c================================================================================
c
c NAME: get_grid_files
c
c PURPOSE: fills grid of TB max/min values constructed from max_grid.f.  
c
c EXTERNALS:
c            hirs1c.inc
c 
c NOTES: Reads 3 days of data for use in time_constraint.f routine.  Also checks 
c  all-sky grid box count values.  If number from daily grid file exceeds 50, then assume
c  navigation error and assign grid box TBmax with missing data value.
c
c HISTORY: Darren Jackson CIRES/ETL April 2002
c
c=================================================================================
      subroutine get_grid_files(iog,gmxmn)

      implicit none

      include   'hirs1c.inc'

      integer   iday,ii,jj,kk,iog(3)
      real      xgrd(nlon,nlat,ntim)
      real      gmxmn(nlon,nlat,ntim,3)
c
c* Read 3 days of max/min grid files
c
      do iday=1,3
         read(iog(iday),rec=1) xgrd    ! read hirs8 max data
         do ii=1,nlon
            do jj=1,nlat
               do kk=1,ntim
                  gmxmn(ii,jj,kk,iday)=xgrd(ii,jj,kk)
               enddo
            enddo
         enddo
c
c* QC check for navigation error
c
         if(iday .eq. 2) then
            read(iog(iday),rec=3) xgrd ! read hirs8 count data
            do ii=1,nlon
               do jj=1,nlat
                  do kk=1,ntim
                     if(xgrd(ii,jj,kk) .gt. 100.) then
                        gmxmn(ii,jj,kk,iday)=missing
                     endif
                  enddo
               enddo
            enddo
         endif

      enddo               

      return
      end