Optimization of GPS L1 acquisition using Radix-4 FFT

The implementation of an acquisition loop for software GPS receiver is still a challenge because of the large number of arithmetic operations involved in an FFT algorithm. Oversampling of the composite signals further compounds this problem. A Radix-4 FFT algorithm was proposed to improve the performance and the results were compared with Radix-2 FFT. To validate the algorithms a software GPS baseband processor was developed in Simulink and tested with real satellite data set. The analysis shows that the Radix-4 FFT is about 23% more efficient than the Radix-2 algorithm.