Faculty of Geosciences and Environmental Engineering Southwest Jiaotong University Chengdu 611756 China;
Division of Geodetic Science School of Earth Science Ohio State University Columbus OH 43210 USA;
Faculty of Geosciences and Environmental Engineering Southwest Jiaotong University Chengdu 611756 China;
Faculty of Geosciences and Environmental Engineering Southwest Jiaotong University Chengdu 611756 China;
Faculty of Geosciences and Environmental Engineering Southwest Jiaotong University Chengdu 611756 China;
Faculty of Geosciences and Environmental Engineering Southwest Jiaotong University Chengdu 611756 China;
Faculty of Engineering Karary University Khartoum 12304 Sudan;