AN EXPERIMENT WITH MARITIME SATELLITE MULTIMODE COMMUNICATIONS AND POSITION FIXING

The National Aeronautics and Space Administration generously provided the use of the ATS-1 and ATS-3 satellites to Exxon and General Electric for one hour each working day over a seven mouth period so that they could evaluate the use of satellite links for maritime users. Voice, teletype, facsimile and video voice communications were conducted between the New York City office of Exxon and the ESSO BAHAMAS, a 32,000 ton tanker in service between Florida and the General Electric Radio-Optical Observatory near Schenectady, New York, and through the ATS-3 satellite between the Observatory and the ship. Exxon tested the link for three types of messages: 1) normal operational messages that comprise all the information exchange that usually takes place using HF telegraphy; 2) new operational messages, information usually sent by air mail either directly to or from the ship or to or from the agent in the ship's next port of call; 3) experimental messages that contain information available on ship or on shore that had never been exchanged between the two points. Examples would be the exchange of pictures from the ship, drawings, etc. Exxon concludes that satellite communications potentially offer a significantly better communications medium than anything presently available to ships at sea. There were no outstanding technical difficulties and the shipborne equipment was operated by the crew with a minimum of training and without the presence of GE or Exxon engineering personnel aboard, after an initial orientation period. User reactions were completely favorable and no problems could be envisioned on the acceptability of an operational system on ships of this kind. Ship positions were determined by two-satellite ranging using NASA's ATS-1 and ATS-3 satellites. The average difference was 1.3 nmi. between the satellite determined fixes and fixes determined by radar sightings of landmarks on voyages between East Coast ports as far north as Philadelphia and the ports of Aruba and Amuay in Venezuela. Factors affecting the accuracy are known and it is reasonable to expect approximately 1 nmi. accuracy for a VHF system if the satellites are tracked at a higher frequency band, and 0.1 nmi. accuracy for an L-band operational system.

  • Supplemental Notes:
    • Presented at the RTCM Assembly Meeting, St. Petersburg, Fla., April 1-3, 1974, with the Propeller Club of the United States. Vol. 1, Papers A-F, Maritime Electronics. Vol. 2, Papers G-N, Maritime Satellite Systems and Maritime Navigation. Vol. 3, Papers O-T, Maritime Telecommunication Trends. Vol. 4, Papers 0A-0I, Maritime Transponders and Collision Avoidance Systems. Sold as a complete 4 volume set for $15.00.
  • Corporate Authors:

    Radio Technical Commission for Marine Services

    /Federal Communications Commission
    Washington, DC  USA  20554
  • Authors:
    • LaRosa, R M
    • Anderson, R E
    • Hoffman, H
  • Publication Date: 1974-4

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00057089
  • Record Type: Publication
  • Source Agency: Radio Technical Commission for Marine Services
  • Report/Paper Numbers: Symposium Papers R
  • Files: TRIS
  • Created Date: Aug 16 1974 12:00AM