A new IMU-aided multiple GNSS fault detection and exclusion algorithm for integrated navigation in urban environments

The performance of Global Navigation Satellite Systems (GNSS) and Inertial Measurement Unit (IMU) integrated navigation systems can be severely degraded in urban environments due to the non-line-of-sight (NLOS) signals and multipath effects of GNSS measurements. A GNSS data quality control algorithm with effective Fault Detection and Exclusion (FDE) is therefore required for high accuracy integrated system-based positioning. Traditional GNSS FDE algorithms are designed for a single failure at a time. In urban, environments affected by NLOS and multipath effects; however, there is increased potential for multiple simultaneous failures. We present a new pseudo range comparison-based algorithm for the dynamic detection and exclusion of multiple failures in an effort to improve GNSS/IMU integrated positioning in urban areas. A FDE scheme with a sliding window and a detector in parallel is proposed by using IMU data and GNSS pseudo range measurements, which allows accurate detection of multiple simultaneous faults of different satellites for real-time GNSS measurement quality control. Experimental results of land vehicle GNSS/IMU integrated positioning accuracy in terms of 3D Root Mean Square Error are 5.39 m and 12.22 m, respectively, for two cases in mid and deep urban canyons. These correspond to improvements of 14.7% and 22.7% over the cases without fault exclusion.