Inside GNSS Media & Research

MAY-JUN 2018

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38 Inside GNSS M A Y / J U N E 2 0 1 8 www.insidegnss.com ellite is particularly interesting and significantly improves the indepen- dent location accuracy. e access to a fih or sixth — or more — satellite allows to even refine the location performance accuracy. c. The pre-operational MEOSAR system used to localize an in-flight activated beacon: the MS804 accident On May 19, 2016, the MS804 f lying from Paris to Cairo crashed into the Mediterra nea n Sea w it h 66 people onboard. Unexpectedly, the distress beacon of t he a i rcra f t (a sta nda rd ELT) transmitted two test messages at 00:36:52 and 00:36:59. ese two mes- sages were received aer radar contact was lost and a few minutes after the reception of the last ADS-B message, probably several seconds before the crash. e two messages were received by several SAR satellites of the Cospas- Sarsat space segment: • 2 GEO satellites: MSG-2 (tracked by the Greek and Turkish GEOLUTs) and MSG-3 (tracked by the French GEOLUT) • 10 MEO satellites: GPS (PRN 1, 3, 9, 17 and 23), Galileo (PRN 8, 14, 20 and 26) and GLONASS K1-2, received by MEOLUTs in Cyprus, France, Norway, Russia, Spain, Tur- key, and USA. e first message was received with very low signal to noise ratio, therefore, only the second one could be used. e beacon model was not equipped with a GNSS receiver, thus no position was encoded in the alert message. Some MEOLUTs could compute an inde- pendent location based on TOA/FOA measurements using standard location algorithm (i.e. not taking into account the fast motion of the beacon) but these locations were highly inaccurate (more than 200 k ilometers away from the crash site). An analysis conducted by CNES using location algorithms adapt- ed to fast motion allowed to compute a better location, a few hours aer the accident. is information was prompt- ly transferred to search teams and was used to localize the wreck and quickly recover the flight recorders. A lt houg h t h is accident d id not involve the use of an ELT(DT), it dem- onstrates the ability of the MEOSAR system to provide reliable informa- tion to find the accident site in a timely manner. GRICAS: Providing an Innovative Solution From the beginning of the MEOSAR system, the European Union (EU) has been deeply involved in the deploy- ment, promotion and enhancement of the system. On one hand, the EU contributes to the space segment of the MEOSAR system with SAR payloads onboard each and every satellite of the Galileo constellation and constituting the Galileo SAR service. On the other hand, EU, via its institutions like the European Commission (EC) or t he European GNSS Agency (GSA), every year funds several research and devel- opment projects working on the devel- opment of the MEOSAR services and the design of new SAR services relying on the Galileo SAR: GRICAS, HELIOS, MAGNIFIC, SAT406M, GRIMASSE, SINSIN, iSSAR... Among those proj- ects, the GRICAS project (Galileo SAR Return-Link Improvement for a better Civil Aviation Safety) is funded by the GSA under the European Union Hori- zon 2020 Research and Innovation program (grant agreement no. 687556). Initiated in February 2016, it was to be concluded in April 2018 and gathers a consortium of seven companies and administrations from France (CNES, ales Alenia Space and ECA GROUP (with its brand ELTA), Italy (STMicro- electronics), Spain (PildoLabs, Aero- club Barcelona Sabadell) and Africa (ASECNA the Agency for Aerial Navi- gation Safety in Africa and Madagas- car). e main objective of the project is to demonstrate the compliance of the Cospas-Sarsat MEOSAR system to the requirements of the Autonomous Dis- tress Tracking function of the GADSS developed by ICAO. In 2017, all the developed operational concepts have been demonstrated through a set of in- flight trials in Europe, testing in par- ticular the first Cospas-Sarsat ELT(DT) (Emergency Locator Transmitter for Distress Tracking) developed for the project. The definition of the opera- tional concept is based on the ED-237 M A SP S pu bl i s he d by E U RO C A E Working Group 98 and the solution proposed is compliant with Cospas- Sarsat specification documents. d. An operational concept that covers all distress situations taking into account consequences of the distress on the cockpit crew GRICAS operational concept is based on three main distress scenarios: • the automatic activation by avionics upon detection of one or several dis- tress situations such as: ■ Criteria defined by EUROCAE as mandatory: • unusual attitude • unusual speed • unusual altitude • total loss of propulsion ■ Additional criteria identified as relevant by the GR ICAS proj- ect: • t ra nsponder codes (750 0, 7600, 7700) • fire • depressurization • the manual activation by crew • the manual remote activation from ground through the Galileo Return- Link Service (not required by ICAO at this time). Based on these scenarios, the solu- tion design requires: • a new type of Cospas-Sarsat aeronau- tical distress beacon called ELT(DT) • an ELT continuously armed and tracking GNSS with its own internal GNSS receiver (GPS + Galileo): ■ The ELT is always ready to be triggered to transmit a distress message as well as the needed data to be localized, as soon as a distress situation is detected. ■ The bi-constellation function of the GNSS receiver also offers robustness to spoofing and jam- ming on GPS signal GRICAS

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