1. School of Geomatics, Liaoning Technical University, Fuxin, China
2. State Key Laboratory of Geo-Information Engineering, Xi’an, China
3. State Key Laboratory of Geodesy and Earths’Dynamics, Innovation Academy for Precision Measurement Science and Technology, CAS, Wuhan, China
4. College of Mining and Geomatics, Hebei University of Engineering, Handan, China