**4. Conclusions**

This paper has developed a dual w-test-based quality control algorithm for IMU/GNSS integrated navigation in urban areas. Simulation and field test results show that the proposed algorithm is capable of achieving quality control for integrated IMU/GNSS navigation. The experimental results in deep urban environments show that the proposed integration algorithm can improve positioning accuracy compared to the cases without fault exclusion by about 24% and 30%, compared to FDE TC by about 8% and 22%, and compared to AKF TC by about 14% and 16% in the horizontal and vertical directions, respectively. However, the current work does not suit for the case of insufficient visible satellites, as the dual w-test cannot be carried out without enough of a degree of freedom in the statistic *SSE*. In future work, we will continue to develop more advanced quality control methods, including seeking a better robust algorithm when the number of satellites is insufficient and designing a corresponding failure detection algorithm according to the failure mechanisms of different sensors, such as inertial sensors, vision sensors, and lidar.

**Author Contributions:** Conceptualization, M.Q. and R.S.; Data curation, F.L.; Formal analysis, M.Q.; Methodology, M.Q. and R.S.; Software, F.L.; Supervision, Z.W. and W.Y.O.; Writing—original draft, M.Q.; Writing—review & editing, R.S. and W.Y.O. All authors have read and agreed to the published version of the manuscript.

**Funding:** This work was supported in part by the sponsorship of the National Natural Science Foundation of China under Grant 71731001, U1933130, 41974033, 42174025, in part by Natural Science Foundation of Jiangsu Province under Grant BK20212569 and in part by Zhe Jiang Key laboratory of General Aviation Operation technology (General Aviation Institute of Zhejiang JianDe) under Grant JDGA2020-11.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

