5.1 Distress Beacons
The types of Cospas-Sarsat 406 MHz distress beacons that are used by the Cospas-Sarsat System are illustrated in Figure 5‑1. Many of these beacons are activated automatically in the event of an accident. Others are designed to be triggered manually; however, once they have been activated, they will transmit their distress messages with no further intervention.
Figure 5‑1: Types of Cospas-Sarsat Distress Beacons
The different types of beacons are designed for use in different environments:
- Aviation: Emergency Locator Transmitter (ELT) and Distress Tracking ELT(DT) (for tracking aircraft in potential distress situations),
- Maritime: Emergency Position-Indicating Radio Beacon (EPIRB) and Ship Security Alerting System (SSAS) beacon (for security situations on SOLAS vessels), and
- Individual: Personal Locator Beacon (PLB) (not necessarily linked to an aircraft or a ship).
When activated, every 406 MHz distress beacon will transmit a signal that contains a digital encoded message, which includes:
· a country code to identify the nation in which the beacon is registered,
· a unique identifier to positively identify the beacon,
· an indication of the type of beacon from which it has been sent.
Some beacons include a receiver for a Global Navigation Satellite System (GNSS) or a link to a source (such as an aircraft navigation system) that is external to the beacon; these beacons will include the beacon location data in the transmitted message.
The characteristics that are necessary for the beacon signals to be compatible with the Cospas-Sarsat System are specified in various System documents[1],[2],[3],[4]. Other characteristics are regulated by national Administrations, separately from the System specifications.
The legal requirements for the carriage of various types of beacons are established by the Government of each country, based on their national requirements. The document C/S S.007 (Handbook of Beacon Regulations) is a summary of available information about the regulations in many countries. It should also be noted that many distress beacons are carried by individuals (and on vessels) on their own initiative, even in cases where there is no legal requirement mandating such carriage. However, the carriage and use of these beacons are still subject to the requirements and restrictions of the national laws on beacon carriage.
Every nation that authorizes the use of 406 MHz distress beacons is required either to maintain a beacon registry or to allow beacons with its country code to be registered in the International Beacon Registry Database (IBRD) operated by Cospas-Sarsat. For each beacon, the registry should contain the beacon identifier and the beacon message data, information about the vessel on which the beacon is carried, and contact information for the owner and operator of the beacon, as well as emergency contacts for someone who is unlikely to be with the beacon. This registry information will be made available, through the national MCC that is responsible for the region that includes the beacon’s nation of registry, to the appropriate RCCs. For those nations that do not operate their own beacon registry, the Programme operates an International Beacon Registry Database (IBRD) that provides the necessary registration services and that can be made available to the appropriate authorities.[5]
[1] The detailed specifications for the First-Generation Beacons (FGBs), which transmit a narrow-band (approximately 3 kHz) signal in a designated frequency channel, are contained in the document C/S T.001, “Specification for [First-Generation] Cospas-Sarsat 406 MHz Distress Beacons”, and (for SSAS beacons) in document C/S T.015, “Cospas-Sarsat Specification and Type Approval Standard for 406 MHz Ship Security Alert System (SSAS) Beacons”.
[2] The detailed specifications for the Second-Generation Beacons (SGBs), which transmit a Code-Division Multiple Access (CDMA) spread-spectrum signal (similar to those used by mobile telephones) that is distributed across the entire 406 MHz frequency band, are contained in the document C/S T.018, “Specification for Second-Generation Cospas-Sarsat 406-MHz Distress Beacons”.
[3] Document C/S T.012, “Cospas-Sarsat 406 MHz Frequency Management Plan”, describes the allocation of frequency channels, within the 406 MHz frequency band, for these beacons.
[4] Reference beacons are described in document C/S T.006, “Cospas-Sarsat Orbitography Network Specification”, and in document C/S T.022, “Cospas-Sarsat MEOSAR Reference Beacon Network Design Guidelines”.
[5] Document C/S D.004, “Operations Plan for the Cospas-Sarsat International 406 MHz Beacon Registration Database”, describes this database and explains how it is to be used. Information about registering a beacon is also available on the Cospas-Sarsat web site: select <Register Your Beacon>, or (on the Professional page) select <Beacons> and then <Beacon Registration>.