Analysis of Coherent Combining for GPS L1C Acquisition

Kelly C. Seals, William R. Michalson, Peter F. Swaszek, Richard J. Hartnett

Abstract:	The GPS L1C signal is similar to other modern GNSS signals in that it has a pilot component and a data component. However, a unique aspect of this signal is an unequal power split between these two components which are transmitted in phase. Channel combining techniques to acquire modern GNSS signals using both components have previously been proposed. In this paper, the single trial detection and false alarm probabilities for GPS L1C acquisition using coherent channel combining over a single spreading code pe- riod are analytically derived taking into account the unique aspects of this signal. The optimal detector for GPS L1C acquisition in additive white Gaussian noise is also derived. A coherent combining tech- nique with unequal power compensation is proposed for dual-component GNSS signals, such as GPS L1C, that have an unequal power split. Simulation results are used to verify the analytical results and to compare the performance of the optimal detector with coher- ent channel combining as well as noncoherent channel combining. It is shown that coherent channel com- bining with unequal power compensation outperforms the other detectors and nearly approaches the perfor- mance of the optimal detector.
Published in:	Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012) September 17 - 21, 2012 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	384 - 393
Cite this article:	Seals, Kelly C., Michalson, William R., Swaszek, Peter F., Hartnett, Richard J., "Analysis of Coherent Combining for GPS L1C Acquisition," Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012), Nashville, TN, September 2012, pp. 384-393.
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