International Cospas-Sarsat Programme
Established | 1 July 1988 | (Date definitive agreement was signed; preceding memorandums of understanding signed 23 November 1979 and 5 October 1984)
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Type | Intergovernmental organization |
Legal status | Active |
Headquarters | Montreal, Quebec, Canada |
Membership | 45 Formally associated "Participant" states and agencies
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Official languages | English French Russian |
Head | Steven Lett (Head of Secretariat) |
Council Chair (rotating) | Henrik Smith (Canada) |
Website | www www |
The International Cospas-Sarsat Programme is a
The term Cospas-Sarsat derives from COSPAS (КОСПАС), an acronym from the transliterated Russian "Космическая Система Поиска Аварийных Судов" (Latin script: "Cosmicheskaya Sistema Poiska Avariynyh Sudov"), meaning "Space System for the Search of Vessels in Distress", and SARSAT, an acronym for "Search And Rescue Satellite-Aided Tracking".[10]
Background
Cospas-Sarsat is best known as the system that detects and locates emergency beacons activated by aircraft, ships and people engaged in recreational activities in remote areas, and then sends these distress alerts to
Between September 1982 and December 2022 the Cospas-Sarsat System provided assistance in rescuing at least 60,636 people in 18,807 SAR events. In 2022 Cospas-Sarsat on average assisted in the rescue of almost ten persons each day. In 2020, 2021 and 2022 (the latest year for which statistics have been compiled), Cospas-Sarsat assistance included the following:[11]
Year | People Rescued | SAR Events → | Aviation | Land | Maritime |
---|---|---|---|---|---|
2022 | 3,223 | 1,144 | 20% | 39% | 41% |
2021 | 3,623 | 1,149 | 18% | 45% | 37% |
2020 | 2,278 | 951 | 23% | 37% | 40% |
These statistics under-count the number of events where Cospas-Sarsat assisted, because they only include cases when an accurate report from SAR personnel is provided back through reporting channels to the Cospas-Sarsat Secretariat.
Cospas-Sarsat does not undertake search-and-rescue operations. This is the responsibility of national administrations that have accepted responsibility for SAR in various geographic regions of the world (typically the same geographic area as their flight information region). Cospas-Sarsat provides alert data to those authorities.
Cospas-Sarsat cooperates with
Cospas-Sarsat only monitors for alerts from
Cospas-Sarsat has received many honors for its humanitarian work, including induction into the Space Foundation's Space Technology Hall of Fame for space technologies improving the quality of life for all humanity.[14][15]
System operation
The system consists of a ground segment and a space segment that include:
- Distress radio-beaconsto be activated in a life-threatening emergency
- SAR signal repeaters (SARR) and SAR signal processors (SARP) aboard satellites
- Satellite ground stationscalled LUTs (local user terminals)
- Mission control centres (MCCs) that distribute to rescue coordination centres distress alert data (particularly beacon location data) generated by the LUTs
- Rescue coordination centres (RCCs) that facilitate coordination of the SAR agency and personnel response to a distress situation.
Beacons
A Cospas-Sarsat
Space segment
The Cospas-Sarsat system operational space segment consists of SARR and/or SARP instruments aboard:[17]
- Five satellites in polar low-altitude Earth orbit with LEOSAR (low-altitude Earth orbit search-and-rescue) payloads (one other in preparation for use),
- Twelve satellites in geostationary Earth orbit with GEOSAR (geostationary Earth orbit search-and-rescue) payloads (two others in preparation for use),
- 48 satellites in medium-altitude Earth orbit with MEOSAR (medium-altitude Earth orbit search-and-rescue) payloads (seven others in preparation for use).
A SARR or SARP instrument is a secondary payload and associated antennas attached to those satellites as an adjunct to the primary satellite mission. A SARR instrument retransmits a beacon distress signal to a satellite ground station in real time. A SARP instrument records the data from the distress signal so that the information can later be gathered by a ground station when the satellite passes overhead.
Ground segment
The satellites are monitored by receiving ground stations (LUTs) equipped to track (point at and follow) the satellites using satellite dishes or phased antenna arrays. LUTs are installed by individual national administrations or agencies. The distress messages received by a LUT are transferred to an associated mission control centre which uses a detailed set of computer algorithms to route the messages to rescue coordination centres worldwide.
System architecture
When a distress beacon is activated, the Cospas-Sarsat system:
- decodes the GPSreceiver incorporated into the beacon's design), and
- performs a mathematical analysis of the signal to calculate the location of the beacon, even if the beacon's location is not reported in the distress message.
The Cospas-Sarsat system is the only satellite distress alerting system that is capable of this dual, redundant means of locating an activated distress beacon.
The SARR and/or SARP instrument typically is attached to a satellite that is being launched primarily for another purpose. The primary mission of all of the LEOSAR and GEOSAR satellites is meteorological (gathering of weather data). The primary mission of all of the MEOSAR satellites is navigation.
LEOSAR
LEOSAR was the original Cospas-Sarsat space segment architecture. The complementary LEOSAR-satellite orbits provide periodic coverage of the entire Earth. Because of their relatively low altitude (and therefore, relatively small "footprint" of visibility of any particular part of the Earth at any given time), there are intervals of time when a LEOSAR satellite may not be over a particular geographic location. So there can be a delay in receiving an alert signal, and a delay in relaying that signal to the ground. For this reason, LEOSAR satellites are equipped with the "store-and-forward" SARP modules in addition to "real-time" SARR modules. The satellite can pass over a remote area of the Earth and receive a distress message, and then forward that data later when it passes into view of a ground station (that typically are located in less remote areas). The five satellites in the LEOSAR constellation have approximately 100 minute orbits. Because of their polar orbits the latency between satellite passes overhead is smallest at the poles and higher latitudes.
The Cospas-Sarsat LEOSAR system was made possible by Doppler processing. LUTs detecting distress signals relayed by LEOSAR satellites perform mathematical calculations based on the Doppler-induced frequency shift received by the satellites as they pass over a beacon transmitting at a fixed frequency. From the mathematical calculations, it is possible to determine both bearing and range with respect to the satellite. The range and bearing are measured from the rate of change of the received frequency, which varies both according to the path of the satellite in space and the rotation of the Earth. This allows a computer algorithm to trilaterate the position of the beacon. A faster change in the received frequency indicates that the beacon is closer to the satellite's ground track. When the beacon is moving toward or away from the satellite track due to the Earth's rotation, the Doppler shift induced by that motion also can be used in the calculation.
GEOSAR
Because their geostationary orbit does not provide a relative motion between a distress beacon and a GEOSAR satellite, there is no opportunity to use the Doppler effect to calculate the location of a beacon. Therefore, the GEOSAR satellites only can relay a beacon's distress message. If the beacon is a model with a feature to report its location (e.g., from an on-board
MEOSAR
The most recent
Operational distribution of MEOSAR alert data began at 1300
With respect to GPS-hosted payloads, experimental
Additionally, the
Ground segment
As of December 2022 the LEOSAR satellites are tracked and monitored by 55 commissioned LEOLUT (low-altitude Earth-orbit local user terminals) antennas, the GEOSAR satellites by 27 commissioned GEOLUT antennas [1] and the MEOSAR satellites by 26 commissioned MEOLUT stations, each having multiple antennas. The data from these earth stations is transferred to and distributed by 32 MCCs established globally, 14 of which are commissioned to process data from all three constellation types.[29][30] (See infobox for the countries and agencies that are ground-segment providers.)
Beacons
Current Beacon Technologies
Most Cospas-Sarsat-compatible 406-MHz beacons also transmit distress or tracking signals on additional frequencies. Most commonly, Cospas-Sarsat beacons have a 121.5-MHz transmitter to provide a signal that can be received by local search crews (airborne, on ground or at sea) using direction-finding equipment. Additionally, the latest
Beacons with such combinations of signals simultaneously allow for global alerting through the 406-MHz transmission to satellites and the swiftest local response from the 121.5-MHz and AIS transmissions (particularly in the maritime environment by nearby vessels).
In response to recent commercial aviation disasters and subsequent ICAO requirements for autonomous tracking of aircraft in distress,
Beacon Transmission Technologies
There has been one transmission modulation method used by Cospas-Sarsat 406-MHz digital beacons since their inception more than 30 years ago, binary phase-shift keying (BPSK), with two allowed bit-string lengths: 112 (with 87 bits of message information) and 144 (with 119 bits of message information). Several message protocols are allowed in the available message-bit string to accommodate different kinds of beacons (ELTs, EPIRBs and PLBs), different vessel/aircraft identifiers, and different national requirements. The time length of these transmissions is approximately one-half second. These narrowband transmissions occupy approximately 3 kHz of bandwidth in a channelized scheme across the assigned 406.0 to 406.1 MHz band.[33]
Cospas-Sarsat has recently specified a new, additional beacon modulation and message scheme based on
History
Conception and demonstration
In the early 1970s, the Space System Group at
First legal framework
On 23 November 1979, a "memorandum of understanding concerning cooperation in a joint experimental satellite-aided search and rescue project" was signed in Leningrad, USSR, among the U.S. National Aeronautics and Space Administration, the USSR Ministry of Merchant Marine, the Centre National d'Etudes Spatiales of France, and the Department of Communications of Canada. Under Article 3 of the memorandum, it was stated that:[36]
"Cooperation will be achieved through effecting interoperability between the SARSAT project and the COSPAS project at 121.5MHz, 243MHz and in the 406.0 – 406.1 MHz band and conducting of tests, mutual exchange of test results and preparation of a joint report. The objective of this cooperation is to demonstrate that equipment carried on low-altitude, near polar-orbiting satellites can facilitate the detection and location of distress signals by relaying information from aircraft and ships in distress to ground stations, where the information processing is completed and passed to rescue services."
"This joint Project will permit the Parties to make recommendations on follow-on global applications."
Development
The first system satellite, "COSPAS-1" (
Prior to the founding of Cospas-Sarsat, the civilian aviation community had already been using the 121.5 MHz frequency for distress, while the military aviation community utilized 243.0 MHz as the primary distress frequency with the 121.5 MHz frequency as an alternate. In each case, detection of the distress signal relied on reception by aircraft passing nearby, and localization of the signal was done with Earth-based direction finding equipment. Satellites made it possible to expand this "local" search paradigm into a global capability.
Each of the four founding Party States took responsibility for one of the major tasks in the project. The United States (with project leadership from NASA's
The Party States led development of the 406-MHz marine
In the early 2000s (in 2003 in the USA) a new type of distress beacon, the personal locator beacon (PLB), became available
The design of distress beacons as a whole has evolved significantly since 1982. The newest 406-MHz beacons often incorporate global navigation satellite system (GNSS) receivers (such as those using GPS). Such beacons determine their location using the internal GNSS receiver (or a connection to an external navigation source) and transmit in their distress message highly accurate position reports. This provides a second method for Cospas-Sarsat to know the location of the distress, in addition to the calculations independently done by Cospas-Sarsat LUTs to determine the location. The distress alert received by the satellites and the beacon location contained in the message and/or calculated from the distress signal are forwarded almost instantly to SAR agencies by Cospas-Sarsat's extensive international data-distribution network. This two-tiered reliability and global coverage of the system has inspired the current motto of SAR agencies: "Taking the 'Search' out of Search and Rescue."[44]
References
- ^ Galileo's Contribution to Cospas-Sarsat
- ^ Cospas-Sarsat website, Formally associated Participant states and agencies
- ^ International Cospas-Sarsat Programme Agreement – UN Treaty Series (PDF)
- ^ Cospas-Sarsat website, "International Cospas-Sarsat Programme Agreement" (PDF)
- ^ "Strategic Goals for the Cospas-Sarsat Programme", Cospas-Sarsat Strategic Plan (PDF), Cospas-Sarsat
- ^ a b c Cospas-Sarsat website, "What is a Cospas-Sarsat 406 MHz Beacon"
- ^ Space Foundation's Space Technology Hall of Fame inducted technology
- ^ The Washington Post, 30 September 1982, page A3
- ^ The Hartford Courant, 25 November 1982, page A6
- ^ "About the Programme - International COSPAS-SARSAT". www.cospas-sarsat.int. Retrieved 2022-12-21.
- ^ Cospas-Sarsat website, "Cospas-Sarsat System Data No.48, December 2022" (PDF)
- ^ Cospas-Sarsat website, "Cospas-Sarsat Strategic Plan", at section 2.1 (PDF)
- ^ AIN Online, "New ELT Rules from ICAO
- ^ Space Foundation Website
- ^ Space Technology Hall of Fame induction ceremony
- ^ Cospas-Sarsat Website, "Handbook of (National) Beacon Regulations", archived from the original on 2017-01-28, retrieved 2017-02-03
- ^ Cospas-Sarsat Website, "Current Space Segment Status and SAR Payloads"
- ^ "SAR/Galileo Satellites Information". European GNSS Service Centre. 4 December 2021. Archived from the original on 4 December 2021. Retrieved 4 December 2021.
- ^ "Search and Rescue (SAR) / Galileo Service". European Union Space Programme Agency. Retrieved 19 December 2021.
- ^ "SAR Payload Characteristics". European GNSS Service Centre. Archived from the original on 19 December 2021. Retrieved 19 December 2021.
- ^ "SAR/Galileo Satellites Information". European GNSS Service Centre. Archived from the original on 4 December 2021. Retrieved 19 December 2021.
- ^ Clark, Nicola; Youssef, Nour (June 2016), "New York Times article, "Black Box from Missing EgyptAir Flight 804 is Said to be Detected"", The New York Times
- ^ GPS World (January 2011) : The Distress Alerting Satellite System (DASS)
- ^ "NASA - Taking the 'Search' out of Search and Rescue".
- ^ "Distress Alerting Satellite System (DASS)". Archived from the original on 11 June 2016.
- ^ "First Galileo personal emergency beacon coming to 19 European countries". GPS World. 26 October 2020. Retrieved 2 December 2021.
- ^ "Galileo Search and Rescue Service – Navipedia". gssc.esa.int.
- ^ "Galileo now replying to SOS messages worldwide". 30 November 2021. Retrieved 30 November 2021.
- ^ Cospas-Sarsat Website, "Cospas-Sarsat System"
- ^ Cospas-Sarsat Website, "Cospas-Sarsat System Data" (PDF)
- ^ ICAO Update on the Global Aeronautical Distress and safety System (GADSS) Global Aircraft Tracking Initiatives (March 2016) (PDF)
- ^ European Commission Proposal for Council Decision (June 2022)
- ^ Cospas-Sarsat website, "Specification for Cospas-Sarsat 406 MHz Distress Beacons", at section 2 (PDF)
- ^ Cospas-Sarsat website, "Specification for Second-Generation Cospas-Sarsat 406-MHz Distress Beacons", at section 2 (PDF)
- ^ ISBN 9780660457819.
- ^ Cospas-Sarsat website, "The History and Experience of the International Cospas-Sarsat Programme for Satellite-Aided Search and Rescue", at page 20 (PDF)
- ^ Hillger, Don; Garry Toth. "COSPAS / SARSAT Program". Colorado State University. Retrieved 6 October 2011.
- ^ Krebs, Gunter Dirk. "Nadezhda". Retrieved 6 October 2011.
- ^ Kramer, Herbert J. "COSPAS-S&RSAT (International Satellite System for Search & Rescue Services)". eoportal. Retrieved 1 April 2023.
- ^ Cospas-Sarsat Website, Information Bulletin, page 2 (PDF)
- ^ The Washington Post, 30 September 1982, page A3
- ^ The Hartford Courant, 25 November 1982, page A6
- ^ "NASA Search and Rescue Mission Office : Emergency Beacons". 20 October 2007. Archived from the original on 20 October 2007.
- ^ "Taking the "Search" Out of "Search-and-Rescue"". 14 March 2016. Archived from the original on 14 March 2016.
External links
- Official Website for the International Cospas-Sarsat Programme
- International Astronautical Federation, "The History and Experience of the International Cospas-Sarsat Programme for Satellite-Aided Search and Rescue" Archived 2017-02-11 at the Wayback Machine
- Official Website for the USA's Sarsat Program
- Official Website for NASA's Search-and-Rescue Mission Office
- "Detailed SARSAT and COSPAS satellite information". Archived from the original on August 15, 2015. Retrieved September 8, 2015.
- "Lay Person Explanation of the Satellite System: COSPAS-SARSAT: 14,000 Lives Saved and Counting". Archived from the original on January 13, 2015. Retrieved September 23, 2006.