소프트웨어 기반 GPS 수신기의 신호 획득 알고리즘 성능 분석

Abstract

In Software-Defined GPS Receiver (SDR), GPS signal acquisition is a significant algorithm to identify the visible satellites. It also finds the code phase and Doppler frequency. After acquisition, the acquired code phase and Doppler frequency are transferred to a tracking loop as initial values to demodulate the navigation data. Acquisition time and detectable signal strength are depending on the performance of acquisition algorithm. In this paper, traditional GPS signal acquisition algorithms are analyzed and compared with the proposed GPS signal acquisition algorithm based on the combination of both coherent and noncoherent approaches. The proposed algorithm is verified by simulations. The results show that the proposed GPS signal acquisition algorithm gives about two times faster acquisition time than the conventional algorithm. In addition, the improved algorithm is more effective in the acquisition of weak signals.