1. College of Astronautics, Nanjing University of Aeronautics and Astronautics, Nanjing, China
2. Institute of Communication Engineering, Army Engineering University of PLA, Nanjing, China
3. Beijing Institute of Control Engineering, Beijing, China
4. Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Kowloon, Hong Kong
5. VTT Technical Research Centre of Finland Ltd., Espoo, Finland