Tight Integration of a GPS Adaptive Array with a Software-Defined Receiver

摘要

The effect of adaptive array processing on the code and carrier phase of the spread spectrum signal is a function of the signal operating environment and the nature of the adaptive processing mechanism. Spatial adaptive processing (SAP) utilizes its degrees of freedom to form spatial nullsrntowards interference sources and Space-Time Adaptive Processing (STAP) proves effective against both wide and narrow band interferers by forming more precise spatiotemporal nullsrnThe effects of adaptive array processing on the GPS signal could vary from ranging errors to loss of phase lock due to distortions imposed on the GPS signal. A significant portion of the work published to date has been apphques which attempt to minimize the impact of the interferer on the desired signal and, to a lesser extent, minimize distortion of the desired signal. Previous work published枷the authors [1] has been directed at carrier phase compensation applied at the tracking loop level in the base-band receiver module to alleviate the effects of phase distortions imposed on the GPS signal as a function of adaptive array processing Previous work by other researchers [2] has suggested the possibility of utilizing a matched filter-like mechanism for code phase compensation in the base-band GPS receiver processing. With the advent of software GPS receivers, it is now possible to implement the aforementioned compensation mechanism in conjunction with null/beam steering base-band modules which are integrated with the GPS receiver processing. This paper describes the results of a project to implement and evaluate the performance of the integrated adaptive antennal GPS software receiver system