Design and Capability Analyze of High Dynamic Carrier Tracking Loop Based on UKF

S. Han , W. Wang, X. Chen, W. Meng

Abstract:	Unscented Kalman filter (UKF) based methods have been developed for the tracking of GPS L1 signal. Optimal Kalman filtering theory makes it possible to maintain locking with large Doppler frequency shift when the receiver works in high dynamic environment. This paper preliminarily investigates the application of UKF approach with high dynamic modeling for Global navigation satellite system (GNSS) carrier tracking. Many estimation problems, including the GNSS carrier tracking, are actually nonlinear. Although it has been common that additional fictitious process noise can be added to the system model, however, the more suitable cure for non convergence caused by unmodeled states is to correct the model. For the nonlinear estimation problem, alternatives for the classical model-based extended Kalman filter (EKF) can be employed. The UKF is a nonlinear distribution approximation method, which uses a finite number of sigma points to propagate the probability of state distribution through the nonlinear dynamics of system. The UKF exhibits superior performance when compared with EKF since the series approximations in the EKF algorithm can lead to poor representations of the nonlinear functions and probability distributions of interest. A novel UKF based carrier tracking loop with high accurate tracking performance is put forward, where a frequency fast pull-in technology is performed to ensure the filter converge fast and another two different carrier amplitude estimation methods are included to make the dynamic model complete. The relationship between the noise parameter of UKF and the equal loop-bandwidth is also studied. Based on this novel loop, a compensated method to reduce hysteresis of the filter is analyzed. The performance of novel method is assessed and compared to conventional method. Simulation results show that the proposed quasi-open-loop structures for high dynamic carrier tracking loop based on UKF can effectively complete the task of carrier tracking in the high dynamic situations, and the carrier tracking precision is improved significantly.
Published in:	Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010) September 21 - 24, 2010 Oregon Convention Center, Portland, Oregon Portland, OR
Pages:	1960 - 1966
Cite this article:	Han, S., Wang, W., Chen, X., Meng, W., "Design and Capability Analyze of High Dynamic Carrier Tracking Loop Based on UKF," Proceedings of the 23rd International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2010), Portland, OR, September 2010, pp. 1960-1966.
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