These statistics are copied from the latest issue of the System Data document, which is available here: http://www.cospas-sarsat.int/en/documents-pro/system-data.

 

Since its inception in 1982 the Cospas-Sarsat System has provided distress alert information which has assisted in the rescue of 41,750 persons in 11,788 distress situations.

In 2015 only, the System provided information that was used to rescue 2,185 persons in 718 distress situations. The locations of these events are depicted on the map below. 

GEOGRAPHIC DISTRIBUTION OF ALL REPORTED SAR EVENTS
FOR WHICH COSPAS-SARSAT DATA WAS USED (2015)

 

The details for specific SAR events assisted by Cospas-Sarsat, as reported by national Administrations to the Cospas-Sarsat Secretariat, are provided in Annex C to document C/S R.007 “Cospas-Sarsat Report on System Status and Operations” availabe under our Professionals webiste under the “System Documents” section (Pro/Documents). Annex C provides both overall statistical information as well as a short description of each SAR event for which Cospas-Sarsat data was instrumental. Each alert is categorized as either:

Only Alert	Cospas-Sarsat was the only source of information provided to SAR authorities.
First Alert	Cospas-Sarsat was the first source of information provided to SAR authorities.
Supporting Data	Information provided by the Cospas-Sarsat System which was not the first or only alert, but was used in conjunction with information from other sources in the SAR operation.
Data not used in SAR	Cospas-Sarsat provided alert and/or location data which was not used by SAR services in support of the search and rescue.

Distress events for which Cospas-Sarsat data was provided to SAR services but was not used, because the necessary information had previously been provided by another source or the distress situation had already been resolved, were not included in the Cospas-Sarsat summary statistics provided at Annex C to document C/S R.007. (In 2015 there were 196 such distress reports).

 

 These statistics are copied from the latest issue of the System Data document, which is available here: http://www.cospas-sarsat.int/en/documents-pro/system-data.

 

As of December 2015 the Cospas-Sarsat System had provided assistance in rescuing at least 41,750 persons in over 11,788 SAR events.

As of April 2017:

Governments and Agencies that are Cospas-Sarsat Programme “Participants”

 

4 Parties to the Cospas-Sarsat Agreement

29 Ground Segment Providers

9 User States

2 Participating Organisations

These statistics are copied from the latest issue of the System Data document, which is available here: http://www.cospas-sarsat.int/en/documents-pro/system-data.

Geographic Distribution of Confirmed SAR Events for which Cospas-Sarsat Data was Used

(January to December 2015)

Distribution of SAR Events Assisted by Cospas-Sarsat by Type of Events
(January to December 2015)

 

 

 

Persons Rescued by Type of SAR Event Assisted by Cospas-Sarsat 
(January to December 2015)

Number of SAR Events and Persons Rescued with the Assistance of Cospas-Sarsat Alert Data

(121.5 and 406 MHz)

(January 1994 to December 2015)

Number of SAR Events Assisted 

by Cospas-Sarsat (January to December 2015)

 

The basic Cospas-Sarsat concept is illustrated in the adjacent figure. The System is composed of:

• distress radiobeacons (ELTs for aviation use, EPIRBs for maritime use, and PLBs for personal use) which transmit signals during distress situations;

• instruments on board satellites in geostationary and low-altitude Earth orbits which detect the signals transmitted by distress radiobeacons;

• ground receiving stations, referred to as Local Users Terminals (LUTs), which receive and process the satellite downlink signal to generate distress alerts; and

• Mission Control Centers (MCCs) which receive alerts produced by LUTs and forward them to Rescue Coordination Centers (RCCs), Search and Rescue Points Of Contacts (SPOCs) or other MCCs.

The Cospas-Sarsat System includes two types of satellites:

• satellites in low-altitude Earth orbit (LEO) which form the LEOSAR System
• satellites in geostationary Earth orbit (GEO) which form the GEOSAR System

The future Cospas-Sarsat System will include a new type of satellite in the medium-altitude Earth orbit (MEO) which will form the MEOSAR System. 

Additional information on the three satellite systems, the LUTs, and the MCCs is provided in the tabs below. 

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The Cospas-Sarsat system only detects and locates distress beacons operating at 406 MHz. 121.5/243 MHz processing by Cospas-Sarsat ceased on 1 February 2009.

The Cospas-Sarsat  System is composed of:

• 406-MHz radiobeacons carried aboard ships (EPIRBs), aircraft (ELTs), or used as personal locator beacons (PLBs);
• ship security alert devices (SSAS);
• polar-orbiting satellites in low Earth orbit from the LEOSAR system and geostationary satellites from the GEOSAR system; and
• a ground segment consisting of satellite receiving stations called Local User Terminals (LUTs), referred to as LEOLUTs for the LEOSAR system and GEOLUTs for the GEOSAR system, and data distribution nodes called Mission Control Centres (MCCs).

406-MHz Beacons

Frequencies in the 406.0 – 406.1 MHz band have been exclusively reserved for distress beacons operating with satellite systems. The Cospas-Sarsat 406-MHz beacons have been specifically designed for use with the LEOSAR system to provide improved performance in comparison to the now obsolete 121.5-MHz beacons. 406-MHz beacons have specific requirements on the stability of the transmitted frequency, and the inclusion of a digital message which allows the transmission of encoded data such as unique beacon identification.

Second-generation 406-MHz beacons were introduced in 1997 which allow the transmission in the 406-MHz message of encoded position data acquired by the beacons from global satellite navigation systems such as GPS, using internal or external navigation receivers. This feature is of particular interest for GEOSAR alerts which otherwise would not be able to provide position information.

LEOSAR System

The Cospas-Sarsat LEOSAR system uses polar-orbiting satellites and, therefore, operates with basic constraints which result from non-continuous coverage provided by LEOSAR satellites. The use of low-altitude orbiting satellites provides for a strong Doppler effect in the up-link signal thereby enabling the use of Doppler positioning techniques. The LEOSAR system operates in two coverage modes, namely local and global coverage.

LEOSAR Local Mode

When the satellite receives beacon signals, the on-board Search and Rescue Processor (SARP) recovers the digital data from the beacon signal, measures the Doppler frequency shift and time-tags the information. The result of this processing is formatted as digital data which is transferred to the satellite downlink for transmission to any LEOLUT in view. This data is also simultaneously stored on the spacecraft for later transmission and ground processing in the global coverage mode.

The diagram to the left depicts a LEOSAR satellite orbiting the Earth and its instantaneous field of view is indicated by the red circle. In this example the beacon located in the Northern Atlantic is within the local coverage area of the LEOLUT located on the north west coast of Africa whereas the beacon located in Antarctica is not.

In addition to the local mode provided by the SARP instrument, a repeater can also provide a local mode of operation. The difference between the SARP and the repeater is that the SARP performs some of the processing onboard the satellite, whereas the repeater simply reflects the beacon signal to the Earth, thereby requiring additional processing on the ground.

LEOSAR Global Mode

The 406-MHz SARP system provides global coverage by storing data derived from onboard processing of beacon signal, in the spacecraft memory unit. The content of the memory is continuously broadcast on the satellite downlink. Therefore, each beacon can be located by all LEOLUTs which track the satellite (even for LEOLUTs which were not in the footprint of the satellite at the time the beacon was detected by the satellite). This provides the global coverage and introduces ground segment processing redundancy.

The diagram to the right depicts a LEOSAR satellite orbiting the Earth in the direction of the north pole. The blue circle represents the satellite field of view at a point in the recent past when the satellite was over the southern Atlantic Ocean. At that point in time the satellite detected the beacon in Antarctica, however, since there were no LEOLUTs in its field of view, a distress alert could not be generated at that time. Nevertheless, the satellite continued to transmit the processed data associated with this distress beacon. When the LEOLUT located on the north west coast of Africa came into the view of the satellite, this LEOLUT received the beacon information and generated a distress alert.

The global mode may also offer an additional advantage over the local mode in respect of alerting time. As the beacon message is recorded in the satellite memory by the first satellite pass which detected the beacon, the waiting time is not dependent upon the satellite achieving simultaneous visibility with the LEOLUT and the beacon. Consequently, the time required to produce alerts could be considerably reduced.

The animated graphic depicts two beacons: the yellow beacon is detected in global mode only whereas the red beacon is detected in both local and global modes.

GEOSAR System

Cospas-Sarsat has demonstrated that the current generation of Cospas-Sarsat beacons could be detected using search and rescue instruments on board geostationary satellites. The GEOSAR system consists of repeaters carried on board various geostationary satellites and the associated ground facilities called GEOLUTs which process the satellite signal.

Geostationary satellites orbit the Earth at an altitude of 36,000 km, with an orbit period of 24 hours, thus appearing fixed relative to the Earth at approximately 0 degrees latitude (i.e. over the equator). A single geostationary satellite provides GEOSAR uplink coverage of about one third of the globe, except for polar regions. Therefore, three geostationary satellites equally spaced in longitude can provide continuous coverage of all areas of the globe between approximately 70 degrees North and 70 degrees South latitude.

Since GEOSAR satellites remain fixed relative to the Earth, there is no Doppler effect on the received frequency and, therefore, the Doppler positioning technique cannot be used to locate distress beacons. To provide rescuers with position information, the beacon location must be either:

• acquired by the beacon though an internal or an external navigation receiver and encoded in the beacon message, or
• derived from the LEOSAR system Doppler processing.

Cospas-Sarsat has demonstrated that the GEOSAR and LEOSAR system search and rescue capabilities are complementary. For example, the GEOSAR system can provide almost immediate alerting in the footprint of the GEOSAR satellite, whereas the LEOSAR system:

• provides excellent coverage of the polar regions (which are beyond the coverage of geostationary satellites);
• can calculate the location of distress events using Doppler processing techniques; and
• is less susceptible to obstructions which may block a beacon signal in a given direction because the satellite is continuously moving with respect to the beacon.

 

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Introduction

The International Cospas-Sarsat Programme initiated the development of the Medium-altitude Earth Orbiting Satellite System for Search and Rescue (MEOSAR system) in 2004, with SAR repeaters placed on the satellites of the Global Navigation Satellite Systems (GNSS) of Europe (Galileo), Russia (Glonass) and the USA (GPS). Early operational capability (EOC) data from the MEOSAR system will be available from late-2016 and full operational capability (FOC) of the system is anticipated in 2018. MEOSAR will initially complement the existing LEOSAR (satellites in low-altitude orbits) and GEOSAR (satellites in geostationary orbit) systems, and will eventually replace the LEOSAR system.

The Cospas-Sarsat System

The Cospas-Sarsat System is comprised of:

• distress radiobeacons (ELTs for aviation use, EPIRBs for maritime use, and PLBs for personal use) which transmit signals during distress situations,
• instruments on board satellites which detect the signals transmitted by distress radiobeacons,
• ground receiving stations, referred to as Local Users Terminals (LUTs), which receive and process the satellite downlink signal to generate distress alerts, and
• Mission Control Centers (MCCs) which receive alerts produced by LUTs and forward them to Search and Rescue Points of Contacts (SPOCs).

The current operational Cospas-Sarsat System includes two types of satellites:

• satellites in low-altitude Earth orbit (LEO) which form the LEOSAR System,
• satellites in geostationary Earth orbit (GEO) which form the GEOSAR System.

The future Cospas-Sarsat System will include satellites in medium-altitude Earth orbit (MEO). Once fully operational, the MEOSAR system will provide global coverage and near-real-time beacon detection and independent location.

The MEOSAR System

Global Navigation Satellite System (GNSS) satellites orbit the Earth at an altitude between 19,000 and 23,000 km, a range considered as medium-altitude Earth orbit. Hence this component of Cospas-Sarsat is known as the Medium-altitude Earth Orbit Search and Rescue system, or MEOSAR. It will complement the existing LEOSAR and GEOSAR systems.

The current LEOSAR and GEOSAR systems that detect and locate distress beacons have shortcomings that MEOSAR will overcome. The GEOSAR system constantly covers the entire Earth except the high-latitude (i.e., polar) regions. While the GEOSAR system can receive beacons distress messages across most of the globe, it cannot locate a beacon unless the location is encoded in the beacon’s message from a local navigation (GNSS) receiver. The LEOSAR system can locate a beacon without location information being transmitted in the beacon message (or can confirm the location even if positon information is transmitted in the beacon message), but the LEOSAR satellites have a view of only a small part of the Earth at any given time, which at times creates a delay in the distress signal reaching a ground station. While LEOSAR and GEOSAR still provide valuable search-and-rescue capabilities, MEOSAR is a revolution in technology.

Once fully operational, the MEOSAR system will offer the advantages of both the LEOSAR and GEOSAR systems without their limitations by providing transmission of the distress message and independent location of the beacon, with near-real-time worldwide coverage. The MEOSAR system will facilitate other planned enhancements for Cospas-Sarsat beacons, such as a return-link-service (RLS) transmission to a distress beacons that will provide, for example, the user with a confirmation that the distress message has been received.

The large number of MEOSAR satellites that will be in orbit when the system is fully operational will allow each distress message to be relayed at the same time by several satellites to several ground antennas, improving the likelihood of quick detection and improving the accuracy of the location determination.

At the beginning of 2013, Cospas-Sarsat entered a Demonstration and Evaluation (D&E) phase for the MEOSAR system to show that MEOSAR performance meets expectations, and that distress alerts received by SAR authorities from the MEOSAR system have the required reliability and accuracy.

The MEOSAR early operational capability (EOC), where distress alerts provided by the MEOSAR system are provided to SAR authorities for operational use, began in December 2016. The EOC phase will be followed by the initial operational capability (IOC) phase that will provide improved MEOSAR performance. When enough MEOSAR satellites and commissioned ground stations (MEOLUTs) are available to provide worldwide, near-real-time coverage, the MEOSAR system will be declared at full operational capability (FOC), which is anticipated in 2018.

The MEOSAR System Concept