jgg     2015 35 (6):  1049-1052    ISSN: 0412-1961  CN: 21-1139/TG Solving the Unknown Parameters in Conditional Adjustment  Models with Linear Inequality Constraints 1 College of Surveying, Mapping and Geo-Informatics, Tongji University, 1239 Siping Road, Shanghai 200092, China 2 Laboratory of Geographic Information Science, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China Received: 2014-10-06  Revised: null  Online: 2015-12-01 Supporting info