procedure dispcorr is used to compute group delays and dispersion corrections for the data read from the .coh file.
The dispersion corrections are computed for every data point, as well as the corrections due to the motions of the siderostat pivots. The latter are solutions for the X, Y, and Z coordinates done by INCHWORM. They are transformed into delays and interpolated to the time stamps of the data points by metrocorr. Both are applied when the point data is averaged. (The delay corrections due to pivot motions are also available in the data file from INCHWORM, in which case the astrocorr procedure is used to just do the interpolation. The results of both procedures are stored in the same variable.)