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 TAS 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 TAS 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 TAS 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.

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


Nicolas REY (TAS-F) 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 (TAS), Lluis Badia (ACBS), Alain Cavan (ELTA), Karine Dupin (ELTA), Christophe Chatain (ELTA), Pauline Martin (TAS), 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!



GRICAS pursue its involvement in COSPAS-SARSAT with participation to TG-1/2017

COSPAS-SARSAT Task Group 1 meeting on “Second generation beacon (SGB) and SGB/FGB ELT-DT development of technical documents” took place in Honolulu, Hawaii, from March 27th to April 3rd and GRICAS consortium participated to present the general progress of the project and contributing to the development of the technical and operational requirements for SGB and SGB/FGB ELT-DT.

After the presentation of an information paper on GRICAS operational concept in April 2016 during COSPAS-SARSAT TG1 on ELT-DT operational and technical requirements, and 2 working papers to debate during the COSPAS-SARSAT Joint Committee 30 last September on respectively proposed updates to C/S T.018 for ELT-DT and operational concept for management of ELT-DT, GRICAS came back this March with 1 working paper on proposed updates to structure and contents of ELT-DT messages and 2 information papers on preliminary homing tests results and project general progress:

  • 6/2 – Rev. 1 Proposed Updates for ELT(DT) Alert and Cancellation Messages
  • Inf. 3 General Progress of the Development of an End-to-End Demonstration and Evaluation of In-Flight Activation of SAR Beacon On-board Aircraft
  • Inf.4 Preliminary Homing Tests with an SGB Signal Generator

During plenary sessions of the TG, GRICAS technical manager had the opportunity to present and defend the proposition for the structure and content of the alert and cancellation message of ELT-DT based on SGB and FGB, which mainly consisted in a proposition of use for the unassigned bits after the approval of the current definition of the so-called messages in December 2016 (to which GRICAS highly contributed thank to the paper presented at the JC-30).

GRICAS work has been very much valued by participants to the meeting in general and the chairman Mr. Anthony Foster from NASA in particular. Mr. Edwin Thiedman, chairman of the Joint Working Group (IMO/ICAO) expressed his interest in having a presentation of GRICAS at the next JWG meeting in October 2017. A certain interest has been expressed by the secretary and the participants regarding the coming in-flight demonstrations results and Mrs. Lisa Mazzuca, head of SAR Office at NASA, requested the possibility for NASA to participate to GRICAS first in-flight demonstration by collecting data with the US MEOLUT, which GRICAS accepted. The participants acknowledged the maturity of the project.

GRICAS projects outcomes has a true impact on the evolution of the documents developed at COSPAS-SARSAT and GRICAS technical manager made sure that is was clear to COSPAS-SARSAT that the future major subjects to be discussed at COSPAS-SARSAT in the coming months (MCC ELT-DT, Homing of SGB, …) do concern the GRICAS consortium as well.

GRICAS Test Readiness Review kicks-off the in-flight demonstration phase

Since GRICAS Critical Design Review in November 2016, the GRICAS engineering team has completed the development and validation of the elements of the final demonstrator of in-flight automatic activation of a SAR beacon on-board an aircraft and performed the integration of the complete final solution: GRICAS ELT-DT prototype based on a SGB, GRICAS ELT-DT Remote Control Panel, On-board Demonstration Platform (emulating the avionics). Unfortunately, the pre-operational Return-Link Service Provider being not yet available, the very last step of integration of the final operational chain could not be performed.

The integration tests have been performed in 5 sessions:

  • Session 1: 25/01/2017, SPIRENT tests in CNES with ELTA and TAS
  • Session 2: 30/01/2017, in ELTA with PILDO
  • Session 3: 31/01/2017 and 01/02/2017, in TAS with ELTA, PILDO and CNES
  • Session 4: 23/02/2017, SPIRENT tests in CNES with ELTA and TAS to complete session 2.
  • Session 5: 15/03/2017 in ACBS with ELTA, TAS and PILDO during GRICAS Test Readiness Review.

The combination of the five session’s results in the execution of the complete integration test plan defined in the GRICAS deliverable Test Case Operational Integration Plan.

Thanks to the CNES, a SPIRENT was used in January (session 1) and February (session 4) to perform tests to assess the capacity of the GRICAS prototype ELT-DT to receive a RLM. The SPIRENT was used to simulate Galileo navigation RF signals including successively the 4 RL messages defined in GRICAS:

  • Manual acknowledgment
  • Automatic acknowledgment
  • Manual activation
  • Manual deactivation

Integration tests sessions 2 and 3 were dedicated to the integration of the complete demonstrator’s chain, session 2 being dedicated to the mechanical, electrical and functional validation of the interface between the ELT-DT and the ODP and session 3 to the entire chain integration. The tests were largely successful with minor unconformity

Finally session 4, the Test Readiness Review, took place in Barcelona Aeroclub de Sabadell on March 15th and confirmed that:

  • The test were completed successfully and non-regression test could even be performed with the same results.
  • The elements integration is ended and validated
  • The test cases are ready
  • The preliminary end-to-end tests are successful
  • The deployment on first demonstration site is ready: the tests were performed in the targeted test aircraft at the Aeroclub de Barcelona Sabadell where GRICAS first in-flight demonstration will take place en of April. See picture here under with GRICAS demonstrator on-board the CESNA 182 test aircraft.

Test Readiness Review proved the maturity of the project to start the in-flight demonstrations. The tests performed in the test aircraft mitigated the risks regarding this first in-flight demonstration.

Let’s meet for the first in-flight demonstration will take place in Barcelona at the Aeroclub of Barcelona Sabadell from April 24th to April 26th for further results!