GPS World, December 2017
URBAN POSITIONING ACCURACY ENHANCEMENT USING 3D BUILDINGS MODEL AND ACCELERATED RAY TRACING By Nesreen I Ziedan Zagazig University Egypt Presented at ION GNSS 2017 September 2017 M ultipath is a major source of positioning accuracy degradation in urban areas Advances in 3D mapping and the availability of 3D city models have encouraged a set of new techniques for multipath mitigation This paper presents three algorithms to enhance the accuracy of urban positioning using all the available line of sight multipath and non line of sight signals An accelerated ray tracing technique that first eliminates the 3D surfaces that are invisible with respect to a position and then analyzes the visible surfaces to predict the existence and path lengths of reflected signals The ray tracing algorithm is applied on the possible range of positions A Markov Chain Monte Carlo based algorithm that applies both the Gibbs sampler and the Metropolis Hastings technique to analyze the received correlated signals to estimate the delays of reflected signals for all the received signals A Van Rossum based technique that measures the discrepancy between the estimated delays and the predicted ones at a range of possible positions where the position that generates the minimum Above The constructed 3D model for 26 buildings below illustration of the direction of recording of surfaces discrepancy is taken as the estimated position Test results indicate the ability of the algorithms to successfully utilize reflected signals to enhance urban positioning accuracy ADVERTISER INDEX COMPANIES FEATURED IN THIS ISSUE ADVERTISER PAGE S CAST NAVIGATION INSIDE FRONT COVER HEMISPHERE GNSS 7 INSTITUTE OF NAVIGATION ION 8 JAVAD 19 26 LIDAR USA 29 NOVATEL BACK COVER RACELOGIC INSIDE BACK COVER ADVERTISER PAGE S SBG SYSTEMS 33 SEPTENTRIO 9 SPIRENT FEDERAL 5 SUZHOU FOIF 45 TALEN X 31 UNICORE COMMUNICATIONS 17 DECEMBER 2017 WWW GPSWORLD COM GPS WORLD 49
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