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dc.contributor.authorvan Grass, Franken_US
dc.contributor.authorYang, Chunen_US
dc.contributor.authorMorton, Yuen_US
dc.contributor.authorBrenneman, Matten_US
dc.date.accessioned2008-12-15T20:27:19Zen_US
dc.date.accessioned2013-07-10T15:07:01Z
dc.date.available2008-12-15T20:27:19Zen_US
dc.date.available2013-07-10T15:07:01Z
dc.date.issued2008-12-15T20:27:19Zen_US
dc.identifier.uri
dc.identifier.urihttp://hdl.handle.net/2374.MIA/269en_US
dc.descriptionThis paper presents a GPS multipath mitigation method using a dual circularly polarized antenna array and a multi-channel receiver. The method is based on the exploitation of both polarization and spatial diversity associated with a GPS signal and its multipath signals available at the receiver input. Conventional GPS antennas are right-hand circularly polarized (RHCP) to suppress multipath contributions to the input. This polarization-based discrimination of multipath signal cannot completely eliminate multipath induced GPS range measurement errors. We present an algorithm that performs spatial processing on the input from the left-hand circular polarized (LHCP) array with an increased relative strength of the multipath signal, thereby providing improved multipath angle of arrival (AOA) estimation. With the known multipath AOA and direct signal AOA (which can be obtained from almanac/ephemeris together with the antenna attitude or estimated in a separate process), we can then take advantage of the spatial diversity of the direct signal and multipath by applying null-steering to the RHCP array input. The paper presents the algorithm and simulation results for a uniform linear array receiving one direct signal and one multipath. Our preliminary studies showed that the multipath AOA estimator produces negligible error if the direct signal and multipath AOA are not close to each other (more than 5 degrees apart) and that the direct signal is not at low elevation. The results also suggested that longer time delay between the direct and multipath signal will increase multipath AOA estimation error but this increase is tolerable. Furthermore, we demonstrated that the multipath estimation improves with increasing spatial diversity for multipath and direct GPS signals even if the signal arrivals are close in time. Finally, we demonstrated that the multipath mitigation technique does produce an improved receiver correlator function which directly impacts the GPS code range measurement accuracyen
dc.titleMitigation of GPS Multipath Using Polarization and Spatial Diversitiesen
dc.typeTexten_US
dc.type.genreArticleen_US


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