wenjie shen, yun lin, North China University of Technology, China; bing han, Aerospace Information Research Institute, Chinese Academy of Sciences, China; yang li, wen jiang, North China University of Technology, China; wen hong, Aerospace Information Research Institute, Chinese Academy of Sciences, China; liangbo zhao, Institute of Remote Sensing Satellite, China; xiaolei ruan, Jiuquan Satellite Launch Centre, China; yanping wang, North China University of Technology, China