Spatial and temporal processing of GPS signals

In this paper we address the problem of navigation data demodulation by an adaptive GPS receiver that utilizes a bank of single-satellite linear-tap-delay filters and employs antenna-array reception. The presence of an antenna array allows the receiver to operate in the spatial domain in addition to the temporal (code) domain. We investigate disjoint-domain as well as joint-domain space-time GPS signal processing techniques and we consider design criteria of conventional matched-filter (MF) type, minimum-variance-distortionless-response (MVDR) type and auxiliary-vector (AV) type. The proposed structures utilize filters that operate at a fraction of the navigation data bit period (1 msec) and are followed by soft-decision detectors. Soft decisions taken over a navigation data bit period are then combined according to a simple combining rule. Simulation results illustrate the bit-error-rate (BER) performance of the investigated design alternatives.