Reliability analysis for non-distorting connection of engineering survey networks

A non-distorting network connection is a complex procedure consisting of a local network adjustment and a subsequent Helmert transformation into the connection points without changing the scale, i.e. isometry transformation. Since a joint adjustment model proposed for this connection in the earlier publication did not turn out sufficient to create a detailed reliability description for the whole procedure, reference had to be made to the original two-step approach. The reliability measures for a joint model and for each of the above mentioned procedural steps of the connection are being analysed. It is shown that the reliability description as based on indices obtained from the joint model should be supplemented with the indices from the two-step model. A specific property of the connection concerning mutual controllability of coordinates of the connection points is formulated on the basis of the Helmert transformation. The theory is illustrated on some numerical examples.