After extensive ground and space testing, the SES-5 GEO satellite has entered into the European Geostationary Navigation Overlay Service (EGNOS) operational platform, broadcasting EGNOS Signal-In-Space (SIS), according to the European GNSS Agency (GSA).
SES-5 — which replaces Inmarsat-4F2 — will ensure reliable EGNOS services until 2026. It has been introduced through EGNOS System Release V241M, which will enable a range of performance improvements. In particular, EGNOS will offer even greater stability during periods of high ionospheric activity.
“SES-5 is the first step of the complete renewal of the EGNOS Space Segment, securing the EGNOS services for the next decade and the future transition to the dual-frequency multi-constellation services,” said Carlo des Dorides, GSA Executive Director. “It will be completed by the introduction of the ASTRA-5B signals and the procurement of a new EGNOS payload which are both planned for 2016.”
SES-5, carrying EGNOS L1 and L5 band payloads, was launched in July 2012. The integration of a second EGNOS SBAS L1/L5 band payload on SES ASTRA-5B GEO satellite is currently ongoing. The introduction of this second SES GEO satellite for EGNOS is planned at the end of 2016. SES won the contract following an open-tender procedure.
“SES is looking forward to many years of successful operation in delivering EGNOS services to the European citizens and beyond,” said Ferdinand Kayser, chief commercial officer at SES.
EGNOS is operated by the European Satellite Services Provider (ESSP), under contract by the GSA on behalf of the European Commission.
By Denis Parrot Guest Columnist, Survey Scene newsletter
I recently read an article by David Doyle entitled “Why Doesn’t my Centimeter Match Your Centimeter?” (May Survey Scene), which painted an interesting portrait of the widespread use of GNSS-based data collection systems. Nowadays, almost everyone can claim to have surveys with centimeter or sub-meter accuracy anywhere in the world, which before was achievable only by a few rare specialists. In many cases, the positions do not always fall at the right place when they are integrated into geographical information systems (GIS). Unfortunately, it is often at this stage that we call on a specialist! The key is in the reference system, also known as datum.
Even if it can become relatively complex when it comes to details, the concept of a reference system when using the GNSS system is essentially identical to conventional surveying techniques. A surveyor always used a reference station for his survey using his theodolite. He stringently maintained his control point network on the territory being surveyed. All his surveys were in reference to his control network (points that are part of a series of controlled polygons). If certain polygons were not well linked to the rest of the network, integration with centimeter precision into the computer-assisted design program (or his geographical information system [GIS]) would be problematic, or even impossible, for the lots linked to the erroneous polygons. And this is exactly what happens with the GNSS system; if the reference is overlooked, GIS integration becomes a real problem.
Without realizing it, GNSS users also use a reference network. If they work in RTK (differential positioning), they use either a VRS (Virtual Reference System) or a station network that sends corrections. In general, these two systems are based on a national reference system (geocentric or not). Users can also use a portable base that they install themselves as needed. When they enter a coordinate into this portable station, they become responsible for the reference system used. During post-processing, the problem remains the same. A position must be entered for the base station and the reference must be known (i.e., the datum).
Example of positions that do not fall at the right place when they are integrated into a geographical information system (GIS).
If they use satellite-based augmentation systems (SBAS), such as the private Omnistar, Veripos or StarFire systems, these systems are generally referenced by a geocentric system (which nowadays includes a temporal drift) defined by international bodies (IGN in France, which maintains, along with several research centers, the International Terrestrial Reference Frame (ITRF)). Today, this method of positioning is known as PPP or precise point positioning.
These different GNSS positioning methods, therefore, do not use the same reference! Each may provide highly accurate coordinates. However, these coordinates are only accurate with regard to their reference. Although this concept may seem very simple, in reality the increasingly common use of these systems by non-specialists often produces strange results.
Below are a few examples of uses that may lead to confusion with reference systems, in terms of “compared with what?”:
A farmer who carries out micro-topography to analyze his fields is pleasantly surprised by the level of altimetric precision he can achieve (within a few cm), using a “single-frequency” receiver. However, when he tries to juxtapose two fields, he may discover an altimetric deviation of up to 2 meters. The reason for this is quite simple: he systematically used local base stations with average coordinates taken in the field as the base coordinates. Normally, he uses one base per field. By not taking into account the consistency of the coordinates for the base stations, without realizing it, this farmer was creating independent references for each of his fields. It is obvious that if the analysis had been done individually on each field, he would not have seen any problem. It is when the two juxtaposed fields are integrated that problems arise.
Photo courtesy of Effigis.
In Quebec, a surveyor uses a Department of Energy and Natural Resources station as a source for RTK differential corrections. This system is referenced to the NAD83 SCRS coordinates system. When he tries to integrate his survey points using the conventional method, which are based on the original NAD83 coordinates system, he will notice inconsistencies of a few to several centimeters. These two coordinate systems (NAD83 ≠ NAD83SCRS) may have inconsistencies of several centimeters from each other.
In Canada, an agronomist surveys the position of trees in the city using a portable GNSS system with an SBAS corrections system. Once the survey has been completed and he integrates the position of the trees into the city’s GIS, these all seem to be off by +/- 1.5 m. The SBAS reference systems are all geocentric (within +/- several cm) compared with the NAD83 SCRS system, which is positioned +/- 1.5 m from the Earth’s center!
These three examples illustrate the type of error commonly found in the “reference system” category. The issue here is not GNSS system performance, since we are assuming that the positions obtained are accurate versus the chosen reference. Neither does the issue concern the variations between different reference systems, or the methods or precision of transformations between one reference system and another (this topic is very broad).
Lastly, we should find the answer to the question “But compared with what?” in what we commonly call “metadata.” Regarding GNSS position, this is information related to creating positions: the reference system used, statistics regarding the position estimate, date, different dilution of precision (DOP) values, type of GNSS signal used, etc.
For your next delivery, simply mention “Precise, but compared with what?” or deliver your positions along with full metadata!
Denis Parrot earned a degree in surveying and mapping from Université Laval in 1981, and began his career working in those fields around the world for five years. He then completed graduate studies in Fredericton, New Brunswick, where he earned a master’s in satellite geodesy. With a passion for his area of expertise, Parrot has been involved since 1991 in a host of projects that employ geospatial information to meet the specific needs of various markets and users. He is currently president at Effigis and responsible for the OnPOZ Product division, including the commercial aspect and R&D activities.
This column originally appeared as a blog at the Effigis Geo Solutions website, and is shared with permission.
NovAtel Inc. has entered an agreement with NEC Corporation to supply reference receiver products for use in the Quazi-Zenith Satellite System (QZSS). QZSS is Japan’s regional satellite-based augmentation system.
The NovAtel receivers to be used by QZSS are based on the company’s third-generation (G-III) family of reference receivers. Designed for integrity monitoring and reference measurement applications, the receivers track signals independently to provide precise code- and carrier-phase reference measurements as well as signal quality measurements and other integrity monitoring metrics. Housed in a 19-inch rack-mount enclosure with AC power supply and integral cooling fans, the G-III reference receivers provide continuous, reliable operation in a reference station environment, NovAtel said.
The G-III receiver platform has been customized to meet the needs of individual satellite networks. In addition to the QZSS G-III product, NovAtel supplies WAAS G-III reference receivers to the U.S. Federal Aviation Administration’s (FAA’s) modernized Wide Area Augmentation System (WAAS) network and IRNSS G-III reference receivers for the ground control segment of the Indian Regional Navigation Satellite System (IRNSS).
Current coverage (left) of WAAS, EGNOS and MSAS; long-term 2020–2025 (right) plan for dual-frequency, dual-GNSS WAAS-EGNOS-MSAS-SDCM-GAGAN.
SBAS Agree to Common Message
Aircraft navigation and safety will benefit from enhanced, reliable satellite navigation signals on a seamless basis across much of the world in the 2020–2025 timeframe. The 28th Satellite-based Augmentation Systems Interoperability Working Group (IWG) came to agreement on standardization of satellite-based augmentation systems (SBAS) in a meeting hosted by the European Space Agency in early April. The group planned a shift from reliance exclusively on GPS to a multi-constellation design employing Galileo, BeiDou and GLONASS after 2020.
The agreement centers around a message definition for a new secondary SBAS channel — to be known as L5, along with the current L1 — for second-generation SBAS systems, which will utilize dual-frequency multi-constellation signals, greatly increasing the accuracy of navigation systems available to airliners by largely eliminating ionospheric errors. Plans also call for an expanded network of stations in the Southern Hemisphere. The IWG document must now be accepted by the official international SBAS standardization bodies: the International Civil Aviation Organisation, the U.S. Radio Technical Commission for Aeronautics (RTCA) and the European Organisation for Civil Aviation Equipment.
The meeting also reported on the state of development of the other global SBAS systems. Along with the four operational systems — the U.S. WAAS, European EGNOS, Japan’s Multi-functional Satellite Augmentation System (MSAS) and India’s GAGAN (GPS and geo-augmented navigation system) — these comprise South Korea’s KASS, China’s Beidou SBAS, Russia’s System for Differential Corrections and Monitoring (SDCM) and the West African Agency for Aerial Navigation Safety in Africa and Madagascar (ASECNA) SBAS.
UAV Integration into Airspace
The Federal Aviation Administration (FAA) announced two new initiatives related to unmanned aircraft systems (UAS) at the Association for Unmanned Vehicle Systems International (AUVSI) Unmanned Systems 2015 conference in Atlanta, Ga., in early May.
FAA Administrator Michael Huertatold a large gathering of national journalists, “The unmanned aircraft industry is changing faster than any segment in the aircraft industry. A new project to harness that energy, the Pathfinder program, is partnering with three leading U.S. companies to expand unmanned aircraft operations in the United States.” The FAA is working with industry partners on three focus areas:
CNN will research visual line of sight (LOS) operations for newsgathering in urban areas. CNN will continue working with Georgia Tech University to improve newsgathering for all organizations.
PrecisionHawk will investigate agricultural operations for rural areas, flying outside LOS.
BNSF Railway, second-largest freight railroad network in North America, will undertake inspection of rail infrastructure, also beyond visual LOS.
Huerta said that the partners, collectively, “are trying to push the envelope, what can we accommodate safely and what can we learn from that.We’ll test a little, learn a little, then test some more. How do we see a staged implementation? To integrate unmanned aircraft, but to do it safely. We’re trying to push the edges of what we can allow, working with partners who have specific uses and resources.”
As to a timeframe to reach new UAV regulations, he replied, “I can’t comment a lot on the rule itself, but it’s fair to say that in the rulemaking comment process [closed on April 24], we received more than 4,500 comments. It’s too early to say how those comments will shape the final rulemaking.
“Assessment will be done in the coming months, perhaps by the end of the year, but that’s an aggressive timetable. That’s not accomplished in six months, nor should it take a million years.”
New Airbus EGNOS-Capable
The new Airbus A350 airliner, now entering service, comes fitted with EGNOS. The EGNOS system is being adopted by European airports to enable satellite-guided landing approaches. The A350’s Satellite Landing System allows pilots to perform precision-landing approaches guided by EGNOS or its U.S. equivalent, WAAS. The capability offers vertical landing guidance down to a minimum of 60 miles.
New Galileo Satellite on the Air
Monitoring by researchers at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt, or DLR) indicates that one of the Galileo full-operational-capability (FOC) satellites launched on March 27 has begun transmitting standard L-band signals using pseudorandom-noise-code identifier 22.
The first E1 and E5 signals from GSAT0204, also known as FOC-FM4 and Galileo 8 and as NORAD object 40545, were received at an International GNSS Service Multi-GNSS Experiment tracking station in Windhoek, Namibia, at about 11:32 UTC May 21. The satellite’s signals were subsequently tracked by a station in Wettzell, Germany, and then by others.
The signals will be set unhealthy for use until satellite commissioning is completed.
News item courtesy of CANSPACE Listserv.
Euroship Gets eLoran as Backup
Container ship in port.
Ship management company EuroShip Services Ltd. has installed eLoran as a backup to GPS to ensure the safety of its vessels operating off the coast of the United Kingdom.
The trial installation may lead to implementation across the full fleet of16 vessels managed by Euroship, working routes in Northern Europe. The land-based radio navigation system is intended to seamlessly take over in the event of a GPS outage. EuroShip plans to simulate GPS outages to test eLoran provision of position, navigation and timing data automatically.
New GPS III RFP
The U.S. Air Force (USAF) has released a draft Request for Proposal for GPS III Launch Services, encompassing launch vehicle production, mission integration and launch operations.USAF reintroduces competition into the Evolved Expendable Launch Vehicle (EELV) program after more than a decade.
GPS III is the first of nine launches the Air Force intends to competebetween now and 2017, followed by 25 more from 2018 to 2022.
It is heartening to see a burgeoning constellation and its operators move on from doubt to certainty, as Galileo prepares for fuller operational capability and the expectations that scope elicits.
To pick up the thread from last month’s column covering keynote speeches at the European Navigation Conference: plenaries subsequent to the opening session focused respectively on “GNSS for Aeronautical Applications: from GPS to Multi-Constellation with Galileo,” and “GNSS Resilience for Terrestrial & Naval Applications.”
Avionics. Benoit Roturier, GNSS and Performance-Based Navigation program head for the French air traffic control agency, Direction des Services de la Navigation Aérienne (DSNA), reviewed the rather complex assembly of air navigation systems gradually coming together. Not quite — or not nearly — a system of systems, as I understand it, more a conglomeration of systems.
Slide from Benoit Roturier’s presentation on behalf of the French air traffic control agency. (Courtesy of Benoit Roturier)
Multi-constellation GNSS combos, with added context from satellite-based augmentation systems (SBAS), target provision of performance-based navigation (PBN) in all phases of flight, with increased robustness and availability, as well as escalating categories of precision approach and landing. Roturier presaged the SBAS message agreement that also took place in April with his observation that “[The] most benefits are achieved with two constellations — but which ones?” As four constellations and two frequencies deliver “many, many potential navigation modes,” how can air traffic controllers limit complexity while achieving maximum benefits? At the very least, there is a need to agree on main mode and reversion modes.
He gave an overview of upgrades planned, in progress, and completed at airports around France. 141 runways are as of January 2015 equipped with PBN, with GNSS and often EGNOS approaches, compared with 260 still relying on older systems. He concluded with a summary of DSNA views, including “SBAS/EGNOS is seen as a free of charge, performing, mature and here to stay technology, supporting navigation and surveillance (ADS-B) performance requirements.”
By the way, June’s EAGER enewsletter column will cover a recent EGNOS demonstration flight and the current state of runway approaches in Europe. Subscribe here for free.
GNSS Resilience. The second plenary, on resilience, brought forth some of the most pointed commentary of the conference. Ignacio Fernández Hernández of the European Commission spoke on Galileo differentiators for resilience: its authentication plans for the Open Service, Commercial Service, and Public Regulated Service, respectively. “The proposed GNSS authentication services are 100 percent backward compatible and interoperable with other receiver-based technologies.”
Slide from presentation by Ignacio Fernández Hernández of the European Commission on Galileo differentiators for resilience. (Courtesy of the EC)
Hernandez proferred the caveat that “some of the required changes to deliver these services (particularly OS authentication) are pending on an impact analysis by industry/ESA and are not yet in the baseline. We hope however to have them in the baseline soon and we’re working hard for it.”
Matteo Paonni of the EC’s Joint Research Centre addressed spectrum management and regulatory issues, specifically the hot-button topic pseudolites. The EC is working closely with the United States and others to limit potential in-band interference risks. Outdoors, pseudolites are clearly undesirable; indoors, they offer some potential, but must be controlled.
Paonni stressed that there is a clear need to protect GNSS spectrum, and that the EC and its member states are doing their utmost to install such protections, and are also promoting GNSS radio-frequency interference detection and mitigation initiatives. Galileo’s PRS is more robust and resilient, but it is not invulnerable. GNSS vulnerabilities should be appreciated and backups put in place for critical systems; backups such as eLORAN, mini atomic clocks, GSM network, and so on.
Michel Monnerat of Thales Alenia Space focused on resilience in the road and LBS sectors. With a wide range of environments, devices and applications coming into play, “we need standardization” to specify levels of integrity and levels of performance for each different set of parameters. Thales Alenia is developing just such a set of performance requirements and references, with a first version set for release and discussion soon.
Slide presented by Michel Monnerat of Thales Alenia Space, which is working on a standardization protocol proposal, to be released soon. (Courtesy of Thales Alenia Space)
EGNOS is Europe’s first venture into satellite navigation. EGNOS broadcasts augmented information through a trio of geostationary satellites linked to a network of monitoring ground stations, to sharpen the accuracy and reliability of GPS signals across the continent. (artist’s concept: ESA)
News from the European Space Agency
The next decade’s aircraft pilots will be able to rely on enhanced, reliable satellite navigation signals on a seamless basis across much of the world, thanks to decisions made at the latest gathering of worldwide satnav augmentation system providers and experts.
The U.S. Wide Area Augmentation System (WAAS) and European Geostationary Navigation Overlay Service (EGNOS) are leading examples of satellite-based augmentation systems (SBAS) that apply additional ground stations and satellite transponders to sharpen the accuracy and reliability of existing satnav services across given geographical regions.
These performance enhancements permit satnav to be employed for safety-of-life services, especially aviation. Such systems are based on the U.S. GPS for now, but plans are being laid to move to a multi-constellation design employing Europe’s Galileo, China’s Beidou and Russia’s GLONASS satnav systems beyond 2020.
The 28th Satellite-based Augmentation Systems Interoperability Working Group (IWG), planning standardization of SBAS systems to come, was hosted at ESA’s ESTEC technical centre at Noordwijk, the Netherlands, on April 1-3.
The ESTEC facility in Noordwijk, The Netherlands. (Photo: ESA)
All participants unanimously endorsed the “message definition” for a new secondary SBAS channel — to be known as L5, along with the current L1 — for the planned second-generation SBAS systems, which will utilize dual-frequency multi-constellation signals.
Using dual frequencies greatly increases the accuracy of navigation systems, by allowing interference from the ionosphere — an electrically active outer layer of Earth’s atmosphere — to be largely subtracted from the final result.
“This definition is presented in what is called the Dual Frequency Multi-Constellation Definition document,” explained Didier Flament, representing ESA. “It represents the outcome of a four-year activity, which started at IWG 19 in Japan, back in 2010, coordinated between all IWG members under the technical leadership of ESA and French space agency CNES on the European side, and the Federal Aviation Authority (FAA) and Stanford University on the U.S. side.
“The formal IWG review loop for the document took six months to conclude, with this IWG 28 then allowing endorsements to be gathered by SBAS project managers, culminating in formal signatures to the document,” Flament said.
SBAS coverage for 2020: Comparing current worldwide SBAS coverage — based on WAAS, EGNOS and MSAS — to the situation envisaged for 2020–25: near-global coverage based on WAAS, EGNOS, MAAS, SDCM and GAGAN, with an expanded network of stations in the southern hemisphere, all based on a common dual-frequency/dual satnav standard being finalized by the SBAS Interoperability Working Group. (Image: ESA)
IWG members now intend to have this document accepted by the official international SBAS standardization bodies: the International Civil Aviation Organisation, the U.S. Radio Technical Commission for Aeronautics (RTCA) and the European Organisation for Civil Aviation Equipment.
“This next step is very important,” added Didier. “Not only for the coming 2016-22 implementation of the European EGNOS v3 but for implementation of other second generation SBAS in other regions of the world.”
The meeting also reported on the state of development of the other global SBAS systems. Along with the four operational systems — the U.S. WAAS, European EGNOS, Japan’s Multi-functional Satellite Augmentation System (MSAS) and India’s GPS-aided geo-augmented navigation or GPS and geo-augmented navigation system (GAGAN) — these comprise South Korea’s KASS, China’s Beidou SBAS, Russia’s System for Differential Corrections and Monitoring (SDCM) and the West African Agency for Aerial Navigation Safety in Africa and Madagascar (ASECNA) SBAS.
The follow-up IWG meeting will take place in October, hosted by the FAA in Washington, D.C., in conjunction with the next RTCA meeting.
Avanti Communications has been appointed by the UK Space Agency to deliver a crucial air navigation project in Africa, SBAS-AFRICA. The satellite operator has been awarded the contract under the agency’s International Partnership Space Programme (IPSP), which exists to open up opportunities for the UK space sector to share expertise in real-world satellite technology and services overseas.
Africa has just 3 percent of global air traffic, and yet air accidents in Africa account for roughly 20 percent of the worldwide total. By demonstrating potential improvements in flight safety via SBAS technologies, the project can provide socio-economic benefits to the continent, according to a news release from Avanti.
Based on prior cost-benefit modeling which identified a €1.7 billion potential economic benefit to the African aviation sector from the deployment of SBAS services, SBAS-AFRICA will help accelerate the adoption of GNSS-based flight operations, positively influence the evolution of aviation safety in Africa and encourage development in the wider African economy.
SBAS-AFRICA will deliver a satellite-based augmentation system for GNSS-based operations in the aviation sector, serving significant parts of Africa in partnership with a number of local stakeholders. The project will use a unique asset, Avanti’s ARTEMIS L1 Navigation transponder, to provide a navigation data broadcast service.
“SBAS-AFRICA brings an innovative and pragmatic approach to deploying SBAS services in Africa,” said Matthew O’Connor, Chief Operating Officer at Avanti Communications. “It establishes crucial collaboration between the UK and a number of African countries, including South Africa and Ghana. Participating countries will benefit hugely from expertise gained, placing them at the forefront of navigation services across the continent and, crucially, helping to improve aviation safety for a major generator of economic benefit in Africa.”
He continued, “The Artemis satellite will play an integral role in this project. We expect that such a showcase for its performance, accuracy and quality will provide further evidence of what can be achieved with this technology and lead to significant commercial opportunities.”
“The UK Space Agency is delighted to play a role in fostering new international partnerships that not only enable innovative UK space companies like Avanti to provide more high-tech exports that can boost our space sector but also allow the UK to widely share the considerable social and economic benefits that space technology and infrastructure can provide,” said David Parker, chief executive of the UK Space Agency.
By Ugo Celestino, European Commission, Antonella Di Fazio, Telespazio SpA, Vicente José Giner Herrera, Ineco, Patrizio Vanni, ENAV SpA, and Francisco Javier Deblas, ESSP.
This article describes a live demonstration of an aviation application in Tunisia, to help the local aviation community in validating the use of the European Geostationary Navigation Overlay Service (EGNOS) to guide airplanes during landing operations. This activity constitutes the first complete experience of EGNOS Safety of Life (SoL) service for aviation approaches outside Europe. We present here the obtained results that are useful not only for Tunisia, but as a valuable case study for other countries outside Europe interested in using EGNOS in aviation.
EGNOS, operational since 2009, has a European regional coverage that could be quite easily extended to areas adjacent to European Union through the deployment of limited additional ground infrastructure elements, but sharing the same existing space segment and leveraging the other core ground infrastructure.
The European Commission has put in place a series of actions since 2006 to support the EGNOS service extension in neighbouring areas. The MEDiterranean follow-Up for EGNOS Adoption (MEDUSA) is an on-going European initiative related to EGNOS extension in the Euromed region, including North African and Middle East countries around the Mediterranean basin: Algeria, Egypt, Israel, Jordan, Lebanon, Libya, Morocco, Palestine, Syria, and Tunisia. MEDUSA runs a program of technical assistance action in these Euromed countries, in order to prepare them for an optimal adoption and exploitation of European GNSS services in their priority market segments.
The Mediterranean Extension of EGNOS
EGNOS is Europe’s first venture into satellite navigation and paves the way for Galileo, Europe’s independent global satellite navigation system currently under deployment.
EGNOS is a satellite-based augmentation system (SBAS), whose signal is compliant to the international SBAS interoperability standards: standards – MOPS (Minimum Operational Performance Standards) and ICAO SARPs (International Civil Aviation Organization Standard and Recommended Practices). In its current version (V2) it augments the open public service offered by the American Global Positioning System (GPS), by providing correction data that enables to improve GPS position accuracy, and provides integrity information about the GPS system (integrity information is fundamental for aeronautical applications like approaches). EGNOS is interoperable with the other equivalent regional systems. Today other SBASs are the U.S Wide Area Augmentation System (WAAS), the Japanese Multi-functional Satellite Augmentation System (MSAS), the Indian GPS Aided Geo Augmented Navigation (GAGAN) and the Russian System for Differential Correction and Monitoring (SDCM). The future version (V3) of EGNOS will augment Galileo signal as well.
Today EGNOS is operational, and available for use in aviation since 2011, giving opportunities for users to have more accurate and reliable positioning for enhancing existing applications, developing new applications and particularly the safety critical ones. Already more than 150 landing procedures are operational across Europe (some of them also in countries out of the European Union, such as Switzerland, Norway, Guernsey), with many others under development to reach 100 percent Approaches with Vertical Guidance (APV) coverage in the European instrumental runways as per ICAO recommendation.
EGNOS provides three services:
EGNOS Open Service (OS), launched in 2009, is delivered free of charge. It is open for use to anyone with an EGNOS-enabled receiver. This can be any receiver compatible with satellite-based augmentation systems. Being based on GPS, the EGNOS signal does not require major changes for receivers. Today, many mass market receivers available on the market are also EGNOS enabled. EGNOS OS is particularly suitable for mass market and some applications like surveying.
EGNOS Safety-of-life Service (SoL) is authorized for European civil aviation and operational since March 2011. EGNOS SoL delivers the integrity message providing the verification of the GPS system and timely warnings (within six seconds), when the system or its data should not be used for navigation. Since integrity relates to the trust that can be placed in the correctness of the location information supplied by GPS, thanks to this feature EGNOS is able to meet the demands of safety-critical applications in sectors such as aviation.
EGNOS Data Access Service (EDAS) launched in 2012, delivers a terrestrial commercial data service. It consists of a server that gets the data directly from EGNOS system and disseminates it via terrestrial networks in real time, within guaranteed maximum delay, security and performance. EDAS is particularly suitable for professional applications. It provides EGNOS raw data and corrections enabling software solutions that implement products and value added services built on them.
EGNOS infrastructure consists of three geostationary satellites over Europe and a network of ground stations (Ranging and Integrity Monitoring Station – RIMS) located to provide services whose coverage includes southern Europe, North Africa and some Middle East countries.
The EGNOS RIMS network supports a flexible network geometry that gradually adapts to service coverage requirements evolution. From the originally envisaged coverage over European Union’s countries, the EGNOS RIMS network is being expanded over Europe’s neighbouring areas, thus increasing the number of beneficiary countries. EGNOS SoL service is highly sought by several non-EU countries for the benefits it can bring to their civil aviation, in providing a solution to comply with ICAO requirements for Performance Based Navigation (PBN).
The present layout of the EGNOS RIMS network is presented in Figure 1.
Figure 1. EGNOS ground segment.
Figures 2 and 3 show respectively today’s coverage of EGNOS OS availability (source: European Satellite Services Provider, the service provider of EGNOS) and the APV-I availability performance commitment provided by EGNOS SoL (source: EGNOS Safety of Life Service Definition Document, EGN-SDD SoL, V2.0, European Commission, 2013), obtained relying on the above presented ground segment.
Figure 2. EGNOS OS Availability.
EGNOS OS Availability. The Figure 2 map is obtained by projecting the error at pseudorange level into the position domain. The computed error assumes that the GPS satellites used are those with an elevation angle above the local horizon (with a mask angle of 5º) and does not consider any possible factor depending on local characteristics that could produce different results (optimistic or pessimistic) with respect to the results computed using real receivers located in the considered areas. Moreover, it represents an estimation of EGNOS OS availability during a very limited period of time being an estimation, thus it does not imply any commitment or reference for the performances which can be obtained during different periods.
Figure 3. EGNOS APV-I Availability.
Other initiatives for a further extension in North Africa and Middle East are already being developed, under the umbrella of the Euromed GNSS programme. In parallel with the infrastructure deployment, the Euromed GNSS programme also includes actions to support the introduction and exploitation of EGNOS services. The first stage was completed in the frame of the Euromed GNSS I/MEdiTerranean Introduction of GNSS Services (METIS) project in the period 2006-2009, the second stage is presently running in the frame of the Euromed GNSS II/MEDUSA project. Further initiatives are being planned for 2015 and beyond.
EGNOS Use in Aviation
EGNOS was initially designed and developed to be used in aviation, similarly to the U.S. Federal Aviation Administration WAAS, to support different types of aviation applications and, in particular, to meet the performance requirements set by the International Civil Aviation Organization (Annex 10) for the implementation of APV-I, which enable the implementation of LPV final approaches, as reported in Table 1.
Table 1. ICAO Operational Requirements.
EGNOS is one of the GNSS elements recognised by ICAO (Annex 10) as a radionavigation aid. It is an important element of a global SBAS systems mosaic, that started with the American system WAAS in 2003, and that is gradually completed by other more recent SBAS: EGNOS itself, MSAS (Japan), GAGAN (India), SDCM (Russia), and some countries like Australia and South Korea that have launched feasibility studies to develop their own SBAS.
It is expected that, in a not too far future, most parts of the world will profit from SBAS services, following the current coverage extension plans and SBAS system evolutions. The final objective, as also shared at ICAO level, is that as many airdromes worldwide, as possible, can offer instrument approaches with vertical guidance, with an outstanding increase in global safety rates.
Additionally, the use of EGNOS allows taking full advantage of GNSS for all phases of flight, including final approach. Therefore, EGNOS means for aviation a fundamental and strategic tool to help meet ICAO’s recommendations, aimed at the adoption of a PBN oriented airspace use policy, for all countries. The 37th Assembly of ICAO (28 September – 8 October 2010) resolved that APV procedures should be implemented as either a primary or backup strategy for precision approaches at all instrument runway ends by 2016.
APV is a major safety initiative. ICAO recognises SBAS and Barometric Vertical Navigation (Baro-VNAV) as the two acceptable (and often complementary) means of implementing APV procedures, which are safer than NPA (Non Precision Approach).
GNSS based navigation enables RNAV (aRea NAVigation) with a higher cost effectiveness in comparison with the old conventional, sensor ground-based, navigation procedures. This is especially true for wide, even desert unequipped areas (or difficult to maintain) like those in North Africa and Middle East.
EGNOS benefits are maximized in final approach manoeuvres, providing GNSS lateral and vertical guidance, and enabling APV-I approaches.
Final approach procedures based on GNSS are classified as RNP approaches (RNP APCH, as shown in the next figure), namely: Lateral Navigation (LNAV) with GPS lateral guidance and no vertical guidance; LP with GPS + SBAS (EGNOS) for lateral guidance (CAT-I localizer performance) and no vertical guidance; Lateral Navigation/Vertical Navigation (LNAV/VNAV) with GPS lateral guidance and Baro-Vertical Navigation (VNAV) vertical guidance (Baro-VNAV approach procedures can be flown with SBAS vertical guidance upon the approval of the Air Navigation Service Provider (ANSP)) and the LPV (Localizer Performance with Vertical Guidance) with GPS + EGNOS for both lateral and vertical guidance.
Figure 4. RNP approaches.
Those procedures not including vertical guidance are intended to be flown with the Constant Descent Final Approach (CDFA) technique (to avoid dangerous dive and drive practices), supported by most Flight Management Systems (FMS).
Regarding the operational LPV main figures, the European regulation (EU OPS -REGULATION (EC) No 859/2008 usually known as EU OPS) allows LPV operational minima (Decision Height – DH) down to 250 ft, expected to be possibly lowered down to 200 ft by 2015 (LPV-200), similarly to what is already permitted by the FAA, in the United Sates for WAAS based LPV approaches (a DH of 200 ft would make LPV approaches very competitive, when benchmarked against ILS CAT-I, precision approach, or even Ground Based Augmentation System (GBAS) CAT-I precision approach).
In the last few years, about 150 LPV procedures (status as of July 2014) have been published in European airports, and the number of procedures and countries introducing EGNOS is continuously increasing.
Euromed GNSS I/METIS and Euromed GNSS II/MEDUSA
In parallel with the development of the infrastructures necessary for extending EGNOS availability across the Euromed region, the European Commission has put in place initiatives to prepare and assist the Euromed countries for the optimal use and adoption of the relevant services.
These consist in two sequential projects, the first being Euromed GNSS I/METIS project and the second being Euromed GNSS II /MEDUSA.
Running from mid 2006 up to the end of 2009, METIS acted as a pioneer in the Euromed countries and built national/regional liaisons with decision-makers and key stakeholders, interested in sharing experience and absorbing know-how. The project assisted the 10 Euromed countries to identify their priorities in relation to the use of EGNOS services, to validate the relevant opportunities from the strategic/social and economic perspectives, and to elaborate a suitable strategy and a plan of actions for facilitating EGNOS adoption and exploitation.
MEDUSA Case Study in Tunisia: LPV Approaches in the Airport of Monastir Using EGNOS
As part of the technical assistance actions programme in the priority domains, MEDUSA implements demonstrations and validations of EGNOS services in concrete applications.
For EGNOS SoL, the technical assistance action consisted in the validation of GNSS approaches, including LPV approaches, designed and constructed in MEDUSA along with the relevant safety assessment and business case for the airport of Monastir in Tunisia (35°45’29’’ N 10°45’17’’ E). The selection of the airport was driven by a trade off between the EGNOS service availability with required APV-I performances and the specific needs of the Tunisian Air Navigation Service Provider – ANSP (OACA, Office de l’Aviation Civile et des Aéroports). According to OACA, Monastir is among the airports in Tunisia presenting favourable conditions, in terms of operational constraints and traffic, for concretely proving the added value of EGNOS for final approaches.
The airport has two runways, RWY 07 and RWY 25, the former is equipped with an ILS CAT-I, the latter only supports NPA approaches. The installation of an ILS in RWY 25 was discarded due to technical constraints. This infrastructure has proven to be insufficient to fully cover the airport needs, that suffers some Delays-Diversions-Cancellations (DDCs) as a result of local specific meteorological conditions, frequent fog banks entering from the sea in the early morning, combined with desert haze. These conditions make LPV ideal procedures, as backups to RWY 07, and enabling APV approaches to RWY 25. Finally, Monastir’s TWR ATC (Tower Air Traffic Control ) staff has been involved in OACA’s PBN development, for which they were ideal candidates to evaluate the benefits possibly achievable from the use of EGNOS.
This MEDUSA’s technical assistance action is the first complete experience for the use of EGNOS SoL service outside Europe. It was conceived as a realistic exercise of RNP APCH procedures implementation, following the guidelines provided by ICAO in the “EUR RNP APCH Guidance Material (EUR Doc 025)” and including all the activities required, from the scenario adequacy study to flight validation and the requirements analysis for the final publication in the AIP (Aeronautical Information Publication). OACA was directly involved in all activities, providing inputs/feedbacks and for training purposes.
A set of three GNSS based approach procedures was produced for each RWY, following ICAO 8168 PANS OPS design principles. The next figures show the combined charts type elaborated, that include minima boxes for three RNP approaches (LNAV, LNAV/VNAV and LPV). The procedures construction preserves the current Monastir arrivals structure, following airspace management principles and facilitating the operational approval. As illustrated in the charts, in both cases for the three minima the calculated OCH (Obstacle Clearance Height) values improve with respect to the already existing conventional approaches, providing significant operational and safety benefits.
Figure 5. GNSS approaches for RWY 07.Figure 6. GNSS approaches for RWY 25.
An on-site GNSS performance monitoring campaign was performed by OACA, with the support of GEMCO’s staff, 3 months before the flight trials schedule, covering both EGNOS and GPS signal performances. Besides, an APV-I availability study for the area and specifically for Monastir airport during 1 month before the flight validation was purposely elaborated by the European EGNOS service provider (ESSP). Both analyses, confirmed suitable APV-I performance in terms of availability and continuity, making feasible the implementation of LPV approach procedures in line with ICAO prescriptions.
The next figures show the EGNOS APV-I availability and continuitymeasured on one day during the period of the flight validation (conducted from 30 January to 1 February 2014), in particular at Monastir airport for the considered time-lag:
APV-I availability was over 99%;
APV-I continuity presented a total value lower than 5×10-4/15s;
95th percentile of Horizontal APV-I accuracy was between 1.1 and 1.2 meters and the 95th percentile of Vertical APV-I Accuracy is around 1.4 meters, thus showing a very good accuracy level;
Horizontal and Vertical safety indexes were lower than 0.25, representing a very good integrity margin.
Additionally, the results of the on-site GNSS performance monitoring campaign showed quite stable performances with small fluctuations during the whole period of observation, and no problems or outages were observed.
(EGNOS APV-I Availability is defined as the percentage of epochs in a month in which the Protection Level are below Alert Limits for this APV-I service (HPL<40m and VPL<50m) over the total period (source: ESSP).
EGNOS APV-I Continuity Risk is defined as the result of dividing the total number of single continuity breaks using a time-sliding window of 15 seconds by the number of samples with valid and available PA navigation solution. A single continuity break occurs if the system is available at one epoch and becomes not available for the following 15 seconds (source: ESSP).)
Figure 7. APV-I availability on 31.01.2014.Figure 8. APV-I continuity on 31.01.2014.
The flight validation campaign was carried out according to ICAO doc 9906 with a Piaggio P180 Avanti II (from ENAV flight inspection department) suitably equipped with UNIFIS 3000 system and a Rockwell Collins FMS 3000 with SBAS LPV approach capabilities.
Figure 9. Piaggio P180 Avanti II aircraft and the FMS messages during the flight validation.
The outcomes of this concrete experience have allowed the Tunisian authorities to identify the main elements for the publication of the validated procedures in their national AIP. They have also contributed to the analysis of the necessary process for the operational adoption of GNSS, including EGNOS, in aviation in countries beyond the EU boundaries.
The activities performed on performance assessment have been preparatory for discussions on GNSS monitoring and data recording on going at ICAO Navigation System Panel level, that would produce ICAO guidelines for States.
Therefore, this Tunisia’s “case study” represents a practical and realistic example that could be beneficial for the other non-EU countries in terms of best practice and lesson learnt. Moreover, methodology and guidelines have been derived to be possibly injected to other non-European countries interested to introduce EGNOS operations in aviation.
Lessons Learned and Outlook
Through its achievements, MEDUSA is opening the way for the introduction of EGNOS SoL service in North Africa and Middle-East region, and it is also defining a suitable path to be followed by other interested non-European countries. Overall, MEDUSA is continuing to confirm the ability to foster cooperation and involvement in EGNOS programme of the great majority of the Euromed countries. Further to Tunisia, other Euromed countries have already expressed their interest in relation to the EGNOS use in aviation, considering each country’s strategy and also in the light of a common shared regional perspective. Besides, the results obtained by MEDUSA are useful also for other regions interested to use EGNOS in aviation.
Additionally, MEDUSA is clearly showing that Euromed region, presently lacking the full support of SBAS technologies, represents an opportunity for EGNOS service extension, with many benefits for the countries of the region and for Europe.
On one hand, being SBAS an effective and efficient technology to enable the aviation community of the Euromed countries to comply with ICAO recommendations on PBN implementation by year 2016 across the region, the services coverage extension of existing SBAS systems (EGNOS in the case of the Euromed countries) can be one of the most efficient ways to move forward. In fact, the Euromed national ANSPs consider the readiness of EGNOS SoL service as one of the main drivers and factors when designing their PBN strategy. EGNOS, which is already operational since 2009 and available for use in aviation since 2011, can deliver added-value services to the Euromed region, just by leveraging the existing European infrastructure with only incremental, marginal and natural extension. The EGNOS coverage extension across the Euromed region can provide significant benefits and particularly to those Euromed countries with few ILS or reduced navaids coverage, and enhance safety and efficiency to the whole aviation community.
On the other hand, the European Union has to gain from an EGNOS-based long term links with its neighbouring regions, by increasing bilateral/multilateral cooperation and interaction (e.g. assistance, mutual cooperation) among public and semi-public bodies (e.g. ANSPs, Civil Aviation Authorities), by strengthening EGNOS SoL coverage in the southern/peripheries of EU (e.g. Malta, Cyprus, Greece, Southernest Italian islands, Canary islands), by pursuing and supporting other EU policies in several sectors (like transports, e.g. harmonizing aviation safety standards across the Mediterranean, Transport Policy of the Mediterranean Partners), and last but not least by achieving a first step towards EGNOS extension to the whole African continent which will bring in similar, additional benefits just described above.
Eos Positioning Systems has introduced a new line of high-accuracy GNSS receivers for smartphones and tablet computers, including both sub-meter and RTK performance for all mobile platforms: iOS, Android, and Windows.
Eos’s entry-level product, the Arrow Lite, is Bluetooth compatible with all mobile devices.
The Arrow 100 is Eos’s advanced real-time, sub-meter GNSS receiver that utilizes both GPS and GLONASS, and is expandable to Galileo, Beidou and QZSS. It offers superior tracking under tree canopy, around buildings and in rugged terrain, the company said. In addition to supporting SBAS in North/Central America, Europe, Northern Africa, Japan, India and Russia, the Arrow 100 also supports OmniSTAR’s worldwide, real-time sub-meter service.
The most advanced Arrow receiver is the Arrow 200, a dual-frequency, multi-constellation RTK GNSS receiver capable of 1-cm accuracy in real time. The Arrow 200 is an iOS-compatible RTK and OmniSTAR receiver that works with all models of iPads and iPhones via wireless Bluetooth connection. An iOS NTRIP app that allows the user to log into any available RTK network. The Arrow 200 will provide quality RTK performance for years to come because it supports current and future satellite constellations: GPS, GLONASS, Galileo, BeiDou and QZSS, the company said. It also supports OmniSTAR’s G2, XP and HP real-time worldwide decimeter services.
“After spending more than 12 years designing high-accuracy Bluetooth GNSS receivers, I believe Eos has set the new standard for high- accuracy GNSS receivers that work across all mobile platforms, no matter if it’s iOS, Android or Windows,” said Chief Technology Officer Jean-Yves Lauture.
All Arrow receivers employ long-range (1-km) universal Bluetooth connectivity so the user can interface to any brand of smartphone or tablet, whether it’s iOS, Android, or Windows-based. A variable-power Bluetooth implementation allows the Arrow receivers to communicate up to one kilometer from the mobile device.
Arrow receivers have been optimized to run all day on battery power. The battery pack is field-replaceable and rechargeable separately. It contains smart charging logic so expensive battery chargers are not needed.
All Arrow receivers have been designed to meet IP-67 specifications for immersion in water and are completely dust-proof so they will survive in the harshest environments.
The Arrow receiver product line is targeted at high-accuracy applications like GIS, environmental, agriculture, electric/gas/water utilities, surveying, machine control, and federal/state/local government.
Telit Wireless Solutions has debuted the Jupiter SL871-S, designed for easy migration between a full-GNSS solution for top-ranked applications and a simple GPS-only solution for less demanding applications. The Jupiter SL871-S is designed to track and navigate GPS and QZSS constellations while ensuring pin-to-pin and protocol compatibility with its multi-constellation companion module, the SL871.
The module comes in a 9.7 x 10.1 millimeter LCC package with an ARM7 baseband processor, embedded ROM memory, and integrated LNA. It delivers geolocation data using NMEA protocol through a standard UART port. It supports ephemeris file injection (A-GPS) as well as Satellite Based Augmentation System (SBAS) for increased position accuracy.
In addition, its extremely low power consumption in all conditions is suited to applications requiring long battery life.
SL871-S has been designed to ensure hardware and software compatibility with SL871, allowing customers to design once and take advantage of the xL871 common form factor. Benefits include:
Pin-to-pin compatibility with SL871 family,
Same protocol used in SL871,
Straightforward migration between full-GNSS solutions and GPS-only solutions,
Satellite Based Augmentation System (SBAS) support for increased position accuracy, and
Assisted GPS.
The SL871-S can replace the SL871, allowing customers to design once and interchangeably mount the appropriate solution depending on the required features.
“The new SL871-S module designed to be easily swapped with other xL871 modules for enhanced simplicity and scalability,” said Taneli Tuurnala, CEO of Telit GNSS Solutions. “It is an ideal example of how buying a module from Telit enables our customers to avert the need to keep track of the latest chipset technology on their own. We keep them on top of the best available technology, pre-packaged in a module that is easy to replace as needed, without having to redesign their entire application to stay up to date.”
The Jupiter SL869-V2S GPS module. Photo: Telit Wireless Solutions
Telit Wireless Solutions, a global provider of high-quality machine-to-machine (M2M) modules and services, today debuted the Jupiter SL869-V2S GPS module, designed for easy migration between a full-GNSS solution for top-ranked applications and a simple GPS-only solution for less demanding applications.
The Jupiter SL869 V2S supports GPS as well as QZSS constellations and is ROM based. Geo-location data is delivered using NMEA protocol through a standard UART port. It supports ephemeris file injection (A-GPS) as well as Satellite Based Augmentation System (SBAS) for increased position accuracy. Its onboard software engine is able to locally predict ephemeris three days in advance starting from ephemeris data broadcast by GNSS satellites, received by the module and stored in the host flash memory.
Key benefits include:
Pin-to-pin compatibility with JN3/xL869 family
Same protocol used in SL869 V2
Straightforward migration between full-GNSS solutions and GPS-only solutions
SBAS support, for increased position accuracy
Assisted GPS
The SL869 V2S can replace the JN3, SL869 or SL869 V2 — allowing customers to design once and interchangeably mount the appropriate solution depending on the required features. The xL869 is Telit’s GNSS unified form-factor family, which allows customers to select among different GNSS technologies and feature sets. Modules in this family are offered in a 16 x 12.2 mm, 24-pad, LCC package.
“The new SL869 V2S module is designed to be easily swapped with other xL869 modules for enhanced simplicity and scalability,” said Taneli Tuurnala, CEO of Telit GNSS Solutions. “It is an ideal example of how buying a module from Telit enables our customers to avert the need to keep track of the latest chipset technology on their own. We keep them on top of the best available technology, pre-packaged in a module that is easy to replace as needed, without having to redesign their entire application to stay up to date.”
EGNOS is Europe’s first venture into satellite navigation. EGNOS broadcasts augmented information through a trio of geostationary satellites linked to a network of monitoring ground stations, to sharpen the accuracy and reliability of GPS signals across the continent. Photo: EGNOS
Europe’s EGNOS augmentation system sharpens the accuracy and reliability of GPS signals so they can safely be used for landing approaches across a growing number of European airports. But aviation is a global enterprise — so the aim is to develop a seamless network of augmentation systems in future.
That is the task of an international group of experts, the Satellite Based Augmentation Systems (SBAS) Interoperability Working Group (IWG), whose 27th meeting took place in Tampa, Florida, September 8-10, hosted by the Institute of Navigation.
Satellite augmentation systems combine dedicated ground stations and satellite transponders to sharpen satnav accuracy and provide integrity data — providing continuously updated reliability levels — across given geographical regions. These systems are based on GPS for now, but plans are to move to a multi-constellation design in the post-2020 era, making use of Europe’s Galileo, China’s Beidou and Russia’s GLONASS systems as well.
SBAS providers from around the globe gathered at Tampa, Florida, for the latest meeting of the SBAS Interoperability Working Group September 8-10. IWG 27 was hosted by the Institute of Navigation. Photo: SBAS
SBAS systems enhance any type of location-based satnav use, but in practice, aviation is the main driver. The ESA-developed European Geostationary Navigation Overlay Service, EGNOS, commenced its general-public Open Service in 2009, with the Safety-of-Life Service for aircraft vertical landing approaches following in 2011.
For next-generation SBAS systems, the IWG is designing a multi-constellation and dual-frequency standard for heightened accuracy and reliability, building up to offering SBAS coverage on a worldwide basis.
Didier Flament, representing ESA — which co-chaired this IWG meeting with the U.S. Federal Aviation Authority — commented: “Among the achievements of the Tampa IWG has been the presentation of an ongoing review of a standard message definition for the new and second SBAS channel — known as L5 — of the second-generation SBAS system, to be used along with the current L1 signal.
ASECNA Member States.
“A single definition coordinated between ESA and the European Commission on one side and the U.S. Federal Aviation Administration on the other is progressing. The formal IWG review loop has started, with the aim of finalizing the convergence for early 2015. The aim is to have it ready to submit to the international SBAS standardization bodies — the International Civil Aviation Organization (ICAO), the U.S. Radio Technical Commission for Aeronautics and the European Organization for Civil Aviation Equipment — in the first quarter of next year.”
The meeting also introduced two new SBAS development projects, adding to the five existing projects presented at IWG 26. The first was presented by the Agency for Air Navigation Safety in western Africa and Madagascar (ASECNA), a public international organization with 18 member states.
China’s BeiDou SBAS development plan, presented at IWG 27 in September 2014.
ASECNA’s project aims to take a two-step approach, commencing with EGNOS-style vertical landing guidance for selected airports, based on EGNOS constituents, with a tentative schedule of 2018, moving to upgrade to the dual-frequency multi-constellation service across the whole of ASECNA airspace after 2020.
The second new project is China’s own BeiDou SBAS. After discussions at ICAO level, China has committed to delivering SBAS services over China that are fully compliant with ICAO standards.
“This new plan has been highly welcomed by the aviation community and other SBAS providers,” Didier said. “Chinese representatives have also confirmed their intention to become part of the SBAS IWG and contribute to the work done to finalise the future standard.”
The follow-up IWG meeting will take place in February 2015 and will be hosted by ASECNA in Dakar, Senegal.
About EGNOS
EGNOS, the European Geostationary Navigation Overlay Service, is Europe’s first venture into satellite navigation. Its development was managed by the European Space Agency (ESA) under a tripartite agreement with the European Commission (EC) and the European Organization for the Safety of Air Navigation (Eurocontrol).
The ownership of the EGNOS assets was transferred from ESA to the EC in April 2009 and EGNOS officially entered service on October 1, 2009. The service is delivered, through a contract with the European GNSS Service Agency (GSA), by the European Satellite Services Provider, ESSP SaS, founded by seven air navigation service providers. ESA is the design and procurement agent for EGNOS on behalf of the EC.
