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EGNOS Future and Evolutions
| EGNOS | |
|---|---|
| Title | EGNOS Future and Evolutions |
| Author(s) | GMV. |
| Level | Basic |
| Year of Publication | 2011 |
The European Space Agency (ESA) is currently completing the final qualification stages of the European Geostationary Navigation Overlay Service (EGNOS) and is in the process of developing the GALILEO system, a self-standing 30 satellite constellation for global satellite navigation. The European GNSS Evolution Program was defined in 2006 by ESA to address the second generation of these systems.[1]
As part of the evolutions considered, three more RIMS are scheduled to be deployed in Agadir (Morrocco), Athens (Greece) and Alexandria (Egypt) providing the extension of EGNOS signal coverage to northern Africa.
Besides, processing improvements are scheduled for the EGNOS signal, including iono algorithm pre-processing fine tuning.
Finally, the deployment of EGNOS v3 is scheduled to cover the Multi-Constellation Regional System (MRS) concept and implement a GPS L5 augmentation service.
GNSS Evolution program FrameWork
As part of the GNSS Evolution program, ESA called for two parallel studies in the scope of a Multi-constellation Regional System (MRS), that is, the evolution of the EGNOS concept to cope within a multi-constellation environment (Galileo, GPS, others GNSS constellations), and a multi-frequency scenario (GPS L1, L5; Galileo L1, E5a, E5b, E6, etc..).[2]
With this multi-constellation scenario, and with multiple frequencies available for navigation, the wide area regional augmentation systems must evolve and need to be adapted to this new behaviour. The next generation of the regional augmentation systems will not only be an adaptation of the architecture to the current state-of-art but also an important change of the concept. Considering only the new approach to the ground segment, this paper presents the alternative implementations of the integrity concepts, the different broadcast means and possible architectures analysed.
MRS mission is a natural evolution of a regional system, such as EGNOS, considering the advent of new constellations and new frequencies in the GNSS panorama. As GNSS modernisation plans are today under definition and other studies are assessing possible evolutions of GNSS systems beyond 2015, the MRS Study is focused on the 2012-2015 timeframe.
EGNOS Evolution Features
As a multi-constellation, multi-frequency and multi-broadcast system, the MRS system shall not only continue providing an SBAS service to L1 users but shall also cover GPS L5 and Galileo L1 and L5/E5 users. The system evolution considers different dissemination channels, including the SBAS GEO (Geostationary Earth Orbit) L1 and L5 channels, Galileo MEO (Medium Earth Orbit) ERIS (External Regional Integrity System) channels and other satellite or terrestrial means to be defined according to regional or user defined interests (e.g. SISNET, LORAN-C, etc).
The high level objectives defined by the Evolution program are the following:[2]
- To maximize European ‘User’ Performance when combining EGNOS and Galileo infrastructures, allowing SoL service provision.
- To optimize cost of operation and infrastructure of both systems when combined in MRS, keeping independence of both systems and ensuring robustness against GNSS failures.
- To provide mainly an integrity service for safety of life aviation or liability critical applications.
- To provide regional GPS and Galileo integrity and continuity by using MRS and Galileo.
- Understood as a multi-constellation (GPS/GAL) multi-frequency (L1/E5) and multibroadcast (GEO, MEO and others) system, to provide a service assuming all combination of mono/multi constellation and mono/multi frequency users.
- To provide better availability of SBAS integrity for regions of poor GEO reception through additional Galileo ERIS MEO broadcast of integrity information or other means.
- To enhance ionosphere monitoring accuracy by adding Galileo observations or decrease number of RIMS.
Benefits and New Services
Forthcoming constellation deployments (GALILEO, GLONASS M, COMPASS), combined with GPS, will enhance EGNOS performances as well as its robustness. Besides, they will allow the development of new services. These services have been studied in the frame of the MRS (Multi-constellation Regional Augmentation System) concept and include: Safety Of Life service (SOL), Open Services (OS), Liability Critical Services (LCS), Commercial Data Dissemination Services (CCDS), detailed below:[3]
- Enhance User performances (SOL, aeronautical users): The existence of more signals belonging to new constellations will provide more information about the ionosphere and consequently better performances, specially under ionsopherically degraded conditions (forecast for the coming years http://science.nasa.gov/science-news/science-at-nasa/2006/10mar_stormwarning/).
- New services (OS, LCS, CDDS):
System Architecture
EGNOS Evolution Performances
Notes
References
- ^ EGNOS Evolution Plans and the GNSS Evolutions Programme; R. Lucas Rodriguez, F. Toran, R. Dellago, B. Arbesser-Rastburg, D. Flament; Proceedings of the 2009 International Technical Meeting of The Institute of Navigation January 26 - 28, 2009
- ^ a b EGNOS Evolutions: the MultiConstellation Horizon MRS; P. Durba, E. Armengou, Indra Espacio (Spain); M. Tossaint, European Space Agency (The Netherlands)
- ^ Multi-Constellatin Regional System (MRS); D. BROCARD, CNES, Toulouse, France; D. FLAMENT,ESA, Toulouse, France; J.C. LEVY, D. LEKAIM, THALES ALENIA SPACE, Toulouse, France; A. CEZON-MORO, S. CILLA-SIMON, J. SIMON, GMV, Madrid, Spain