The integrity monitoring of GNSS on Android smartphones in urban scenario

With the development of Global Navigation Satellite Systems (GNSS) and the widespread use of Android smartphones, there are higher demands from the general users for Location-Based Services (LBS). Addressing the issues of poor positioning performance of Android smartphones in urban environments, susceptibility to environmental interferences, and low positioning reliability, this paper employs two integrity monitoring methods in urban environments to monitor the standard Single Point Positioning (SPP) of smartphones to enhance the credibility of smartphone positioning. Furthermore, the paper tests the impact of Least Squares Variance Component Estimation (LS-VCE) on Advanced Receiver Autonomous Integrity Monitoring (ARAIM) in urban canyon environments. Experimental results indicate that using different integrity monitoring methods can improve smartphone positioning availability to varying degrees in urban environments. ARAIM, compared to Receiver Autonomous Integrity Monitoring (RAIM), demonstrates advantages in computation time, positioning errors and discrete trends. In open scenarios, ARAIM achieves a horizontal and vertical availability of 99.987%, while in semi-open scenarios, the horizontal and vertical availability of ARAIM is 99.904% and 56.970% respectively. Despite eliminating integrity risks in semi-open scenarios through refinement of the random model, the ARAIM algorithm provides a more conservative protection level. The refinement of the random model reduces the dispersion of positioning errors and increases the number of resolved epochs by 19.5%.