GOES Imager Navigation

last update 2 June 2002

NESDIS provides regular updates to the orbital status of the GOES satellites. Here is a sample listing:

 DATE:    10 MAY 2002(J-130)
  SUBJECT: NAVIGATION SUMMARY

                      (STORAGE) (STORAGE) (WEST)  (STORAGE) (EAST)
                      GOES-12a  GOES-11b GOES-10c GOES-9d  GOES-8e
  POSITION             89.952   101.130  135.166  105.746  75.319
  DRIFT RATE            0.028W    0.019E   0.028W   0.007W  0.040E
  FUEL REMAINING       82.359    95.142   33.158   20.324   9.409
  OXIDIZER REMAING    140.110   153.737   58.808   30.962  13.780
  INCLINATION           0.169     0.327    0.323    0.058   0.093
  MANEUVER DATE       --------  -------- -------- -------- --------
  MANEUVER TYPE       --------  -------- -------- -------- --------
  PROPELLANT COST     --------  -------- -------- -------- --------

                    GOES-7g  GOES-3g  MET-7h   MET-6h   MET-5h
  POSITION         172.713   107.545   0.227  350.938   62.949
  DRIFT RATE         0.040W    0.014W  0.017W   0.003E   0.014W
  FUEL REMAINING     6.305ef   2.173e  21.981   8.664    5.268
  INCLINATION        7.075    13.282   0.278    1.978    4.976
  SPIN RATE         100.711  100.411  99.832   99.872   99.778
  MANEUVER DATE    -------- -------- -------  -------- --------
  MANEUVER TYPE    -------- -------- -------  -------- --------
  FUEL COST        -------- -------- -------  -------- --------

  COMMENTS:
  (a)  GOES-12 data propagated from OATS orbit epoch 01/353 18:00 UTC.
        Fuel and oxidizer remaining are estimates after ZAP 1 01/354.
  (b) GOES-11 data propagated from OATS orbit epoch 02/121 06:00 UTC.
      Fuel and oxidizer remaining are estimates after RESPIN/ZAP2 01/164.
  (c) GOES-10 data propagated from OATS orbit epoch 02/130 06:00 UTC.
      Fuel and oxidizer remaining are estimates after EW 21 02/113.
  (d) GOES-9 data propagated from OATS orbit epoch 02/019 00:00 UTC.
      Fuel and oxidizer remaining are estimates after ZAP 3 02/017.
  (e) GOES-8 data propagated from OATS orbit epoch 02/130 12:00 UTC.
      Fuel and oxidizer remaining are estimates after EW 40 02/120.
  (f) Predicted  value. GOES-7 fuel after EW 02/106.  GOES-3  fuel  after
      REOR on 99/272.
  (g) Fuel uncertainty +/- 5 kilograms - no N/S maneuvers.
  (h) GOES-3,  and -7 data propagated from orbit epoch 02/105  00:00  UTC
      and 02/106 00:00 UTC respectively.
  (i) METEOSAT-5, -6 AND -7 data from orbit epoch 02/126 00:00 UTC.
  (j) GOES-2 was deorbited with 6 Station-Keeping Maneuvers from May 1-5,
      2001. It will no longer be updated in this document.

  Definition of terms:

  SK   --  Stationkeeping                POSITION       --  Degs W Long
  NS   --  Inclination change            DRIFT RATE     --  Degs/Day
  REOR --  Spin axis reorientation       SPIN RATE      --  RPM
  EW   --  In-plane station change       FUEL,OXID,PROP --  Kilograms

Do-It-Yourself Navigation

You are taking a big project if you want to personally navigate GOES images to latitude-longitude coordinates. You need to be able to receive the 2 Gbit/sec GVAR data stream at 1685 MHz to get at the constantly changing orbit-and-attitude information you need.

NESDIS provides a GOES Earth Location Users Guide (ELUG). Two major sites for GOES technical information are the Office of Satellite Operations (OSO) and the Office of Satellite Development (OSD). They reorganize their web sites frequently, so you will have to click-search for the information you want.

An easy thing to do is to use our "nav" lat-long coordinate files within the sectors that we serve from GOES-EAST and GOES-WEST. The associated "readme.nav.txt" files tell you how to interpret these "nav" files.

NOAA provides two kinds of navigation information, both inside the raw GVAR data broadcasts.

The documentation for the complex raw GVAR data stream is a few hundred pages long, embedded in an even larger "Operational Ground Equipment" (OGE) document. You can get a paper or PDF copy of the entire OGE document from NOAA-NESDIS in Washington DC.
There also is NOAA technical report NESDIS-82: "An Introduction to the Goes I-M Imager and Sounder Instruments and the GVAR Retransmission Format", which summarizes sevral aspects.
To get the original copy of the OGE complete document, try various word processor formatted files in our anonymous ftp account. These are several of attempts to translate the original digital OGE document -- none of them with any diagrams, unfortunately.
More recently, NOAA reformated the OGE document as PDF.

The documentation for the algebraic orbit-attitude-projection solution is also avaialable from NOAA-NESDIS. There are FORTRAN routines for carrying out the projection algorithm listed in that image-navigation document. We don't have a digital copy of that document.

All we do have is the digital form of the FORTRAN routines that NOAA-NESDIS was actually using as of mid-October 1995 (but not the same code listed in the doucmentation). You can get a copy of the NESDIS mid-October 1995 FORTRAN version via anonymous ftp. If you want the entire distribution as a tar-ball, get it here.

To compile this FORTRAN, we made some adjustments and we have some advice:

1) The navigation FORTRAN code was made to work on a HP Unix workstation
with the following modifications:

******************Shu Yang's Notes On 03/16/95 ************************
C       In order to make this program work, I made the following minor
C  modifications:

C  1) INCLUDE SYNTAX in main and all subroutines:
C               from $INCLUDE:'FILE.NAME' to INCLUDE 'FILE.NAME'.

C  2) REAL-TO-INTEGER CONVERSION FUNCTION in function GATT:
C               from I=INT4(IR) to I=INT(IR).

C  3) FORMAT SYNTAX in format lines 1100, 1200, 1300, 1400, 1500, 1600,
C       1700, 1800 and 1950:
C               from / to // between two data and adding ,/ at the end.
C 4) SYNTAX in subroutine TIMEX:
C               from c to C for a comment line.

C***********************************************************************

The above comments are at the very beginning of the main program.


2) As for the compiling error messages, only the first one generally makes
sense.  Many error messages are generated because the compiler has gone to
a wrong track since it met the first error.  In many cases, your correction
of one error will erase quite a lot error messages.


3) When compiling this software, I made sure that a certain data type
occupied the same storage space in different computers (e.g., 4 bytes for
storage of a floating number).  And when testing the software, I made sure
that the data were read into the program correctly.

We have not seen any other information about GOES navigation on the net. Please let me know of any useful links you find.

Good luck.


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mail icon Dennis.F.Chesters@nasa.gov
GOES Project