Vector angle grouping-based solution separation for multipath/NLOS detection and exclusion with the enhancement of doppler test

In urban areas, global navigation satellite system (GNSS) measurements are susceptible to multipath and non-line-of-sight (NLOS) effects, significantly degrading GNSS performance. Nowadays, multipath/NLOS effects have become the main cause of GNSS measurement fault in an urban environment. Our work mainly focuses on improving GNSS performance in urban areas without using any additional sensors. To achieve this, Doppler test-enhanced fault detection and exclusion (FDE) scheme is proposed to mitigate the influence of multipath/NLOS effects on GNSS positioning. The research is conducted in two folds. First, according to vector angle grouping (VAG) and multiple hypothesis solution separation (MHSS), the fault mode determination process is described. Since the spatial characteristic of multipath/NLOS effects are considered, the fault mode determined by VAG is able to monitor multiple measurement faults caused by multipath/NLOS effects. Second, by introducing Doppler test, Doppler test-enhanced FDE scheme is designed. The proposed FDE scheme combines VAG-based MHSS FDE and the continuity of users’ motion, which can obtain more accurate exclusion options. Experiments are carried out based on the open-source dataset, UrbanNav. The results suggest that the proposed algorithm can improve the navigation accuracy about 50% over the traditional receiver autonomous integrity monitoring-based Consistency Check method.