1. Air Traffic Control Research Office, Naval Aeronautical University of PLA, Yantai, China
2. College of Communication Engineering, Army Engineering University of PLA, Nanjing, China
3. College of Electronic and Information Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, China
4. Ministerial Key Laboratory of JGMT, Nanjing University of Science and Technology, Nanjing, China