SBAS Flight Trials in European Eastern countries where EGNOS is still not available

Taking into account the widespread availability of aRea NAVigation (RNAV) capabilities onboard the aircraft and in particular the increasing use of GNSS systems, navigation is moving from conventional towards RNAV. RNAV is a method of navigation which permits aircraft operations on any desired flight path within the coverage of referenced navigation aids, prescribed limits of selfcontained aids or within a combination of both. The RNAV method covers not just en route and terminal area but also approach, where RNP 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. Nowadays, with the availability of SBAS integrity services, GNSS provides alternative and more precise navigation means flying RNP approach procedures (APV SBAS to LPV minima). On the 2 of March 2011 the EGNOS Safety-of-Life Service (SoL) was officially declared operational for aviation. Now, there are more than 40 APV SBAS procedures published in almost 40 airports in France, Switzerland, Germany, Italy and the Bailiwick of Guernsey. Also, by the end of 2011, the use of EGNOS for flying existing RNP approach procedures in Germany (82 APV Baro procedures in 38 airports) was approved 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 along 2013. However, EGNOS service is still not available all over Europe. One of the main objectives of the EEGS2 [2] project (EGNOS Extension to Eastern Europe: Applications) funded by the 7th Framework Programme of the European Commission (FP7/2007-2013) under the grant agreement number 287179 and reviewed by the European GNSS Agency (GSA) is to demonstrate through flight trials the benefits of EGNOS in areas of Eastern Europe where EGNOS is not yet available and prepare the civil aviation authorities and navigation service providers of those areas for the future usage of EGNOS. Not only through the flight trials will the countries where EGNOS has not yet coverage familiarize with EGNOS procedures but also pilots will be able to really understand and feel the EGNOS performances and advantages. These flight trials will contribute to the adoption of SBAS systems in countries where the EGNOS signal is not yet available. The International Civil Aviation Organization (ICAO), in its Assembly meeting (36th Assembly meeting on 18th – 28th September 2007) strongly recommended the implementation of LPV approach procedures, for all instrument runway ends, either as the primary approach or as a back-up for precision approaches by 2016, with intermediate milestones of 30% by 2010 and 70% by 2014. For that purpose a system in order to conduct those flight trials has been developed. This system has been designed to be a plug and play device. It is composed of two different sub-systems. The first one, on ground, is capable of broadcasting the magicSBAS [3] signal in the airfield and the surrounding area, and the second one, located onboard, which consists of an easily transportable rack plus a wirelessly operated tablet providing guidance to the pilot. This onboard system only needs a GPS antenna as the system works autonomously with rechargeable batteries. magicSBAS is a state-of-the-art operational SBAS testbed developed by GMV to offer non-safety critical SBAS augmentation to any interested region. The algorithms implemented in magicSBAS have been fully developed by GMV and are the result of more than 15 years of experience in the development of EGNOS and other SBAS programs. The magicSBAS algorithms, originally designed to mimic EGNOS performances over the ECAC service area, have been further optimized and tuned to provide the best performances in other regions of the world (South America, South Africa, Russian Federation, etc.) and to extend EGNOS performances to Eastern and Southern Europe. On ground, a mobile base station receives the magicSBAS EGNOS-like signal through an internet connection, which is then broadcasted by a radio modem transmitter in a free UHF band. The signal is received onboard the aircraft through the radio modem receiver installed in the rack. Then, the GPS signal and the magicSBAS EGNOS-like signal are transmitted to the tablet device via Wi-Fi. The tablet contains an application SW including real-time data processing and graphical plots for monitoring and providing guidance to the pilot through a CDI/VDI display. The benefits and main features of the application are:  A Plug and Play Modular System which allows easy transportation, configuration and installation both on ground and onboard.  The possibility of flying any LPV procedures defined in the airfield in places where a SBAS signal is not available. Vertical Guidance to the pilot via a CDI/VDI through a touch screen tablet device located in the cockpit without cabling.  Power supply autonomy since the systems onboard work with rechargeable batteries;  Real-Time, Standalone & Autonomous data processing.  Processing of GPS + magicSBAS or any available SBAS signal.  Easy comparison of magicSBAS and SBAS performances. This paper will present the architecture of the system, the preparation of the flights trials and the results obtained during the different flights throughout Europe. INTRODUCTION The International Civil Aviation Organization (ICAO), in its Assembly meeting (36th Assembly meeting on 18th – 28th September 2007) strongly recommended the implementation of LPV approach procedures, for all instrument runway ends, either as the primary approach or as a back-up for precision approaches by 2016, with intermediate milestones of 30% by 2010 and 70% by 2014. In Europe those recommendations are driven by the ATM Master Plan and the SESAR programme. In this context Eurocontrol has the mandate to develop a draft interoperability implementing rule on performance based navigation that will define navigation requirements and identify the functionalities required in en-route and terminal airspace, including arrival, departure, and also approach. Apart from this mandate other initiatives are needed at European level in other to implement the PBN concept. Those initiatives cover better understanding of PBN and RNP APCH, global approval of GPS usage, ICAO provisions, guidance for implementation and the supporting groups like the ICAO PBN Task Force and the Eurocontrol RAISG. Also there are some implementation projects funded by Eurocontrol, EC and GSA. In line with those initiatives the EEGS2 project has been focused in demonstrating and showing in the Eastern Countries of Europe the following issues:  The performances of an SBAS system from the point of view of the aeronautical users.  The steps that the ANSP has to follow in order to design, approve and certify an LPV procedure. The following paragraphs will review the status of EGNOS in the Eastern European countries, the LPV procedures and the work done in the scope of this project in order to conduct the flight trials. LPV PROCEDURES Localizer performance with vertical guidance (LPV) are the highest precision GPS (EGNOS/WAAS enabled) aviation instrument approach procedures. Those procedures provide horizontal and vertical guidance with SBAS to the pilot to LPV minima. This height depends on the obstacles during the approach which can be up to 250 feet. The main advantage from the point of view of the ANSP is that it is not required any navaid in the airport and from the point of view of the pilot the procedure does not depend on the temperature as it happens with APV Baro procedures. In USA more than 3000 LPV procedures have been designed and approved and in Europe there are 63 procedures implemented and 374 planned. It is expected to have 393 implemented by the end of 2016. EGNOS IN EASTERN EUROPEAN COUNTRIES The coverage of the EGNOS signal in the European Eastern Countries is improving but still is not enough for the implementation of LPV procedures. The figure below presents the availability of APV I procedures in Europe during June 2013. Figure 1EGNOS Availability in June 2013 (courtesy of the ESSP) The figure shows that the availability of EGNOS does not reach some countries in the Eastern part of Europe. During the first phase of the project [1] it was demonstrated that by using magicSBAS tool with one additional station located in East-Ukraine and some improvements in the ionospheric algorithms the Eastern and Southern Countries of Europe would have enough availability as can be observed in the following figure: Figure 2 magicSBAS improved availability Currently, all the European actors, like the European Commission (EC), GSA, the EGNOS service provider (ESSP) and the European industry are working together on improving that availability to cover the whole Europe extension. FLIGHT TRIALS The idea of the flight trials was to use the signal generated by magicSBAS in order to conduct the trials. This signal currently covers all the eastern European countries and allows us to use an EGNOS-like signal in the target area. For that purpose it was proposed to send that message in the surroundings of the airport via radiofrequency link. The message would be read at the airport through internet and sent via radiofrequency signal through a radio modem. There was also the possibility of reading the message via 3G, but this option was discarded from the beginning as the 3G coverage is not good at altitudes higher than 500 meters. However this option, as it will be shown, demonstrated to be a good choice in some particular flights.