Detailed Beacon Types

A 406-MHz beacon designed for use in an aircraft is known as an Emergency Locator Transmitter (ELT). One designed for use aboard a marine vessel is called an Emergency Position-Indicating Radio Beacon (EPIRB). More information on SSAS beacons is available in the first tab below.  A beacon designed to be carried by an individual is known as a Personal Locator Beacon (PLB).  Sometimes PLBs are carried aboard aircraft or vessels, but you must check with local authorities about the circumstances under which this is permitted.  

Only beacons operating at 406 MHz are compatible with the Cospas-Sarsat System.

Information regarding beacon selection and purchase is provided at "How Do I Select and Purchase a 406 MHz Cospas-Sarsat Beacon?" (Public/Beacon Ownership).

Our "Beacon Coding Guide & Tutorial" (Pro/Beacons/Beacon Information) provides both an interactive description on beacon message protocol selection and guidelines on beacon message coding.

The information provided in this portion of the website is intended as a summary of the information provided in the following Cospas-Sarsat System documents (Pro/Documents):

  • C/S G.005 "Cospas-Sarsat Guidelines on 406 MHz Beacon Coding, Registration, and Type Approval".

  • C/S S.007 "Handbook of Beacon Regulations"; 

  • C/S T.001 "Specification for Cospas-Sarsat 406 MHz Distress Beacons"; and
  • C/S T.015 "Cospas-Sarsat Specification and Type Approval Standard for 406 MHz Ship Security Alert System (SSAS) Beacons";

The above documents can be downloaded free of charge from the Professionals website at Pro/Documents/System Documents. If the information provided on the website conflicts with that provided in documents C/S G.005, C/S T.001 and C/S T.015, the official System documents shall take precedence.

Furthermore, individual administrations may have additional national beacon technical and coding requirements that are not addressed in the above documents.

Special Purpose Beacons

Further information about three types of special purpose beacons are presented in the tabs below. 

 

 

  • SSAS Beacons
  • Reference Beacons
  • Orbitography Beacons

Ship Security Alert System (SSAS)

  • 05 May 2005 A new system that contributes to the International Maritime Organization’s (IMO) efforts to strengthen maritime security and suppress acts of terrorism against shipping has been implemented by Cospas-Sarsat. Modifications have been made to the Cospas-Sarsat System to provide discrete security alerts and the Cospas-Sarsat 406 MHz Ship Security Alert System (SSAS) now complies with IMO requirements.

    System Status

    In 2004, two system tests were performed to demonstrate that the Cospas-Sarsat system was capable of supporting SSAS processing. Type-approval of several new 406 MHz beacons for SSAS use has been completed. A comprehensive list of Cospas-Sarsat approved SSAS beacons, with associated manufacturer information, is available on the Cospas-Sarsat website.

    Implementation History

    At its 31 st Session in October 2003 the Cospas-Sarsat Council approved the implementation of a 406 MHz Ship Security Alerting System (SSAS) in the Cospas-Sarsat System. The Cospas-Sarsat SSAS implementation complies with IMO requirements as outlined in SOLAS Chapter XI-2 “Special Measures to Enhance Maritime Security” and Resolutions MSC.136(76) and MSC.147(77) on performance standards for SSAS. The required minimal modifications to the System were initially implemented and tested in May and September 2004. On the basis of those tests and in view of the redundancy in the Cospas-Sarsat Ground Segment, the System is now considered capable of supporting SSAS processing .

    Cospas-Sarsat, as an intergovernmental organization, will provide this service on a long-term basis free-of-charge to the end user. Additionally, Cospas-Sarsat provides a robust alerting capability with satellites in both low-earth and geostationary orbits, an automated data distribution network over reliable communication links, a process to register beacon owner information with national authorities and a process to type approve devices to ensure reliable operations.

    Implementation Details

    There are two major elements to the 406 MHz SSAS: the transmitter required for initiating SSAS alerts and a methodology for distribution of SSAS alert messages in the Cospas-Sarsat Ground Segment.

    A specific 406 MHz beacon coding protocol defined in document C/S T.001, “Specification for Cospas-Sarsat 406 MHz Distress Beacons”, is used to discriminate a ship security alert from a distress alert. The agreed specification for the SSAS beacon provides for accurate Global Navigation Satellite System (GNSS) encoded location information in the beacon message and requires the inclusion of the vessel MMSI for the beacon identification. The specification prohibits use of a homing device in order to make beacon transmissions covert.

    The Cospas-Sarsat specification only deals with the electrical and transmission requirements that ensure the compatibility of the SSAS beacon with the satellite processing system. National Administrations and standards organizations (e.g. RTCM in the United States) have defined additional requirements for 406 MHz SSAS beacon activation and installation.

    Alert Distribution Procedures

    The distribution of SSAS alerts within the Cospas-Sarsat Ground Segment uses a modified version of the standard data distribution procedure. As in normal Cospas-Sarsat operations, all Local User Terminals (LUTs) receive the 406 MHz SSAS beacon messages, retrieve the GNSS encoded location, and generate a Doppler location (LEOLUTs only). The ship security alert data is then passed to a Mission Control Centre (MCC) where it is automatically routed to the MCC that serves the Flag State identified in the beacon message, regardless of the physical location of the beacon. That MCC then delivers the ship security alert to a single point of contact identified by the Flag State as its "competent authority", per SOLAS Chapter XI-2 Regulation 6.2.1. In the Cospas-Sarsat implementation of SSAS, a vessel cannot send a ship security alert directly to its Company. A sample alert message can be found below.

    System Level Tests

    The SSAS functionality of the Cospas-Sarsat System was tested in 2004. In the future, the Cospas-Sarsat SSAS will be routinely tested as part of the annual System-wide test of the Cospas-Sarsat Ground Segment.

    Competent Authorities

    IMO has made available (Circular letter No. 2514, 8 December 2003) a web-based reporting system that allows Administrations to supply the information required by SOLAS regulation XI-2/13, including points of contact for competent authorities for distribution of ship security alerts. IMO invited SOLAS Contracting Governments to nominate a single national point of contact for maritime-security matters. Details on use of the IMO Global Integrated Shipping Information System (GISIS) database are available on the IMO website www.imo.org.

    In addition to providing the required information to IMO, Administrations that decide to use the Cospas-Sarsat System for ship security alerting should contact their supporting Cospas-Sarsat MCC to coordinate a method for distribution of SSAS alerts. The MCC serving a given Flag State can be identified in document C/S A.001, “Cospas-Sarsat Data Distribution Plan”, Annex I/D; contact information for the MCC can be found in Annex II/A.

    Sample SIT 185 Ship Security Alert

    SIT 185

    406 MHz SHIP SECURITY ALERT

    (to be transmitted only to competent security authority)

    (LEOSAR - with encoded position)

    1. SHIP SECURITY COSPAS-SARSAT POSITION RESOLVED ALERT

    2. MSG NO. 17002 UKMCC REF 12345

    3. DETECTED AT 10 JUL 04 2130 UTC BY SARSAT 09

    4. DETECTION FREQUENCY 406.0281 MHZ

    5. COUNTRY OF BEACON REGISTRATION 232/G.BRITAIN

    6. USER CLASS – SHIP SECURITY WITH ENCODED POSITION – MMSI LAST SIX DIGITS 387718

    7. EMERGENCY CODE - NIL

    8. POSITIONS

    RESOLVED - 55 23.2N 022 29.9W

    DOPPLER A - 55 19.1N 022 25.4W

    DOPPLER B -

    ENCODED - 55 23.2N 022 27.0W UPDATE TIME UNKNOWN

    9. ENCODED POSITION PROVIDED BY EXTERNAL DEVICE

    10. NEXT PASS TIMES

    RESOLVED - 10 JUL 04 2201 UTC

    DOPPLER A - NIL

    DOPPLER B - NIL

    ENCODED - NIL

    11. HEX ID 1D18BD50C0FFBFF

    12. ACTIVATION TYPE - MANUAL

    13. BEACON NUMBER ON AIRCRAFT OR VESSEL - NIL

    14. OTHER ENCODED INFORMATION

    A. ENCODED POSITION ACCURACY - 4 SECONDS

    15. OPERATIONAL INFORMATION

    REGISTRATIONAL INFORMATION AT UKMCC

    TELEX: 75194 UKMCCK G

    AFTN: EGQPZSZX

    TELEPHONE: (44-1343) 836015

    16. REMARKS - This is a ship security alert. Process this alert according to relevant security requirements.

    END OF MESSAGE

Cospas-Sarsat Reference Beacons

Identification

Lat. / Long.

Location

Elevation
(metres)

Time Interval
(secs)

Transmit Frequency (MHz)

CANADA 
A79EE E26E3 2E1D0

53°40.72'N 
113°18.90' W

Edmonton

654

50

406.021843

FRANCE 
9C7FEC2AACD3590 *

49°21.09' S 
070°15.36' E

Kerguelen

80

30

406.021856

RUSSIA 
A23C0 00000 00000 *

55°37.20' N 
037°30.48' E

Moscow

T.B.D.

50

406.022103

UK 
9D1FC FA7AB 0D990

51°10.20' N 
004°03.06' W

Combe Martin

265

50

406.022000

Notes:

* Indicates that this location has not yet been provided in the Bureau International de l'Heure (BIH) Geodetic Reference System

Reference beacons are beacons which are installed and operated on a semi-permanent basis. Users should consult the national MCC for current status information. These beacons may not meet the orbitography specifications. Reference beacons must meet the following requirements:

- be encoded with a test protocol; transmit with a repetition period of 50 + 2.5 sec and preferably be varied over that range; and
- transmit at 406.022 MHz + 1 kHz.

Orbitography Beacons

The same orbitography / reference beacon should not be used for both Doppler location accuracy assessment and orbit updates.

Cospas-Sarsat System Orbitography Beacons

Identification

Lat. / Long.

Location

Elevation (metres)

Time Interval (secs)

Transmit Frequency (MHz)

DENMARK
9B621 97CA7 03500

77°27.885' N
069°13.033' W

near Thule

36.59

30

406.021870

FRANCE
9C600 00000 00001

43°33.60' N
001°28.80' E

Toulouse

214.27

30

406.022000

FRANCE *
9C634 E2AB5 09240

43°33.60' N
001°28.80' E

Toulouse

214.27

30

406.034000

NORWAY
A0234 BF8A7 335D0

78°13.739' N
015°23.730' E

Longyearbyen

502.4

30

406.022001

USA
ADC268F8E0D3730 **

77°50.762' S
166°42.707' E

McMurdo Station, Antarctica

170.962

30

406.022000

Notes:

* This second French beacon has all the characteristics of an orbitography beacon, except the transmit frequency of 406.034 MHz, set to avoid interference with the Sarsat time calibration beacon. The beacon will be equipped by default with an LHCP antenna to support MEOSAR applications with the DASS proof-of-concept constellation.

** Indicates that this location was provided in the International Earth Rotation System (IERS) Terrestrial Reference Frame or ITRF-93. Other locations are provided in the Bureau International de l'Heure (BIH) Geodetic Reference System.