Analysis of precision characteristics of HNGG2017

Precision evaluation and verification is the precondition for the construction and application of GNSS quasi-geoid model. In view of the HNGG2017 model in Hunan Province, a large number of GNSS/leveling observations and historical models are introduced, and a comprehensive checking method for internal and external accuracy and characteristic areas is proposed. The checking results show that the internal and external coincidence accuracy of the model is better than 2.2 cm. Compared with the historical model, the accuracy of the new model has been significantly improved in the northern Changde Hanshou and the southwestern Yongzhou Jiangyong areas. At the same time, the raw level data of Hupingshan area in northern Hunan may have systematic errors, which needs to be verified by more data.