EGNOS data access service (EDAS) : service definition document.
Date: 2015-04-09
Institutions: European GNSS Agency
Subjects: information technology, information technology applications, satellite, satellite communications, satellite navigation, technical standard

EGNOS Data Access Service (EDAS)
Service Definition Document

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Service Definition Document

DOCUMENT CHANGE RECORD

Revision

Date

Summary of changes

1.0

2.0

2.1

26/07/2012

First release of the document

10/04/2013

New services available: FTP, SISNeT, Data filtering, Ntrip

19/12/14

SL1 decomissioned
Resolution time for EDAS request improved  
Observed EDAS services performances updated
EDAS service is clarified to be free of charge

EGNOS Data Access Service (EDAS)
Service Definition Document

The European GNSS Agency produced this document  
under tasks entrusted by the European Commission

Precise navigation,  
powered by Europe

CONTENTS 

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT 
1  EXECUTIVE SUMMARY 
2 

INTRODUCTION 
2.1 

PURPOSE AND SCOPE OF THE DOCUMENT 

2.2 

TERMS AND CONDITIONS OF EDAS SERVICES USE, INCLUDING LIABILITY 

2.3  REFERENCE DOCUMENTS 

3  EGNOS DATA SERVICE (EDAS) OVERVIEW 

3.1 

EGNOS OVERVIEW 

3.1.1 EGNOS Services 

3.1.2 EGNOS:  The European SBAS 

3.1.3 EGNOS Architecture 

3.1.4 EGNOS Organisational Framework 

3.2 

EDAS OVERVIEW 

3.2.1 Introduction 

3.2.2 Overview of the Current Architecture 

3.2.3 The EDAS System 

3.2.4 The EDAS Client Software 

3.2.5 Data Available from EDAS 

4  EDAS SERVICES 

4.1  MAIN DATA STREAM SERVICES 

4.1.1 EDAS SL0 (ASN.1) 

4.1.2 EDAS SL2 (RTCM 3.1) 

EDAS DATA FILTERING SERVICES 

EDAS FTP SERVICES 

EDAS SISNET SERVICE 

EDAS NTRIP SERVICE 

4.2 

4.3 

4.4 

4.5 

5  EDAS PERFORMANCES 

5.1 

5.2 

EDAS SERVICES AVAILABILITY 

EDAS SERVICE LATENCY 

6  EDAS USER SUPPORT 
EGNOS HELPDESK 

6.1 

6.2 

6.3 

6.4 

6.5 

6.6 

EDAS REGISTRATION 

EDAS REGULAR/URGENT REQUEST 

EDAS FIRST CONNECTION SUPPORT 

EDAS POINT-TO-POINT CONNECTIVITY SUPPORT 

EDAS INCIDENT MANAGEMENT / COMMUNICATION 

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7  EDAS ONLINE INFORMATION 

7.1 

EGNOS MONTHLY PERFORMANCE REPORT 

7.2 

EDAS WEBSITE 
8  EDAS APPLICATIONS 
EDAS CLIENT SW 

8.1 

8.2 

EXAMPLES OF EDAS BASED SERVICES/APPLICATIONS 

APPENDIX A  DEFINITIONS 
APPENDIX B  OBSERVED EDAS PERFORMANCES 
APPENDIX C 
APPENDIX D 
APPENDIX E 

APPLICATION FORM FOR EDAS SERVICE 
EDAS DATA FILTERING SERVICE: CONFIGURATION 
ACRONYMS 

Table of Figures
FIGURE 3.1 
FIGURE 3.2 
FIGURE 3.3 
FIGURE 3.4 
FIGURE 3.5 
FIGURE 5.1 
FIGURE 7.1 
FIGURE 7.2 
FIGURE 8.1 
FIGURE 8.2 

EDAS HIGH-LEVEL ARCHITECTURE 
EXISTING AND PLANNED SBAS SYSTEMS 
EGNOS ARCHITECTURE 
EGNOS RIMS SITES 
EDAS ARCHITECTURE 
EDAS SERVICES PERFORMANCE MEASUREMENT POINT 
EDAS SECTION IN MAY 2014 EGNOS MONTHLY PERFORMANCE REPORT 
EDAS SECTION AT THE EGNOS USER SUPPORT WEBSITE 
EDAS CLIENT SW: LOGIN WINDOW 
RIMS GROUP DISTRIBUTION 

Table of Tables
TABLE 3.1 
TABLE 3.2 
TABLE 3.3 
TABLE 3.4 
TABLE 4.1 
TABLE 4.2 
TABLE 5.1 
TABLE 5.2 
TABLE 8.1 
TABLE 8.2 
TABLE 8.3 

GEOS USED BY EGNOS 
WHERE TO FIND INFORMATION ABOUT EGNOS 
EDAS RAW DATA SUMMARY 
EGNOS MESSAGE TYPES 
EDAS FTP SERVICE: AVAILABLE DATA SETS. 
EDAS NTRIP MESSAGE TYPES PROVIDED IN RTCM 2.1, 2.3 AND 3.1 FORMATS. 
EDAS SERVICES AVAILABILITY 
EDAS SERVICES LATENCY 
EDAS AVAILABILITY FROM JANUARY 2014 TO SEPTEMBER 2014 
EDAS LATENCY FROM JANUARY 2014 TO SEPTEMBER 2014 
RIMS SITES INCLUDED PER GROUP NAME 

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EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT1

1

1

EXECUTIVE SUMMARY 

The  European  Geostationary  Navigation  Overlay 
Service (EGNOS) provides an augmentation signal to 
the Global Positioning System (GPS) Standard Positioning 

The document describes the EDAS system architecture 

and provides an overview of the current EDAS services 

with regards to the information that is transmitted and 

Service (SPS). Presently, EGNOS augments GPS using 

data formats. The brief description of each EDAS Service 

the L1 (1,575.42 MHz) Coarse/ Acquisition (C/A) civilian 

is presented, along with the minimum EDAS services 

signal function by providing correction data and integrity 

performance. The EDAS SDD does not intend to give an 

information for improving positioning and navigation 

exhaustive description of the message structure and data 

services over Europe.

formats; it is not intended to be an Interface Control 

EGNOS provides three services: 

•  Open Service (OS), freely available to any user;

EGNOS interfaces with users, as well as guidelines to 

The document also includes high level information on 

Document (ICD).

• 

• 

Safety of Life (SoL) Service, that provides the most 
stringent level of signal-in-space performance to all 

services performance (publicly available). The observed 

performance of the EDAS services over a specified period 

Safety of Life user communities;

is also given in appendix B.

register as EDAS user or to check the monthly EDAS 

EGNOS Data Access Service (EDAS) for users who 
require enhanced performance through Internet 

This document is not intended to address EGNOS Open 

Service (OS) or EGNOS Safety of Life (SoL) performance. 

connection for commercial and professional use.

Information about the EGNOS OS and the EGNOS SoL 

is available in separate documents called the “EGNOS 

The EGNOS Data Access Service (EDAS) aims at providing 

Service Definition Document – Open Service” (EGNOS 

ground-based access to EGNOS data. EDAS services are 

SDD OS – [RD-1]) and the “EGNOS Service Definition 

accessible through the Internet with the condition to be 

Document – Safety of Life Service” (EGNOS SDD SoL - 

a registered user.

[RD-2]) respectively.

This version of the “EDAS Service Definition Document” 

This document will be updated in the future as required 

(referred as EDAS SDD) is intended to provide information 

in order to reflect any changes to the EDAS services.

on the EDAS services, which are oriented to users in 

different domains of application such as Location Based 

Services (LBS), a broad range of services in professional 

GNSS markets, Assisted-GNSS (A-GNSS) concepts, and 

related R&D activities.

7

2

INTRODUCTION 

2.1 Purpose and Scope
of the Document

•	 Section	5	“EDAS	Performances”	describes the 
EDAS services performance in terms of availability 

and latency (for the real-time data services);

The EGNOS Data Access Service (hereinafter referred 

to as “EDAS”) Service Definition Document (hereinafter 

referred to as “EDAS Service Definition Document” or 

•	 Section	6	“EDAS	User	Support” deals with the 
communication channels available to EDAS users for 

“EDAS SDD”) presents the characteristics of the services 

any request related to the service, the steps to be 

offered to users by EDAS, including a detailed description 

completed to become an EDAS user, and the support 

of all the necessary information for users to get access to 

services and communications that EDAS users will 

EDAS services and benefit from them. The current EDAS 

receive in case of any incident; 

SDD (this document) includes, with respect to the previous 

release, updated information related to the EDAS services: 

Service Level 0 and 2, Data Filtering, NTRIP, SISNET and 
FTP (available to users since 26th July 2012), along with 
the decommissioning of Service Level 1 on 1st July 2014.

•	 Section	7	“EDAS	Online	Information” provides 
the main sources of information available for EDAS 

users concerning EDAS performance and status;

The EDAS services performance currently available to 

•	 Section	8	“EDAS	Applications”	 describes the 
application that allows users to access EDAS data 

registered users both in terms of availability and latency 

and also some additional information of interest;

is also detailed.

The EDAS SDD comprises 8 main sections and 5 appendices:

•	

“Appendix	A	Definitions” includes the glossary of 
terms and definitions;

•	 Section	1	“Executive	Summary” is an executive 

•	

summary of the document;

“Appendix	B	Observed	EDAS	Performances” 
provides  EDAS  services  availability  performance 

between January 2014 and May 2014;

•	 Section	2	“Introduction”	defines the scope of the 
document, the relevant reference documents and 

deals with the terms and conditions of EDAS use, 

•	

“Appendix	C	Application	Form	for	EDAS	Service” 
shows the application form that needs to be filled by 

including liability, and the intended lifetime of the 

those willing to register as EDAS users;

Service;

•  Section	 3	 “EGNOS	 DATA	 SERVICE	 (EDAS)	
Overview”	gives a brief description of the EGNOS 
system and services, focusing mainly on a high-level 

description of EDAS architecture and the provided 

data;

•	

“Appendix	 D	 EDAS	 Data	 Filtering	 Service:	
configuration”	provides the initial configuration 
of the EDAS Data Filtering Service, mainly in terms 

of groups of stations available;

•	

“Appendix	E	List	of	Acronyms”	provides a list of 
acronyms.

•	 Section	4	“EDAS	Services”	introduces the EDAS 
services:  Service  Level  0,  Service  Level  2,  Data 

As mentioned, the fourth section introduces the EDAS 

Filtering, NTRIP and FTP Services;

services, which are the following:

8

9

 
•  Main Data Streams: EGNOS data, which covers 
EGNOS messages, GNSS observation and navigation, 

EDAS user has to fill in. Finally, Appendix D provides 

additional information about the EDAS Data Filtering 

is provided through Internet in real-time in different 
formats depending on the Service1:
Service Level 0: ASN.1 format
• 

• 

Service Level 2: RTCM 3.1

•  Data Filtering: Filtering capabilities to allow receiving 
EGNOS data from only certain subsets of RIMS stations 

Service.

2.2	Terms	and	Conditions
of EDAS Services Use, 
Including Liability

when connecting to EDAS Service Level 0 and/or 2.

EDAS has been designed and developed with the general 

• 

FTP Service: An FTP historical site containing EGNOS 
ground stations data, SBAS messages, main data 

goal to provide ground-based access to EGNOS data. EDAS 

is accessible upon registration through the connection to 

a dedicated Internet domain (egnos-edas.eu). EDAS is 

streams raw data and IONEX data files in different 

free of charge and can only be used for non-safety critical 

formats for downloading.  

•  SISNET Service: EGNOS messages provided in real 
time using the SISNeT protocol defined by European 

purposes, i.e. purposes that have no impact on the safety 

of human life and where a failure in availability, integrity, 

continuity or accuracy of the EDAS services could not cause 

any kind of direct or indirect personal damage, including 

Space Agency (ESA).

bodily injuries or death.

•  Ntrip  service:  GNSS  data  from  EGNOS  ground 
stations and DGNSS corrections are sent in real time 

Although care has been taken in designing, implementing 

and operating the EDAS system, as well as in providing 

using Ntrip protocol.

EDAS  services,  it  is  not  meant  to  offer  a  service 

guarantee or liability from the EGNOS service provider 

The EDAS minimum performance is given in section 5.  

or from the European Union (EU). The minimum level 

The sixth, seventh and eighth sections are oriented to 

of performance against which the EDAS system has 

EDAS users too, providing complementary information to  

been  designed  is  provided  in  this  document  (EDAS 

section 4 and covering other important aspects like the 

SDD) solely for the reasons of transparency in order 

user support services, the main sources of information 

to enable the user to make a sound decision regarding 

available through the Internet with regards to EDAS 

EDAS use. However, actual EDAS performance may 

services and performance as well as the user application 

differ in the future.

side.  Appendix  A  may  be  visited  by  all  readers  if  a 

particular concept mentioned in this document is not 

Users have certain obligations to exercise due care in 

familiar. Appendix B provides a summary of the real 

using EDAS. Before any use of EDAS, all users should 

EDAS services availability performance from January 

study this EDAS SDD in order to understand if and how 

2014 to May 2014. Appendix C shows the application 

they can use EDAS, as well as to familiarise themselves 

form that anyone interested in being registered as an 

with EDAS features.

1  Service Level 1 was decommissioned on 1st July 2014. This Service is covered by Service Level 2.

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EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT 
2   –   I N T R O D U C T I O N

DISCLAIMER OF LIABILITY

The European Union as the owner of the EDAS system, the European GNSS Agency (GSA) as EGNOS 

programme	manager	and	ESSP	SAS	as	its	service	provider	expressly	disclaim	all	warranties	of	any	kind	

(whether	expressed	or	implied)	with	respect	to	EDAS,	including,	but	not	limited	to	the	warranties	

regarding	availability,	continuity,	accuracy,	integrity,	reliability,	fitness	for	a	particular	purpose	or	

meeting	the	users’	requirements.	No	advice	or	information,	whether	oral	or	written,	obtained	by	a	user	

from the European Union, GSA or ESSP SAS and its business partners shall create any such warranty.

By using EDAS, the user agrees that neither European Union nor GSA nor ESSP SAS shall be held 

responsible	or	liable	for	any	direct,	indirect,	incidental,	special	or	consequential	damages,	including	

but	not	limited	to,	damages	for	interruption	of	business,	loss	of	profits,	goodwill	or	other	intangible	

losses,	resulting	from	the	use	of,	misuse	of	or	the	inability	to	use	EDAS.

2.3 Reference Documents

RD

[RD-1]

[RD-2]

[RD-3]

[RD-4]

[RD-5]

[RD-6]

Document Title

EGNOS Service Definition Document – Open Service
http://egnos-portal.gsa.europa.eu/library/technical-documents  

EGNOS Service Definition Document – Safety of Life Service
http://egnos-portal.gsa.europa.eu/library/technical-documents

ICAO Annex10 Volume I  (Radio Navigation Aids) – November 2012  amendment 87

EGNOS Data Access Service Applications – GSA Leaflet v2
http://www.gsa.europa.eu/sites/default/files/content/edas_applications_v2_en.pdf

The EGNOS Data Access System (EDAS):  
The Vehicle To The Future EGNOS Commercial  Data Distribution Service, White Paper, GSA

RTCM Recommended standards for Differential NavStar GPS service,  
RTCM Paper 194-93/SC104-STD, v2.1, 3rd January 1994 

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RD

[RD-7]

[RD-8]

[RD-9]

[RD-10]

[RD-11]

[RD-12]

[RD-13]

[RD-14]

[RD-15]

[RD-16]

[RD-17]

Document Title

EDAS Content and Access – GSA Leaflet v3
http://www.gsa.europa.eu/sites/default/files/content/edas_applications_v3_en.pdf

RTCM recommended standards for differential GNSS Service Version 3.0.  
Developed by RTCM Special Committee No. 104

RTCM recommended standards for differential GNSS (Global Navigation Satellite Services Version 
3.1. Developed by RTCM Special Committee No. 104  (1st July  2011)

EDAS Client SW User Manual, ESSP-DRD-6977.
http://egnos-user-support.essp-sas.eu/egnos_ops/edas_doc/ 

SISNeT User Interface Document, E-RD-SYS-31-010, Version 3, Revision 1, 15/05/2006.
http://www.egnos-pro.esa.int/Publications/SISNET/SISNET_UID_3_1.pdf

Information technology – Abstract Syntax Notation One (ASN.1): Specification of basic notation. 
INTERNATIONAL STANDARD ISO/IEC 8824-1. ITU-T RECOMMENDATION X.680

EGNOS Message Server (EMS) User Interface Document, E-RD-SYS-E31-011-ESA, Issue 2, Revision 
0, November 26, 2004.
http://www.egnos-pro.esa.int/ems/EMS_UID_2_0.pdf 

IONEX: The Ionosphere Map Exchange Format Version 1, Schaer, S., W. Gurtner, J. Feltens, 
February 25, 1998.
ftp://igscb.jpl.nasa.gov/igscb/data/format/ionex1.pdf

Networked Transport of RTCM via Internet Protocol (Ntrip), version 1.0,  
http://www.rtcm.org/orderinfo.php 

RINEX: The Receiver Independent Exchange Format Version 2.11, IGS/RTCM RINEX Working Group, 
10th December 2007. http://igscb.jpl.nasa.gov/igscb/data/format/rinex211.txt 

Proposal for a new RINEX-type Exchange File for GEO SBAS Broadcast Data, 19th December 2003. 
ftp://igscb.jpl.nasa.gov/igscb/data/format/geo_sbas.txt 

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EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT3

EGNOS DATA SERVICE (EDAS) 
Overview

3.1 EGNOS Overview

3.1.1 EGNOS SERVICES

civil aviation but the EGNOS SoL service might also be 

used in a wide range of other application domains (e.g. 

maritime, rail, road…) in the future. In order to provide 

the SoL Service, the EGNOS system has been designed so 

EGNOS provides corrections and integrity information to 

that the EGNOS Signal-In-Space (SIS) is compliant to the 

GPS signals over a broad area centred over Europe and it 

ICAO SARPs for SBAS [RD-3]. 

is fully interoperable with other existing Satellite-Based 

Augmentation Systems (SBAS) systems.

EGNOS provides three services: 

The EGNOS SoL service has been available since 2nd March 
2011, and the corresponding SDD is [RD-2]. 

•  Open Service (OS), freely available to any user;

• 

Safety of Life (SoL) Service, that provides the most 

stringent level of signal-in-space performance to all 

EGNOS Data Access Service (EDAS)
EDAS is the EGNOS terrestrial commercial data service 

Safety of Life user communities;

which offers ground-based access to EGNOS data in real 

• 

EGNOS Data Access Service (EDAS) for users who 

time and also in a historical FTP archive to authorised users 

require enhanced performance for commercial and 

(e.g. added-value application providers). EDAS is the single 

professional use.

point of access for the data collected and generated by 

the EGNOS ground infrastructure (RIMS and NLES) mainly 

All  these  EGNOS  services  are  available  and  granted 

distributed over Europe and North Africa. 

throughout their respective service areas. 

Open Service (OS)
The main objective of the EGNOS OS is to improve the 

achievable positioning accuracy by correcting several error 

Next figure shows the EDAS high level architecture.

3.1.2 EGNOS: THE EUROPEAN SBAS

sources affecting the GPS signals. The corrections trans-

EGNOS is part of a multi-modal inter-regional SBAS service, 

mitted by EGNOS contribute to mitigate the ranging error 

able to support a wide spectrum of applications in many 

sources related to satellite clocks, satellite position and 

different user communities, such as aviation, maritime, 

ionospheric effects. The other error sources (tropospheric 

rail, road, agriculture. Similar SBAS systems, designed 

effects, multipath and user receiver contributions) are local 

according to the same standard (i.e. SARPs [RD-3]), have 

effects that cannot be corrected by a global augmentation 

already been commissioned by the US (Wide Area Aug-

system. Finally, EGNOS can also detect distortions affecting 

mentation System – WAAS) and Japan (MTSAT Satellite 

the signals transmitted by GPS and prevent users from 

based Augmentation System –MSAS-). Implementation 

tracking unhealthy or misleading signals.
The EGNOS OS has been available since 1st October 2009, 
and the corresponding SDD is [RD-1]. 

of analogous systems is being developed in other regions 

of the world (e.g. GPS Aided GEO Augmented Navigation 

–GAGAN- in India and System of Differential Correction 

Safety of Life (SoL) Service
The main objective of the EGNOS SoL service is to support 

and Monitoring –SDCM- in Russia). The worldwide exist-

ing and planned SBAS systems are shown in Figure 3.2.

civil aviation operations down to LPV minima. At this 

In addition, most of these systems have plans to extend 

stage, a detailed performance characterisation has been 

their service areas to neighbouring regions, thus paving 

conducted only against the requirements expressed by 

the way for near global SBAS coverage.

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E G N O S 	 D A T A 	 A C C E S S 	 S E R V I C E 	 ( E D A S )   S E R V I C E   D E F I N I T I O N   D O C U M E N T

Figure 3.1

EDAS High-Level Architecture

Figure 3.2

Existing	and	planned	SBAS	systems

WAAS

EGNOS

SDCM

MSAS

GAGAN

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EGNOS STATIONSNETWORKSERVICEPROVIDERSEDASFINALUSERSEDASUSERSEDASEWANINTERNET RF/GSMINTERNETGPS/GLONASSGPS/GLONASSEGNOS GEOINTERNETINTERNET3   –   E G N O S   D A T A   S E R V I C E   ( E D A S )   O V E R V I E W

3.1.3 EGNOS ARCHITECTURE

are handled in such a way that, at any point in time, at least 

two of the three GEOs broadcast an operational signal. 

The EGNOS functional architecture is shown in Figure 3.3.

Since it is only necessary to track a single GEO satellite 

In order to provide its services to users equipped with 

switching capability in case of interruption and ensures 

appropriate receivers, the EGNOS system comprises two 

a high level of continuity of service.

link to benefit from the EGNOS Services, this secures a 

main segments: the Space Segment, and the Ground 

Segment. 

It is intended that the EGNOS space segment will be 

replenished over time in order to maintain a similar level of 

EGNOS Space Segment
The EGNOS Space Segment comprises 3 geostationary 

redundancy. The exact orbital location of future satellites 

may vary, though this will not impact the service offered 

(GEO) satellites broadcasting corrections and integrity 

to users. Similarly, different PRN code numbers may be 

information for GPS satellites in the L1 frequency band 

assigned to future GEOs. However, all SBAS user receivers 

(1,575.42 MHz). At the date of publication the 3 GEOs 

are designed to automatically detect and use any code 

used by EGNOS are (see table 3.1).

in a pre-allocated set reserved for SBAS. Such evolutions 

will therefore be transparent for end users and will not 

EGNOS GEO satellites INMARSAT 3F2 AOR-E (PRN 120) 

necessitate any human intervention or change of receiving 

and 4F2 EMEA (PRN 126) are currently part of the EGNOS 

equipment. For this purpose, and whenever there could 

operational platform and are transmitting the opera-

be any relevant information complementing the SDD, an 

tional Signal-In-Space (SIS) to be used by EGNOS users.  

EGNOS Service Notice is publishe (http://www.essp-sas.

SES-5 (PRN 136) is part of the EGNOS TEST Platform broad-

eu/service_notices) and distributed.  

casting the TEST SIS.

This space segment configuration provides a high level 

EGNOS Ground Segment
The EGNOS Ground Segment comprises a network of 

of redundancy over the whole service area in case of a 

Ranging Integrity Monitoring Stations (RIMS), four Mission 

geostationary satellite link failure. The EGNOS operations 

Control Centres (MCC), six Navigation Land Earth Stations 

Table 3.1

GEOs used by EGNOS

GEO Name

PRN Number

Orbital Slot

INMARSAT 3F2 AOR-E

INMARSAT 4F2 EMEA

SES-5

15.5 W

25.0 E

5 E

PRN 120

PRN 126

PRN 136

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E G N O S 	 D A T A 	 A C C E S S 	 S E R V I C E 	 ( E D A S )   S E R V I C E   D E F I N I T I O N   D O C U M E N T

Figure 3.3

EGNOS architecture

15

Space SegmentGround SegmentPerformance Assessmentand Check-out FacilityApplication SpeciﬁcQualiﬁcation FacilityNLESNavigationLand EarthStationsMCCMissionControlCentresRIMSRanging &IntegrityMonitoringStationsGEOEWAN (EGNOS Wide Area Network)PACFASQFGPSUser Segments3   –   E G N O S   D A T A   S E R V I C E   ( E D A S )   O V E R V I E W

(NLES), and the EGNOS Wide Area Network (EWAN) which 

This function requires a dense network of monitoring 

provides the communication network for all the compo-

stations. For this reason, the ionospheric model broadcast 

nents of the ground segment. Two additional facilities are 

by EGNOS is not available for the whole geostationary 

also deployed as part of the ground segment to support 

broadcast area but is only provided for a region centred 

system operations and service provision, namely the  

over Europe.

Performance Assessment and Checkout Facility (PACF) and 

the Application Specific Qualification Facility (ASQF), which 

These three sets of corrections are then broadcast to 

are operated by the EGNOS Service Provider (ESSP SAS).  

users to improve positioning accuracy.

Ranging	Integrity	Monitoring	Stations	(RIMS)
The main function of the RIMS is to collect measurements 

In addition, the CPF estimates the residual errors that can 

be expected by the users once they have applied the set 

from GPS satellites and to transmit these raw data every 

of corrections broadcast by EGNOS. These residual errors 

second to the Central Processing Facilities (CPF) of each 

are characterised by two parameters:

MCC. The current RIMS network comprises 39 RIMS sites 

located over a wide geographical area. 

•  User Differential Range Error (UDRE): this is an esti-

Figure 3.4 shows the geographical distribution of the 

of clock and ephemeris error correction for a given 

RIMS already in operation and the RIMS currently under 

GPS satellite.

mate of the residual range error after the application 

deployment.

Central Processing Facility (CPF)
The Central Processing Facility (CPF) is a module of the 

MCC that uses the data received from the network of 

•  Grid Ionospheric Vertical Error (GIVE): this is an esti-

mate of the vertical residual error after application of 

the ionospheric corrections for a given geographical 

grid point.

RIMS stations to:

These two parameters can be used to determine an aggre-

• 

Elaborate clock corrections for each GPS satellite in 

gate error bounded by the horizontal and vertical position 

view of the network of RIMS stations. These correc-

errors. Such information is of special interest for Safety 

tions are valid throughout the geostationary broadcast 

of Life users but may also be beneficial to other commu-

area (i.e. wherever the EGNOS signal is received).

nities needing to know the uncertainty in the position 

• 

Elaborate ephemeris corrections to improve the accu-

determined by the user receiver. 

racy of spacecraft orbital positions. In principle, these 

corrections are also valid throughout the geostation-

Finally, the CPF includes a large number of monitoring 

ary broadcast area. However, due to the geographical 

functions designed to detect any anomaly in GPS and 

distribution of the EGNOS ground monitoring net-

in the EGNOS system itself and is able to warn users 

work, the accuracy of these corrections will degrade 

within a very short timeframe (less than Time To Alert 

when moving away from the core service area.

(TTA)) in case of an error exceeding a certain threshold. 

• 

Elaborate a model for ionospheric errors over the 

These monitoring functions are tailored to the Safety 

EGNOS service area in order to compensate for ion-

of Life functions and will not be further detailed in this 

ospheric perturbations to the navigation signals.

document. 

16

E G N O S 	 D A T A 	 A C C E S S 	 S E R V I C E 	 ( E D A S )   S E R V I C E   D E F I N I T I O N   D O C U M E N T

Figure 3.4

EGNOS RIMS sites

LYR

MON

KOU

JME

TRO

KIR

RKK

EGI

TRD

GVL

LAP

HBK

MON

KOU

GLG

SWA

MLG

PAR

TLS

PDM

CRK

SDC

LSB

ACR

MAD

LPI

AGA

CNR

NOU

ALB

ZUR

BRN

WRS

HBK

SOF

ATH

ROM

CTN

DJA

GOL

ALY

ABS

17

3   –   E G N O S   D A T A   S E R V I C E   ( E D A S )   O V E R V I E W

Navigation	Land	Earth	Stations	(NLES)
The messages elaborated by the CPF are transmitted to 

ICAO (International Civil Aviation Organization) Standards 

and Recommended Practices throughout the European 

the NLESs. The NLESs (two for each GEO for redundancy 

Civil Aviation Conference (ECAC) region, including the 

purposes) transmit the EGNOS message received by the 

operation and technical management of EGNOS.

CPF to the GEO satellites for broadcast to users and to 

ensure the synchronisation with the GPS signal.

ESSP SAS is a company established by a number of major 

European Air Navigation Service Providers. The founding 

Central Control Facility (CCF)
The EGNOS system is controlled through a Central Control 

members of ESSP are the Air Navigation Service Providers 

of France (DGAC/DSNA), Germany (DFS), Italy (ENAV SpA), 

Facility (CCF) located in each of the Mission Control Cen-

Portugal (NAV-EP), Spain (ENAIRE), Switzerland (skyguide) 

tres. These facilities are manned on a 24/7 basis in order 

and the United Kingdom (NATS). The ESSP SAS has its 

to ensure permanent service monitoring and control.

headquarters and operations unit in Toulouse (France), 

3.1.4  EGNOS ORGANISATIONAL  

FRAMEWORK

3.1.4.1  Bodies Involved in the EGNOS Programme 
and Service Delivery
The European Union (EU) is the owner of the EGNOS 

and its service provision unit in Madrid (Spain).                            

3.1.4.2	 How	to	Get	Information	on	EGNOS	and	
EGNOS	Applications	or	Contact	the	Service	Provider
A number of websites and e-mail addresses are made 

available by the EC, GSA, the ESA, the EGNOS Service Pro-

vider and other organisations to provide detailed infor-

system. The European GNSS Agency (GSA) according to 

mation on the EGNOS programme, the system status and 

the delegation agreements with the European Commis-

system performance, as well as a number of useful tools.  

sion (EC) is in charge of the tasks associated with the 

Table 3.2 lists the main sources of information about EGNOS. 

exploitation phase of EGNOS, overall EGNOS operational 

programme management and as such, is responsible for 

taking decisions regarding the system exploitation, evo-

3.2 EDAS Overview

lutions and promotion of the services and applications.

3.2.1  INTRODUCTION2

The European Space Agency (ESA) led the technical devel-

opment of the EGNOS system in the past and is now 

EDAS allows registered users to plug into EGNOS to receive 

mandated by the European Commission to play the role 

the internal data collected, generated and delivered by 

of a design and procurement agent for system evolutions. 

EGNOS. EDAS therefore provides an opportunity to deliver 

The European Satellite Services Provider (ESSP) SAS is 

EGNOS data to users who cannot always view the EGNOS 

the EGNOS Services Provider within Europe, certified 

satellites (such as in urban canyons), or to support a variety 

according to the Singe European Sky (SES) regulation as Air 

of other services, applications and research programmes.

Navigation Service Provider (ANSP). ESSP SAS provides the 

EDAS services are intended to be delivered and maintained 

EGNOS OS, EDAS Services and SoL Service compliant with 

over the long term.

2  From EGNOS Data Access Service Applications – GSA Leaflet v2
   http://www.gsa.europa.eu/sites/default/files/content/edas_applications_v2_en.pdf

18

19

 
 
Table 3.2

Where	to	find	information	about	EGNOS

Topic

Organisation

Web/contact details

EGNOS Programme:
EC	institutional	information	about	
the EGNOS Programme 

EGNOS general information and 
EGNOS applications

EGNOS Status and Performance
ESSP	official	reporting	of	the	system	
status, performances, services, 
news,	applicable	documentation,	
service	notices	etc.

EGNOS User Support 
ESSP dedicated service to users on 
EGNOS	status,	system	description,	
real	time	services	performances,	
forecasts, FAQs, etc.
A	specific	EDAS	section	is	also	
available.

EGNOS Helpdesk
Direct point of contact for any 
question	related	with	the	EGNOS	
system, its performances and 
applications.

EGNOS System 
ESA dedicated services and 
detailed	technical	information	on	
EGNOS

EGNOS receivers
EASA	mailbox	for	any	question	
related	to	service	difficulties	or	
malfunctions	of	EGNOS	certified	
receivers

EDAS
General	information	about	EDAS

EC

http://ec.europa.eu/enterprise/policies/satnav/index_en.htm 

GSA

http://www.egnos-portal.eu

ESSP

http://www.essp-sas.eu

ESSP

http://egnos-user-support.essp-sas.eu/

ESSP

egnos-helpdesk@essp-sas.eu
+34 911 236 555

ESA

http://www.esa.int/esaNA/egnos.html

EASA

egnos@easa.europa.eu

GSA/EC/ ESSP

http://www.gsa.europa.eu/egnos/edas

18

19

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT3   –   E G N O S   D A T A   S E R V I C E   ( E D A S )   O V E R V I E W

3.2.2  OVERVIEW OF THE CURRENT

ARCHITECTURE3

For FTP Service, SISNET Service and NTRIP Service, the 

EDAS Client SW is not required and in consequence, only 

one interface exists:

The EDAS architecture is decomposed into two separate 

• 

The interface between the EDAS system and the 

elements:

Users. This interface is external to the EDAS perimeter.

• 

EDAS system, implementing the interface with the 

EGNOS infrastructure and performing the necessary 

3.2.3  THE EDAS SYSTEM

data processing to provide the different EDAS Services 

through Internet.

The EDAS system is fed by EGNOS data. It provides, among 

• 

The EDAS Client SW, resident at user level, imple-

others, the following functions:

menting the external interface of some of the EDAS 

•  Allows accepting connection from Users with correct 

services (EDAS Main Data Streams and EDAS Data 

credentials.

Filtering service). The EDAS Client SW is responsible 

• 

Introduces  an  additional  security  layer  between 

for basic security functions and for the interface with 

EGNOS and the Users.

the EDAS through the appropriate communication 

• 

Protects EGNOS proprietary protocols and data 

means. The SW tool is provided to EDAS users after 

formats.

registration (see section 6.2 for EDAS registration 

• 

Processes EGNOS data and produces the different 

details) in order to retrieve data from the Main Data 

products provided through EDAS services.

Services (SL0 and SL2) and the Data Filtering Service.

The interface with the Users is done via Internet or ded-

icated Frame Relay lines.

EDAS comprises a number of communication protocols 

defined by the following interfaces:

3.2.4  THE EDAS CLIENT SOFTWARE

• 

The interface between the EGNOS core and EDAS 

system. This interface belongs to the EGNOS system.

The EDAS Client SW is a platform-independent interface 

For the EDAS Service Level 0 (SL0), Service Level 2 (SL2) and 

system for the reception of Service Level 0, Service Level 2 

the Data Filtering, the following interfaces are available:

and Data Filtering (both over Service Level 0 and Service 

element allowing the connection of Users to the EDAS 

• 

The interface between the EDAS system and the 

Level 2).

EDAS Client SW. This interface is internal to the EDAS 

perimeter, and it is not accessible to the Users. 

Users make use of this software component to obtain 

• 

The interface between the EDAS system Client SW and 

the EGNOS products in real-time from the EDAS system, 

the Users. This is the interface available to Users, in 

then perform the necessary processing and finally provide 

order to obtain and process the EGNOS data according 

services to end users via non-GEO means. 

to their specific needs.

3  Updated from EGNOS Data Access Service Applications – GSA Leaflet v2 

http://www.gsa.europa.eu/sites/default/files/content/edas_applications_v2_en.pdf 

20

21

 
Figure 3.5

EDAS Architecture

EGNOS

EDAS

EDAS User
(Data Provider)
Perimeter

User
Application
Demonstrators
Perimeter

Client SW

Service Provider
Demonstration 1

User Apps

Client SW

Service Provider
Demonstration 1

User Apps

FTP Client

User Apps

SISNeT Client

User Apps

Ntrip Client

User Apps

EDAS SL0,
SL2

EDAS data
ﬁltering

EDAS FTP

EGNOS messages

GNSS corrections
(RTCM)

20

21

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT3   –   E G N O S   D A T A   S E R V I C E   ( E D A S )   O V E R V I E W

The generic information needed by users to make use of 

the EDAS Client SW is provided in [RD-10]. The EDAS Client 

SW is made available to EDAS users upon registration. 

3.2.5.1	 Raw	Observations	from	the	RIMS	and	NLES	
Networks6
The data collected by the RIMS network includes dual-fre-

However, the interface between the Client Software and 

quency GPS data, GLONASS L1, and the EGNOS geostation-

the EDAS system belongs to the EDAS internal perimeter, 

ary L1 SIS. The data collected by the NLES network includes 

so the corresponding Interface Control Document (ICD) 

only the GPS data. For each RIMS/NLES and each tracked 

will not be visible to the Service Providers/EDAS users.

satellite a set of observables is provided. Therefore, at 

3.2.5  DATA AVAILABLE FROM EDAS4

a given time, information from each RIMS/NLES will be 

provided with a set of observables from visible satellites. 

Service providers can access EDAS to form new innova-

This data is provided by EDAS in real-time with an update 

tive applications, to integrate into existing services, or 

rate of one second. Each message contains a variable 

to support research programmes. These uses exploit the 

number of sections (depending on the number of tracked 

different types of the data available from EDAS.

satellites). The summary table below lists all the raw 

observables provided from the RIMS/NLES network. For 

The real-time and historic data provided by EDAS are 

details on the format and specific EDAS service in which 

mainly:

• 

The GPS, GLONASS5 and EGNOS GEO observations 
and navigation data collected by the entire network 

the information summarized in Table 3.3 is made available 

to EDAS users, please refer to section 4 (“EDAS Services”).

of RIMS (RIMS A, B) and NLES.

• 

The EGNOS augmentation messages, as normally 

3.2.5.2	 EGNOS	Augmentation	Message7
This is the EGNOS augmentation message as uplinked 

received by users via the EGNOS geostationary sat-

and broadcast from the EGNOS geostationary satellites. 

ellites.

The augmentation message from EGNOS has been inter-

•  Differential GNSS (DGNSS) and RTK (Real-Time Kin-

nationally standardized along with all other space-based 

ematic)  messages  allowing  users  implementing 

augmentation system (SBAS) [RD-3].

advanced positioning techniques.

Please refer to section 4 for a description of the different 
services and the formats in which the above data are 

The EGNOS SIS Navigation Data is composed of distinct 

Message Types (MT) as defined in the SBAS standard. 

The provided message types are summarized in the table 

made available to EDAS users.

(Table 3.4).

The EGNOS augmentation message is transmitted per 

second and each message is 250 bits long.

4  Extracted from EGNOS Data Access Service Applications – GSA Leaflet v2 

http://www.gsa.europa.eu/sites/default/files/content/edas_applications_v2_en.pdf 

5  No commitment on GLONASS data is provided.
6  Extracted from EDAS Content and Access – GSA Leaflet v3 

http://www.gsa.europa.eu/sites/default/files/content/edas_applications_v3_en.pdf

7  Extracted from EDAS Content and Access – GSA Leaflet v3 

http://www.gsa.europa.eu/sites/default/files/content/edas_applications_v3_en.pdf

22

23

Table 3.3

EDAS raw data summary

For each RIMS (and NLES) and  
each visible GPS satellite

For each RIMS (not NLES) and  
each visible GLONASS satellite

For each RIMS (not NLES) and  
each visible EGNOS GEO

GPS	navigation	
data 

GPS L1 code 
measurements

GPS L2 code 
measurements

GLONASS 
navigation data 

GLONASS L1 code 
measurements

GEO navigation 
data 

GEO L1 code 
measurements

GPS receiver 
channel status

GPS L1 phase 
measurements 
(accumulated 
Doppler 
from satellite 
acquisition)

GPS L2 phase 
measurements 
(accumulated 
Doppler)

GLONASS receiver 
channel status

GPS L1 signal  
C/N0 ratio

GPS L2 signal  
C/N0 ratio

GPS L1 code 
carrier phase 
coherency 
indicator

GPS L1 signal 
status

GPS L1 signal 
quality

GPS L2 code 
carrier phase 
coherency 
indicator

GPS L2 signal 
status

GPS L2 signal 
quality

GEO receiver 
channel status

GLONASS 
L1 phase 
measurements 
(accumulated 
Doppler)

GLONASS L1 
signal C/N0 ratio

GLONASS L1 
code carrier 
phase coherency 
indicator

GLONASS L1 
signal status

GLONASS L1 
signal quality

GEO L1 phase 
measurements 
(accumulated 
Doppler)

GEO L1 signal C/
N0 ratio

GEO L1 code 
carrier phase 
coherency 
indicator

GEO L1 signal 
status

GEO L1 signal 
quality

Table 3.4

EGNOS Message Types 

Message Type

Contents

Purpose

0

1

2-5

6

7

98

10

12

17

18

24

25

26

27

63

Don’t Use (SBAS test mode)

Discard any ranging, corrections and integrity data from that PRN signal. 
Used also during system testing

PRN Mask

Fast corrections

Indicates the slots for GPS and GEO satellites provided data

Range corrections and accuracy

Integrity information

Accuracy-bounding information for all satellites in one message

Fast correction degradation factor

Information about the degradation of the fast term corrections

GEO ranging function 

EGNOS satellites orbit information (ephemeris)

Degradation parameters

Information about the correction degradation upon message loss

SBAS network Time/UTC offset 
parameters

Parameters for synchronisation of SBAS Network time with UTC

GEO satellite almanacs

GEO Almanacs

Ionospheric grid point masks

Indicates for which geographical point ionospheric correction data is 
provided

Mixed fast/long-term satellite error 
corrections

Fast-term error corrections for up to six satellites and long-term satellite 
error correction for one satellite in one message

Long-term satellite error corrections

Corrections for satellite ephemeris and clock errors for up to two satellites

Ionospheric delay corrections

Vertical delays/accuracy bounds at given geographical points

EGNOS service message

Defines the geographic region of the service

Null message

Filler message if no other message is available

8  MT9 is broadcast with some information about the orbital position of the broadcasting GEO satellite. At this stage, the EGNOS system does not support the Ranging 

function which is described in ICAO SARPs as an option. This is indicated by a special bit coding of the Health and Status parameter broadcast in MT17.

22

23

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT4

EDAS SERVICES

This section presents a high level description of the EDAS 

services, classified as “Main Data Stream Services” (section 

4.1.1  EDAS SL0 (ASN.1)
A  detailed  definition  of  the  SL0  messages  delivered 

4.1) and the rest of services (Data Filtering, FTP, SISNet 

through the EDAS Client SW can be found in [RD-10]. 

and Ntrip) in sections from 4.2 to 4.5 respectively.

The messages delivered through EDAS SL0 are:

4.1 Main Data Stream Services

• 

EGNOS SBAS messages.

•  Receiver measurement messages.

•  RIMS raw measurements.

The following Service Levels and Formats are provided 

•  NLES cyclic feedback.

by EDAS:

• 

Service Level 0 (SL0): it is needed to either transmit 

data in raw format, or transmit them in a format that 

allows a complete reconstruction after decoding.

• 

Service Level 2 (SL2): it is used to transmit data in 

•  ATC information9.
•  RIMS APC data.

4.1.2  EDAS SL2 (RTCM 3.1)
A detailed description of the Service Level 2 Messages 

RTCM 3.1 standard [RD-9]. It includes data from 

can be found in [RD-10]. The following RTCM messages 

Service  Level  1  which  was  decommissioned  on  
1st July 2014.

are provided:

•  Message 1004. Extended L1&L2 GPS RTK Observables.

•  Message 1005. Stationary RTK Reference Station ARP.

In order to retrieve data from these services, a software 

•  Message 1007. Antenna Descriptor. 

application named “Client Software”, which is made avail-

•  Message  1010.  Extended  L1-Only  GLONASS  RTK 

able to users after registration (see section 6.2 for EDAS 

Observables.

registration details), is to be used.

•  Message 1013. System Parameters.

•  Message 1019. GPS ephemerides.

The data format and the detailed information about 

•  Message 1020. GLONASS ephemerides. 

how to retrieve data from Main Data Streams Services 

•  Message 4085. 

is described in [RD-10], which is available to EDAS users 

after registration.

Apart from the messages defined in the RTCM 3.1 standard 

[RD-9], some EDAS specific messages have been defined 

for SL2. In SL2, all EDAS defined messages are encoded 

with Message Number 4085 (EDAS proprietary message), 

and can be distinguished by the message subtype [RD-10].

• 

• 

• 

• 

• 

• 

• 

• 

Subtype 0. GPS/GLONASS/GEO Ephemeris.

Subtype 1. GEO Observations.

Subtype 2. NLES Cyclic Feedback. 

Subtype 3. ATC Information9. 

Subtype 4. RIMS APC data.

Subtype 5. Ionospheric and UTC data.

Subtype 6. GPS Almanac.

Subtype 7. RIMS Status.

9  currently not provided by EDAS. 

24

E G N O S 	 D A T A 	 A C C E S S 	 S E R V I C E 	 ( E D A S )   S E R V I C E   D E F I N I T I O N   D O C U M E N T

4.2 EDAS Data Filtering 

Services

details). The list of groups available, the exhaustive list of 

data delivered and the user manual to retrieve the data 

can be found in the Client Software User Manual [RD-10], 

The EDAS Data Filtering Service allows EDAS users to 

which is available to users after registration. For infor-

access a subset of the SL0 or SL2 data (hence the data 

mation, the current service configuration is illustrated in 

are available in ASN.1 and RTCM 3.1 formats respec-

Appendix D (“EDAS Data Filtering Service: configuration”).

tively). By selecting one of the predefined RIMS groups 

available and the data rate (1 Hz or 1/30 Hz), EDAS users 

may reduce the bandwidth consumption and amount of 

4.3 EDAS FTP Services

data to be processed on the user side with respect to the 

The EDAS FTP Service enables EDAS users to get EDAS/

corresponding SL0 or SL2. 

EGNOS historical data in different formats and data 

rates. The different sets of data available for download, 

In order to retrieve data from these Service Levels, it is 

as well as their format, data rates and maximum storage 

necessary the same Client Software application as for the 

period,  are  summarized  hereafter.  For  a  high  level 

Main Data Stream Services, which will be available to users 

definition of each format, please refer to “Appendix 

after registration (see section 6.2 for EDAS registration 

A Definitions”. 

Table 4.1

EDAS FTP service: available data sets

DATA SET

GPS & GLONASS10 
Observations	from	RIMS	
A&B	stations.

GPS and GLONASS10 
Navigation	Files	from	
RIMS	A&B	Stations	and	
consolidated12.

EGNOS messages

EDAS SL0 raw data

EDAS SL2 raw data

Ionospheric data

FORMAT

RINEX 2.11

RINEX 2.11

RINEX-B

EMS

ASN.1

RTCM 3.1

IONEX 1.0

RATE

1 Hz

1/30 Hz

1 Hz

1 Hz

1 Hz

1 Hz

1 Hz

1 / 2 h

PERIODICITY OF 
PUBLICATION

MAXIMUM STORAGE 
PERIOD

15 min

1 day

1 day

1 day

1 hour

15 min

15 min

1 day

2 years11

2 years13 

2 years13

6 months13

6 months13

2 years13

10 No commitment on GLONASS data is provided.
11 Starting from April 08th 2014.
12 Consolidated GPS/GLONASS navigation file: daily GPS/GLONASS broadcast ephemeris file. This daily file is a merge of the individual RIMS site navigation files into 
one, providing non-redundant ephemerides data. In consequence, this consolidated navigation file can be utilized by users instead of the individual navigation 
files per station.

13 Starting from March 1st 2013.

24

25

 
4   –   E D A S   S E R V I C E S

EDAS users may access this service using a standard FTP 

The Ntrip protocol has been designed to disseminate 

client.

differential correction data or other kinds of GNSS stream-

ing data to stationary or mobile users over the Internet. 

Specific guidelines for the access and usage of the EDAS 

Ntrip is becoming the “de facto” protocol for GNSS data 

FTP service, including naming conventions and folder 

dissemination in real time.

structure (EDAS FTP-User Information Package), are avail-

able for users after registration (see section 6.2 for EDAS 

Specific guidelines for the access and usage of the EDAS 

registration details).

4.4 EDAS SISNeT Service

Ntrip service (EDAS Ntrip-User Information Package) are 

available for users after registration (see section 6.2 for 

EDAS registration details). 

The EDAS SISNeT service provides access to the EGNOS 

GEO satellites messages transmitted over the Internet 

through the SISNeT protocol. The EDAS SISNeT service is 

fully compliant with the SISNeT protocol which has been 

defined by ESA. For a full description of this protocol, 

please refer to SISNeT User Interface Document [RD-11] 

which is publicly available. 

EDAS SISNeT users can select the most convenient way 

for retrieving SISNeT Messages. Since the information is 

sent by means of an open standard protocol, it is possi-

ble for the user to develop its own application or use an 

existing one.

Specific guidelines for the access and usage of the EDAS 

SISNeT service (EDAS SISNeT-User Information Package) 

are available for users after registration (see section 6.2 

for EDAS registration details). 

4.5 EDAS Ntrip Service

The EDAS Ntrip Service provides GNSS data (RTCM for-

mat) coming from the EGNOS network through the Ntrip 

protocol [RD-15] in real-time. In fact, EDAS disseminates 

GNSS data in RTCM 2.1, 2.3 and 3.1 formats through the 

Ntrip protocol. Below it is presented the different Message 

Types provided according to the RTCM format.

26

27

Table 4.2

EDAS NTRIP Message Types provided in RTCM 2.1, 2.3 and 3.1 formats.

Message Name

Message Types

RTCM 2.1

RTCM 2.3

RTCM 3.1

Differential	GPS	Corrections

GPS Reference Station Parameters

Reference	Station	Datum	

RTK Uncorrected Carrier Phases

RTK Uncorrected Pseudoranges

Extended Reference Station Parameters 

Antenna	Type	Definition	Record	

Antenna Reference Point (ARP)

Differential	GLONASS	Corrections

Differential GLONASS Reference Station Parameters

Extended	L1&L2	GPS	RTK	Observables

Stationary RTK Reference Station ARP

Antenna	Description

L1-Only GLONASS RTK Observables

Auxiliary	Operation	Information

GPS Ephemerides

GLONASS Ephemerides

1

3

N/A

18

19

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

1

3

4

18

19

22

23

24

31

32

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

N/A

1004

1005

1007

1010

1013

1019

1020

26

27

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT5 EDAS Performances 

This section presents the EDAS Services performance in 

5.1 EDAS Services Availability

terms of availability and latency:

Table 5.1 provides the minimum availability of the EDAS 

•  Availability: percentage of time in which EDAS is 

services.

providing its services according to specifications (see 

[RD-10] for a detailed description of EDAS services 

It should be noted that EDAS services availability perfor-

messages). The availability of EDAS services is meas-

mance is nominally higher than the above figures. Please 

ured at the EDAS system output (excluding external 

refer to Appendix B (Observed EDAS Performances) to 

network performance).

check the history of EDAS Services availability performance 

• 

Latency: time elapsed since the transmission of the 

between January 2014 and May 2014.

last bit of the navigation message from the space 

segment (EGNOS and GPS/GLONASS satellites) until 

the data leave the EDAS system (formatted according 

5.2 EDAS Service Latency

to the corresponding service level specification). 

Table 5.2 provides the maximum latency of the EDAS 

EDAS latency is a one-way parameter defined for 

services.

real-time services.

It should be highlighted that EDAS services latency perfor-

mance is nominally lower than the above figures. Please 

refer to Appendix B (Observed EDAS Performances) to 

check the history of EDAS Services latency performance 

between January 2014 and May 2014.

Table 5.1

EDAS services availability

SL0

SL2

SISNeT

FTP

Data 
Filtering

Ntrip

EDAS Services Availability

98.5%

98.5%

98%

98%

98%

98%

28

29

Figure 5.1

EDAS services performance measurement point

EGNOS System
Architecture
Perimeter

EGNOS
Data Server
Perimeter

EDAS User
(Data Provider)
Perimeter

User
Application
Demonstrators
Perimeter

EGNOS

EDAS

EDAS SL0,
SL1, SL2

EDAS data
ﬁltering

EDAS FTP

EGNOS messages

GNSS corrections
(RTCM)

Client SW

Service Provider
Demonstration 1

User Apps

Client SW

Service Provider
Demonstration 2

User Apps

FTP Client

User Apps

SISNeT Client

User Apps

Ntrip Client

User Apps

EDAS
Services
Latency

EDAS
Services
Availability

Table 5.2

EDAS services latency

SL0

SL2

SISNeT

FTP14

Data Filtering

Ntrip

SL0

SL2

EDAS Services Latency

1,3 
seconds

1,450 
seconds

1,150 
seconds

N/A

1,6 
seconds

1,75 
seconds

1,75 
seconds

28

29

14 Latency only defined for real-time services.

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT6

EDAS User Support 

6.1	EGNOS	Helpdesk

Before proceeding with the submission of the registration 

information, users are asked to carefully read and explic-

A single point of contact for the EGNOS users’ community, 

itly accept the conditions of use for the EDAS Service and 

including EDAS users, is available through the EGNOS 

personal data management.

Helpdesk. 

After the verification of the provided data, the EGNOS 

EDAS users are welcome to contact the EGNOS Helpdesk for 

Helpdesk will provide the user with the configuration 

EDAS registration and for any request or question related to 

details necessary to activate the requested EDAS account.

EDAS including but not limited to EDAS services status and 

performance, connectivity issues, technical specifications, 

Additionally, the necessary credentials will be provided in 

data streams structure, conditions of use, etc. Prior to that, 

order to allow the user to download the EDAS Client SW 

users are kindly requested to read the FAQs available at the 

and specific user documentation from the EGNOS User 

ESSP (www.essp-sas.eu) and EGNOS User Support websites 

Support Website (http://egnos-user-support.essp-sas.eu/).

(http://egnos-user-support.essp-sas.eu/).

The EGNOS Helpdesk operates 365 days per year on an H24 

basis (operating language is English). Users may contact 

6.3 EDAS Regular/Urgent 

Request

the EGNOS Helpdesk by e-mail or by phone.

EDAS related requests are classified in two categories by 

the EGNOS Helpdesk:

• 

• 

EGNOS Helpdesk e-mail: egnos-helpdesk@essp-sas.eu.

EGNOS Helpdesk phone number: +34 911 236 555.

• 

6.2	EDAS	Registration

EDAS urgent request15: inquiries signalling techni-
cal failures of EDAS (temporary service outage) are 
tagged as high priority requests. The resolution time16 
for this kind of requests is one hour at maximum.  

EDAS is accessible upon registration. In order to request 

an EDAS account, the online version of the application 

• 

EDAS regular request: all the inquiries not falling in 

form described in “Appendix C Application Form for EDAS 

Service” and available at the EDAS section of the User 

Support website (http://egnos-user-support.essp-sas.eu/) 

shall be submitted to the EGNOS Helpdesk (egnos-help-

desk@essp-sas.eu).

the previous category are normal priority requests. 
The resolution time17 for this kind of requests is 3 
working days18.

15 For urgent requests, it is recommended to contact the EGNOS Helpdesk by phone.
16 Resolution time for this kind of requests shall be understood as the time it takes to the EGNOS Helpdesk to inform the user on whether a specific EDAS service is 

up/down.

17 Resolution time for this kind of requests shall be understood as time it takes to the EGNOS Helpdesk to provide the user with the requested information. In 

specific cases (e.g. interaction with other entity required), the EGNOS Helpdesk may contact the users to inform that the request is being processed and that the 
resolution time will be enlarged.

18 Spanish working days.

30

31

6.4	EDAS	First	Connection	

Support

In order to set up the EDAS Client SW, the user has to 

follow the indications provided in [RD-10]. In case that 

the connection is not achieved, the user is advised to refer 

to the troubleshooting section of [RD-10].

If the case is not covered in [RD-10], the user should 

submit the case to the EGNOS Helpdesk.

6.5 EDAS Point-To-Point 
Connectivity	Support

For those EDAS users interested in having a guaranteed 

bandwidth, it is possible to contract a Point-To-Point 

(PTP) line. In case of deciding to contract a dedicated 

line, users are welcome to contact the EGNOS Helpdesk 

(egnos-helpdesk@essp-sas.eu) for support. Note that the 

procurement of the line (including negotiation with local 

telecomm providers) shall be done by the user.

6.6 EDAS Incident 
Management / 
Communication

Planned maintenance activities on the EDAS system that 

could result in a service outage or degradation will be 

notified to registered EDAS users by e-mail at least three 

working days in advance.

30

31

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT7

EDAS	Online	Information 

7.1 EGNOS Monthly 

Performance Report

(http://www.essp-sas.eu/monthly_performance_reports) 

since May 2011.

EDAS services performance is regularly made available 

The EDAS services performance for the subject month 

to EDAS users and the general public through the EGNOS 

can be found in section 5 of the EGNOS Monthly Perfor-

Monthly  Performance  Report.  The  EGNOS  Monthly  

mance Report.

Performance  Report  is  published  at  ESSP  website  

Figure 7.1

EDAS	section	in	May	2014	EGNOS	Monthly	Performance	Report

32

33

7.2 EDAS Website

mation regarding EDAS to the general public. Upon 

registration, EDAS users are granted access to the EDAS 

The EDAS dedicated section at the EGNOS User Sup-

restricted area of the EGNOS User Support Website 

port website (http://egnos-user-support.essp-sas.eu/

where the necessary development material is available 

egnos_ops/edas_intro)provides all the relevant infor-

for download. 

Figure 7.2

EDAS	section	at	the	EGNOS	User	Support	Website

32

33

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENT8

EDAS	Applications 

8.1 EDAS Client SW

Figure 8.1

EDAS Client SW: login window

The EDAS Client SW is a platform-independent interface 

element allowing users to connect to the following EDAS 
services: SL0, SL2 and Data Filtering19 (both over SL0 and 
SL2). This tool is available for users after registration (see 

section 6.2 for EDAS registration details).

Users make use of this software component to obtain the 

EGNOS products in real-time from the EDS, then perform 

the necessary processing and finally provide services to 

end users via non-GEO means.

The EDAS Client SW is in charge of handling the connec-

tion between users and EDAS servers for the Main Data 

Streams and the Data Filtering Services, through a specific 

protocol (this protocol is internal to EDAS perimeter and 

hence not made available to the general public). Once the 

connection is established, the EDAS servers will start send-

ing EDAS data to the preferred port of the machine where 

the EDAS Client SW is running. Details on the EDAS Client 

SW installation, behaviour and typical connection issues 

that new EDAS users may face can be found in [RD-10].

EDAS Client SW can be launched through a user-friendly 

Graphical User Interface and through command line. Using 

this application, user can easily configure the Service from 

which retrieving data and for the case of Data Filtering, 

the RIMS site group and the data rate. Additionally, time 
stamping capabilities20 are also offered to EDAS users as 
the EDAS Client SW allows discarding EDAS messages if 

older than a certain configurable threshold and also 

delaying  the  delivery  of  EDAS  messages  a  certain 

configurable time.

19 In order to access the EDAS Data Filtering Service, EDAS Client SW version 2 or later is required. 
20 Data Stamping functions may require a duly synchronized user platform (e.g. NTP server)

34

35

EDAS Client SW: login window

8.2	Examples	of	EDAS	based	
services/applications

•  Development and validation of added value appli-

cations.

There are different manufacturers that provide tools and/

• 

Supporting geodetic and mapping research.

or compilers to use the information packaged in RTCM 

(SL2) and ASN.1 (SL0) standards.

•  Application of DGNSS and RTK positioning techniques 

in areas close to EGNOS stations in order to enhance 

Regarding RTCM, there are several available tools through 

precision.

the Ntrip protocol, such as the BKG NTRIP Client (BNC) (fur-

ther information in http://igs.bkg.bund.de/index_ntrip.
htm web site). For Linux environment there is also a gpsd21 
package containing a RTCM decoder (its manual page can 

• 

EGNOS messages through SISNeT for mobile receivers 

with Internet access, irrespective of the GEO visibility 

conditions in order to improve accuracy with respect 

be found at http://manpages.ubuntu.com/manpages/

to GPS.

hardy/man1/rtcmdecode.1.html).

•  Research initiatives linked to the analysis of the 

Regarding EDAS services applications, there is an extensive 

atmosphere behaviour.

range of possibilities, such as the ones listed here:

•  Offline and real-time processing for GNSS perfor-

•  Redistribution of EGNOS augmentation messages: 

mance analysis.

used in urban canyons for user communities with 

their own equipment standards

•  A-GNSS for LBS: this application can be used by many 

user communities, such as: 

•   Mobile network operators.

•   Third parties in order to offer successful LBS in 

urban areas.

•   Emergency services using the position informa-

tion of mobile phones.

•   Network operators in order to use input data to 

support current or future A-GNSS services.

• 

Professional GNSS Services/products: for users within 

surveying, oil and gas exploration, mapping, construc-

tion, tracking, agriculture and more.

21 Global Positioning System - daemon

34

35

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENTAPPENDIX A 
Definitions

Term

Availability

Latency

A-GNSS

ASN.1

Cyclic	Redundancy	Check	(CRC)

EMS

IONEX

Ntrip

Definition

When applied to EDAS services, percentage of time in which 
EDAS is providing its services according to specifications 
(see [RD-10] for a detailed description of EDAS services 
messages). The availability of EDAS services is measured 
at the EDAS system output (excluding external network 
performance).

When applied to EDAS services, it shall be understood as 
time elapsed since the transmission of the last bit of the 
navigation message from the space segment (EGNOS and 
GPS/GLONASS satellites) until the data leave the EDAS 
system (formatted according to the corresponding service 
level specification). EDAS latency is a one-way parameter.

Technique that allows a GNSS receiver acquiring a position fix 
within seconds by sending assistance data from a server via 
the radio network. 

Notation called Abstract Syntax Notation One (ASN.1) to 
define the syntax of information data. It defines a number 
of simple data types and specifies a notation for referencing 
these types and for specifying values of these types.

Please refer to [RD-12] for further details.

Error-detecting code commonly used in digital networks and 
storage devices to detect accidental changes to raw data.

EGNOS Message Server format has been defined by ESA for 
the provision of EGNOS messages.

EMS format 2.0 is described in [RD-13].

IONosphere map Exchange format: Common data format 
that supports the exchange of 2 and 3 dimensional TEC maps 
given in an ionospheric grid.

IONEX 1.0 format (the one selected for the provision of 
ionosphere related information for the EDAS FTP Service) is 
described in [RD-14].

“Networked Transport of RTCM via Internet Protocol” (Ntrip) 
stands for an application-level protocol streaming Global 
Navigation Satellite System (GNSS) data over the Internet. 
Ntrip is a generic, stateless protocol based on the Hypertext 
Transfer Protocol HTTP/1.1. 

The full protocol description [RD-15] can be purchased at 
http://www.rtcm.org/orderinfo.php. 

36

37

Term

RINEX

RINEX-B

RTCM

RTK 

SISNeT

Definition

Receiver Independent Exchange Format (RINEX) is data 
interchange format for raw satellite navigation system data.

RINEX 2.11 version (the one selected for the EDAS FTP 
Service) is described in [RD-16].

Receiver Independent Exchange Format (RINEX) type for 
broadcasting of GEO satellite data.

RINEX-B format (one of the formats selected for the EGNOS 
GEO satellites navigation message provision for the EDAS FTP 
Service) is described in [RD-17]. 

Standard format that is used on Differential GNSS services 
worldwide. Version 3 of this standard supports very high 
accuracy navigation and positioning through a broadcast 
to mobile GNSS receivers, which allows the receivers to 
compensate for errors that exist in satellite positioning 
without augmentation. This latest edition includes an 
interoperable definition for Network Real-Time Kinematic 
(Network RTK) operation, which supports centimeter-level 
accuracy positioning service over large regions.

Full description of RTCM formats are given respectively in 
[RD-6], [RD-8] and [RD-9].

Real Time Kinematic (RTK) navigation is a technique which 
based on the phase measurements of GNSS signals and 
real-time corrections from a reference station, can provide 
centimetre level accuracy.

Specific protocol for the transmission of EGNOS messages 
over TCP/IP developed by ESA.

Please refer to [RD-11] for a detailed description of SISNeT 
protocol.

36

37

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENTAPPENDIX B 
Observed EDAS performances

Below, the performance of EDAS Services performance 

from January 2014 to September 2014 is presented: 

•  Availability:  Percentage  of  time  during  which 

the  service  provides  the  data  according  to  the 

specifications.

• 

Latency: Average of the percentile 95% latencies 

monitored for every 5 minutes period within the 

month.

Table 8.1

EDAS availability from January 2014 to September 2014

Availability (%)

EDAS Service

Jan 
2014

Feb 
2014

Mar 
2014

Apr 
2014

May 
2014

Jun 
2014

July 
2014

Aug 
2014

Sept 
2014

SL 0

SL 2

99.95%

99.99% 100.00%

99.99% 100.00%

99.32%

100%

100%

99,93% 

99.95%

99.99% 100.00%

99.99% 100.00%

99.30%

100%

100%

99,89% 

Ntrip Service

99.13%

99.96%

99.99%

99.96%

99.46%

99.41%

99.98%

100%

99,69% 

SISNET

SISNET GEO1

99.36%

99.38%

99.45%

99.29%

99.39%

98.58%

99.14%

99.26%

98.92%

SISNET GEO2

99.33%

99.41%

99.38%

99.25%

99.49%

98.27%

98.06%

99.25%

99.05%

Data Filtering Service

DF RIMS A

99.93%

99.98%

99.98%

99.93%

99.96%

99.26%

99.96%

99.96%

99.82%

 DF Central

99.93%

99.98%

99.97%

99.93%

99.96%

99.24%

99.95%

99.98%

99.81%

DF MEDA

99.93%

99.96%

99.97%

99.92%

99.96%

99.24%

99.95%

99.94%

99.81%

DF NorthEast

99.93%

99.97%

99.97%

99.92%

99.96%

99.24%

99.93%

99.96%

99.82%

DF NorthWest

99.93%

99.96%

99.97%

99.94%

99.96%

99.25%

99.97%

99.98%

99.81%

DF SouthWest

99.93%

99.98%

99.97%

99.92%

99.96%

99.26%

99.95%

99.91%

99.80%

FTP Service

99.35%

99.49%

99.85%

99.95%

99.87%

98.40%

100%

99.96%

99.76%

38

39

Table 8.2

EDAS latency from January 2014 to September 2014

Availability (%)

EDAS Service

Jan 
2014

Feb 
2014

Mar 
2014

Apr 
2014

May 
2014

Jun 
2014

July 
2014

Aug 
2014

Sept 
2014

SL 0

SL 2

554.10

539.54

528.87

525.53

531.10

529.17

539.77

532.87

501.01

559.42

543.93

532.94

529.63

534.77

533.83

544.58

539.77

542.43

Ntrip Service

931.26

255.57

256.97

336.83

391.23

262.23

267.84

246.97

246.57

SISNET

SISNET GEO1

323.90

262.25

175.61

249.37

133.32

72.50

314.68

300.71

315.77

SISNET GEO2

331.32

253.00

167.39

241.17

135.58

72.53

308.74

301.52

318.10

Data Filtering Service

DF RIMS A

502.23

489.14

502.48

569.13

548.71

507.30

581.39

2174.42

1017.57

 DF Central

584.20

452.60

428.17

477.62

486.83

431.14

902.47

1369.03

946.79

DF MEDA

597.90

482.76

482.87

530.63

537.77

479.4

934.19

712.61

835.3

DF NorthEast

187.03

184.67

200.19

249.53

251.42

201.53

747.9

1545.45

818.4

DF NorthWest

457.26

444.57

460.90

527.80

520.45

492.97

780.03

2109.77

985.5

DF SouthWest

644.32

498.48

504.77

575.10

554.42

498.53

580.68

2173.26

444.00

38

39

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENTAPPENDIX C 
application	form	for	EDAS	service

The EDAS application form is implemented through a 

web form that can be filled on-line at the EGNOS User 

Support website (http://egnos-user-support.essp-sas.eu/

egnos_ops/user/register) 

40

41

40

41

APPENDIX D 
EDAS	data	filtering	service

Configuration	

The following groups are currently configured for the 

EDAS Data Filtering service (see Figure 8.2):

As a complement to the information provided about the 

EDAS Data Filtering Service in section 4.2, the configuration 

•  GROUP RIMS_A: This group corresponds to all the 

of this service is described hereafter (in terms of groups 

RIMS A of the EGNOS system.

of RIMS stations available in the service configuration). 

The information in this section intends to illustrate the 

•  GROUP Central: This geographical group involves all 
the RIMS A sites located approximately in the centre 

way in which the EDAS Data Filtering service groups can 

of Europe. 

be defined. 

•  GROUP NorthWest: This geographical group gathers 
the  RIMS  A  sites  located  over  the  Northwest  of 

Please be aware that this information is only indicative and 

Europe.

the list of RIMS groups available may evolve with time. In 

order to check the up to date service configuration, the 

reader may refer to [RD-10] available at the EDAS spe-

cific section of the EGNOS User Support Website (http://

•  GROUP NorthEast: This geographical group includes 
the RIMS A sites located over the Northeast of Europe.
•  GROUP SouthWest: This geographical group gathers 
the  RIMS  A  sites  located  over  the  Southwest  of 

egnos-user-support.essp-sas.eu/).

Europe.

•  GROUP MEDA: This geographical group gathers the 

RIMS A sites located over the Mediterranean area.

Table 8.3

RIMS sites included per Group Name

Group Name

RIMS sites included

GROUP RIMS_A

All RIMS A 

GROUP Central

ZURA, BRNA, TLSA, PDMA, SWAA, ALBA, WRSA, ROMA, SOFA, ATHA, CTNA 

GROUP NorthWest

RKKA, EGIA, JMEA, TRDA, ALBA, SWAA, GLGA, CRKA, BRNA

ACR

GROUP NorthEast

TRDA, ALBA, WRSA, BRNA, GVLA, LAPA, TROA, KIRA, LYRA 

GROUP SouthWest

ROMA, CTNA, DJAA, TLSA, SDCA, LSBA, MLGA, PDMA, MADA, ACRA, LPIA, CNRA, 
NOUA, AGAA 

GROUP MEDA

MLGA, PDMA, CTNA, DJAA, ATHA, ALYA, GOLA, TLSA, ROMA, SOFA, ABSA 

LYR

JME

TRO

KIR

North-East

RKK

EGI

TRD

North-West

GVL

LAP

GLG

SWA

TLS

PDM

MLG

CRK

SDC

LSB

BRN

WRS

PAR

Central

ZUR

SOF

ATH

ROM

CTN

DJA

MEDA

GOL

ALY

ABS

MAD

LPI

AGA

CNR

South-West

NOU

42

43

Figure 8.2

RIMS	group	distribution

LYR

JME

TRO

KIR

North-East

RKK

EGI

TRD

North-West

GVL

LAP

GLG

SWA

BRN

WRS

PAR

Central

ZUR

TLS

PDM

MLG

SOF

ATH

ROM

CTN

DJA

MEDA

GOL

ALY

ABS

CRK

SDC

LSB

ACR

MAD

LPI

AGA

CNR

South-West

NOU

42

43

APPENDIX E 
Acronyms

The following table provides the definition of the acronyms used in this document.

Acronym

A-GNSS

ANSP 

AOR 

APC 

ARP

ASN 

ASQF

ATC 

C/A

CCF 

CPF 

CRC 

DAB

DFS 

DGAC 

DSNA 

EASA 

EC

ECAC 

EDAS 

EDS 

EGNOS 

EMS

ENAIRE 

ENAV 

ESA 

ESSP 

EU 

Definition

Assisted GNSS

Air Navigation Service Provider 

Atlantic Ocean Region 

Antenna Phase Centre 

Antenna Reference Point

Abstract Syntax Notation 

Application Specific Qualification Facility

Air Traffic Control 

Coarse/Acquisition

Central Control Facility 

Central Processing Facility  

Cyclic Redundancy Check

Digital Audio Broadcast

Deutsche Flugsicherung 

Direction Générale de l´Aviation Civile 

Direction des Services de la Navigation Aérienne 

European Aviation Safety Agency 

European Commission

European Civil Aviation Conference 

EGNOS Data Access Service 

EGNOS Data Server 

European Geostationary Navigation Overlay Service

EGNOS Message Server

Aeropuertos Españoles y Navegación Aérea 

Ente Nazionale Di Assistenza Al Volo 

European Space Agency 

European Satellite Services Provider 

European Union 

44

45

Acronym

EWAN 

FAQ 

FTP 

Definition

EGNOS Wide Area Network 

Frequently Asked Questions 

File Transfer Protocol 

GAGAN 

GPS Aided GEO Augmented Navigation 

GEO 

GIVE 

GNSS 

GPS 

GSA 

HTTP 

ICAO 

ICD 

IONEX

IOR 

IP 

ISO 

ITU 

LBS 

LPV 

MCC 

MSAS 

MTSAT

NATS 

NLES 

NTP

NOF 

NTRIP 

OS 

Geostationary Satellite 

Grid Ionospheric Vertical Error 

Global Navigation Satellite System 

Global Positioning System 

European GNSS Agency 

HyperText Transfer Protocol 

International Civil Aviation Organization 

Interface Control Document 

IONosphere map Exchange format

Indian Ocean Region 

Internet Protocol 

International Organization for Standardization 

International Telecommunications Union 

Location Based Services 

Localizer Performance with Vertical guidance 

Mission Control Centre 

MTSAT Satellite-based Augmentation System 

Multi-Function Transport Satellite

National Air Traffic Services 

Navigation Land Earth Station 

Network Time Protocol

Navigation Overlay Frame 

Networked Transport of RTCM via Internet Protocol 

Open Service 

44

45

EGNOS DATA ACCESS SERVICE (EDAS) SERVICE DEFINITION DOCUMENTA P P E N D I X   E   -   A C R O N Y M S

  Acronym

Definition

PA 

PACF 

PRN 

PTP 

QA 

RD 

R&D

RDS 

RIMS 

RINEX 

RTCM 

RTK 

SARPs 

SBAS 

SDCM 

SDD 

SES 

SIS 

SP 

SPS 

SW 

TEC

TCP 

TTA 

UDRE 

US 

UTC 

WAAS 

Product Assurance 

Performance and Check-out Facility 

Pseudo-Random Number 

Point-To-Point 

Quality Assurance 

Reference Document 

Research & Development

Radio Data System 

Range and Integrity Monitoring Station 

Receiver Independent Exchange Format 

Real Time Correction Message 

Real Time Kinematic 

Standards and Recommended Practices 

Satellite-Based Augmentation System 

System of Differential Correction and Monitoring 

Service Definition Document 

Single European Sky 

Signal-In-Space 

Service Provider 

Standard Positioning Service 

Software 

Total Electron Content

Transport Control Protocol 

Time-To-Alert 

User Differential Range Error 

United States 

Coordinated Universal Time 

Wide Area Augmentation System 

46

More information on the European Union is available on the Internet (http://europa.eu).
Luxembourg: Publications Office of the European Union, 2015

ISBN: 978-92-9206-023-7
doi: 10.2878/655999

© European GNSS Agency, 2015
This information can be republished without charge provided the European GNSS Agency (GSA) is acknowledged.
If you do republish, we would be grateful if you link back to the GSA website (www.gsa.europa.eu).

Document subject to terms of use and disclaimers p. 6 – 8
EGNOS Data Access Service (EDAS) SDD, Issue 2.1

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