GRICAS ELT(DT) at the forefront of Autonomous Distress Tracking of GADSS solutions

In-flight remote activation of COSPAS-SARSAT distress beacon thanks to Galileo Return-Link Service: a solution to MH370 disappearance? GRICAS demonstrates its feasibility!

After the success of the demonstration in Barcelona in April 2017, two more field trials have been conducted over the past 10 days, using the GRICAS SGB ELT(DT) on-board an aircraft to automatically trigger the transmission of distress signals.

But GRICAS project was looking for a more ambitious goal to reach: remote activation of a beacon on-board a non-cooperative aircraft, and that is what they succeeded to do. On November the 29th and December the 6th 2017, the pre-operational Galileo Return Link Service operated by CNES in Toulouse was used to transmit the 4 RLM defined within the GRICAS operational Concept:

  • Activation of an ELT(DT)
  • Deactivation of an ELT(DT) (activated by a RLM)
  • Acknowledgement of the reception of cancellation messages after an automatic activation
  • Acknowledgement of the reception of cancellation messages after a manual activation by crew

The 4 RLM were sent to the GRICAS SGB ELT(DT) installed on-board the flying test airplanes used for the field trials. The first field trial took place at the Aeroclub of Sabadell near Barcelona, on-board the same Cessna 182 used in April 2017. The 4 GRICAS Return-Link test cases were successfully transmitted and received by the beacon and the whole GRICAS operational concept was validated. It is to be noted that the automatic activation scenario was fully automatic, with a triggering command sent to the beacon by the Beacon Activation Logic (or Triggering Logic) under a unusual altitude criteria detected thanks to the internal GNSS receiver of the beacon.

The 6th of December, the second field trial was conducted in Toulouse, on-board a Falcon 20 provided by SAFIRE (lien). The same scenarios were successfully completed, using automatic trigger based on an altitude threshold and the Galileo Return-Link Service. The test was even more ambitious this time, as the test airplane flew above 10.000 m (32.800 ft) with a typical cruise velocity of 800 km/h, which corresponds to an altitude and a speed representative of a commercial aircraft (A320 for example) specifically identified as the target of the GADSS concept of ICAO.


GRICAS demonstration platform integrated in a 4U rack and including the GRICAS ELT(DT) SGB


SAFIRE test aircraft FALCON 20 ued for GRICAS 3rd field trial

GRICAS participates to C/S JC-31 in Montreal

GRICAS consortium (CNES, Thales Alenia Space and ELTA) participated to Cospas-Sarsat Joint Committee 31 in October2017in Montreal, Canada, to present the progress of GRICAS project and the results of the two first GRICAS in-flight demonstrations. GRICAS consortium released 8 papers directly linked to GRICAS progress and outputs, both working and information papers, all very well received and debated during the plenary and splinter meetings of the Joint Committee and the Operational and Technical Working Groups:

  • JC-31-0414: MEOLUT and MCC interface specifications for moving beacons
  • JC-31-0432: Recommendations for ELT(DT) cancellation management by MCC and RCC
  • JC-31-Inf-01: Localization performances of SGB ELT(DT) prototype on-board an aircraft and a rotorcraft
  • JC-31-Inf-02: considerations on location of moving beacons in the MEOSAR system
  • JC-31-Inf-05: Performance results on C/S T.001 static and moving beacons
  • JC-31-Inf-06: Performance results on SGB static and moving beacons
  • JC-31-Inf-07: Considerations on operational management of moving beacons at MEOLUT and MCC level
  • JC-31-Inf-40: Considerations on ELT(DT) position errors

GRICAS, thanks to Thales Alenia Space, the project coordinator, was the major contributors to publications on the most sensitive items of the meeting with a total of 16 papers addressing:

  • Moving beacons including ELT(DT)
  • Performances and impacts of SGB
  • Interferences in the SAR band
  • Reference beacons for the MEOSAR

The participation of GRICAS partners to C/S meetings has been very much appreciated.The quality and relevance of the presented papers (all addressing major agenda items) were highlighted several times by the Secretariat of C/S and the key delegations (Canada, USA, Russia, France, United-Kingdoms…).The involvement of GRICAS consortium and the operational and technical approach led to excellent working relationships with the JC participants. GRICAS consortium, in particular through Thales Alenia Space representation,distinguishes itself from its competitors with a dual approach well balanced between operational and technical problematic. It is now known as a COSPAS/SARSAT partner looking for solution fitting the expressed needs and difficulties of the SAR operators. Its contribution to the Operational Working Group is valued and appreciated as much as its participation to the Technical Working Group.

GRICAS consortium took the opportunity of a SAR responders splinter gathering most of the SAR operators attending the C/S JC-31 to remind them of the necessity to express their needs and difficulties in SAR operations so that Research and Development projects like GRICAS and future H2020 European projects of GSA can work on developing appropriate solutions and make C/S MEOSAR and Galileo SAR the best solution to SAR challenges.

Finally, C/S participants are now looking forward to hearing from GRIMASSE project progress as they expect GRIMASSE consortium to pursue for General Aviation the actions initiated with GRICAS to help bring C/S MEOSAR and Galileo SAR to their best potential.

GRICAS 2nd field trial on-board a helicopter: a new success for the ELT-DT SGB prototype

After the successful testing on-board a CESSNA 182 late April 2017 with the complete GRICAS team, the Thales Alenia Space members of the GRICAS H2020 project conducted a new field trial with the GRICAS ELT-DT based on a COSPAS-SARSAT SGB this time on-board a helicopter.


The main objectives of the test were to:

  • Test the GRICAS ELT-DT SGB on-board an helicopter, including in particular automatic triggers
  • Analyze the performances during various trajectories with higher dynamic than during 1st field trial
  • Analyze the impact of the rotor on the quality of the SAR transmission

Test equipment and environment

The test helicopter, an AS 350 B2 “Squirrel” Eurocopter, was equipped with the exact same test platform as the one used for the first field trial:

  • An ELT-DT prototype (distress tracking) based on a Second Generation COSPAS-SARSAT distress beacon representative of what a real ELT-DT could be (in terms of electronic components, mechanical and functional interfaces and functions implemented) integrating a GNSS chipset Galileo and GPS compatible.
  • A remote control panel for the ELT-DT, based on the existing remote control panels for ELT present in the cockpits.
  • An on-board demonstration platform emulating the Beacon Activation Logic (based on avionics) and then sending the automatic triggering commands to the beacon and the GNSS receiver of the avionics (GPS only). The ODP also provides the logging functions and the GNSS reference trajectory.

The ELT-DT prototype was connected to the SAR antenna of the rotorcraft and an additional GNSS antenna, used to feed the on-board demonstration platform and the beacon, was set on the left door of the helicopter.

The same MEOLUT was used as well: the L-band MEOLUT Next located in Thales Alenia Space and implementing a SGB real-time processing software.

Test plan

Only three test cases were planned for this field trial:

  • Automatic activation by the ODP emulating the avionics
  • Automatic activation under detection of an unusual flight altitude
  • Manual activation

But a particular attention was dedicated to the trajectories:

  • Linear trajectory at constant altitude
  • Circular trajectories
  • Saw tooth trajectory with various vertical speeds
  • Static flight

Tests results:

On Monday 17th of July, the Thales Alenia Space engineers met the helicopter pilot and mechanics at the flight-club of Graulhet, region of Toulouse, France, to integrate the test equipment in the rotorcraft and prepare the flights. A first set of ground tests was performed with excellent results and good reception rate at the MEOLUT.

Tuesday 18th of July was the day selected for the flights due to a good Galileo coverage over the region of Toulouse during the entire afternoon. After a second set of ground tests and some final adjustments, the ground team and the flight team were ready for take-off and flight tests.

From a global point of view, the tests were all successful; in particular the automatic activation under detection of an unusual flight altitude was successful several times. The beacon transmissions were received correctly by the MEOLUT despite the effects of the rotor pales on the transmission and for all the trajectories even the most constraining, in particular the circles and the saw-tooth trajectories.

The detection rate in single-burst (reception via at least one satellite) was around 90%, under the detection rate observed during previous flight tests (100%) but still satisfying. We however clearly observed effects due to the rotor degrading the demodulation performances of the visible satellites ahead of the rotorcraft, and Thales Alenia Space engineers are then processing the raw signal and data collected in detail to come up with more conclusive analysis.Detailed results of the performances analysis will be published at COSPAS-SARSAT Joint Committee 31 in October 2017.

Thales Alenia Space team addresses special thanks to PILDO and ECA Group for providing the equipment used for the tests.



Nicolas REY (Thales Alenia Space in France) on-board the AS 350 B2 "Squirrel" during the tests of the GRICAS ELT-DT prototype based on COSPAS-SARSAT SGB developped by ELTA (ECA Group) using the On-board Demonstration Platform developped by PILDO. Both test elements where developped in the frame of the GRICAS project.


The GNSS antenna (flat and white antenna) was mounted on a PVC support and attached to the left door of the rotorcraft


The ELT-DT prototype was connected to the SAR antenna of the rotocraft.

COSPAS-SARSAT TG-2 2017: GRICAS impresses the participants with the first flight tests results

From June 20th to June 26th, GRICAS technical manager took part to COSPAS-SARSAT TG-2 on “Second-generation beacon (SGB) and SGB/FGB ELT(DT) development of operational documents, development of C/S A.003 (system monitoring and reporting), and QMS” in Montréal, Quebec, Canada.

GRICAS presented the information paper 10 “Localization Performances Of SGB ELT(DT) On-Board A Flying Airplane”. This paper presented the results of the first in-flight test of GRICAS end-to-end demonstrator of an Autonomous Distress Tracking system based on C/S SGB. The demonstrator completed successfully the Test Case Plan developed by the engineering team to validate the compliance of GRICAS solution to ICAO recommendations and EUROCAE specifications and thus demonstrated the relevance of using C/S for Autonomous Distress Tracking.

France, as leader of the GRICAS project, organized and supervised the first in-flight demonstration of the ELT(DT) SGB prototype on-board a CESSNA 182 test airplane in April 2017 (see previous posts on this web site for more information). The results of the real-time processing and the post-processing of the data collected for the SGB ELT(DT) reception and independent localization performances were gathered in the paper. For comparison purpose, few tests were also conducted with an FGB (typical ELT), for which the results are also provided. A proposition to use the 9 spare bits in Rotating Field 1 for ELT-DT was also presented to provide pitch and roll angle values.

Concluding the presentation of the paper, France invited the Task Group to:

Note that the project which started beginning of 2016 to demonstrate the operational and performance compliance of the Cospas-Sarsat System to the ICAO requirements, based on end-to-end demonstrations, using an SGB mounted on aircraft coupled with a second-generation capable MEOLUT, has successfully performed its first in-flight demonstration;

Note that the performances of single-burst moving SGB independent localisation with accuracy are better than 1 km at 95%

Note that it is recommended the MEOLUTs to transmit to the MCC for fast-moving beacons all single-bursts localizations. Since there can be until 6 single-bursts localizations per minute, it is in addition recommended to transmit several dated positions inside the same message to the MCC, to separate the capability to deliver several positions and the requirements on latency and volume flow. For instance, this could be one SIT message per 30 seconds containing at maximum 3 positions. The same logic would be applied for communications of SIT between MCCs.

Note the second and third in-flight demonstrations will take place in July 2017 in the region of Toulouse on-board an helicopter, in Dakar in September 2017 on-board an ATR 42 and finally end of 2017 or beginning of 2018 on-board a Falcon 20 or a ATR 42 with RLS use. All the results available on time will be reported to Joint Committee 31 in October 2017 and to the adequate C/S meetings in 2018 for the last field trials.

Note the possible use of the spare bits in C/S T.018 Rotating Field 1 proposed in this paper.

GRICAS results were very well received by TG-2 participants. And “the Task Group noted general agreement to: thank France for initiating and conducting its ambitious in-flight SGB ELT(DT) demonstration test campaign and for providing the results of its first test to this meeting; and invite France to continue its SGB ELT(DT) demonstrations, and share the collected test data and results with interested participants.” (extract from C/S TG-2 report).

But beyond presenting of the general progress of the project, the first in-flight tests results and the planning of future in-flight field trials, GRICAS consortium is also involved in several major topics discussed during C/S TG-2 like the MEOSAR QMS definition, the writing of C/S ELT-DT ConOps or the technical and operational discussions on the definition of an ELT combining both the DT and AF capacities.

TG-2 was also the opportunity to talk about the NASA/GRICAS cooperation on SGB ELT-DT development. Summer will now be dedicated to analyzing in a more detailed way the data collected during GRICAS 1st field trial and also to collect some more during the next field trial this time on-board an helicopter flying in the region of Toulouse. GRICAS being willing to promote SGB development and ELT-DT in particular, the information related the next field trial and the following ones will be made available upon request to any COSPAS-SARSAT participants.


GRICAS successfully triggers automatically a Second Generation distress beacon on-board a flying aircraft!

GRICAS 1st in-flight demonstration took place from April 24th to April 26th 2017 in the flight-club of Sabadell, close to Barcelona, Spain.
After 15 months of operational concept definition, solution design and demonstrator development, including 3 months of integration, verification and validation, GRICAS end-to-end demonstrator of an Autonomous Distress Tracking system based on Cospas-Sarsat distress beacon and space segment flew for the first time and completed successfully the Test Case Plan developed by the engineering team to demonstrate the compliance of GRICAS solution to ICAO recommendations and EUROCAE specifications. As reminder, GRICAS end-to-end demonstrator is composed of:

  • An ELT-DT prototype (distress tracking) based on a Second Generation COSPAS-SARSAT distress beacon representative of what a real ELT-DT could be (in terms of electronic components, mechanical and functional interfaces and functions implemented) integrating a GNSS chipset Galileo and GPS compatible.
  • A remote control panel for the ELT-DT, based on the existing remote control panels for ELT present in the cockpits.
  • An on-board demonstration platform emulating the Beacon Activation Logic (based on avionics) and then sending the automatic triggering commands to the beacon and the GNSS receiver of the avionics (GPS only). The ODP also provides the logging functions and the GNSS reference trajectory.
  • A L-band MEOLUT Next in Thales Alenia Space implementing a SGB real-time processing software

The pre-operational RLSP (Return Link Service Provider) being still under development the RLM reception (for remote activation, deactivation and acknowledgment), the reception of a real RLM transmitted via the Galileo satellites could only be tested on ground through emulation of the Return-Link signal with a Spirent signal generator, and was not considered in the in-flight demonstration. However, the reception and processing by the beacon of the complete Galileo navigation signal through its GNSS chipset proved its capability to receive and process a RLM encoded in it.
On Monday 24th of April, the GRICAS engineering team met at the aeroclub to finalize the integration and prepare the in-flight demonstration, installing the demonstrator on-board the Cessna 182 test aircraft. The excellent results of dry-run and non-regression tests and the very good weather condition encouraged the team and the test pilot to do the first flight test one day earlier than initially planned and for the very first time the GRICAS ELT-DT flew, was activated on flight and transmitted a distress signal, well received and processed by the French MEOLUTs (in real-time by the L-band chains in Thales Alenia Space and by sampling and post-processing by the S-band chains in CNES)
Tuesday 25th of April was the D-Day of GRICAS project, the date expected by the entire consortium and sponsors of the SGB solution for Autonomous Distress Tracking. Indeed, that day was specifically dedicated to tests with automatic activation of the beacon based on commands transmitted by the Beacon Activation Logic to the ELT-DT. More than 1 hour of the SGB ELT-DT transmitted signals were recorded and for comparison an hour of FGB classical ELT transmission was also recorded in-flight on the same test environment to provide comparison elements of the performances of SGB and FGB for independent localization of fast moving beacons. The aircraft trajectory inluded various attitude variations and curves to assess the performance of GNSS receiver and MEOSAR independent localization with high beacon motion dynamic. One of the tests performed was entirely automatic, the beacon being triggered automatically by the beacon activation logic based on GNSS information on the flight altitude of the test airplane. As a sake of simplicity and because GRICAS project never aimed at developing a representative beacon activation logic based on flight-dynamic engineering, the used Beacon activation logic computed an automatic trigger based on a too high altitude (instead of a low altitude). The reader will anyway note the representativeness of the automatic activation process though the source of the trigger is not part of the triggers specifically listed by EUROCAE. After take-off, the pilot pursues the ascent until overtaking a threshold altitude (agreed with the GRICAS engineers and encoded as the threshold altitude in the beacon activation logic of GRICAS). The BAL, collecting the position data provided by the GNSS of the demonstrator (emulating the GNSS receiver of the avionics for the tests), identifies the unusual altitude, computes a trigger “Unusual altitude” and sends it to the ELT-DT. The ELT-DT receives the trigger and start transmitting a distress signal every 10s with the relevant “activation method” encoded. The French MEOLUTs receive and process the signal being able to compute in real time a single and multi-burst independent localization, and to deliver the alerts to Barcelone team in less than 60 seconds. Finally, after 15 minutes, the pilot flies again under the threshold altitude, the BAL computes a cancellation trigger, the beacon starts transmitting a cancellation message, as well received, processed and delivered to Barcelona operators by the French MEOLUTs.
The GRICAS team was able to complete the Test Case Plan within this single day of test, thanks to the excellent results and because no dysfunction were to deplore.
Finally, Wednesday 26th of April, the weather conditions being not propitious to a lot of flight tests, the pilot and the flight team performed a set of touch-and-go with the ELT-DT SGB prototype, we could collect at MEOLUT levels data with significant variation of vertical speeds to be post-processed to assess the performances of independent localization as a complement of horizontal curves that were tested the days before.
GRICAS manager insisted on the unique aspects of GRICAS’s demonstration and the excellent results:

  • It was the first time a prototype representative of what a real ELT-DT SGB could be flew and was automatically triggered in-flight
  • It was the first time an independent localization of an SGB was computed during a transmission on-board a flying airplane and this was done only using Galileo SAR segment
  • Finally it was also the first time FGB and SGB modulated distress messages transmitted on-board a flying airplane was recorded (in the same test environment) to provide consistent data to compare the relative performances of both modulations for independent localization of fast moving beacon.

NASA showing interest for GRICAS in-flight tests, the GRICAS manager communicated them the flight hours and they were able to detect and record the messages transmitted by the GRICAS ELT-DT with their MEOLUT based in Greenbelt, Maryland, US.

Groupe photo: A smiley team on a rainy day! GRICAS team (from left to right: Daniel Martinez (PILDO), Nicolas Rey (Thales Alenia Space), Lluis Badia (ACBS), Alain Cavan (ELTA), Karine Dupin (ELTA), Christophe Chatain (ELTA), Pauline Martin (Thales Alenia Space), Tim Dufourmont (NLR for GSA), Josep Montolio (PILDO)) successfully completed the Test Case Plan for this first in-flight demonstration of GRICAS operational concept and solution! Congratulations!