Direct P-Code Acquisition Based on Wavelet Filtering
Compared with the C/A-Code, GPS P-Code offers much higher accuracy but also the higher tolerance to jamming and spoofing. It has large Doppler frequency shift, long code period and high code rate. According to these characters, a new scheme for direct P-Code acquisition using auxiliary acquisition is proposed in the paper, which estimates the phase and Doppler of received P-Code signal in the two dimensional search. In order to finish the auxiliary acquisition rapidly, the wavelet is used to decrease the quantity of data. True phase alignment is detected using a conventional parallel search scheme, where the initial phase and Doppler are set to the values obtained by the auxiliary acquisition and whose amount of parallel channels is required less. The result of computation shows the proposed scheme achieve the priori information of phase and Doppler faster and correctly.
KeywordsGPS DSP Direct P-code acquisition Wavelet Auxiliary acquisition
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