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Galileo overall Architecture Definition

European Union
Complete with results
Project Acronym
STRIA Roadmaps
Connected and automated transport (CAT)
Network and traffic management systems (NTM)
Transport policies


Background & Policy context

The Galileo system is the European-led global navigation satellite system. The system will provide position determination, navigation, timing, and communication services world-wide, to global user communities.

The Galileo system will provide different levels of services for professional users, mass market, and safety of life applications. The set of services, clearly defined by their performance and availability will be provided on a global, regional, or local level.

  • To provide the mission and system requirements, taking inputs from the application task (task1), GEMINUS study and from past studies (ESA Comparative System Study), and including a focus on navigation, communication and Search And Rescue (derived from SARGAL study outputs) requirements as well as revenue generation, international, legal and standardisation issues. It must be noted that additional requirements are derived from tasks 6 and 13 for safety and security respectively. To perform technical trade-offs related to GALILEO navigation function and the potential communication function, as key inputs for architecture tasks.
  • The navigation signals are considered in a specific trade-off analysis, including the signal structure and the cryptology associated with access control.
  • The deployment strategy, the support to operations and the Integrated Logistic Support (ILS) concepts are analysed and requirements are derived.
  • A technical baseline document is produced in order to provide an updated issue of open trade-off and scenarios to be analysed by architecture and component design activities.

Due consideration shall be granted to Assembly, Integration and Validation (AIV) aspects, Qualification needs, Deployment and operations of the system, certification plan and Integrated Logistic Support (ILS). These aspects have very significant impacts on systém development plan and cost assessment. In that sense, the separation of the global component into a “classical” space segment and an “advanced” mission segment is very important.

Indeed, the space segment will allow to provide “core services” (navigation functions without integrity and without encryption features, for example) with a limitation of risks, and will be qualified first. The mission segment will allow to provide the “full services” and will be qualified later, making use of the space segment.


Parent Programmes
Institution Type
Public institution
Institution Name
European Commission, Directorate-General for Energy and Transport (DG TREN)
Type of funding
Public (EU)


The implementation plan first defined the main programme phases : definition, design and development, validation, deployment and replenishment. Then 3 scenarii were considered : a Final Operational Capability (FOC) with 30 satellites in 2008, a FOC with 30 satellites in 2008 with an Initial Operational Capability (IOC) with 24 satellites before 2007, and finally a FOC with 30 satellites in 2006.

The assessment of the scenarii considered a set of key parameters : In-Orbit Validation effectiveness, success of the deployment schedule, certification feasibility and operational capability effectiveness. As a conclusion, the third scenario is proposed to be discarded because of the various criticalities identified, and the scenario 2 is proposed to be the baseline due to its better certification feasibility and operational capability effectiveness.

Technical Implications

The overall Galileo requirements have been derived from these analyses and from the identification of design requirements.

First, the proposed security policy identified the need for dedicated encrypted services for strategic applications to allow full availability in periods of crisis or conflicts. Second, the integration of EGNOS has been determined following a two steps approach : first an optimisation of Galileo architecture, then an optimisation of the integration of EGNOS, in terms of services and in terms of architecture. A set of objectives were fixed, e.g. no impact on EGNOS development plan, guaranty of the continuity of EGNOS service. The optimisation proposed a phased approach, based on a unique step to accommodate GPS modernisation involving the new L5 frequency as well as Galileo integrity monitoring.

The cost of Galileo infrastructure up to the FOC is estimated at approximately 3.2 billion Euro. Target recurrent costs of user terminals are also provided.

Concerning Galileo benefits, the analysis considered the period 2001–2020 and provided annual supplier and user net benefits, as well as social benefits. Total benefits are estimated at 74 billion Euro over the period, from which 6 billion Euro shall be subtracted for the investment costs. Annual curves are provided, showing positive net benefits after 2008 and a predominance of user benefits over producer benefits, which confirms the value of Galileo as a public good. The result is an IRR of around 75%, and a high growth of employment resources

Policy implications

The funding of the Galileo programme is open to a partnership between public and private contributions. This is reflecting the two-fold nature of Galileo system which is strategic and commercial. However, in such an early phase of the programme, it appears difficult to raise a real interest from private investors when the suitability of the performance of the future system with respect to non-mature user needs is not fully demonstrated.

Therefore, it can be noted that the actual private investment is not enough consolidated and therefore it is recommended that flexibility is kept in the private funding plan in order to allow for the consolidation of revenues.

Organisational framework

The organisational framework shall be established in the very short term, identifying the main actors in Galileo and their respective roles. This is the necessary basis to define the responsibilities in Galileo, the associated liabilities and the subsequent legal framework. It is also necessary to determine the decision process without which the management of the programme and the control of planning and cost is not possible. This organisational framework is understood in a large sense, identifying both institutional and private bodies involved.

Decision process

A decision process shall be defined and agreed among the actors identified in the organisational framework. This decision process needs to be defined according to the programme development plan in order to limit the risk of delays.

Due consideration shall be granted to the identification of the right entity in charge of a given decision or supporting the decision process. The experience shows that a number of actors provide recommendations reflecting internal interests that are usually not the interest of the programme.

The independence of some actors is therefore of paramount importance.


Due consideration shall be granted to the consolidation and the evolution of requirements for Galileo.

Monitoring of user needs and markets

The continuation of user need monitoring and market analyses, which provid


Lead Organisation
EU Contribution
Partner Organisations
EU Contribution


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