1. Naval University of Engineering, Wuhan, China
2. GNSS Research Center, Wuhan University, Wuhan, China
3. Key Laboratory of Geological Survey and Evaluation of Ministry Education, China University of Geosciences, Wuhan, China
4. School of Geodesy and Geomatics, Wuhan University, Wuhan, China
5. State Key Laboratory of Resources and Environmental Information System, Chinese Academy of Sciences, Beijing, China