Hello Romina,

So, my question is, knowing the precision of each measurements of points that make up the circles around the axes, is it possible to do a network adjustment and determine a variance-covariance matrix that includes the invariant points of VLBI and SLR?

JAG3D is a network adjustment application. You are able to estimate all points that are connected by (terrestrial) observations. The invariant points of the telescopes are - to my understanding - not part of you observation procedure and therefore not part of the network adjustment. You can export the fully populated covariance matrix of the network and can thread this matrix as well as the circle-arc points as incoming in a further analysis step (outside from JAG3D). Please take a look to Figure 1 to get an impression of the procedure we used so far.

Kind regards
Micha