NLOS exclusion using consistency check and city building model in deep urban canyons

Lots of studies are focused on improving GNSS positioning in urban environments. One of the promising solution is to take advantage of city building models to mitigate, detect or even correct the reflection signals. The studies that corrected NLOS and used it as an addition measurement usually assumes the travelling path of the NLOS is single reflected. In the case of middle urban canyons, this assumption should be correct in most of the cases. Because of the dense and modern buildings in deep urban canyon, the possible reflection paths of GNSS signals are increased dramatically. As a result, a two or multipath reflected NLOS signal became easily observed. This paper applies the consistency check in the developed 3D map based positioning method to exclude the abnormal reflection signals. According to the experiment result, the positioning result with the consistency check outperforms the positioning result without it. The mean of positioning error of the 3D map method with consistency check is about 3.8 meters in the deep urban environment.