OPTIMUM SEMICODELESS CARRIER-PHASE TRACKING OF L2

K. T Woo

Peer Reviewed

Abstract:	This paper discusses the performance of various codeless and semicodeless techniques used to obtain the carrier phase of the GPS L2 signal without knowledge of the encrypted Anti-Spoofing AS Y-code. Four known techniques have been published in the past: squaring, cross-correlation, P-code aided L2 squaring, and Z-tracking. All these techniques perform significantly worse than an ideal phase lock loop. Five new techniques are presented in this paper: 1 code-aided L2 Costas loop with W-bit integrate and dump arm filtering, 2 P-code aided L1, L2 cross-correlation, 3 soft decision Z-tracking, 4 optimum L2 demodulation motivated by maximum a posteriori MAP estimation theory, and 5 linear approximation of the MAP approach. The first three are modifications of existing techniques, with improved performance. Techniques 4 and 5 are optimum and near-optimum techniques based on statistical estimation theory, and provide the best performance in squaring loss and mean time to cycle slip.
Published in:	NAVIGATION: Journal of the Institute of Navigation, Volume 47, Number 2
Pages:	82 - 99
Cite this article:	Woo, K. T, "OPTIMUM SEMICODELESS CARRIER-PHASE TRACKING OF L2", NAVIGATION: Journal of The Institute of Navigation, Vol. 47, No. 2, Summer 2000, pp. 82-99.
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