Sample Fraction & Doppler Effect Compensation Algorithm for Acquisition of Weak GPS Signals

U. Ahmad, C.W. Sik, S. Park, L. Dong-Sun

Abstract:	This paper concerns to the acquisition of Global Positioning System L1 C/A coded. It specifically addresses the issues of acquiring very low power signals which are attenuated due to special circumstances such as indoor environment or forest canopy etc. Acquisition of weak GPS signals requires longer processing time than usual one millisecond coherent integration. Increasing the integration time incurs additional computations and complexity to acquisition process. Signal folding coherent integration is an efficient method to reduce these computational requirements. However, the coherent integration length is limited to 10 milliseconds, making the acquisition of weak signal impossible beyond certain threshold due to Sample Fraction and Doppler Effects. The proposed method specifically addresses these two issues and extends the limit on integration time while retaining the reduced computational burden. The resulting algorithm can successfully acquire very weak Global Positioning System (GPS) L1 band C/A coded signals.
Published in:	Proceedings of the 2011 International Technical Meeting of The Institute of Navigation January 24 - 26, 2011 Catamaran Resort Hotel San Diego, CA
Pages:	826 - 833
Cite this article:	Ahmad, U., Sik, C.W., Park, S., Dong-Sun, L., "Sample Fraction & Doppler Effect Compensation Algorithm for Acquisition of Weak GPS Signals," Proceedings of the 2011 International Technical Meeting of The Institute of Navigation, San Diego, CA, January 2011, pp. 826-833.
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