The EGNOS NOTAM Proposals Service

Juan Vazquez, Miguel Angel Sanchez, Jesus Cegarra

Abstract:	With the widespread availability of RNAV capabilities on-board aircraft and in particular the increasing use of GNSS, air navigation is moving from conventional towards RNAV. Area Navigation (RNAV) is a method of navigation which permits aircraft operation on any desired flight path within the coverage of referenced navigation aids or within prescribed limits of self-contained aids, or within a combination of both. The RNAV method covers not just en route and terminal area but also approach, where RNAV approach procedures are described by a series of waypoints, legs and altitude constraints stored in the onboard navigation database. Initially, RNAV procedures were used for en-route and terminal area navigation, and for non-precision approaches, using lateral guidance only. Now, with the availability of SBAS services, GNSS provides alternative and more precise navigation means allowing flying RNAV approach procedures [1] (APV Baro -to LNAV/VNAV minima- and APV SBAS -to LPV minima-). On March 2nd 2011, the European Satellite Services Provider (ESSP), as EGNOS service provider, officially declared the start of the EGNOS Safety-of-Life (SoL) Service for aviation. EGNOS is the European SBAS service. Soon after the EGNOS SoL service was officially available, France published the first APV SBAS procedures in Europe at Pau Pyrénées, Clermont-Ferrand Auvergne and Paris Le Bourget airports. The second half of 2011 brought new APV SBAS procedures in Switzerland (Les Eplatures and Saint Gallen-Altenrhein airports) and the State of Guernsey (Alderney airport). By the end of 2011, the use of EGNOS vertical guidance for flying the existing RNAV approach procedures (APV Baro) in Germany was approved by the authorities meaning that, as of December 2011, a total of 80 APV Baro procedures in 37 German airports could be flown with EGNOS (for the vertical guidance too). EGNOS-based approach procedures implementation is now ramping up in Europe, with a total of 102 APV SBAS and APV Baro procedures in 54 airports now available and more than 50 planned to be published in 2012. Since March 2011, the ESSP is providing the EGNOS NOTAM proposals service to any airport having an EGNOS based approach procedure published. This publication is only possible after the signature of an EGNOS Working Agreement between the ESSP and the ANSP providing Air Traffic Services. The agreement includes the EGNOS NOTAM proposals service as one of the main enablers for the EGNOS based approach procedures implementation. The EGNOS NOTAM proposals service predicts EGNOS based approach unavailability taking into account scheduled and unscheduled outages/failures of GPS and EGNOS system assets. These predictions, based on the current and expected GPS and EGNOS system status, are performed by the EURONOTAM Tool (developed by GMV AD for EUROCONTROL inside the GISE project). Once an unavailability of the EGNOS SoL service is predicted, the EURONOTAM Tool generates airport-specific EGNOS NOTAM proposals in ICAO format, which are then delivered via AFTN to the concerned NOF (either directly or through the European AIS Database –EAD-). The current service provides EGNOS NOTAM proposals 72 hours in advance for scheduled events (in line with ICAO SARPS recommendation) whereas the EGNOS NOTAM proposals caused by unscheduled events are delivered within 16 hours at maximum (according to ICAO SARPS recommendation, unscheduled events should be notified within 15 minutes). ESSP is working to improve the EGNOS NOTAM proposals service aiming at fully meeting the applicable ICAO recommendations. This paper will start by briefly explaining the different activities and projects which were carried out in the past years in Europe and which resulted in the current EGNOS NOTAM proposals service. The context in which the current EGNOS NOTAM Proposals service was developed and is now operated will be clarified by providing an overview of the European concept for GNSS NOTAM and the applicable ICAO recommendations. This introduction will allow the reader easily identifying the level of compliance of the current service with respect to these standards. For the description of the service itself, two complementary aspects will be considered: ? The software and hardware architecture behind the EGNOS NOTAM Proposals Service, which are the main technical enablers in order to achieve an optimal service performance. ? The interfaces of the EGNOS NOTAM proposals service and the roles that the different involved entities play. Then, a summary of results of the first year of operation and the updated status in terms of countries/airports (and EGNOS based procedures) subscribed to the service will be provided. The paper will conclude by presenting the EGNOS NOTAM proposals service evolution roadmap, which has been defined by ESSP and contains the foreseen or potential service improvements. The EGNOS NOTAM service evolution roadmap will provide a high level view on ESSP plans to gradually improve the current service with the objective of not only maintaining the current quality standards but also enhancing the service aiming at bringing it to a level fully compliant with the applicable ICAO recommendations.
Published in:	Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012) September 17 - 21, 2012 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	188 - 202
Cite this article:	Vazquez, Juan, Sanchez, Miguel Angel, Cegarra, Jesus, "The EGNOS NOTAM Proposals Service," Proceedings of the 25th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS 2012), Nashville, TN, September 2012, pp. 188-202.
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