SBAS is this acronym of Satellite Based Augmentation System, which currently enhances the performances of the US Global Positioning System (GPS), and in the future of other constellations like GALILEO.

EGNOS (European Global Navigation Overlay System) is the European SBAS developed by Thales Alenia Space on behalf the European Commission and the European Space Agency. It is operational today and reaches the end of its certification process that will allow the utilisation of the services for safety-of-life applications across Europe as of 1st quarter of 2011. The SBAS signals are broadcast by geostationary satellites that cover today Europe and already the entire African continent. The service provided could be extended over Africa through extension of the EGNOS system with some adaptations and the installation of ground facilities in African territory and connected to the European network, or alternatively to an independent EGNOS-like African system.

When compared to GPS only, EGNOS services allows users to get:

- An improved accuracy of positioning by using the EGNOS differential corrections. This is available to all users equipped with EGNOS receivers, even low cost ones (Open Service)

- a warranted integrity for Safety-Of-Life users equipped with MOPS (Minimum Operational Performance Standards) certified receivers. This is mainly for aeronautical users; two levels of services are provided by EGNOS allowing use in NPA and APV1 flight phases

Questions on the opportunity and the way to deploy a SBAS in Africa have been addressed since more than 10 years now.

Technical studies, funded by ESA (European Space Agency), of the extension of EGNOS over Africa have been performed by Thales Alenia Space, Industrial Prime contractor of the European SBAS system.

Testbed has been developed (ESTB - EGNOS Signal TestBed) and different experimentations like the "Crossing Africa with EGNOS" lead by ASECNA in 2005 and other tests in MEDA, East Africa, South Africa have been performed.

European Commission has supported or is supporting studies on different aspects of the problem: Euromed GNSS-I and Euromed GNSS II specifically dedicated to the extension of the EGNOS coverage to the MEDA countries, Establishment of GNSS regional plans (METIS, SIRAJ), EGNOS extension over South Africa (ESESA), Awareness to user communities of possible GNSS application (AFSAGA), and Technical analysis of ionosphere scintillation issue in equatorial area (CIGALA)., …

ICAO clearly promotes GNSS technology and usage to increase the overall safety of air transport, notably with reduction of accidents during the airport approach and landing phase, and the coverage of areas not equipped with the traditional navigation aids will be enabled.

The improved integrity will also benefit to the ADS-B new surveillance technology.

The ICAO AFI Planning and Implementation Regional Group (APIRG) endorsed the SBAS implementation in its Navigation Strategy.

For the African continent in particular, SBAS system will increase the access to remote area with less well-equipped airport, and therefore facilitate de-enclosing and economical development.

SBAS services have also positive impacts in other applications and transport domains, such as land management (for surveying, cadastre, and others), maritime safety along the shores and in approaching ports, rail transportation, in the oil and mining industries and will allow the development of LBS (Location Based Services) applications.

Any initiative aiming at deploying SBAS infrastructure in Africa shall rest on three pillars:

• Knowing accurately the needs and the addressable markets, which have been assessed in the various studies mentioned earlier and during Cost- Benefit Analysis performed,
• Identifying and assessing some remaining technical specific issues such as:
• any phenomenon linked with Ionosphere scintillation and Ionosphere bubbles.
• a deep knowledge of the communication network architecture and capabilities in order to build a reliable network of receiving sensors (RIMS).
• Implementing field trials to facilitate an early adoption of the system, and validate its ad equation with the expected needs.

These conditions can be addressed with an integrated and long-term collaboration between European and African Iindustries and Academic Structures. Ideas for such collaboration could cover:

• Creating an African GNSS Academy to build a solid framework for Academic exchanges between Europe and Africa on GNSS topics as well as to prepare the basis of common researches on specific technical topics.
• Creating a European-African dynamic around a common research plan, with tangible objectives and cross- fertilisation of ideas.
• Creating a GNSS Performances Assessment Laboratory, supported by the GNSS Academy, and supporting the common research plan. The laboratories will be all together connected together and will constitute an African Ionosphere observatory.
• Creating an African GNSS test area ("GNSS test range") that can also host conferences and meetings for education.

• Creating a cycle of GNSS conferences in Africa to collect and understand the main needs drivers, to favour the adoption of GNSS in Africa, to identify the most appropriated early field trials to be implemented as well as to exchange on researches results, while consolidating the GNSS ecosystem in Africa.

A factor for SBAS development and more generally economic development is education, today there are specialized centers of GNSS learning in Europe, there are too few in Africa. On the other hand, whatever its retained architecture, EGNOS extension, system integrated with EGNOS, or independent from EGNOS, an African SBAS development and deployment will take advantage of the unique experience gained during EGNOS developments and operation in the context of  Single European Sky initiative to federate the needs of different European countries. This strong background associated with specific African answers on aspects like Governance, Certification, Operations, Infrastructure choice of implantation will allow progress on the development of an African SBAS.

In Europe, EGNOS is owned and managed by the European Union while the European Space Agency, who led the design and development of the system, is now the design and procurement agent through a delegation agreement with the European Commission. The operations of EGNOS are managed through a contract with the European Commission, by the European Satellite Services Providers, ESSP SaS, founded by seven air navigation services providers.

The delivery of EGNOS SIS (Signal In Space) involves four majors actors, namely: the European Commission as owner, The European Space Agency as design agent, the ESSP as certified Service Provider, Industry Prime as "Product Developer".

As Adam Smith said in his book "The Wealth of Nations": it is competition that drives efficiency and innovation. During previous studies on SBAS, the African continent has been divided in four areas: Mediterranean, West Africa, East Africa, and Southern Africa.

Hazard or opportunity? Those major regions may have a different role to play to answer remaining technical and operational questions and develop pre-operational regional solutions:

-           what are the performances required?

-           how bi-frequencies signal usage will improve ionosphere delay estimation in equatorial regions?

-           does the fading impact the reception of the geostationary satellite signal?

-           set-up new experimentations, taking advantage of European EGNOS building blocks (RIMS, NLES, payload, various simulators) to convince and get support from non-aviation user's communities, and propose pre-operational regional solutions.

The Ppolitical willingness is there, the strategic pPartnership between Africa and European Union mentions as a priority the satellite navigation.

The Second Action Plan (2011-2013) for the Implementation of the Africa-EU Strategic Partnership, adopted at the Africa-EU Summit held in Tripoli on 29-30 November 2010, suggests the development of satellite navigation in Africa as part of the 3rd Thematic Partnership on Regional Economic Integration, Trade and Infrastructure1.

European Commission proposes as a preliminary step towards the system implementation and exploitation, to carry a preparatory phase of support for capacity building.

Is there a better project than SBAS implementation for insuring and promoting the Single African Sky, a good flag for the future African Space Agency?

SBAS systems are durable, United States made the SBAS choice with the WAAS system, INDIA with the GAGAN system, Europe with the EGNOS system, JAPAN with MSAS system, …

Waiting for the Galileo constellation, the bi-frequencies signal, the new version of EGNOS isn't for Africa a lack of confidence and a risk to jeopardize its future?

As expressed a number of options are possible to finally provide over Africa a level of service similar to the one currently deployed over Europe or a global LPV-200 coverage, progressive approach with incremental or parallel deployment of means over Africa can be defined, NPA (Non Precision Approach) service on North Africa, Prototype of APV-1 service on limited area, NPA service over Africa, with the aim to finally synchronize an African system with the European one.

European industries with the lessons learned from EGNOS definition, deployment, and maintenance are ready to support Africa and reduce risk and cost of the design and the deployment of the SBAS system that Africa is needing and waiting for.