The COSPAS-SARSAT system is an international satellite-based search and rescue system that has helped save over 20,000 lives since 1982. It detects and locates transmissions from emergency beacons on ships, aircraft, and worn by individuals. The system is composed of distress radiobeacons, satellites equipped to detect beacon signals, ground receiving stations, and mission control centers that forward alerts to rescue authorities. It operates using both low Earth orbit and geostationary satellites to provide global coverage and allow for location of distress signals.

1. G.O.C. FOR GMDSS
Module 3
Day 12

2. COSPAS-SARSAT
WHAT IS THE
MEANING

3. COSPAS : COMIECHESKAY
SISTYEMA
POISKA
AVARINICH
SUDOV
SARSAT – Search And Rescue
Satellite Aided Tracking

5. There are three types of emergency beacons:
1) Emergency Position Indicating Radio
Beacons (EPIRBs) for maritime applications,
2) Emergency Locator Transmitters (ELTs) for
aviation applications, and
3) Personal Locator Beacons (PLBs) for
individuals in distress. Emergency beacons
may transmit on 121.5, 243.0 (military) and 406
MHz. Satellite notification of 121.5 MHz alerts
are being phased out in the near future 406
MHz has become the international standard
providing far better accuracy and fewer false
alert search initiations.

6.  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.

7. 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

9. COSPAS-SARSAT is an
international, humanitarian
satellite-based search and
rescue system that has helped
save over 20,000 lives worldwide
since its inception in 1982 (total
as of June 2005).

10. The system, which operates 24
hours a day, 365 days a year,
detects and locates transmissions
from emergency beacons carried by
ships, aircraft, and individuals. Use
of the COSPAS-SARSAT system
is FREE to the beacon operator.

11. Sponsored by Canada, France,
Russia, and the United States, the
system aims to reduce the time
required to alert rescue authorities
whenever a distress situation
occurs. The rapid detection and
location of a downed aircraft, a ship,
or an individual in distress are of
paramount importance to survivors
and to rescue personnel.

13. 5. EMERGENCY RADIO BEACONS
According to 1988 SOLAS Amendments
(Chapter IV, Part C, Regulation 7) every ship
covered by the SOLAS convention shall be
provided with an Emergency Position
Indicating Radio Beacon (EPIRB). EPIRBs are
mandatory from August 1, 1993. Two types of
EPIRBs can be used:
The 406 MHz COSPAS/SARSAT EPIRB, using
polar orbiting satellites
The VHF EPIRB, using the VHF DSC channel 70.

15. 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;
.

16. • 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

17. The Cospas-Sarsat LEOSAR System
Cospas-Sarsat has demonstrated
that the detection and location of 406
MHz and 121.5 MHz distress beacon
signals can be greatly facilitated by
global monitoring based on low-
altitude spacecraft in near-polar
orbits.

18. The nominal LEOSAR system
configuration comprises four satellites.
Russia supplies two COSPAS satellites
placed in near-polar orbits at 1,000 km
altitude and equipped with SAR
instrumentation at 121.5 MHz and 406 MHz.
The USA supplies two NOAA
meteorological satellites of the SARSAT
system placed in sun-synchronous,
near-polar orbits at about 850 km
altitude, and equipped with SAR
instrumentation at 121.5 MHz and 406
MHz supplied by Canada and France.

19. When viewed from the Earth, the satellite
crosses the sky in about 15 minutes,
depending on the maximum elevation
angle of the particular pass.
Complete, yet non continuous coverage
of the Earth is achieved using simple
emergency beacons operating on 406
MHz to signal a distress. The coverage
is not. continuous because polar orbiting
satellites can only view a portion of the
Earth at any given time

20. Sarsat satellites (but not Cospas or
GEOSAR satellites) are also capable of
relaying 243 MHz beacon transmissions
(243 MHz beacons have similar
characteristics to 121.5 MHz beacons).
Each satellite makes a complete orbit of
the Earth around the poles in about 100
minutes, traveling at a velocity of 7 km
per second. The satellite views a "swath"
of the Earth of approximately 6000 km
wide as it circles the globe, giving an
instantaneous "field of view" about the
size of a continent.

23. Consequently the System cannot produce
distress alerts until the satellite is in a
position where it can "see" the distress
beacon.
However, since the satellite onboard 406
MHz processor includes a memory
module, the satellite is able to store
distress beacon information and
rebroadcast it when the satellite comes
within view of a LUT, thereby providing
global coverage.

25. Global beam coverage
Each satellite is equipped with a
single global beam that covers up to
one-third of the Earth's surface, apart
from the poles. Overall, global beam
coverage extends from latitudes of
−82 to +82 degrees regardless of
longitude. Regional spot beam
coverage

26. Regional spot beam coverage
Each regional beam covers a fraction of the
area covered by a global beam, but
collectively all of the regional beams offer
virtually the same coverage as the global
beams. Use of regional beams allow user
terminals (also called mobile earth stations)
to operate with significantly smaller
antennas. Regional beams were introduced
with the I-3 satellites. Each I-3 satellite
provides four to six spot beams; each I-4
satellite provides 19 regional beams

27. Narrow spot beam coverage
Narrow beams are offered by the three Inmarsat-4
satellites. Narrow beams vary in size, tend to be
several hundred kilometers across. The narrow
beams, while much smaller than the global or
regional beams, are far more numerous and
hence offer the same global coverage. Narrow
spot beams allow yet smaller antennas and much
higher data rates. They form the backbone of
Inmarsat's handheld (GSPS) and broadband
services (BGAN). This coverage was introduced
with the I-4 satellites. Each I-4 satellite provides
around 200 narrow spot beams.

28. With the older type of beacons operating
at 121.5 MHz, the system coverage is
neither global nor continuous because
detection of the distress depends on the
availability of a ground receiving station in
the satellite field of view at the same time
that the satellite receives the beacon
signal.

30. As described above, a single satellite, circling
the Earth around the poles, eventually views the
entire Earth surface. The "orbital plane", or path
of the satellite, remains fixed, while the Earth
rotates underneath it.
At most, it takes only one half rotation of the Earth
( 12 hours) for any location to pass under the
orbital plane.
With a second satellite, having an orbital plane at
right angles to the first, only one quarter of a
rotation is required, or 6 hours maximum.
Similarly, as more satellites orbit the Earth in
different planes, the waiting time is further
reduced.

31. The LEOSAR system calculates the
location of distress events using
Doppler processing techniques.
Doppler processing is based upon
the principle that the frequency of
the distress beacon, as "heard" by
the satellite instrument, is affected
by the relative velocity of the
satellite with respect to the beacon.

32. By monitoring the change of the beacon
frequency of the received beacon signal and
knowing the exact position of the satellite, the
LUT is able to calculate the location of the
beacon
The LEOSAR COSPAS-SARSAT system uses
two modes for detection and location of
beacons
- the realtime mode;
- the global coverage mode

33. Both the 121.5 MHz and 406 MHz systems
operate in the realtime mode, while only
the 406 MHz system operates in the
global coverage mode
1. Realtime 121.5 MHz mode: If an LUT
and beacons are in view of the satellite, a
repeater onboard the satellite relays the
121.5 MHz signals directly to the LUT
where it is received and processed

35. Trying to locate a person alone, in the water, is
an extremely difficult task in good conditions,
but in poor conditions or at night it's almost
impossible. This Personal Locator Beacon PLB-
8 system has been designed specially for
people who operate in remote hostile
environments. The PLB-8 is a low cost
emergency radio transmitter. When activated the
beacon transmits on 121.5Mhz (International
Distress Frequency) which will assist the Search
and Rescue services to locate your position in
an emergency situation.

36. 2. Realtime 406 MHz mode: When the
satellite receives the 406 MHz beacon
signals, the Doppler shift is
measured and the digital data is
recovered from the beacon signal.
This information is retransmitted to
any LUT in view in real time; this data
is also stored for later transmission
to earth by satellite.

37. 3. Global 406 MHz mode: Only the 406 MHz
beacon provides full global coverage. This is
because the data received from the beacon is
stored in the satellite and relayed to the LUT
when satellite to LUT visibility can be
achieved. The mean notification time (the
period from activation of an EPIRB to
reception of a valid alert message by the
appropriate RCC) in this mode of operation is
currently about one and a half hours, but may
be reduced if more satellites are employed.

38. GEOSAR and LEOSAR system capabilities
The GEOSAR and LEOSAR system 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 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

40. Radio Frequency Spectrum
The radio frequency spectrum is divided into
frequency bands. The major bands used in the
Maritime communications are