Abstract: With the completion of the global networking of the BeiDou Navigation Satellite System (BDS), its regional service performance has been significantly improved,which provides an important opportunity for the application of BDS-based regional continuous operation reference station (CORS) geodesy.In this study,based on the observation data of 31 Kunming Metropolitan Comprehensive Satellite Positioning Service System (KMCORS) reference stations in Kunming and surrounding areas from 2022 to 2024,baseline resolution and coordinate leveling of the dual systems (BDS and GPS) were performed using GAMIT/GLOBK software,and a high-precision 3D velocity field model was constructed by analyzing and reconstructing the coordinate time series.The results show that: ①The positioning accuracy of BDS and GPS is comparable in the north (N) and east (E) directions,but BDS is slightly inferior to GPS in the vertical (U) direction; ②According to the Pearson correlation coefficient,BDS stations exhibit stronger spatial correlation characteristics,and the spatial filtering method based on principal component analysis significantly improves the accuracy of BDS and GPS coordinate time series; ③The common-mode error of BDS and GPS can be effectively corrected.After correction,the velocity estimates of both systems converge,with average rates of 14.92 mm/a (N), 32.87 mm/a (E), 8.05 mm/a (U) for BDS and 15.23 mm/a (N), 32.62 mm/a (E), 4.96 mm/a (U) for GPS.This study demonstrates that the BDS positioning accuracy of KMCORS is comparable to GPS and can be effectively applied in urban coordinate frame maintenance and crustal deformation monitoring.

Key words: BDS, KMCORS, coordinate time series, common-mode error, 3D velocity field