequency shift when the receiver works in high dynamic environment. A carrier tracking loop based on UKF with high accurate tracking performance, which can work in high dynamic environment, is put forward. This paper studies a novel feedback method of voltage-controlled oscillator in a carrier tracking loop based on UKF, which can improve the measurement accuracy and enhance the robustness of the UKF carrier tracking loop. Since the measured data has been modulated by navigation message, this paper amends the model of measurement equation to tally with the actual measured data. Finally, in a high dynamic environment with acceleration over 100g and normal signal strength, the measurement accuracy of carrier phase is better than 0.5mm, and the measurement accuracy of carrier frequency is better than 0.5HZ.