Search and Rescue (SAR) / Galileo Service

Reaching you faster when every second counts

Global Search and Rescue (SAR) operations quickly locate and help people in distress. The SAR/Galileo service, launched on 15 December 2016 as part of Galileo Initial Services, contributes to these live-saving efforts by swiftly relaying radio beacon distress signals to the relevant SAR crews by means of dedicated payloads on-board Galileo satellites, supported by three ground stations strategically deployed across Europe.

On January 21 2020, the SAR/Galileo Return Link Service (RLS) was declared operational. Now, Galileo not only locates people in distress and makes their position known to the relevant authorities, the SAR/Galileo RLS provides an automatic acknowledgement message back to the user informing them that their request for help has been received.

How the SAR/Galileo service works



The SAR/Galileo service is the biggest contributor to the Cospas-Sarsat MEOSAR programme in terms of ground segment and space segment assets. It provides the following two services:

  1. SAR/Galileo Forward Link: relay of Cospas-Sarsat 406Mhz distress signals to the ground;
  2. SAR/Galileo Return Link: unique return link alert that informs the sender that their distress alert has been received.

These SAR/Galileo services are fully integrated into the Cospas-Sarsat system. The SAR transponder on Galileo satellites picks up signals emitted from distress beacons in the 406 – 406.1 MHz band and broadcasts this information to dedicated ground stations (MEOLUTs) in the L-band at 1544.1 MHz. These downlink signals transmitted by the Galileo SAR payloads are used by the MEOLUTs to generate an independent location of the beacon, which is then relayed to first responders through dedicated Cospas-Sarsat Mission Control Centres.

 


  

What is Cospas-Sarsat?

Cospas-Sarsat is a non-profit satellite-based search and rescue distress alert detection and information distribution system. It provides accurate, timely, and reliable distress alert and location data to SAR authorities, increasing the survival chances for people in distress by reducing the time it takes to locate them and relay this information to responders.

Established in 1979 by Canada, France, the USA and the former Soviet Union, the Cospas-Sarsat Programme currently has 45 countries and organisations that maintain, co-ordinate and operate the interoperable ground and space segments in line with Cospas-Sarsat specifications and performance standards.

The system is available to maritime and aviation users and to individual persons in distress situations on a non-discriminatory basis. It is free of charge for the end-user. The figure below shows the main components of the system:

  • Distress beacons operating at 406 MHz (users);
  • SAR payloads on satellites in low-altitude, medium and geostationary Earth orbit;
  • Ground receiving stations (LUTs) spread around the world; and
  • A network of Mission Control Centres (MCCs) to distribute distress alert and location information to SAR authorities, worldwide.

COSPAS-SARSAT System Overview

COSPAS-SARSAT System Overview

  

What it means for you

With contributions from Galileo and other GNSS providers, Cospas-Sarsat has been able to transition from its original design based on satellites in low Earth orbits (LEOSAR), later complemented by geostationary orbit satellites (GEOSAR), towards MEOSAR - a solution based on medium orbit satellites such as Galileo.

The MEOSAR system 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. Users benefit from:

  • Global coverage;
  • Single burst detection and location capability;
  • Reduced detection time from hours to just minutes after the distress beacon is activated;
  • Improved independent GNSS localisation of the distress alert under 5 km or better 95% of the time;
  • Improved availability with increased satellite redundancy;
  • Better signal detection in difficult terrain and weather conditions;
  • Automatic acknowledgment to the person in distress thanks to SAR/Galileo RLS.

With the introduction of the Return Link Service (RLS) Galileo became an even greater differentiator in search and rescue operations. The RLS relies on Galileo’s E1 navigation signal and is available worldwide for RLS-enabled beacons. Thanks to the improvements offered by the SAR/Galileo service, more lives are being saved. Read more here.

 

Table 1: SAR/Galileo Forward Link Service Location Quality MPLs

SAR/GALILEO FORWARD LINK SERVICE LOCATION PERFORMANCE MPL CONDITIONS AND CONSTRAINS

Location Probability after 1 transmitted burst

>90%

  • Calculated over a calendar month
  • From any point in the European SAR service coverage area defined in Figure below.

Location Probability after 12 transmitted bursts

>98%

Location Accuracy after 1 transmitted burst within 5km

>90%

Location Accuracy after 12 transmitted bursts within 5km

>95%

Source: Galileo Search and Rescue Service Definition Document, table 12, page 30.

 

Figure - European SAR/Galileo forward link service coverage and SAR/Galileo sites

COSPAS-SARSAT System Overview

Source: Galileo Search and Rescue Service Definition Document, figure 3, page 8.

 

Table 2: SAR/Galileo Forward Link Service Location Accuracy within 2[km] Expected Value

SAR/GALILEO FORWARD LINK SERVICE LOCATION PERFORMANCE EXPECTED VALUE CONDITIONS AND CONSTRAINS

Location Accuracy after 12 transmitted bursts within 2km

>90%

  • Calculated over a calendar month
  • From any point in the European SAR service coverage area defined in Figure 3.

Source: Galileo Search and Rescue Service Definition Document, table 13, page 31.

 

Table 3: SAR/Galileo Return Link Service Latency and Reception Probability MPLs

SAR/GALILEO RETURN LINK SERVICE PERFORMANCE MPL CONDITIONS AND CONSTRAINS

Galileo System Message Delivery Latency within 15 min

>99%

  • Calculated over a calendar month
  • Including the RLSP processing time up to Galileo satellite broadcast.
  • From any point in the Service coverage area
  • Refer to section 4.4 for the boundaries of the monitored Loop.
  • RLM beacon decoding is outside the perimeter

Return Link Message Reception Probability

>99%

 
  • Calculated over a calendar month
  • From any point in the Service coverage area
  • Refer to section 4.4 for the boundaries of the monitored Loop.
  • RLM beacon decoding is outside the perimeter of the Galileo

Source: Galileo Search and Rescue Service Definition Document, table 16, page 32.

 

Table 4: End-to-End Return Link Service Delivery Loop Latency Expected Performance

END-TO END RETURN LINK SERVICE PERFORMANCE EXPECTED VALUE CONDITIONS AND CONSTRAINS

End to End Message Delivery Loop Latency within 30 min

>95%

  • The expected Endto-End RLS latency within 30min is the arithmetical sum of the CospasSarsat and Galileo performance contributions with 15 minutes allocated to the Cospas-Sarsat Front End Loop and 15 minutes for the Galileo RLM Delivery Loop.
  • The expected value assumes a beacon position within the MEOSAR RLS service coverage. In case the beacon location confirmation can only be achieved by LEOSAR, the expected End-to-End latency will grow on average. Refer to sec. 4.7 for a further usage assumption regarding RLS

Source: Galileo Search and Rescue Service Definition Document, table 17, page 33.

Updated: Apr 01, 2020