GPS ELEVATION FITTING BASED ON EM ALGORITHM FOR LACK OF DATA
缺失数据下基于EM算法的GPS高程拟合

Restricted by the observing conditions,some important data of GPS elevation fitting are often missed or not enough.Using conventional methods will reduce the fitting accuracy of the quasi-geoid.By use of the EM algorithm with the addition of "potential data",conditional expectation of the missing data,it can effectively improve the accuracy of GPS elevation fitting for lack of data.