Frequently Asked Questions


What is SARSAT?
SARSAT is an acronym for Search and Rescue Satellite Aided Tracking. The United States is a founding party in the international Cospas-Sarsat program.

What is COSPAS?
Cospas is a Russian acronym for “Space System for Search of Vessels in Distress”.

What is the Cospas-Sarsat Program?
The Cospas-Sarsat Program is an international organization that provides space-based relay of distress signals, or alerts, from emergency beacons that use the 406 megahertz (MHz) frequency. Cospas-Sarsat provides the alerts to search and rescue (SAR) authorities internationally.
The governments of Canada, France, Russia and the United States (the Parties) have signed an agreement to provide for the long-term operation of the system and to support the objectives of the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO) concerning search and rescue. In addition to the four Parties and the two Participating Organizations (IMO and ICAO), Cospas-Sarsat international participation includes 29 ground segment providers and 9 user states.

When was Cospas-Sarsat Formed?
The first Cospas satellite launch was in 1982, during the same year, the first rescue using the system was recorded. The system was declared operational in 1985. At this time the four member nations of Cospas-Sarsat were working under a Memorandum of Agreement. As the program matured, it was decided to have an intergovernmental agreement between the Governments of Canada, France, United States, and at that time the Union of Soviet Socialist Republic. This intergovernmental agreement was signed in 1988 and established the Cospas-Sarsat Council and the Secretariat.

What is the Cospas-Sarsat Secretariat?
The Cospas-Sarsat Secretariat is the permanent administrative organization of the international program responsible for assisting the Cospas-Sarsat Council in implementing the Program. The Secretariat contains a small, specialized, and dedicated staff that assists in organizing meetings, administering the international budget, and providing technical and operational assistance.

Why is the National Oceanic and Atmospheric Administration (NOAA) involved in Search and Rescue?
NOAA operates the nation’s civil environmental satellites. These satellites are used to monitor the weather. These satellites also carry instruments that detect 406 MHz emergency beacons. As NOAA operates the satellites that carry search and rescue instruments, and operates the equipment to receive and process distress signals, it is the lead agency in the United States for the Cospas-Sarsat Program. NOAA also represents the United States to the international Cospas-Sarsat Program.

What other agencies are involved with Cospas-Sarsat in the United States?
Besides NOAA, the partners in the national Cospas-Sarsat program are the U.S. Air Force, responsible for inland search and rescue coordination, the U.S. Coast Guard, responsible for maritime search and rescue and the National Aeronautics and Space Administration (NASA), responsible for research and development.


Why do you refer to beacons as “406 MHz emergency beacons”?
The beacons associated with the Cospas-Sarsat program only operate in the 406.0 MHz to 406.1 MHz frequency band to transmit their digital messages to satellites. This frequency is restricted in the International Telecommunication Union (ITU) Radio Regulations to low power satellite emergency position-indicating beacons in the mobile satellite service. The “406” differentiates these beacons from older 121.5 MHz beacons that could not be uniquely identified.

What is an Emergency Position-Indicating Radio Beacon (EPIRB)?
An EPIRB is an emergency position-indicating radio beacon used in maritime watercraft. It is a device that can be automatically or manually activated to transmit a distress signal to a satellite. EPIRBs that activate automatically typically have a hydro-static release mechanism that allows the beacon to release from its bracket, float to the surface and start transmitting. The beacon, along with the bracket, has to sink to approximately 3 meters before it will activate automatically. This should be taken into account when mounting an automatic type EPIRB.

What is an Emergency Locator Transmitter (ELT)?
An ELT is an emergency locator transmitter used in aircraft. It is a device that can be automatically or manually activated to transmit a distress signal to a satellite. ELTs that activate automatically typically have a “G” or gravity switch that triggers the ELT when it senses that a crash has occurred.

What is a Personal Locator Beacon (PLB)?
A PLB is a personal locator beacon designed to be carried by an individual. They can only be activated manually. PLBs can be used by people operating in remote areas.

What is a location protocol 406 MHz emergency beacon?
All 406 MHz emergency beacon types (EPIRBs, ELTs, and PLBs) have certain models that are equipped with Global Position System (GPS) receivers. 406 MHz emergency beacons with GPS receivers can include the GPS derived location of the beacon in the digital message transmitted by the beacon. Thus, when the alert message is received by Search and Rescue authorities they will have a location to begin their search.

How can I contact my 406 MHz beacon manufacturer?
See the list of Cospas-Sarsat approved manufacturers from the Cospas-Sarsat website.

What is the difference between ELTs that operate at 121.5 MHz and those that operate at 406 MHz?
121.5 MHz beacons transmit an analog signal that can only be detected by personnel monitoring 121.5 MHz on a radio on the ground or in an aircraft. 121.5MHz is no longer detected by Cospas-Sarsat satellites. The analog signal does not contain any information about the beacon or its user. Alternatively, 406 MHz beacons transmit a digital signal that contains information on the type of beacon and the owner. Additionally, 406 MHz beacons can be linked to registration information that can provide search and rescue forces valuable information when responding to a distress signal.

Why can’t I register a 121.5 MHz ELT?
A 121.5 MHz emergency beacon transmits an analog signal that does not contain identifying information. Therefore, there is no way to register a 121.5 MHz beacon.

What is the beacon identification code?
The beacon ID, also referred to as the Unique Identification Number (UIN) is comprised of 15 hexadecimal characters. Hexadecimal characters are made of numbers (0 through 9) and the letters A, B, C, D, E and F. This code enables the beacon to be uniquely identified, and connected to a specific person or entity.

How do I test my emergency beacon?
406 MHz emergency beacons should only be tested using the “self-test” feature of the beacon or the beacon should be taken to an authorized dealer or test facility. Always refer to the manufacturer’s instructions when conducting a self-test of your emergency beacon. 406 MHz emergency beacons should never be activated unless you are in grave and imminent danger.

What is a false alert?
A false alert is an activation of an emergency beacon in a non-distress situation. Examples of false alerts include accidentally turning on an emergency beacon, improperly testing a beacon or incorrectly mounting an emergency beacon so that it falls out of its bracket and activates.

What can I do to reduce false alerts?
You have the primary responsibility to prevent false alerts. You should ensure that you only activate an emergency beacon in situations of grave and imminent danger. You should also follow the manufacturer’s instructions for testing your beacon. Lastly you should ensure that automatically activated beacons are properly mounted so that a simple “bump” will not cause them to fall out of their bracket and activate.

What should I do if I have accidentally activated my emergency beacon?
If for any reason your beacon is activated accidentally you should contact the appropriate rescue coordination center:

    1. U.S. Coast Guard at 1-855-406-USCG (8724)
    2. U.S. Air Force Rescue Coordination Center at 800-851-3051
    3. Alaska Rescue Coordination Center at 800-420-7230.

If you cannot contact these organizations directly, you should use any means available to inform the appropriate authorities that a false alert has been transmitted and should be cancelled.

How can I dispose of my 406 MHz emergency beacon?
You should ensure that when you dispose of your beacon (for example when it is damaged) it should be made inoperable, either by removing its battery and, if possible, returning it to the manufacturer, or by demolishing it. If a beacon is to be returned to the manufacturer with the battery still installed, it should be wrapped in tin foil to prevent transmission of signals during shipment. Please update your Beacon Registration if you sell or dispose of a registered 406 MHz beacon.


What satellite systems does SARSAT use to relay of distress signals, or alerts, from 406 MHz emergency beacons?
The current U.S. SARSAT system utilizes three types of satellites to relay distress signals. Low Earth Orbiting Search and Rescue (LEOSAR) Satellites, Geostationary Search and Rescue (GEOSAR) Satellites and Medium Earth Orbiting Search and Rescue (MEOSAR) Satellites are all used to relay distress signals from 406 MHz emergency beacons .

What is the difference between a geostationary orbit, medium earth orbit and a low earth/polar orbit?
A satellite in a geostationary orbit is at an altitude of 22,300 miles (35,890 kilometers). The satellite moves in a circular orbit in the equatorial plane around the Earth at the same speed that the Earth rotates. Because of this, it appears to remain over a fixed point on the Earth’s surface. This position is ideal for making uninterrupted observations of the weather or environmental conditions in a given area. This same principle allows it to monitor for 406 MHz distress beacons. However, satellites in geostationary orbit cannot see the polar regions of the world.

GNSS satellites in the GPS, GLONAS, and GALILEO global positioning constellations operate in medium earth orbit at an altitude between 19,000 and 24,000 km. The constellation consists of at least 24 satellites arranged in orbits so than no less than four SAR equipped satellites will be visible from anywhere on Earth at any time. Reverse triangulation algorithms using frequency difference of arrival (FDOA) and time difference of arrival (TDOA) allows for near instantaneous global detection and position fixes after one beacon burst.

A low earth/polar orbit allow the satellites to observe the entire Earth’s surface as it rotates beneath it. Most of these orbits are at an altitude of 500 miles (800 km) and take about 100 minutes to revolve around the earth. The sun-synchronous orbit is a special case of a polar orbit with inclination of 98.7 degrees, that precesses at exactly the required rate (~ 1 degree per day) to remain in the same local time plane as the Earth rotates around the sun. Satellites in polar orbit provide emergency beacon users with global coverage (including the Polar Regions).

Why are there three different satellite systems?
Each system has certain advantages that when combined provide a more responsive overall system.

What are the advantages of the Low Earth Orbiting Search and Rescue (LEOSAR) Satellites?
The LEOSAR satellites can compute a location for a 406 MHz emergency beacon using a method called “Doppler shift”. Computing a location using Doppler shift requires the satellite to be moving. The geostationary satellites cannot independently compute a location for a 406 MHz emergency beacon. The LEOSAR satellites also provide global coverage, including the Polar Regions, for 406 MHz emergency beacon detection.

What are the advantages of the Geostationary Search and Rescue (GEOSAR) Satellites?
While the GEOSAR satellites cannot provide an independent location of a 406 MHz emergency beacon they can provide near-instantaneous detection. On average, the GEOSAR satellites provide a 46-minute time advantage over a LEOSAR satellite for first detection of a 406 MHz emergency beacon. However, the geostationary satellites cannot detect 406 MHz emergency beacons in the Polar Regions.

If a 406 MHz emergency beacon is equipped with a Global Position System (GPS) receiver, the digital message transmitted by the beacon can contain the GPS-generated position of the beacon.

What are the advantages of the Medium Earth Orbiting Search and Rescue (MEOSAR) Satellites?
MEOSAR provides an enhanced distress alerting capability characterized by near instantaneous global detection of emergency beacons, improved location accuracy, high levels of redundancy and availability, robust beacon communication links, and improved flexibility against obstruction and interference. With decreased detection times and increased accuracy, MEOSAR will not only equate to reduced costs, but most importantly, result in more lives saved.


What is a local user terminal?
Cospas-Sarsat ground stations are called Local User Terminals (LUTs). These satellite receiving units are the ground stations that receive emergency beacon distress alerts relayed from the satellites. There are three-types of LUTs, Low Earth Orbiting LUTs (LEOLUTs), Geostationary LUTs (GEOLUTs) and Medium Earth Orbiting LUTs (MEOLUTs). Once a signal is received and processed at the LUT, it is transmitted to the mission control center (MCC) that operates that particular LUT. The LUTs are fully automated and completely unmanned at all times.

What is a LEOLUT?
A LEOLUT tracks the low earth orbit search and rescue (LEOSAR) satellites as they pass across the sky and receives the distress signals relayed by them. Each LEOLUT usually consists of a tracking-enabled antenna, a processor, and communications equipment. LEOLUTs track, receive and process alerts from the POES, European Meteorological Operational (METOP) satellites, and the Russian Nadezhda satellites.
In the U.S., dual LEOLUTs are located at:

    • Andersen Air Force Base (AFB), Guam
    • USCG Communications Station, Hawaii
    • NOAA Command and Data Acquisition station, Alaska
    • USCG Communications Station, Florida

Dual LEOLUTs at each site allow NOAA to resolve satellite tracking conflicts and provides redundancy in case of failure.

What is a GEOLUT?
A GEOLUT is fixed on one of the geostationary search and rescue (GEOSAR) satellites and receives the distress signals detected by them. GEOLUTs track, receive and process alerts from the SAR payloads on the GOES East and GOES West satellites. In the U.S., two GEOLUTs are located in Suitland, Maryland. Both GEOLUTs perform error detection and correction on 406 MHz distress beacon messages and automatically generate alert messages to the USMCC.

What is a MEOLUT?
MEOLUTs track, receive and process alerts from the SAR payloads on US GPS satellites, European Union Galileo satellites and Russian Federation GLONASS satellites.
In the U.S., six channel MEOLUTs are located at:

    • USCG Communications Station, Hawaii
    • USCG Communications Station, Florida

Once a signal is received and processed at the LUT it is transmitted to the mission control center (MCC) that operates that particular LUT. The LUTs are fully automated and completely unmanned at all times.
The GEOLUTs are located in Suitland, Maryland at the U.S. Mission Control Center housed in NOAA’s Satellite Operations Facility on the Suitland Federal Center.


What is a Mission Control Center (MCC)?
A mission control center (MCC) serves as the hub of information sent by the Cospas-Sarsat system. All Cospas-Sarsat MCCs are interconnected through regional MCCs that handle data distribution in a particular area of the world. Currently, there are six (6) data distribution regions served by the United States, France, Russia, Australia, Japan and Spain. The system utilizes several communication modes to ensure the reliable distribution of alert data and system information.

Where is the United States MCC located?
The United States Mission Control Center (USMCC) is located in Suitland, MD, a suburb of Washington, DC.

What are the functions of the USMCC?
The main function of an MCC is to collect, store, and sort alerts from LUTs and other MCCs, and to distribute alerts to search and rescue authorities and other MCCs.

The MCC will Validate, match, and merge alerts to improve location accuracy and determine the correct destination. The MCC also correlates alerts with registration records and appends that information to the alert to assist with rescues. The MCC geographically sort and then transmit alerts to appropriate Rescue Coordination Centers (RCCs) and SAR Points of Contact (SPOC). Redundant data is filtered by the MCC and system support and monitoring is performed.

Additionally, the USMCC performs the role of coordinating spacecraft operations and is operated by the National Oceanic and Atmospheric Administration (NOAA). The USMCC is manned 24 hours a day, 365 days a year.


Why should I register my 406 MHz emergency beacon?
Registration is free and can result in a more efficient search and rescue (SAR) effort.
Unlike registration for a manufacturer warranty, beacon information is used by Search and Rescue (SAR) authorities along with the distress signal from your beacon, solely to help locate you and save your life in an emergency.

Beacon registration is required by Federal regulations (Title 47 of the CFR , Parts 80, 87 and 95). Failure to register the beacon, or to notify the National Oceanic and Atmospheric Administration (NOAA) of a change in beacon ownership, could result in penalties and/or fines issued to the owner by the Federal Communications Commission.

What happens to my information after I register my beacon?
The registration information is only released to search and rescue authorities such as the U.S. Coast Guard and the U.S. Air Force. In certain cases NOAA may release your registration information to beacon manufacturers or service agents so that they may send you urgent service announcements.

NOAA, under the Privacy Act of 1974 (as amended), is required to adopt minimum standards for the collection and processing of personal information and to publish detailed descriptions of these procedures. The Privacy Act also limits the making of such records available to other public and private agencies or parties. Lastly, it requires agencies to make records on individuals available to them upon request, subject to certain conditions and exclusions.

Ultimately, your registration information ends up in the hands of the search and rescue authorities who are responsible for responding to search and rescue incidents. When you activate your 406 MHz emergency beacon, the digital alert message received through the Cospas-Sarsat system contains the Unique Identification Number (UIN) of your 406 MHz emergency beacon. When this digital message is received at the U.S. Mission Control Center, the UIN is automatically compared to the NOAA registration database. If the UIN is found in the NOAA registration database your registration information is automatically appended to the alert message that is forwarded to the responsible search and rescue authority.

How can I register my 406 MHz EPIRB, ELT or PLB or update my information?
There are several ways to register your 406 MHz beacon with NOAA. The preferred method of registration is to register your beacon online at

Alternatively, you may mail the original, signed form to NOAA at: (NOTE: U.S. Postal Mail only! No courier deliveries are accepted at this address. Please contact the SARSAT RGDB at 301-817-4515 or toll-free at 1-888-212-SAVE (7283) for information on other delivery options.)

1315 East West Hwy
Silver Spring, MD 20910

Or you could fax the signed form to NOAA at 301-817-4565.

How do I update my beacon registration information?
You can go to to make the update. If you have not previously accessed your beacon registration using the internet, choose the 2nd option (Access Beacon Previously Registered By Mail) on the web site.

How long is my registration information valid in the NOAA registry?
You should update your registration when any information changes, so that search and rescue authorities can respond effectively if your beacon is activated. NOAA requests that your registration information is verified every two years.

Why do I have to re-new my registration every two years?
Your registration information must be accurate so that it can be used to help you in case of an emergency. The International Maritime Organization (IMO) recommends that registration information be updated periodically. Nationally, the Federal Communications Commission (FCC) requires that 406 MHz EPIRB owners “advise NOAA in writing upon change of vessel or EPIRB ownership, transfer of EPIRB to another vessel, or any other change in registration information.” Furthermore, the FCC requires that “aircraft owners shall advise NOAA in writing upon change of aircraft or ELT ownership, or any other change in registration information. Fleet operators must notify NOAA upon transfer of ELT to another aircraft outside of the owner’s control, or another change in registration information.” More importantly, accurate registration information could help save your life.

How do I change registration information if I purchased a beacon from someone else?
You cannot register the beacon until the previous owner has informed NOAA that the beacon has been sold. Otherwise NOAA would have the same beacon registered with two different owners in the registration database. This could cause a delay by search and rescue authorities responding to a distress. The previous owner can inform NOAA they have sold their beacon by updating the status of the beacon in the registration database at or by contacting the beacon registration staff at 888-212-7283. After NOAA has been informed by the original owner that the beacon was sold you will be able to register it as a “NEW REGISTRATION”. If you have problems registering a beacon you purchased from someone else contact the beacon registration staff at 888-212-7283 and they will help you resolve the problem.

What if my beacon is lost?
Inform NOAA immediately at 1-888-212-SAVE (7283) that your beacon has been lost. We’ll update your beacon registration information with the appropriate information.

What if my beacon is stolen?

  1. Report to your local police department that the beacon has been stolen.
  2. Contact NOAA at 1-888-212-SAVE (7283) with the following information so your beacon registration information can be updated with the appropriate remarks:
    • Police Department Name
    • Police Phone Number
    • Police Case Number


What is Return Link Service?
An RLS-enabled beacon is a beacon that has the Return Link Service feature.  This feature is an indication (e.g., a light or text display) on the beacon that confirms to the user that the distress signal from the beacon has been received and localized by the Cospas-Sarsat system and forwarded to government authorities for action.  It does NOT mean that a rescue has yet been organized/launched, only that the distress alert has been received and routed to the appropriate government agencies.   For further information about how the Return Link Service feature works, and performance expectations, you can watch the Cospas-Sarsat video on RLS and read the related sections of the SAR/Galileo Service Definition Document.

Is Return Link Service available in the United States?
As of 1 June 2022, RLS equipped EBIRBs and PLBs, coded with USA County Codes, are legal for sale and use in the United States.

Do beacons equipped with Return Link Service still need to be registered?
As with any 406 MHz Distress Beacon registration is required, is free of charge, and can be accomplished at