Research on unified technology of elevation datum of digital twin basic data

In order to meet the strong demand of digital twin construction for basic geographic information data, such as twin watershed, and to ensure the unification of the elevation datum of engineering construction, based on GNSS observation technology and gravity field model, we carried out this research.We constructed a high-precision regional quasi geoid model considering terrain features, thus forming a unified model library of digital twin basic data elevation datum.Through two evaluation methods of model accuracy and detection accuracy, the accuracy of elevation correction results of the elevation model and multi-source basic data surveyed in multi-scene was evaluated.The results showed:(1) The internal coincidence accuracy of the quasi geoid model was ±2.6 cm and the external coincidence accuracy was ±3.1 cm, which was better than the fitting algorithm of EGM 2008 model combined with quadric surface fitting, fulfilling the specification requirements;(2) The mean square error of elevation correction results of multi-source basic data was within ±10 cm, meeting the accuracy requirements of digital twin construction for basic data.The method is simple, accurate and has a wide application prospect.It can not only be used in digital twin construction and other fields, but also provides technical support for large-scale regional engineering survey and land-sea elevation datum unification.