High Dynamic GPS Signal Tracking Based on UKF and Carrier Aiding Technology

Abstract

Due to the impacts of the loop bandwidth, the high dynamic environment could cause the carrier tracking loop of the GPS receiver loss of lock, and the pseudo-code tracking loop errors increased. According to the characters of the high dynamic environment, a GPS IF digital signal source is firstly designed here, then an improved carrier tracking loop based on the UKF is proposed, which works steady and has high tracking accuracy. Besides, the estimates of the Doppler frequency shift and its derivative is also extracted by UKF to aid pseudo-code tracking loop. To certain extent, with carrier aiding, the dynamics of the code loop is eliminated to decrease the tracking errors. Finally, all designs in this paper are completed by Matlab and evaluated by computer simulation. Results show that: the signal source design is proper, the proposed carrier tracking loop works steady, and the errors of the code tracking loop is decreased significantly.