Introduction to EDAS

EDAS -the EGNOS Data Access Service- allows users to plug into EGNOS ground infrastructure to receive the data collected, generated and delivered by the EGNOS system. EDAS therefore provides the opportunity for service providers to deliver EGNOS data to users who cannot always view the EGNOS satellites (such as in urban canyons) or to support a variety of other value added services, applications and research programs. The details and conditions of EDAS are described at the EDAS Service Definition Document.

In order to get access to EDAS please follow the instructions at the EDAS registration form.

For additional information, please contact egnos-helpdesk@essp-sas.eu or +34 911 236 555.

Data available from EDAS

EDAS is the single point of access for the data collected and generated by the EGNOS infrastructure composed of ground stations distributed over Europe and North Africa. The main types of data provided by EDAS are:

  • Raw GPS, GLONASS and EGNOS GEO observations and navigation data collected by the entire network of Ranging and Integrity Monitoring Stations (RIMS) and Navigation Land Earth Stations (NLES)

  • EGNOS augmentation messages, as normally received by users via the EGNOS Geostationary satellites

EDAS Services 

 The data collected by the EGNOS network includes dual-frequency GPS data, GLONASS L1, and EGNOS Geostationary Signal in Space (SIS) received by the RIMS sites and the NLES stations. For each ground station a set of observables is provided, including navigation data and pseudo-range measurements of the visible satellites, along with the SBAS augmentation messages of EGNOS Geostationary satellites. These data are provided through different Services in different formats in order to meet different set of applications and needs.

The Services provided by EDAS are the following:

  • Main Data Streams: EGNOS data is provided through Internet on real-time in ASN.1 format (Service Level 0), RTCM 3.0 format (SL1) and RTCM 3.1 format (SL2), covering:

    • Raw GPS, GLONASS and EGNOS GEO observations and navigation data received at the RIMS sites

    • EGNOS augmentation messages.

  • Data Filtering: Filtering capabilities to allow receiving EGNOS data from only certain subsets of RIMS stations when connecting to EDAS Service Level 0 and 2 and/or at a reduced data rate.

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

  • FTP Service: Historical EGNOS data available through an FTP site, including:

    • GPS and GLONASS mixed observation data in RINEX 2.11 format

    • GPS and GLONASS navigation data in RINEX 2.11 format

    • EGNOS messages in EMS format and RINEX B 2.10 format

    • EDAS Service Level 0 and Service Level 2 raw data

    • Ionosphere maps providing TEC information of the area monitored by EGNOS in IONEX 1.0 format

  • NTRIP Service: provides GNSS data (RTCM format) coming from the EGNOS network through the Ntrip protocol in real-time.

Further information about the aforementioned services is provided in EDAS Services section.

 

Raw observations from EGNOS network

The raw observation data gathered by EGNOS stations, including RIMS sites and NLES stations, is provided by EDAS in real-time with an update rate of one second.

The summary table below lists all the raw observables provided from the EGNOS network. For details on the format and specific EDAS service in which the information summarized in this table is made available to EDAS users, please refer to EDAS Services

 

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

GLONASS L1 phase measurements (accumulated Doppler)

GEO receiver channel status

GEO L1 phase measurements (accumulated Doppler)

 

GPS L1 signal C/N0 ratio

GPS L2 signal C/N0 ratio

 

GLONASS L1 signal C/N0 ratio

 

GEO L1 signal C/N0 ratio

 

GPS L1 code carrier phase coherency indicator

GPS L2 code carrier phase coherency indicator

 

GLONASS L1 code carrier phase coherency indicator

 

GEO L1 code carrier phase coherency indicator

 

GPS L1 signal status

GPS L2 signal status

 

GLONASS L1 signal status

 

GEO L1 signal status

 

GPS L1 signal quality

GPS L2 signal quality

 

GLONASS L1 signal quality

 

GEO L1 signal quality

EGNOS augmentation message

This is the EGNOS augmentation message as uplinked and broadcast from the EGNOS geostationary satellites. The augmentation message from EGNOS has been internationally standardized along with any other Space-Based Augmentation System (SBAS). Therefore, its content and format is precisely defined in the following public document: Minimum Operational Performance Standards for Global Positioning System/Wide Area Augmentation System Airborne Equipment, Ref. RTCA DO-229, Revision D, Issued 13 December 2006.

The EGNOS augmentation message is transmitted per second and each message is 250 bits long. The EGNOS augmentation message is formed by a number of different message types, which are summarized in the table below. 

Type

Contents

 

0

Don't use for safety applications (for SBAS testing)

1

PRN Mask assignments, set up to 51 of 210 bits

2 to 5

Fast corrections

6

Integrity information

7

Fast correction degradation factor

9

GEO navigation message (X, Y, Z, time, etc.)

10

Degradation Parameters

12

SBAS Network Time/UTC offset parameters

17

GEO satellite almanacs

18

Ionospheric grid point masks

24

Mixed fast corrections/long term satellite error corrections

25

Long term satellite error corrections

26

Ionospheric delay corrections

27

SBAS Service Message

28

Clock-Ephemeris Covariance Matrix Message

63

Null Message