The EGNOS NOTAM Proposals Service: Towards Full ICAO Compliance

J. Vázquez, M.A. Sánchez, J. Cegarra, P.D. Tejera, P. Gómez Martínez

Abstract:	“The EGNOS NOTAM Proposals Service” paper presented by ESSP (the EGNOS Services Provider) at the ION GNSS 2012 introduced the EGNOS NOTAM proposals service and its architecture. The EGNOS NOTAM proposals service is a key enabler for the publication of EGNOS based approach procedures in Europe, as it provides the different States with the required information to establish a NOTAM service covering this type of procedures as it is required by ICAO regulation. Last year, an overview was given covering the harmonized European approach for GNSS NOTAM (defined by Eurocontrol based on the continuous exchanges between civil aviation authorities, European ANSPs, Eurocontrol and ESSP) as well as ESSP role as data originator within the aeronautical information data chain. Also, the compliance status against the ICAO SARPs recommendations for a NOTAM service and the service operations concept were also introduced. The EGNOS NOTAM proposals service (operational since the official declaration of the start of the EGNOS Safety-of-Life Service for aviation in March 2011) predicts EGNOS based approach availability taking into account scheduled and unscheduled outages/failures of GPS and EGNOS system assets. These predictions are performed by the Euronotam Tool (developed by GMVAD for EUROCONTROL inside the GISE project) which implements a service volume model. 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-). Currently, there are more than 40 APV SBAS procedures published in almost 40 airports in France, Switzerland, Germany, Italy and the Bailiwick of Guernsey. Additionally, by the end of 2011, the use of EGNOS for flying the existing RNAV approach procedures (82 APV Baro procedures in 38 airports) in Germany was approved by the authorities meaning that they could be flown with EGNOS (for the vertical guidance too). EGNOS-based approach procedures implementation is now ramping up in Europe, with more than 100 APV SBAS procedures planned to be published in 2013. This process is expected to continue to speed up in the coming years due to the wider consensus in the aviation community with regards to the added value that GNSS can bring to all phases of flight, including approach. In the 37th ICAO General Assembly Resolution (A37-11), ICAO encourages States to complete a PBN implementation plan as a matter of urgency to achieve the implementation of approach procedures with vertical guidance (APV), Baro-VNAV and/or augmented GNSS, for all instrument runway ends (either as back-up for precision approaches or as primary approach) by 2016. Focusing on the compliance status against the ICAO SARPs recommendations, it was shown that the current service is enough to enable EU States to comply with the 72 hours advanced notice required for scheduled events. However, the current service delivers EGNOS NOTAM proposals for unscheduled events within 16 hours at maximum (instead of the recommended 15 minutes delay for a NOTAM Service). The main obstacle for the reduction of the gap with respect to the recommendation for unscheduled events was the lack of a real-time GNSS system asset status data source. However, the situation has changed drastically and the obstacles that were limiting the performance of the EGNOS NOTAM Proposals Service are no longer present. This paper will present the major changes that are now taking place in the EGNOS system interfaces and in the NOTAM proposals service both at architectural and operations concept level, with respect to the status that was presented last year: • The architectural changes mainly concern the deployment of a real-time interface with the EGNOS system (providing GPS and EGNOS system assets status information) and the automation of the Euronotam Tool, both planned to be operational by mid 2013. These two changes will provide the EGNOS NOTAM Proposals Service with the means to obtain and process EGNOS and GPS real-time status information with minute level delays. • In terms of the operations concept, a progressive transition from fixed hours check based operations (current service) to H24 reactive operations with minute level reaction times has been initiated (by mid 2013, the service reaction time is expected to be reduced to 2 hours during working hours). The above aspects are the main enablers for a potential fully ICAO compliant EGNOS NOTAM Service to be provided to end users by EU States. In order to achieve this target, ESSP and EC (European Commission, owner of the EGNOS system and EGNOS programme manager) have jointly defined an evolution plan for the EGNOS NOTAM proposals service, which, through a series of operations upgrades, will progressively extract the maximum benefit from the existing infrastructure or, in other words, provide an H24 service with minute level reaction times for unscheduled events at EGNOS and GPS system level. Additionally, the first operations baseline upgrade (first step towards an H24 reactive service), which will already enable a very significant reduction in the service reaction time to unscheduled events, planned for mid 2013, will be presented. Also, a summary of results of the first months of operation of the new infrastructure with the evolved operations concept will be provided. These results will be compared against the results that would have been achieved with the legacy service architecture and operations in terms of number of system events detected and assessed (in terms of performance impact at user level), NOTAM proposals issued and reaction times. Finally, the new compliance status against the ICAO recommendations for a NOTAM service and the remaining steps and associated milestones towards a full compliance will be presented.
Published in:	Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013) September 16 - 20, 2013 Nashville Convention Center, Nashville, Tennessee Nashville, TN
Pages:	301 - 315
Cite this article:	Vázquez, J., Sánchez, M.A., Cegarra, J., Tejera, P.D., Martínez, P. Gómez, "The EGNOS NOTAM Proposals Service: Towards Full ICAO Compliance," Proceedings of the 26th International Technical Meeting of the Satellite Division of The Institute of Navigation (ION GNSS+ 2013), Nashville, TN, September 2013, pp. 301-315.
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