jgg     2010 30 (第3期):  83-87    ISSN: 0412-1961  CN: 21-1139/TG EFFECTS OF HORIZONTAL VARIATION OF TROPOSPHERIC DELAY ON GPS SURVEYING Chen Zhaohua ;and Dai Wujiao Department of Survey Engineering and Geomatics, Central South University, Changsha 410083 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null