Run GLOBK to get 3-epoch (4-yr) time series

The key user-specific controls for this step (also incorporated in the sh_glred runs within each year) are the list of sites to be used in defining the reference frame, and the a priori coordinates for these sites. Here we use the same sites and coordinate file (igb14_comb.apr) as in the single-year solutions, but this may not always be the case. For the multi-year repeatabilities, we will use the combined H-files (.GLX) created in the year gsoln/ directories. So create a solution directory at the top level

$ mkdir vsoln

then change to the new directory and create a list of combined h-files for globk:

$ cd vsoln
$ ls ../????/gsoln/H*GLX > eura.gdl

Also copy the default template globk.cmd and glorg.cmd files to this directory, either using the same sh_glred -cmd, as before, or directly from ~/gg/tables/. For large or complex data sets, it’s helpful at this point to run glist which will check for blunders and give you a list of all the sites used and their spans. Program glist2cmd can then be helpful in establishing a use_site list. It may also be desirable to aggregate the data within each year, both to save time in the multi-year combination and to provide more representative long-term statistics. The procedure for doing this is given in the file sGPS_recipe.txt in the documentation directory on the web site.

$ rm globk_replong.org globk_replong.log
$ glred 6 globk_replong.prt globk_replong.log eura.gdl globk.cmd >& glred.out

Unlike in sh_glred, the rm command may be needed here since glred will concatenate the new .log and .org files with any previous files of the same name. The globk_replong.prt will not be created since we have set prt_opt NOPR in globk.cmd.