Evaluation of multi-GNSSs and GPS with 3D map methods for pedestrian positioning in an urban canyon environment

Highly accurate pedestrian position information is required inmany applications, especially in automatic driving system. Global Positioning System (GPS) developed by American has proven itself reliability in most of the environments. Unfortunately, urban areas contain the signal reflection, known as multipath and non-line-of-sight (NLOS) effects. In addition, the lake of line-of-sight (LOS) satellites caused by the blockage of skyscrapers also severely degrades the accuracy and availability of the GPS positioning. To solve these problems, a solution that interoperated several Global Navigation Satellite Systems (GNSSs) is proposed. However, the actual difficulty of satellite positioning in urban area is the distorted satellite distribution. This paper proposes a GPS with 3D map ray tracing positioning method to conquer the difficulty. The proposed method takes the advantage of the non-LOS (NLOS) and uses it as an additional measurement. Significantly, these measurements are sourced from the satellites that should be blocked. Thus, the dilution of precision (DOP) can be greatly improved. To verify the performance of the proposed method, real data is collected at Tokyo urban area. This paper compares the performance of GPS/GLONASS and the proposed GPS with 3D map ray tracing methods. The results reveals the proposed method is capable of identifying which side of street the pedestrian stands and the GPS+GLONASS method is not.