jgg     2010 30 (6):  57-59    ISSN: 0412-1961  CN: 21-1139/TG A NEW VARIANCE COMPONENT ESTIMATION METHOD USED FOR COLLOCATION Li Weiwei 1) ; and Shen Yunzhong 1,2) 1)Department of Surveying and Geo-informatics, Tongji University, Shanghai 2000922Key Lab. of Advanced Surveying Engineering of State Bureau of Surveying and Mapping, Shanghai 200092 Received: 1900-01-01  Revised: 1900-01-01  Online: null Supporting info null