Semi-Coherent and Differentially Coherent Integration for GPS L1C Acquisition

K.C. Seals, W.R. Michalson

Abstract:	As with other modern GNSS signals, the GPS L1C Signal is split into a pilot component and a data component. A unique aspect is the unequal power split between the two components with 75% power in the pilot component and 25% power in the data component. Several detectors for GPS L1C acquisition are examined in this paper including those that use the pilot only and those that combine both the data and pilot components. The special case of acquisition when the pilot overlay code phase is known is examined in addition to when this code phase is unknown. Detector performance is presented based on single trial false alarm and detection probabilities using Monte Carlo simulations. Detectors that use differentially coherent integration are considered for their potential performance improvement when the total integration time is extended for challenging GNSS environments. A new technique that adapts semi-coherent integration to use knowledge of the pilot overlay code phase is presented and shown to improve detection performance over coherent integration of the pilot component alone. Limits on C/N0 for this technique as well as semi-coherent integration are suggested for when their performance degrades to that of coherent integration on the pilot or noncoherent integration of pilot and data components.
Published in:	Proceedings of the ION 2013 Pacific PNT Meeting April 23 - 25, 2013 Marriott Waikiki Beach Resort & Spa Honolulu, Hawaii
Pages:	123 - 130
Cite this article:	Seals, K.C., Michalson, W.R., "Semi-Coherent and Differentially Coherent Integration for GPS L1C Acquisition," Proceedings of the ION 2013 Pacific PNT Meeting, Honolulu, Hawaii, April 2013, pp. 123-130.
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