The Pulling of Delay Lock Loop under Strong Multipath

Sergey V. Lyusin

Abstract:	Analysis of GPS receivers operating in urban areas shows that severe multipath effects may result in sufficient delaying of transient processes in a Delay Lock Loop (DLL). Subsequent sections discuss the cause of this: distortions of discriminator characteristic of DLL due to strong reflected signal. It was also observed that these distortions worsen tracking quality while in synchronous mode. The paper demonstrates several methods to reduce the time of transient processes. It is shown, in particular, that traditional methods including either switching of DLL bandwidth or correlator width during the pulling process can reduce transient time only by 1.5-2.5 times while the algorithm consisting in simultaneous varying of both loop bandwidth and correlator width gives sufficiently more promising gain up to 5-10 times.
Published in:	Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999) September 14 - 17, 1999 Nashville, TN
Pages:	1225 - 1234
Cite this article:	Lyusin, Sergey V., "The Pulling of Delay Lock Loop under Strong Multipath," Proceedings of the 12th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1999), Nashville, TN, September 1999, pp. 1225-1234.
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