利用CORS站实现高程基准动态维护的研究

Using CORS stations for dynamic maintenance of elevation benchmark technology

针对我国许多地区出现地面沉降,高程控制网难以反映实际情况,而使用传统水准测量对高程控制网复测工作量大、成本高、观测周期长的问题,该文提出了一种以CORS站作为核心节点对区域高程参考框架进行动态维护的方法。利用CORS站数据和地表质量负荷数据,分别采用CEEMDAN算法和“移去-计算-恢复”法,计算CORS站大地高变化和沉降区负荷形变场变化,以确定站点的正常高变化,对CORS站点正常高进行动态修正。基于2012—2021年北京沉降区CORS站数据及地表质量负荷数据,得出的CORS站正常高变化与北京测绘设计研究院水准测量的结果对比,对于观测质量较好的CORS站其中最大值9.2mm,最小值为0,平均误差2.7mm,RMSE为3.6mm,证明正常高变化平均精度达到2.7mm,可以选取长期连续观测、数据质量良好的CORS站作为高程控制网的核心结点,能够实现基于CORS站数据的区域高程参考框架动态维持。

There are many areas in China where ground subsidence occurs,and the elevation control network is difficult to reflect the actual situation.The use of traditional leveling to the elevation control network retesting workload,high cost,long observation period.In response to this problem,this paper proposes a method to dynamically maintain the regional elevation reference frame with the CORS station as the core node.Using the CORS station data and surface mass loading data,the CEEMDAN algorithm and the“remove-calculate-restore”method are used to calculate the changes in the geodetic height of the CORS station and the changes in the load deformation field of the subsidence zone,respectively.The normal height change of the station is determined by this method,and the normal height of the CORS station is dynamically corrected.The results of the normal height change of CORS stations derived in the paper are based on the data of CORS stations in the subsidence zone of Beijing from 2012 to 2021 and the data of surface mass loading.The obtained results are compared with the results of the level measurement of Beijing Institute of Surveying and Mapping,and the results show that the maximum value of the difference of the CORS stations with better observation quality is 9.2 mm,the minimum value is 0,the average error is 2.7 mm,and the RMSE is 3.6 mm.The results prove that the average accuracy of the normal height change reaches 2.7 mm,and that the CORS stations with long-time continuous observation and good-quality data can be selected as the core nodes of the elevation control network.The core node of the elevation control network can realize the dynamic maintenance of regional elevation reference frame based on CORS station data.