corr'.

               [1,1] = size(trgepc); double = class(trgepc)

               'trgepc' is expressed as seconds past J2000 TDB.

      srfvec   is the vector from the observer's position at `et' to
               the aberration-corrected (or optionally, geometric)
               position of `spoint', where the aberration corrections
               are specified by `abcorr'. `srfvec' is expressed in the
               target body-fixed reference frame designated by
               `fixref', evaluated at 