1. Key Laboratory of Roads and Railway Engineering Safety Control, Shijiazhuang Tiedao University, Ministry of Education, Shijiazhuang 050043, China
2. School of Civil Engineering, Shijiazhuang Tiedao University, Shijiazhuang 050043, China
3. College of Astronautics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
4. GNSS Research Center, Wuhan University, 129 Luoyu Road, Wuhan 430079, China