1Guangzhou Urban Planning and Design Surveying Research Institute,23 Jianshe Road,Guangzhou 510060,China;2State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing,Wuhan University,129 Luoyu Road,Wuhan 430079,China;3Space Technology Applications and Research,Asian Institute of Technology,Bangkok 12120,Thailand;4Presidential Secretariate,Wuhan University,Luojia Hill,Wuhan 430072,China;5Research Center of GPS,Wuhan University,129 Luoyu Road,Wuhan 430079,China