Problems of accuracies in combined terrestrial and statellite control networks

Summary The combination of terrestrial and satellite aided network observations requires hybrid models of two kinds: a hybrid functional model and a stochastic model being able to process the heterogeneous observations approapriately. An appropriate combination of stochastic information means to adjoin proper weights to the various types of observations on one hand and on the other hand to separate the relelevant internal accuracy from that accuracy which is affected by a number of network external influences. The first task can be overcome by the technique of estimating variance components of the individual observation groups, the second one can be handled by applying S-transformations to covariance matrices. The paper deals with problems of the hybrid stochastic model. Examples are given.