Information Engineering University, Zhengzhou 450001, China;
Xi' an Research Institute of Surveying and Mapping, Xi' an 710054, China;
Information Engineering University, Zhengzhou 450001, China;
State Key Laboratory of Geo-Information Engineering, Xi' an 710054, China;
Xi' an Research Institute of Surveying and Mapping, Xi' an 710054, China;
Chang' an University, Xi' an 710054, China;
PLA University of Science & Technology, Nanjing 210007, China;