5G Enhanced BDS Positioning in Urban Obstructed Environments: A Smartphone Field Test Case

The rapid growth of location-based services (LBS) and the increasing reliance of smartphones on global navigation satellite system (GNSS) have made improving positioning accuracy in complex urban environments a critical challenge. Although GNSS itself is limited by signal blockage and multipath effects in urban canyons, integrating fifth-generation (5G) technology offers significant potential to enhance positioning performance. Therefore, we propose a smartphone-based BeiDou navigation satellite system (BDS)/5G hybrid positioning solution, which combines the time of arrival (ToA) and angle of arrival (AoA) measurements from 5G field tests to improve positioning accuracy. We first start from the Fisher information matrices (FIM) to theoretically prove the gains of 5G to BDS positioning. Additionally, we introduce a carrier-phase-based 5G ToA ranging method that achieves a precision of about 10 cm in static conditions. The results from experiments on two different smartphones demonstrate that the hybrid positioning system consistently outperforms standalone BDS SPP. In the open-sky static scenario, horizontal accuracy improved by 5-22% and vertical accuracy by 29-32%. In the heavily obstructed Static-3 scenario, horizontal accuracy improved by approximately 14% for both devices, while vertical accuracy improved by over 17%. This robust performance was confirmed in the dynamic test, where the 3D RMS error improved by 40.8% for the K50 and 32.4% for the P40. And 5G AoA contributes to BDS positioning improvements more stably than ToA, even though ToA can achieve centimeter-level accuracy. The findings suggest that the BDS/5G hybrid positioning method can effectively mitigate the limitations of satellite-based positioning for smartphones in obstructed environments.