Accuracy analysis of BDS-3 PPP-B2b precise point positioning over Sri Lanka

The BeiDou Navigation Satellite System (BDS-3) provides a real-time precise point positioning (PPP) solution with its BDS PPP-B2b signal, which does not rely on local base stations, and therefore has become a promising solution for GNSS-based surveying applications in real-time. The present study assesses the accuracy, convergence duration and environmental impact of PPP-B2b in the case of Sri Lanka in comparison with traditional post-processed GNSS approaches such as Differential Global Navigation Satellite System (DGNSS), Single Point Positioning (SPP), and PPP-Static. The study was carried out in three different sites Maharagama (open field), Thalangama (semi-urban, adjacent to a body of water) and Diyagama (dense urban area) to evaluate PPP-B2b’s performance on varying terrain-different environmental conditions. The results demonstrate that PPP-B2b allows sub-meter positioning with an average horizontal accuracy of 0.4 m and vertical accuracy of 2.3 m, and the open-field site (Maharagama) experiences the best accuracy due to geomorphological factors and complete satellite visibility, whereas Thalangama gave moderate deviations due to multipath generated from reflections on the water. Diyagama site had the least accuracy, because of signal obstruction, urban canyon and increasing the convergence time. Even though PPP-B2b is a low-cost and independent solution that does not require terrestrial infrastructure, it is limited by several factors that result in high convergence time (typically up to 10-15 minutes) and errors generated through multipath and ionospheric delay. These limitations notwithstanding, satellite-based PPP services such as PPP-B2b are still viable options for real-time positioning and atmospheric applications that do not require internet connectivity.