Patent ID: 7447259

Claim:
A signal processing apparatus (SPA) for acquiring direct sequence spread spectrum (DSSS) signals, comprising: a module configured to sample a received DSSS signal at a predetermined sampling rate; a module configured to cross-correlate, in a parallel fashion, time and frequency shifted versions of the sampled DSSS signal with samples of a locally generated replica of a pseudo random noise (PN) code sequence used to spread a spectrum of the received DSSS signal in order to obtain cross-correlation values; and a Doppler compensator coupled to the cross-correlating module and configured to process the obtained cross-correlation values to compensate for shifts in at least one of (i) a carrier frequency and (ii) a code rate of the received DSSS signal resulting from time-companding of the received DSSS signal, wherein the cross-correlating module comprises a bank of code-matched filters configured to compute short-time correlations (STCs) in parallel.