  We propose an efficient offline pointing calibration method for operational
antenna systems which does not require any downtime. Our approach minimizes the
calibration effort and exploits technical signal information which is typically
used for monitoring and control purposes in ground station operations. Using a
standard antenna interface and data from an operational satellite contact, we
come up with a robust strategy for training data set generation. On top of
this, we learn the parameters of a suitable coordinate transform by means of
linear regression. In our experiments, we show the usefulness of the method in
a real-world setup.
