1. The College of Engineering Science and Technology, Shanghai Ocean University, Shanghai 201306, China
2. The Merchant Marine College, Shanghai Maritime University, Shanghai 201306, China
3. The Department of Geodesy, German Research Centre for Geosciences (GFZ), 14473 Potsdam, Germany
4. Institute of Geodesy and Geoinformation Science, Technical University of Berlin, 10623 Berlin, Germany