Modified Two-Dimension Folding Method for Fast P-Code Acquisition

Due to the Global Navigation Satellite System in high dynamic environment, the vital restriction for P-code Acquisition should be the Doppler frequency offset and large uncertainty phase of P-code. To accelerate the P-code acquisition process, the two-dimension folding method is proposed in this paper, by folding local frequency cells and generating code with little burden increase. Furthermore, to counteract the coherent integration noise causing by local frequency and code folding, a modified method is presented. Preliminary result shows that the mean acquisition time of the modified method reduces significantly, with less than -1dB degradation in detection performance. And, it can be eliminated when the SNR exceed -13dB.