Dynamically and economically updating the National Elevation Datum with the assistance of InSAR: A case study in North China Plain

Land subsidence significantly impacts the accuracy of the National Elevation Datum in China. In order to solve this issue, a dynamic and economical way was proposed to update the National Elevation Datum with the assistance of InSAR in the North China Plain, which served as the research area. Moreover, the GNSS result was used to correct the InSAR result for the vertical deformation field, which has a relatively unified deformation reference. By integrating the vertical deformation field with the national elevation control point, an analysis and evaluation of changes in the National Elevation Datum were conducted. In addition, a regional remeasurement scheme was formulated to achieve dynamic updates and maintenance of the National Elevation Datum on a regional scale. Through data acquisition and processing, we successfully improved reliability within the main subsidence areas for future use. As a result, updating the elevation values utilize a regional update method, and a dynamic and economical technical process to update the National Elevation Datum is shown in the study.