An Innovative Acquisition Method for the GPS and Galileo Combined Signal

Yao-Cheng Lin, Chih-Cheng Sun

Abstract:	This paper proposes a method to acquire the L1B signal transmitted by GIOVE-A satellite and the L1 signal for GPS satellite simultaneously. This concept is similar to the Multi-C/A code acquisition method we proposed in last paper. In the Multi-C/A code acquisition method, we combine two or more PRN codes of GPS L1 signal to acquire GPS signal. In this paper, we combine the PRN codes of the GIOVE-A L1B and GPS L1 signals to acquire signal. The single frequency receiver for GPS L1 signal can receive the L1B signal transmitted by GIOVE-A, because the center frequency of the L1B and GPS L1 signals are the same. However, the bandwidth of the L1B signal is twice as wide as of GPS L1 signal; the receiver for GPS L1 signal can receive the half bandwidth of L1B signal. In this paper, we use the real data collected by a software receiver to implement and evaluate the proposed acquisition method. Because the data length of GIOVE-A L1B signal is four times as that of GPS L1 C/A signal, the computation load for processing acquisition for the GIOVE-A L1B signal is equivalent to the computation load for processing acquisition for the GPS L1 signal with coherent integration time of 4 ms. When acquiring GPS L1 signal with coherent integration time of 4 ms, the S/N and the probability of detection will be enhanced. The benefit for using the combined code, which includes GPS L1 C/A code and GIOVE-A L1B BOC(1,1) code, is to use the same computation to acquire both signals simultaneously. This concept can therefore acquire the GIOVE-A L1B and GPS L1 signals at the same time and reduce the computation load greatly.
Published in:	Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007) September 25 - 28, 2007 Fort Worth Convention Center Fort Worth, TX
Pages:	203 - 210
Cite this article:	Lin, Yao-Cheng, Sun, Chih-Cheng, "An Innovative Acquisition Method for the GPS and Galileo Combined Signal," Proceedings of the 20th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2007), Fort Worth, TX, September 2007, pp. 203-210.
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