In this paper, an effect on a GPS receiver by spoofing signal is analyzed and a GPS spoofing algorithm for GPS L1 C/A spoofing signal is proposed. A proposed spoofing signal detection algorithm monitors the correlation function distortion by the spoofing signal. If detected distortion is over a spoofing signal detection threshold, we can determine that the spoofing signal is received. The correlation function distortion can be found with relationship between early, prompt, late tap. Also, to prevent the false alarm of spoofing detection, the spoofing signal detection threshold is calculated from the statistical characteristics of GPS correlation values. For verifying the suggested method, a MATLAB-based simulation platform is implemented. This platform tracks GPS signal and measures the correlation values. By using this platform, the spoofing effect is observed and the spoofing detection performance is verified.

Keywords: GPS spoofing, spoofing detection, correlation function distortion