De-spreading Delay-and-multiplication Method for GPS Signal Acquisition

J. Fan and G. Ma

Abstract:	Having the advantage of removing the frequency error, the delay-and-multiplication method (DMM) reduces the amount of search steps and eliminates the effect of data transaction in GPS signal acquisition. But its probability of detection (Pd) is reduced due to the increased noise power created by delay-and-multiplication operation of signal and noise. This paper proposes a de-spreading delay-and-multiplication method (DDMM), whose performance is improved greatly compared with that of the DMM. The DDMM implements the de-spreading of GPS signal to narrow the signal bandwidth before the delay-and-multiplication operation and applies narrow-band filters to reduce the noise bandwidth. The Monte Carlo simulation shows that the Pd of the DDMM can reach 0.9982 while the Pd of the DMM is 0.3214 at the situation that carrier to noise ratio (C/N0) is 44 dB-Hz and the probability of false alarm (Pfa) is 0.2. And when the frequency error is larger than 400Hz, the Pd of the DDMM is higher than the traditional acquisition method which uses two dimensional search pattern. The DDMM is also applied to the acquisition of recorded GPS signals in an experiment, and all of the satellite signals at present are detected.
Published in:	Proceedings of the 2014 International Technical Meeting of The Institute of Navigation January 27 - 29, 2014 Catamaran Resort Hotel San Diego, California
Pages:	849 - 852
Cite this article:	Fan, J., Ma, G., "De-spreading Delay-and-multiplication Method for GPS Signal Acquisition," Proceedings of the 2014 International Technical Meeting of The Institute of Navigation, San Diego, California, January 2014, pp. 849-852.
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