Design of GPS Receiver Code and Carrier Tracking Loops for Multipath Mitigation

Gadallah El-SayedA., Meir Pachter, and Stewart L. De Vilbiss

Abstract:	This paper introduces the design of a modijied Phase-Lock Loop (PLL) for carrier tracking and a Delay-Locked Loop (DLL) for code tracking for multipath efiects, mitigation in the GPS receiver . The dynamic carrier and code tracking performance of the PLL and DLL is dependent on the basic characteristics of the phase detector in the PLL and the discriminator in the DLL, respectively. The slopes of these character-istics must cross the zero point, namely the equilib-rium point, for accurate tracking. Mzdtipath forces the equilibrium point to move, causing false tracking of the received signal. The modified PLL and the mod-ified DLL can correct the shift of the equilibrium point due to muitipath. The modified PLL and the modified DLL can cancel the muhipath effect to properly align the received carrier and code signal with the local car-rier and code replica. These modified tracking loops are endowed with a new estimator , named here the %-deploying estimator”, which can detect the num-ber of multipath components and estimate the muh?i-path parameters. In this paper the investigation and analysis of the designed loop is performed. The sim-ulation of the tracking loop’s dynamic performance is done in the cases of absence and presence of multi-path. The paper also investigates the performance in noise of the tracking loop in both cases.
Published in:	Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998) September 15 - 18, 1998 Nashville, TN
Pages:	1041 - 1053
Cite this article:	El-SayedA., Gadallah, Pachter, Meir, De Vilbiss, Stewart L., "Design of GPS Receiver Code and Carrier Tracking Loops for Multipath Mitigation," Proceedings of the 11th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1998), Nashville, TN, September 1998, pp. 1041-1053.
Full Paper:	ION Members/Non-Members: 1 Download Credit Sign In