subroutine orb_save
c
c----------------------------------------------------------------------|
c                                                                      |
c      save the orbit parameters for the time specified.               |
c                                                                      |
c----------------------------------------------------------------------|
c      written by     r. l. west     bcss      3-dec-1987              |
c----------------------------------------------------------------------|
c      modified by     r. l. west     bcss      7-nov-1991             |
c           incorporated the use of iwindow in determining when to     |
c           collect the orbital parameters                             |
c----------------------------------------------------------------------|
c                                                                      |
c      variable     meaning                                            |
c        ***          ***                                              |
c                                                                      |
c----------------------------------------------------------------------|
c                                                                      |
c      common       purpose                                            |
c        ***          ***                                              |
c                                                                      |
c----------------------------------------------------------------------|
c                                                                      |
c      sub/func     purpose                                            |
c        ***          ***                                              |
c                                                                      |
c----------------------------------------------------------------------|
c                                                                      |
c      warning:                                                        |
c                                                                      |
c      does not check for year crossing!!!                             |
c                                                                      |
c----------------------------------------------------------------------|
c                                                                      |
c      note:                                                           |
c                                                                      |
c      to be used in conjuction with the routine orboftr               |
c                                                                      |
c----------------------------------------------------------------------|
c
      logical     igot_orbit, in_inc
c
c      integer*2   header(24), i, in, jdat(2812)
      integer*2   header(24), i, jdat(2812)
c
      integer*4   in
      integer*4   ifirst(2), iflag1, iflag2, ims, iorbyd, iorboft, 
     *            iorbtime, irb_ms, irb_yd, ire_ms, ire_yd, 
     *            itime(2,13), iwb_ms,iwb_yd, iwe_ms, iwe_yd, iwindow, 
     *            iyd
c
      real        orbs(4,13), r
c
      equivalence (jdat(1),header(1))
c
      data        igot_orbit/.false./,
     *            in_inc/.false./
c
      common      /blktim/iyd,ims,
     *            /maf1/jdat,
     *            /orbdat/itime,orbs,
     *            /orbit/iorboft,iwindow,iorbyd,iorbtime,in,ifirst
c
c-----------------------------------------------------------------------
c     *** calculate begin and end time of current record ***
c-----------------------------------------------------------------------
c
      irb_yd = iyd
      ire_yd = iyd
      irb_ms = ims
      ire_ms = irb_ms + 7999
      if (ire_ms .ge. 86400000) then
         ire_ms = ire_ms - 86400000
         ire_yd = ire_yd + 1
      end if
c
c-----------------------------------------------------------------------
c     *** calculate search time interval ***
c-----------------------------------------------------------------------
c
      iwb_yd = iorbyd
      iwb_ms = iorbtime - iwindow
      if (iwb_ms .lt. 0) then
         iwb_ms = iwb_ms + 86400000
         iwb_yd = iwb_yd - 1
      end if
      iwe_yd = iorbyd
      iwe_ms = iorbtime + iwindow
      if (iwe_ms .ge. 86400000) then
         iwe_ms = iwe_ms - 86400000
         iwe_yd = iwe_yd + 1
       end if
c*      type *, iwb_ms,iorbtime,iwe_ms,irb_ms,ire_ms
c      
c-----------------------------------------------------------------------
c-----------------------------------------------------------------------
c
      call cmptm2 (ire_yd, ire_ms, iwb_yd, iwb_ms, iflag1)
      call cmptm2 (irb_yd, irb_ms, iwe_yd, iwe_ms, iflag2)
      if (iflag1 .lt. 0) then     ! record prior to orbit
c*         type *, 'before'
         return
      else if (iflag2 .gt. 0) then     ! record after orbit
c*         type *, 'after'
         if (igot_orbit) then
            igot_orbit = .false.
            in_inc = .false.
            return
         end if
         in = in + 1
         itime(1,in) = iorbyd
         itime(2,in) = iorbtime
         iorbtime = iorbtime + iorboft
         if (iorbtime .ge. 86400000) then
            iorbtime = iorbtime - 86400000
            iorbyd = iorbyd + 1
         end if
         return
      else     ! record within interval
         call cmptm2 (irb_yd, irb_ms, iorbyd, iorbtime, iflag1)
         if (iflag1 .lt. 1) then
c*            type *, 'during before'
            if (.not. in_inc) then
               in = in + 1
               in_inc = .true.
            end if
c*            type *, in
            itime(1,in) = irb_yd
            itime(2,in) = irb_ms
            r = 0.0
            do i =1, 3
               r = r + float(header(i+8)) * float(header(i+8)) * 1e-6
            end do
            r = sqrt(r)
            orbs(1,in) = r
            orbs(2,in) = float(header(15)) * 0.01
            orbs(3,in) = float(header(19)) * 0.01
            orbs(4,in) = float(header(17)) * 0.01
            igot_orbit = .true.
         else
c*            type *, 'during after'
            if (igot_orbit) then
               iorbtime = iorbtime + iorboft
               if (iorbtime .ge. 86400000) then
                  iorbtime = iorbtime - 86400000
                  iorbyd = iorbyd + 1
               end if
               igot_ornit = .false.
               in_inc = .false.
               return
            end if
            if (.not. in_inc) then
               in = in + 1
               in_inc = .true.
            end if
c*            type *, in
            itime(1,in) = irb_yd
            itime(2,in) = irb_ms
            r = 0.0
            do i =1, 3
               r = r + float(header(i+8)) * float(header(i+8)) * 1e-6
            end do
            r = sqrt(r)
            orbs(1,in) = r
            orbs(2,in) = float(header(15)) * 0.01
            orbs(3,in) = float(header(19)) * 0.01
            orbs(4,in) = float(header(17)) * 0.01
            igot_orbit = .true.
         end if
      end if
c
c-----------------------------------------------------------------------
c-----------------------------------------------------------------------
c
      return
      end