If you wish to contribute or participate in the discussions about articles you are invited to contact the Editor

GALILEO Public Regulated Service: Difference between revisions

From Navipedia
Jump to navigation Jump to search
No edit summary
No edit summary
Line 14: Line 14:
[[File:egnos_2.png‎|300px|Galileo Open Service|thumb]]
[[File:egnos_2.png‎|300px|Galileo Open Service|thumb]]


The Galileo Open Service (OS) provides positioning, velocity and timing information that can be accessed free of direct user charge. This service is suitable for mass-market applications, such as in-car navigation and hybridisation with mobile telephones. The Open Service is accessible to any user equipped with a receiver, with no authorisation required. While up to three separate signal frequencies are offered within the Open Service, cheap single-frequency receivers will be used for applications requiring only reduced accuracy. In general, Open Service applications will use a combination of Galileo and GPS signals, which will improve performance in severe environments such as urban areas. The timing service is synchronised with UTC when used with receivers in fixed locations. This timing service can be used for applications such as network synchronisation or scientific applications.<ref name="GALHLD"> [http://ec.europa.eu/dgs/energy_transport/galileo/doc/galileo_hld_v3_23_09_02.pdf Galileo Mission High Level Definition], v3, September 2002.</ref>
Galileo is a civil system that also includes a robust and access-controlled service for government-authorised applications. The Public Regulated Service (PRS) will be used by groups such as police, coast-guards and customs. Civil institutions will control the access to the encrypted PRS. Access by region or user group will follow the security policy rules applicable in Europe.  
   
   
The Open Service does not offer integrity information, and the determination of the quality of the signals will be left entirely to the users. There will be no service guarantee or liability from the Galileo Operating Company on the Open Service.<ref name="ESA_GALILEO">[http://www.esa.int/esaNA/galileo.html ESA Galileo web page]</ref>
The PRS is operational at all times and in all circumstances, including during periods of crisis. A major PRS driver is the robustness of its signal, which protects it against jamming and spoofing.<ref name="ESA_GALILEO">[http://www.esa.int/esaNA/galileo.html ESA Galileo web page]</ref>


<ref name="GALHLD"> [http://ec.europa.eu/dgs/energy_transport/galileo/doc/galileo_hld_v3_23_09_02.pdf Galileo Mission High Level Definition], v3, September 2002.</ref>


[[File:Galileo Frequencies.gif‎|200px|Galileo Signal Frequencies|left|thumb]]
[[File:Galileo Frequencies.gif‎|200px|Galileo Signal Frequencies|left|thumb]]

Revision as of 10:20, 12 April 2011


GALILEOGALILEO
Title GALILEO Public Regulated Service
Author(s) GMV
Level Basic
Year of Publication 2011
Logo GMV.png


The GALILEO System will be an independent, global, European-controlled, satellite-based navigation system and will provide a number of guaranteed services to users equipped with Galileo-compatible receivers. The GALILEO Public Regulated Service (PRS) provides position and timing restricted to government-authorised users, for sensitive applications which require a high level of service continuity. It will be encrypted and designed to be more robust, with anti-jamming mechanisms and reliable problem detection. This service is intended for security and strategic infrastructure (e.g. energy, telecommunications and finance).[1] [2]


Purpose

Galileo Open Service

Galileo is a civil system that also includes a robust and access-controlled service for government-authorised applications. The Public Regulated Service (PRS) will be used by groups such as police, coast-guards and customs. Civil institutions will control the access to the encrypted PRS. Access by region or user group will follow the security policy rules applicable in Europe.

The PRS is operational at all times and in all circumstances, including during periods of crisis. A major PRS driver is the robustness of its signal, which protects it against jamming and spoofing.[3]


[4]


Galileo Signal Frequencies

Performance and features

The Galileo Open Service is realized by using the signals at L1, E5a and E5b, whether data or pilot. Several combinations are also possible, such as a dual frequency service based on using L1 and E5a (for best ionospheric error cancellation) or single frequency services (at L1, E5a, E5b or E5a and E5b together) in which case the ionospheric error is removed using a model, and even triple frequency services using all the signal together (L1, E5a and E5b), which can be exploited for very precise, centimetric applications.[3].[5]

The performance objectives in terms of position accuracy and availability will be competitive with respect to existing GNSS and further planned evolutions. In addition, the Open Service will also be interoperable with other GNSS, in order to facilitate the provision of combined services. [4]

Service Performances for Galileo Open Service
Galileo Open Service (positioning & timing)
Single Frequency (SF) Dual Frequency (DF)
Coverage Global
Accuracy (95%) Horizontal: 15 m Horizontal: 4m
Vertical: 35 m Vertical: 8m
Availability 99.8 %
Timing Accuracy wrt UTC/TAI 30 ns
Ionospheric Correction Based on SF Model Based on DF Measurements
Integrity No

Implementation

The Open Service signals are separated in frequency to permit the correction of errors induced by ionospheric effects by differentiation of the ranging measurements made at each frequency. Each navigation frequency will include two ranging code signals (in-phase and quadrature). Data are added to one of the ranging codes while the other “pilot” ranging code is data-less for more precise and robust navigation measurements.

During the Initial Operational Capability (IOC) phase, the GALILEO open service, the search and rescue service and the PRS will be provided. At this stage, however, accuracy and availability will not yet have reached their optimum levels.[1]

To know more information about Performances of each Galileo Service see the article Galileo Performances.

Notes

References