Abstract—The accuracy of the positions of a pedestrian is veryimportant and useful information for the statistics, advertisement,and safety of different applications. Although the GPS chip ina smartphone is currently the most convenient device to obtainthe positions, it still suffers from the effect of multipath andnonline-of-sight propagation in urban canyons. These reflectionscould greatly degrade the performance of a GPS receiver. Thispaper describes an approach to estimate a pedestrian position bythe aid of a 3-D map and a ray-tracing method. The proposed approachfirst distributes the numbers of position candidates arounda reference position. The weighting of the position candidates isevaluated based on the similarity between the simulated pseudorangeand the observed pseudorange. Simulated pseudoranges arecalculated using a ray-tracing simulation and a 3-D map. Finally,the proposed method was verified through field experiments in anurban canyon in Tokyo. According to the results, the proposedapproach successfully estimates the reflection and direct paths sothat the estimate appears very close to the ground truth, whereasthe result of a commercial GPS receiver is far from the groundtruth. The results show that the proposed method has a smallererror distance than the conventional method.Index Terms—3-dimensional digitalmap, GNSS,GPS, non-lineof-sight (NLOS) propagation, ray tracing