Noncoherent Late Minus Early Power Code Tracking Performance With Front End Filtering

Jack K. Holmes

Abstract:	This paper presents new results for the tracking error variance performance for a BPSK direct sequence modulated, late squared minus early squared code tracking loop with the front end filter bandwidth taken into account in the analysis. Previous results for this loop have not included the effect of the front end filter however it has a major impact on code tracking performance. This analysis was motivated by the need to appraise the bandwidth requirements of the civilian users of the GPS C/A code. The application here was to the C/A code, but the results are more general. It was found that the receiver front end bandwidth that the C/A code passes through, determines the tracking accuracy that can be obtained, and the greater the front end filter bandwidth the better the tracking error performance that is possible as long as the only corrupting force is thermal noise. The analysis is based on a linearization of the tracking loop. The solution obtained here depends upon the front end receiver bandwidth B, the arm filter bandwidths B2 , the closed loop bandwidth B L , the carrier to noise density ratio C/N 0 , the autocorrelation function of the code R(t) (which is modeled as a random binary valued () ±1 sequence), and the crosscorrelation between the bandpass filtered code and the unfiltered code, ~ () Rt. Both the front end and arm filters are assumed to be ideal bandpass filters.
Published in:	Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997) September 16 - 19, 1997 Kansas City, MO
Pages:	583 - 591
Cite this article:	Holmes, Jack K., "Noncoherent Late Minus Early Power Code Tracking Performance With Front End Filtering," Proceedings of the 10th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS 1997), Kansas City, MO, September 1997, pp. 583-591.
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