COSPAS-SARSAT: Difference between revisions
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'''COSPAS-SARSAT''' is the International Satellite System For Search and Rescue. Its space segment consists of two complementary constellations, of multiple satellites, which support worldwide [[search and rescue]] operations. One constellation is in [[satellite orbits#low earth orbit|low earth orbit]], while the other is in [[satellite orbits#geostationary orbit|geostationary orbit]]. | '''COSPAS-SARSAT''' is the International Satellite System For Search and Rescue. Its space segment consists of two complementary constellations, of multiple satellites, which support worldwide [[search and rescue]] operations. One constellation is in [[satellite orbits#low earth orbit|low earth orbit]], while the other is in [[satellite orbits#geostationary orbit|geostationary orbit]]. | ||
As of 2009, all satellites listen on the single international rescue frequency of 406 MHz. | As of 2009, all satellites listen on the single [[UHF satellites|UHF]] international rescue frequency of 406 MHz. | ||
The actual satellites that detect signals are operated by different countries; the rescue signal receiver, processor, and downlink are usually secondary payloads on a satellite that performs other services. | The actual satellites that detect signals are operated by different countries; the rescue signal receiver, processor, and downlink are usually secondary payloads on a satellite that performs other services. | ||
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*Umited States: Geostationary operational environmental satellite (GOES) | *Umited States: Geostationary operational environmental satellite (GOES) | ||
===LEOSAT=== | ===LEOSAT=== | ||
If the beacon has no navigational receiver, or the receiver is malfunctioning, the LEO satellites can determine the beacon's surface coordinates by the Doppler effect of the radio signal received by satellites in known orbital positions. | If the beacon has no navigational receiver, or the receiver is malfunctioning, the LEO satellites can determine the beacon's surface coordinates by the [[Doppler effect]] of the radio signal received by satellites in known orbital positions. | ||
Since the LEOSAT constellation spiral in a "ball of twine" orbit around the earth, they do provide polar coverage. Since they move in relation to the beacon, if an obstruction blocks the beacon signal to GEO, one of the LEO satellites will usually move into a position in which it has line of sight to the beacon. | Since the LEOSAT constellation spiral in a "ball of twine" orbit around the earth, they do provide polar coverage. Since they move in relation to the beacon, if an obstruction blocks the beacon signal to GEO, one of the LEO satellites will usually move into a position in which it has line of sight to the beacon. | ||
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Obviously, the EPIRBs are an essential part of the system. Once a satellite detects a signal, it sends it to an appropriate Local User Terminal under its orbit. There are 45 LUT for LEOSAR and 19 for GEOSAR; since geostationary satellites are in a fixed position relative to the Earth, not as many stations are needed. | Obviously, the EPIRBs are an essential part of the system. Once a satellite detects a signal, it sends it to an appropriate Local User Terminal under its orbit. There are 45 LUT for LEOSAR and 19 for GEOSAR; since geostationary satellites are in a fixed position relative to the Earth, not as many stations are needed. | ||
There are 29 Mission Control Centres (MCCs) that receive LUT messages, correlate observations, and then dispatch appropriate [[search and rescue]] organizations. | There are 29 Mission Control Centres (MCCs) that receive LUT messages, correlate observations, and then dispatch appropriate [[search and rescue]] organizations.[[Category:Suggestion Bot Tag]] | ||
Latest revision as of 16:00, 22 July 2024
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 COSPAS-SARSAT is the International Satellite System For Search and Rescue. Its space segment consists of two complementary constellations, of multiple satellites, which support worldwide search and rescue operations. One constellation is in low earth orbit, while the other is in geostationary orbit. As of 2009, all satellites listen on the single UHF international rescue frequency of 406 MHz. The actual satellites that detect signals are operated by different countries; the rescue signal receiver, processor, and downlink are usually secondary payloads on a satellite that performs other services. OrganizationCOSPAS-SARSAT's secretariat is based in Canada, although there are Local User Terminals all over the world. The headquarters location was agreed among Canada, the Republic of France, the Russian Federation and the United States of America. To coordinate worldwide technical requirements, COSPAT-SARSAT cooperates with the International Telecommunications Union, the International Maritime Organization, and the International Civil Aviation Organization. Space segmentAt present, there are 5 satellites in each constellation. GEOSATGeosynchronous satellites "stare" at the earth's surface and can almost immediately detect an emergency position indicating radio beacon (EPIRB) transmission, which may contain a position determined by a GPS receiver in the beacon. They are the early warning part of the system. Among their limitations is that they have relatively poor coverage of the high latitudes (i.e., Arctic or Antarctic) GEOSAT orbiters include:
LEOSATIf the beacon has no navigational receiver, or the receiver is malfunctioning, the LEO satellites can determine the beacon's surface coordinates by the Doppler effect of the radio signal received by satellites in known orbital positions. Since the LEOSAT constellation spiral in a "ball of twine" orbit around the earth, they do provide polar coverage. Since they move in relation to the beacon, if an obstruction blocks the beacon signal to GEO, one of the LEO satellites will usually move into a position in which it has line of sight to the beacon.
Ground segmentObviously, the EPIRBs are an essential part of the system. Once a satellite detects a signal, it sends it to an appropriate Local User Terminal under its orbit. There are 45 LUT for LEOSAR and 19 for GEOSAR; since geostationary satellites are in a fixed position relative to the Earth, not as many stations are needed. There are 29 Mission Control Centres (MCCs) that receive LUT messages, correlate observations, and then dispatch appropriate search and rescue organizations. |
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