1. School of Surveying and Geo-Informatics, Shandong Jianzhu University, Jinan, China
2. First Institute of Oceanography, Ministry of Natural Resources, Qingdao, China
3. College of Electrical Engineering, Naval University of Engineering, Wuhan, China
4. College of Geodesy and Geomatics, Shandong University of Science and Technology, Qingdao, China