GPS Receiver C/A Code Rapid Acquisition Technology Research

摘要

Combining with advantages of delay-and-multiply and sequence generated by the shift-and-add property of gold code still has good auto-correlation and cross-correlation, this article proposes a new C/A code rapid acquisition algorithm based on FFT. Mainly, the input signal is multiplied by a version of itself that has been delayed by an integer number of chips which can avoid serial search carrier doppler frequency and correlate new signal with one satellite C/A code to generate correlation result, then correlate it with pre-generated 32*1023 gold code correlation table values of 32 satellite instead of correlating with 32 satellite C/A code, and it realizes parallel search satellite number and code phase. When determine the initial position of C/A code and can get corresponding frequency by FFT. Through theoretical derivation and simulation analysis shows that the new algorithm can effectively fast complete signal acquisition. And compared with traditional FFT acquisition algorithm, signal compression method and delay-and-multiply method, the computational complexity of the new algorithm are reduced to 95%, 90% and 22%.