International Cospas-Sarsat Programme

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International Cospas-Sarsat Programme

Programme International Cospas-Sarsat (French)

Международной Программе Коспас-Сарсат (Russian)
Cospas-Sarsat Logo v2 3D.jpg
Established 1 July 1988 (definitive agreement signed; preceding memorandum of understanding signed 5 October 1984)
Type Intergovernmental Organization
Headquarters Montreal, Quebec, Canada
Membership
Official language
English
French
Russian
Head of Secretariat
Steven Lett
Council Chair (rotating)
Andrey Kuropyatnikov (Russian Federation)
Website www.cospas-sarsat.int
Heritage Logo
Logo as Used Until 1992

The International Cospas-Sarsat Programme is a non-profit, intergovernmental humanitarian cooperative of 43 nations and agencies (see box on right) dedicated to detecting and locating radio beacons activated by persons, aircraft or vessels in distress, and forwarding this alert information to authorities that can take action for rescue.[2][3][4] The system utilizes a network of satellites that provide coverage anywhere on Earth. Distress alerts are detected, located and forwarded to over 200 countries and territories at no cost to the receiving government agencies.[5] Cospas-Sarsat was conceived and initiated by Canada, France, the United States, and the former Soviet Union in 1979.[6] The first rescue using the technology of Cospas-Sarsat occurred in 1982.[7][8] The definitive agreement of the organization was signed on 1 July 1988.



Background[edit]

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 search-and-rescue (SAR) authorities. Distress beacons capable of being detected by the Cospas-Sarsat System (406-MHz beacons) are available from several manufacturers and vendor chains. Cospas-Sarsat does not make or sell beacons.

Between September 1982 and December 2015 the Cospas-Sarsat System provided assistance in rescuing at least 41,750 persons in 11,788 SAR events. In 2014 and 2015 (the last year for which statistics have been compiled), Cospas-Sarsat assistance included the following:[9]

Year People Rescued SAR Events
2014 2,354 685
2015 2,185 718
SAR Events 2014 2015
Aviation 16% 17%
Maritime 47% 48%
Land 37% 35%

These statistics under-report the events where Cospas-Sarsat assisted, because they only include events 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 United Nations-affiliated agencies, such as the International Civil Aviation Organization (ICAO), the International Maritime Organization (IMO), and the International Telecommunication Union (ITU), among other international organizations, to ensure the compatibility of the Cospas-Sarsat distress alerting services with the needs, the standards and the applicable recommendations of the global community.[10] Cospas-Sarsat is an element of the IMO's Global Maritime Distress Safety System (GMDSS), and is expected to become a component of ICAO’s Global Aeronautical Distress and Safety System (GADSS). The IMO requires automatic-activating Cospas-Sarsat beacons (EPIRBs, see below) on all vessels subject to requirements of the International Convention for the Safety of Life at Sea (so-called SOLAS-class vessels), commercial fishing vessels, and all passenger ships in international waters. Similarly, ICAO requires Cospas-Sarsat beacons aboard aircraft on international flights. [11] National administrations often impose requirements in addition to the international requirements of those agencies.

Cospas-Sarsat only monitors for alerts from distress beacons that transmit on 406 MHz (so-called 406 beacons). Older, beacons that transmit only a legacy analogue signal on 121.5 MHz or 243 MHz rely on being received only by nearby aircraft or rescue personnel. For satellite reception of alerts by Cospas-Sarsat the beacon must be a model that transmits at 406 MHz.[12]

Cospas-Sarsat has received many honors for its humanitarian work. One recent honor was induction into the Space Foundation’s Space Technology Hall of Fame for space technologies improving the quality of life for all humanity.[13][14]

System Operation[edit]

New C-S System Overview.jpg

The system consists of a ground segment and a space segment that include:

Beacons[edit]

A Cospas-Sarsat distress beacon is a 406-MHz radio transmitter that can be activated in a life-threatening emergency to summon assistance from government authorities. Beacons are manufactured and sold by dozens of vendors. They are classified in three main 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). And one that is designed to be carried by an individual is known as a personal locator beacon (PLB). Sometimes PLBs are carried aboard aircraft or vessels, but whether this satisfies safety requirements depends on local regulations.[15] A Cospas-Sarsat 406-MHz beacon does not transmit until it is activated in an emergency (or when certain testing features are activated by the user). Some beacons are designed to be manually activated by a person pressing a button, and some others are designed for automatic activation in certain circumstances (e.g., ELTs may be automatically activated by a physical shock, such as in a crash, and EPIRBs may be automatically activated by contact with water).

Space Segment[edit]

The Cospas-Sarsat system space segment consists of SARR and/or SARP instruments aboard:

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[edit]

The satellites are monitored by receiving ground stations equipped to track (point at) the satellites using satellite dishes or phased antenna arrays called local user terminals (LUT). 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[edit]

When a distress beacon is activated, the Cospas-Sarsat system:

  • decodes the binary coded message of the beacon, which contains information such as the identity of the vessel/aircraft and, for beacons equipped with the feature, the location of the beacon derived from a local navigation source (such as a GPS receiver incorporated into the beacon’s design).
  • 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[edit]

Example of LEOSAR Signal Footprint.

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 obits the latency between satellite passes overhead is smallest at the poles and higher latitudes.

The Cospas-Sarsat 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[edit]

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 GPS receiver) then that location is relayed to SAR authorities. While the inability to independently locate a beacon is a drawback of GEOSAR satellites, those satellites have an advantage in that the present constellation well covers the entire Earth in real time, except for the polar regions.

MEOSAR[edit]

The most recent space segment augmentation for Cospas-Sarsat is MEOSAR. MEOSAR blends the advantages of the LEOSAR and GEOSAR systems, while avoiding the drawbacks. Over time there will be more than 70 MEOSAR satellites, and the MEOSAR system will become the dominant space-segment capability of Cospas-Sarsat. In addition to the number of satellites, the MEOSAR system benefits from relatively large satellite footprints and sufficient satellite motion relative to a point on the ground to allow the use of Doppler measurements as part of the method of calculating a distress beacon’s location. MEOSAR consists of SARR transponders aboard navigation satellites of Europe, Russia and the United States. These satellite constellations are those of Europe's Galileo constellation, the Russian Federation’s Glonass spacecraft (Glonass-K1 having been launched on 26 February 2011), and the U.S. GPS. The current payloads aboard GPS satellites are also known as the Distress Alerting Satellite System (DASS) by NASA.[18] Operational distribution of MEOSAR alert data began at 1300 UTC on 13 December 2016. This operational phase of MEOSAR is known as the early operational capability (EOC), and is being carried out in parallel with continued testing and adjustment with the contemporaneous demonstration and evaluation (D&E) phase. Ultimately, the MEOSAR system will be able to provide near-instantaneous detection, identification, and location-determination of 406 MHz beacons. The location of a distress beacon is calculated by the receiving LUT by analyzing the frequency-difference-of-arrival (related to Doppler-induced variations) and/or the time-difference-of-arrival. The Galileo component of the MEOSAR system will be able to download information back to the distress radio-beacon by encoding "Return Link Service" messages into the Galileo navigation data stream. Currently it is planned that this capability will be used to activate an indicator on the beacon to confirm receipt of the distress message.

Ground Segment[edit]

LEOSAR satellites are monitored by 44 LEOLUTs (low Earth orbit local user terminals).[19]

History[edit]

The first system satellite 'COSPAS-1' (Kosmos 1383) was launched from Plesetsk Cosmodrome on June 29, 1982.[20][21][22] Cospas-Sarsat began tracking the two original types of distress beacons, EPIRBs and ELTs, in September, 1982. In the early 2000s (in 2003 in the USA) a new type of distress beacon became available, [1]:

  • PLBs (Personal Locator Beacons), are for personal use and are intended to indicate a person in distress who is away from normal emergency services (i.e. Phone-Based Services, such as 1-1-2 or 9-1-1)

The four founding countries led development of the 406 MHz marine EPIRB for detection by the system. The EPIRB was seen as a key advancement in SAR technology in the perilous maritime environment. 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 the alternate. ELTs for general aviation were constructed to transmit on 121.5 MHz, a frequency monitored by airliners and other aircraft. Military aircraft beacons were manufactured to transmit at 243.0 MHz, in the band commonly used by military aviation. Early in its history, the Cospas-Sarsat system was engineered to detect beacon-alerts transmitted at 406 MHz, 121.5 MHz and 243.0 MHz. More recently, the Cospas-Sarsat system has been designed to detect only alerts transmitted at 406 MHz (see below). This allows the system to be optimized for the increasingly sophisticated 406 MHz beacons, and avoids problems (including false alerts) from the less-sophisticated legacy 121.5 MHz and 243.0 MHz beacons. Many ELTs include both a 406 MHz transmitter, for satellite detection, and a 121.5 MHz transmitter that can be received by local search crews using direction-finding equipment.

The design of distress beacons as a whole has evolved significantly since 1982; the newest 406 MHz beacons incorporate GPS receivers; such beacons transmit highly accurate positions of distress almost instantly to SAR agencies via the GEOSAR satellites. The advent of such beacons has created the current motto of SAR agencies --- "Taking the 'Search' out of Search and Rescue." (See MEOSAR below.) [2]

COSPAS (КОСПАС) is an acronym for the Russian words "Cosmicheskaya Sistema Poiska Avariynyh Sudov" (Космическая Система Поиска Аварийных Судов), which translates to "Space System for the Search of Vessels in Distress". SARSAT is an acronym for Search And Rescue Satellite-Aided Tracking.[23]


See also[edit]

References[edit]

  1. ^ Galileo’s Contribution to Cospas-Sarsat 
  2. ^ International Cospas-Sarsat Programme Agreement – UN Treaty Series (PDF) 
  3. ^ International Cospas-Sarsat Programme Agreement – Cospas-Sarsat Website (PDF) 
  4. ^ Cospas-Sarsat Strategic Plan, at section 3, "The International Cospas-Sarsat Programme provides accurate, timely and reliable distress alert and location data to help search and rescue authorities assist persons in distress." (PDF) 
  5. ^ Cospas-Sarsat Website 
  6. ^ Space Foundation's Space Technology Hall of Fame inducted technology 
  7. ^ The Washington Post, 30 September 1982, page A3 
  8. ^ The Hartford Courant, 25 November 1982, page A6 
  9. ^ Cospas-Sarsat System Data (PDF) 
  10. ^ Cospas-Sarsat Strategic Plan, at section 2.1 (PDF) 
  11. ^ AIN Online, “New ELT Rules from ICAO 
  12. ^ Cospas-Sarsat Website, “What is a Cospas-Sarsat 406 MHz Beacon” 
  13. ^ Space Foundation Website 
  14. ^ Space Technology Hall of Fame induction ceremony 
  15. ^ Cospas-Sarsat Website, “What is a Cospas-Sarsat 406 MHz Beacon” 
  16. ^ Cospas-Sarsat Website, “Current Space Segment Status and SAR Payloads” 
  17. ^ Cospas-Sarsat Website, “Status of Cospas-Sarsat MEOSAR Payload Instruments” 
  18. ^ NASA Search and Rescue Mission Office : Distress Alerting Satellite System (DASS)
  19. ^ Summary Status
  20. ^ Hillger, Don; Garry Toth. "COSPAS / SARSAT Program". Colorado State University. Retrieved 6 October 2011. 
  21. ^ Krebs, Gunter Dirk. "Nadezhda". Retrieved 6 October 2011. 
  22. ^ Kramer, Herbert J. "COSPAS-S&RSAT (International Satellite System for Search & Rescue Services)". eoportal. Retrieved 6 October 2011. 
  23. ^ Cospas-Sarsat. "Cospas-Sarsat Acronyms / Definitions". Archived from the original on 2007-09-01. Retrieved 2007-09-24. 

External links[edit]


Coordinates: 41°08′04″N 16°50′04″E / 41.13444°N 16.83444°E / 41.13444; 16.83444