Abstract:

[Objective] According to the problem of the regional applicability of real-time precise point positioning (RT-PPP) performance and applications affected by ionospheric activity, [Methods] this paper selects the Hunan region, which is located in the transition zone between middle and low latitudes and has complex and hilly terrain, and uses State Space Representation (SSR) products to carry out RT-PPP performance and atmospheric analysis. [Result] Based on the experimental results using HNCORS data, the quality assessment of SSR products shows that, except for the three IGSO satellites (C38-C40) in the BDS-2 and BDS-3 constellations, the real-time orbits of other satellites reach an accuracy of 1-9 cm, and the accuracy of the real-time clock error reaches 0.2-0.3 ns. In terms of the atmospheric environment, the ionospheric activities inferred from the stations in the southern part of Hunan are generally higher than those from the stations in the northern part of Hunan, while the Zenith Total Delay (ZTD) trends obtained from ionosphere-free(IF) combination and undifferenced uncombined (UDUC) models are basically the same, with a difference of only about 2 mm. However, the difference between two stations in the same area with large altitude differences can be as high as 26 mm and as low as 6 mm. In terms of positioning performance, the average values of 3D RMS/STD for static PPP can reach 3.2/2.0 cm, and those for kinematic PPP can reach 11.9/10.7 cm. The convergence time for static PPP is generally within 30 minutes, with the fastest being 10 minutes. The convergence time for kinematic PPP is generally within 60 minutes, with the fastest being 13 minutes.

Key words: PPP-SSR, real-time orbit/clock, convergence time, positioning accuracy, atmospheric analysis, BDS/GNSS