EXPERIMENT AND RESULTS OF HIGH PRECISION LAND SUBSIDENCE MONITORING USING FUSED BDS/GPS DATA AND STATIC RELATIVE POSITIONING

Beidou Navigation Satellite System(BDS) of China has formally provided the service of continuous passive positioning, navigation and timing for most area of Asia-Pacific since December 27, 2012. In order to inquire the effect and precision of the high precision land subsidence monitoring using fused BDS/GPS observation data, five GNSS receivers which can synchronous receive the signal of BDS and GPS are used to monitor the land subsidence of Xi'an repeatedly at 9 points of the original GPS network. Then 4 session observation data which continue over 10 hours are processed and analyzed. The results indicate that the internal accordant accuracy of baseline which merges the BDS and GPS data is improved greatly relative to the accuracy of baseline solved using the single GPS observation data. The average error of horizontal direction is improved from 5mm to 3mm, and the average error of vertical direction is improved from 17mm to 12mm. In the mean time, the external accordant accuracy of monitor results is also enhanced greatly. The average error of X,Y,Z direction is improved from 6mm,15mm and 10mm to1.5mm,8mm and 5mm respectively. Those phenomena indicate that the internal and external accordant accuracy of results for high precision land subsidence monitoring can be improved obviously using the fused BDS/GPS observation data.