NOAA KLM User's Guide

Section 5.2

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5.2 Alternate Sources and Forms of Satellite Prediction Position Information

The primary source for orbital prediction information for NOAA operated satellites is directly from NOAA via the Global Telecommunications System (GTS) or the Internet, and the main form of this information is the TBUS bulletin. Many HRPT and APT station operators, and some government agencies, do not have access to the GTS or Internet and must be able to obtain orbital prediction information from other sources.

These alternate sources include, but are not limited to, WEFAX broadcasts from U.S. geostationary satellites, electronic mail, telephone bulletin board systems, high frequency radio broadcasts, commercial environmental data providers, and the Aeronautical Fixed Telecommunications Network (AFTN).

NOAA maintains an Internet site (the NOAASIS) that always has the current TBUS bulletins. The TBUS bulletin is also broadcast once daily as part of the WEFAX transmission from U.S. geostationary satellites, for stations within range and with the proper receiving equipment.

With the proper receiving equipment and teleprinter, some station operators are able to intercept the GTS radio-teletype (RTTY) meteorological transmissions containing the TBUS message. A number of major communications centers on the GTS relay this information via radio-teletype, especially for the use of ships on the high seas. Potential users would have to contact the nearest major center for frequencies and schedules.

In Africa and parts of the Middle East, a number of government meteorological services receive the TBUS bulletin as part of the Meteorological Data Distribution (MDD) broadcast via the METEOSAT geostationary satellite. Satellite readout station operators without other sources of orbital information are urged to contact an office of their national meteorological service to see if arrangements can be made to obtain copies of these messages.

The nonprofit, Radio Amateur Satellite Corporation (AMSAT) and its affiliates around the world serving the amateur radio community, broadcast the two line element messages daily via packet radio teletype. These broadcasts can be received in many parts of the world.

As of mid-1995, the U.S. Coast Guard included the TBUS message in high frequency, radio teletype broadcasts directed at the eastern and central North Pacific Ocean.

A more complete list of satellite navigation sources and points of contact is included in Appendix E.

Apart from the TBUS messages, the other most common form for transmitting orbital information are the two-line element (TLE) messages. These have the advantage of being very compact, and can be incorporated into many computer programs which will produce accurate satellite tracking and gridding information. The two-line, mean Keplerian orbital elements are derived from the NORAD SGP4 (Simplified General Perturbation) model. While similarly named elements appear in both the two-line and TBUS messages, the values are not interchangeable between systems to compute satellite tracks using the TBUS or NORAD two-line elements. Doing so will result in large errors. Details on decoding the two-line element messages appear in Appendix A.

5.2.1 Sources of Orbital Information for NOAA Polar Orbiting Satellites

5.2.1.1 Internet

NOAASIS World Wide Web site

Operated by NOAA/NESDIS and has orbital elements (TBUS and two-line) for all NOAA satellites, operating schedules, technical information and documents.

URL: http://noaasis.noaa.gov/NOAASIS/

For further information, contact NESDIS via email at satinfo@noaa.gov
fax: 301-457-5620
telephone: 301-457-5681 x126
mail:

Direct Readout Services Coordinator
 
NOAA/NESDIS E/SP3
 
FOB4, Room 3320
 
5200 Auth Road
 
Suitland, MD 20746-4304 USA

Celestial World Wide Web site

Operated by T. S. Kelso, has two-line elements for all NOAA satellites, and many other satellites.

URL: http://www.celestrak.com.

Florida State University

Provides the current TBUS only, in directory /pub/weather/satellites/.

URL ftp://ftp.met.fsu.edu

"WXSAT" email listserver

This is a privately run service that will email orbital elements, satellite schedules, and other items of interest, without charge. To subscribe and receive additional information, send an email to:

wxsat-request@met.fsu.edu.

The email should contain no "subject" line, and the text of the message should read: "subscribe (enter your name)."

5.2.1.2 Telephone Bulletin Board Systems (BBS)

Dial-in telephone Bulletin Board Systems (BBS) have been replaced with the increasingly widespread use of the Internet. If any direct readout users or Bulletin Board System operators are aware of such telephone dial-in systems distributing meteorological satellite orbital elements, please advise satinfo@noaa.gov with complete information.

5.2.1.3 Amateur Radio Transmissions

For more information on these broadcasts of satellite prediction messages, available in much of the world via the Radio Amateur Satellite Corp., contact:

AMSAT-NA
850 Sligo Avenue, Suite 600
Silver Spring, MD 20910 USA

5.2.1.4 Commercial On-Line Services

Orbital elements are available in the Space Forum of the Compuserve Information Service and the Astronomy Forum of America On Line. Further information about any of these service providers is available from:

America On Line
8619 Westwood Center Drive
Vienna, VA 22182 USA

Compuserve Information Service
5000 Arlington Centre Blvd.
Columbus, OH 43220 USA

Additions and corrections to this list of sources for satellite orbital elements should be mailed to:

Direct Readout Services Coordinator,
NESDIS Direct Services Division, E/SP3,
FOB4, Room 3320
5200 Auth Road
Suitland, MD 20746-4304 USA

Amended April 16, 2003


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