Institute of Surveying and Mapping, Information Engineering University, Zhengzhou 450052, China;
School of Surveying & Land Information Engineering, Henan Polytechnic University, Jiaozuo 454000, China;
Institute of Surveying and Mapping, Information Engineering University, Zhengzhou 450052, China;
Institute of Surveying and Mapping, Information Engineering University, Zhengzhou 450052, China;