Study of Direct Acquisition of GPS P-Code in Low-SNR

XFAST and average-method are two typical methods for GPS P-code acquisition in frequency domain. This study compares the performance of P-code direct acquisition using the two methods, analyzes the feasibility of direct P-code acquisition in low-SNR according to Average-Method, conducts MATLAB simulation and tries to configure a hardware realization method based on large-point FFT with fixed-point data format in FPGA. The new method can satisfy the detecting rate 90% and false alarm rate 10^-7 under -134 dBm input signal power with the lowest hardware resources compared with those of XFAST and direct FFT and shorten the acquisition time. The hardware system based on FPGA was designed and verified to be able to meet the design requirement.