Direct P(Y)/M-code Acquisition Based on Time-Frequency Folding Technique

Hong Li, Mingquan Lu, Zhenming Feng

Abstract:	In Global Positioning System (GPS), the direct acquisition of P(Y)-code and M-code is desirable to provide high accuracy for code-ranging and high tolerance for jamming and spoofing. However, due to the extremely long period and the very high chip rate of P(Y)/M-code, the direct acquisition is difficult. In the paper, a time-frequency folding technique is proposed to accelerate search process. The proposed technique has such characteristics: to reduce the frequency cells to be searched, several frequency cells are added together; to decrease the code phases to be searched, multiple code phases are added together. Although after the two adding operations, the correlation properties of P(Y)/M-code are degraded, which leads to worse detection performance, both frequency cells and code phases in search space do be reduced. The reduction enables the method based on the time-frequency folding technique to have a better parallel searching capability and a potential of outperforming other methods. In modernized GPS, the designed M-code is stronger than P(Y)-code in power level. It implies parallel searching capability will take a more important role in acquisition performance than detection performance. Thus, M-code provides the situation of the proposed method outperforming others.
Published in:	Proceedings of the 21st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2008) September 16 - 19, 2008 Savannah International Convention Center Savannah, GA
Pages:	167 - 173
Cite this article:	Li, Hong, Lu, Mingquan, Feng, Zhenming, "Direct P(Y)/M-code Acquisition Based on Time-Frequency Folding Technique," Proceedings of the 21st International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2008), Savannah, GA, September 2008, pp. 167-173.
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