Hello DrB

I just have a question about the orientation aproximation. If not checked my adjustment is horrible (about 5 varians factor), if checked the same is less than 1.

When you take measurements with a classic total station, you cannot observe direction angles (i.e., azimuths), only directions. Consequently, the orientation parameter of each set is an arbitrary but unknown parameter that must be estimated. The estimated values describe the difference between the zero point of the encoder at each station and the x-axis of your (local or global) frame. If you was able to observe true azimuths, i.e. using a gyroscope, the orientation parameter is known and - in this case - not part of the unknown parameters.

Kind regards
Micha