Acquisition of direct sequence spread spectrum signals using sliding correlators

Abstract

The application of a digital sliding correlator for the acquisition of direct sequence (DS) spread spectrum signals is examined. The mean acquisition time of the correlator is computed and compared with that of an analogue sliding correlator. For the same length of PN-sequence generator the digital sliding correlator outperforms the analogue sliding correlator in terms of mean acquisition time. Furthermore, the digital sliding correlator exhibits a constant and comparable mean acquisition time, as the correlation length increases, when compared with other fast acquisition schemes for DS spread spectrum signals such as, rapid acquisition by sequential estimation (RASE), recursion-aided RASE (RARASE) and the digital matched filter. Experimental tests are carried out for both digital and analogue sliding correlators. Measurements of the mean acquisition time for both correlators are made. Shorter mean acquisition times are recorded for the digital sliding correlator in the presence of additive white gaussian noise and multi-tone interference.