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Research On Multipath Mitigation Algorithm For GPS Receiver

Posted on:2015-05-20Degree:MasterType:Thesis
Country:ChinaCandidate:L FangFull Text:PDF
GTID:2180330422484632Subject:Communication and Information System
Abstract/Summary:PDF Full Text Request
GPS has been widely used in navigation and commercial products to provide locationinformation. So the interference suppression in the system has become the research hotspot.There are many signal interference factors, such as multipath error. Especially in the urbanenvironment, where has many high-rise buildings and bridges. Multipath is one of the mainerror sources of GPS measurement. It can’t be eliminated by differential technology or errormodeling, like the ionosphere and troposphere errors. Therefore, the mitigation of multipatheffect becomes the hot and difficult problem in the global satellite navigation system. In thispaper, the main work is as follows.This paper mainly introduces the tracking loop of GPS receiver based on the overview ofthe basic parts of the GPS system and the structure and features of GPS signal. An algorithmis designed and simulated using Kalman Filter to replace the loop filter of carrier trackingloop.The research is mainly focused on the sources and characteristics of multipath based onthe analysis of the main source and characteristics of the GPS system measurement. In thispaper, it mainly studies the multipath signals’ influence on GPS tracking loop based on thegeneral mathematical model of multipath signal.In this paper, it firstly analyzes the classic multipath mitigation algorithms based ondiscriminator function, such as narrow correlator, Strobe correlator and ELS multipathmitigation technology. For the performance of these algorithms is limited by receiver’sfront-end bandwidth and noise, a multipath suppression algorithm is proposed based onRandomized Hough Transform (RHT) to estimate the slope of correlation peak. Thencomparing the performance of this algorithm with ELS multipath mitigation technology bysimulating and analyzing based on MATLAB.The MEDLL is simulated in this paper, the performance of which is limited by the noiseand the number of correlators. For the problem of MEDLL, a modified MEDLL algorithmbased on Kalman Filter is proposed. Then through the simulation based on MATLAB toanalysis the performance of the algorithm proposed.In order to suppress the multipath signal, Extended Kalman Filter is applied in the GPStracking loop to estimate the parameters of input signal.
Keywords/Search Tags:GPS, Kalman Filter, multipath, RHT, MEDLL, Extended Kalman Filter
PDF Full Text Request
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