Multipath Rejection Through Spatial Processing

摘要

The development of low cost, small size antenna arraysrnand digital antenna electronics has resulted in small,rnaffordable GPS phased arrays and digital receivers thatrnare suitable for commercial applications. NAVSYS HighgainrnAdvanced GPS Receiver (HAGR) product includesrnthe capability to spatially process signals from up to 16-rnantenna elements. Previous papers have presented thernHAGR?s capability to perform beamforming, in bothrnstatic and mobile environments, providing over 10 dB ofrnadditional signal gain on each satellite tracked. Thisrncapability results in highly accurate code and carrierrntracking providing superior performance for highrnaccuracy applications, such as kinematic GPS.rnIn this paper, a further enhancement to the HAGR digitalrnsignal processing is described. A spatial signalrnprocessing algorithm has been developed that allowsrnmultipath signals to be detected and an adaptive antennarnarray pattern is then used to minimize their receivedrnsignal power while still applying gain in the direction ofrnthe direct GPS signals. Test data is included showing thernbenefit of this method in reducing the multipath errors onrnboth the pseudo-range and carrier-phase observations.