1. School of Astronautics, Northwestern Polytechnical University, Xi’an 710 072, China
2. Xi’an Institute of Electromechanical Information Technology, Xi’an 710 065, China
3. National Key Laboratory of Aerospace Flight Dynamics, Northwestern Polytechnical University, Xi’an, China
4. Research Center for Unmanned System Strategy Development, Northwestern Polytechnical University, Xi’an, China