1. Ph.D. Student, National Key Laboratory of Aerospace Flight Dynamics, School of Astronautics, Northwestern Polytechnical Univ., Youyi West St., Beilin District, Xi’an, Shaanxi 710072, China.
2. Professor, National Key Laboratory of Aerospace Flight Dynamics, School of Astronautics, Northwestern Polytechnical Univ., Youyi West St., Beilin District, Xi’an, Shaanxi 710072, China (corresponding author).