Deeply Integrated Code Tracking: Comparative Performance Analysis

D. Gustafson, J. Dowdle

Abstract:	New algorithms for GPS code tracking have been devel-oped recently based on deep integration concepts, nonlin-ear filtering methods and extended range correlation. Hardware-in-the-loop demonstrations of Deep Integration algorithms conducted at Draper Laboratory [1,2,3] have indicated that improvements of up to 15 dB in broadband antijam capability can be expected relative to current gain scheduled tightly-coupled tracking loops for some scenar-ios. These results verify earlier analytical predictions. The reported results summarized overall performance data using relatively complex scenarios (e.g., inertial aiding, full 6D, 4 or more satellites in view, guided munitions, etc.). Specific sources of improvement were not identi-fied. Performance comparisons are inevitably scenario-dependent. With this in mind, the objective of this paper is to provide comparative performance analyses in a few simple generic scenarios with a minimum number of vari-able parameters and to identify and quantify the sources of improvement available through the use of Deep Inte-gration. Three types of P-code tracking loops were con-sidered: (1) Deeply Integrated, (2) Fixed-Gain, and (3) Adaptive Gain. The latter two loops are meant to repre-sent traditional tightly-coupled systems. Broadband Gaussian jamming was assumed throughout. Perform-ance was estimated using Monte Carlo simulation. Loss-of-lock probability was selected as the performance crite-rion. The results indicated that the Deeply Integrated loop consistently outperformed the other two loops in scenar-ios with high dynamics and/or high levels of jamming. In addition, the Deeply Integrated loop outperformed the adaptive gain loop under extended-range conditions, where the adaptive loop employed traditional flattop or linear extended-range detector shapes.
Published in:	Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003) September 9 - 12, 2003 Oregon Convention Center Portland, OR
Pages:	2553 - 2561
Cite this article:	Gustafson, D., Dowdle, J., "Deeply Integrated Code Tracking: Comparative Performance Analysis," Proceedings of the 16th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GPS/GNSS 2003), Portland, OR, September 2003, pp. 2553-2561.
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