The National Natural Science Foundation of China(41274010,40974007,40901172);National Key Basic Research and Development Program of China(2012AA121301);Hunan Provincial Natural Science Foundation of China(12JJ4035);Postgraduate Autonomous Exploration Project of Central South University(2013zzts055);China Scholarship Council(201406370079).
At present,the principal data processing methods involving complex observations are based on two strategies according to characteristics of the observation process,i.e.,step-by-step and direct resolution.However,these...