jgg     2011 31 (1):  132-137    ISSN: 0412-1961  CN: 21-1139/TG DOWNWARD CONTINUATION OF SATELLITE GRAVITY GRADIENT DATA Liu Xiaogang 1) ;Li Shanshan 1) ; and Wu Xing 2,3) 1)Institute of Surveying and Mapping, Information and Engineering University, Zhengzhou 4500522)Center for Engineering Design and Research Under the Headquarters of General Equipment, Beijing 1000283)Institute of Hydrographic Survey and Charting, Tianjin 300061 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null