Dynamic Maintenance of the Elevation Reference Frame Based on Continuous Operation Reference Stations

In areas where urban land subsidence is frequent and significant, there are problems with heavy workload, high cost, long observation period, and difficult technical maintenance of the regional elevation reference frame in leveling measurement.In this paper, we propose a method of using continuous operation reference stations (CORSs) as nodes to perform dynamic maintenance of regional elevation reference frames.Using continuous years of Global Navigation Satellite System (GNSS) observation data and surface mass load data (land hydrology, atmospheric pressure, and sea level elevation), we calculate the normal height variation of CORSs, dynamically correct the normal height of CORSs, and verify the accuracy of the calculated CORS normal height variation results using multiperiod leveling observation data.The results showed that the average difference between the normal height variation determined using CORSs data and surface mass load data and the normal height variation of the station obtained by two-stage leveling measurement is 4.37 mm, and the calculated average accuracy of the normal height variation of CORSs is about 5.42 mm.CORSs demonstrating long-term stable continuous observation can be selected as nodes of the elevation control network to achieve the dynamic maintenance of the regional elevation reference framework using CORS data.The research results can provide exploratory experience for future elevation benchmark maintenance work in Beijing.