Hello Jan,

Is there a sensible way to judge whether a given σ is "small enough" across observation types with different units/physical dimensions – for example, by comparing standardized residuals or weight contributions after a first adjustment run, rather than the raw σ values themselves? Or would you simply convert everything to a common measure (e.g. via the resulting positional effect) before comparing?

There are several criteria that can be used to check the strength of the pseudo-observation. If an observation is (quasi-)fixed, the related post-fit residual must be close to zero. Since precise measurements verify inaccurate ones (a laser tracker verifies the tape measure, but not the other way around), precise measurements exhibit only minimal redundancy. Thus, the redundancy should be very small. A (quasi-)fixed observation is (nearly) a perfect observation and is interpreted as the true value in a statistical sense. Thus, test statistics such as normalized residual tests (e.g. Tprio/Tpost) should be close to zero. Just evaluate e.g. the post-fit residual and adapt the corresponding weight - if required.

Attached two pics for better understanding the network.

Thank you. Although I now have a general idea of how the network is configured. However, I still can't quite picture the whole thing clearly enough (in my mind) to give a concrete answer to your third question from the last post. The implications aren't entirely clear to me. I don't have any 'best practices'-tips in this field - that's my problem (it is not a matter of the least-squares method). To get an appropriate answer to your last question, you should consult someone else who is more familiar with a gyro-theodolite. Don't get me wrong. I don't want to brush you off, and I'm happy to keep answering any other questions you have about JAG3D.

All the best
Micha