Comparison of noncoherent matched filter acquisition using median filter and transversal filter in AWGN channel and CW jamming

This paper introduces analysis and simulations results of a DS spread spectrum system in which code acquisition is based on a matched filter, a matched filter and a median filter and a matched filter and a transversal filter. Noncoherent structures are used due to the lack of knowledge of the carrier phase in the acquisition process. The probabilities of detection and false alarms and the mean acquisition times are calculated in the AWGN channel and with continuous tone jamming with ideal autocorrelation of the spreading code being assumed. The probabilities are also measured by simulations. The effect of CW jamming can be eliminated by both methods, so the comparisons are made in the AWGN channel. Fixed thresholds of the comparator and constant false alarm probabilities (CFAR criteria) are both used. The results are similar to those achieved by using coherent structures. The median filter structure has a better performance compared to transversal filter structure, even though the difference between the median filter and an equal length transversal filter is not significant in the CFAR case