.. _intro_proc_glorg:

:file:`glorg.cmd`
-----------------

The :program:`glorg` command file has the form:

.. literalinclude:: glorg.cmd
   :language: text

Frame definition (stabilization or spatial filtering) is accomplished in :program:`glorg` by specifying a set of sites for which the *a priori* coordinates are known at the level you expect the frame to be defined (usually 1–2 mm horizontal, 2–5 mm vertical) and the parameters you want to estimate in order to minimize the coordinate adjustments for these sites.
If an :content:`apr_file` is included in the :program:`glorg` command file, its coordinates will supersede those used in GAMIT or :program:`globk`, so it is not necessary to use the same *a priori* coordinates for all three programs.
For :program:`glorg`, the only coordinates that matter are those for the stabilization sites.
The :content:`pos_org` command specifies the parameters to be estimated, either translation only (omit the last three entries) or translation and rotation.
The rules for :content:`stab_site` are the same as those for :content:`use_site` in the :program:`globk` command file.
See :numref:`intro_prod_refframe` for a more comprehensive discussion of reference frame definition.

The next two entries in the file control the weighting of the quasi-observations (site coordinates) in the stabilization.
For :content:`cnd_hgtv` the first two values specify (for position and velocity, respectively) the down-weighting of heights relative to horizontal coordinates.
The default is 10, under the assumption that the uncertainties in heights are about three times higher than for the horizontal coordinates;
however, you can increase this ratio if want to define only a horizontal frame or you know that the height estimates are unreliable.
The last two values set limits on the uncertainty in height allowed to have a site included and serve to remove from the stabilization poorly determined sites.
For :content:`stab_it` the first value is the number of iterations used in the stabilization, the second the amount of reweighting that can take place between iterations, and the third the ratio of residual to uncertainty (sigma) allowed before a site is removed from the stabilization.
You can change the last value to fine-tune the inclusion or exclusion of sites from the frame definition.
These commands are discussed in more detail in the :program:`glorg` help file and Section 3.2 of the `GLOBK Reference Manual <http://geoweb.mit.edu/gg/docs/GLOBK_Ref.pdf>`_.