1. The Research Institute of Pilotless Aircraft, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
2. Key Laboratory of Unmanned Aerial Vehicle Technology of Ministry of Industry and Information Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
3. The College of Astronautics, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China