An Experiment for the Combined Adjustment of the Doppler Satellite and the Geodetic Networks

In this paper some theoritical problems in the combined adjustment of the Doppler satellite and the geodetic networks are tested and verified through some experimental computation.The conclusions arc summarized as follows:(1) There exists the equiva fence not only among the three models with seven transformation parameters(i.c.Bursa,Molodensky and Vcis models),but also among transformation parameters for the simplified Bursa and Molodensky models with four.five or six parameters.(2) For a combined adjustment of a specific satellite and geodetic network optimum adjustment results can be abtained through the selection of mathematical models with suitable number of transformation parameters.Generally speaking,for a network covering a rather large region,the models with seven parameters should be adopted,while for that covering a small region,simplified models with parameters less than seven should be adopted.The anthors propose a method using the linear test of hypothesis for the selection of suitable parameters for a specific network.(3) If in a combined adjustment some priori properties(such as a priori variance and a priori expectation) of the three rotation parameters(i.c.Euler's angles) are known,then it is possible to increase greatly accuracy of solutions for the three shift parameters.But in this case the known priori properties must be tested and verified to make sure that they are comparable with the observations and their accuracy.Otherwise,the accuracy of the combined adjustment might be decreased.