1. College of Geodesy and Geomatics, Shandong University of Science and Technology, 579 Qianwangang Rd., Huangdao District, Qingdao 266590, China (Corresponding author), e-mail: kqlabc3334@hotmail.com, https://orcid.org/0000-0002-4288-9894
2. State Key Laboratory of Mining Disaster Prevention and Control co-founded by Shandong Province and Ministry of Science and Technology, Shandong University of Science and Technology, 579 Qianwangang Rd., Huangdao District, Qingdao 266590, China
3. College of Geodesy and Geomatics, Shandong University of Science and Technology, 579 Qianwangang Rd., Huangdao District, Qingdao 266590, China
4. Inst. of Space Science, Shandong University, 180 Wenhuaxi Rd., Weihai 264209, China