# Group station calculation test (Allgemeines)

Hi,
In the context of group station calculation, we would like to create fixed links between double points of the geodetic network. Physically, we have for example 2 measurement stations, one has references; the other does not. The 2 measurement stations are connected to each other thanks to close points measured by the 2 stations. These close points are called double points; they have fixed vectors.
Thus, at the input of JAG3D, we would like to insert 2 types of fixed data: the coordinates of the reference prisms and the fixed vectors between the double points.
We tried to insert this information as a GNSS3D vector between the double points of the network but it did not work: the vectors were considered as observations and readjusted. We could insert them in the Hz, V, D observations but we did not find the option to consider an observation as fixed. Could you help us on this point?
Thank you,
Regards,
Antoine C.