Mathematical analyses of matched spectrum interference signal on post-correlation C/N0 for the GPS receivers

Interference is one of the major concerns when using global positioning system (GPS) receivers. The interference signals may cause severe performance degradation to the GPS receiver performance. It can decrease the post-correlation carrier to noise ratio (C/N_o), causes the position error or even completely prohibit the acquisition or tracking of satellites. This paper analyzes the matched spectrum interference (MSI) effect on the GPS receiver correlator output. Novel analytical expressions for the MSI power at the correlator output are derived. The post-correlation carrier to noise ratio (C/N_o) is analytically derived in the presence of MSI and additive white Gaussian noise (AWGN). The time-frequency cross correlation function is defined and analyzed. The effects of the correlator coherent integration time and cross correlation sequence (CCS) spectral line in the MSI effect are also investigated. The derived analytical expressions are verified with the aid of computer based simulations.