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 (currently 34) distributed over Europe and North Africa. The three 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
In addition, EDAS provides the
Antenna Phase Centre Coordinates , which is a list of the geographical coordinates of all RIMS stations.
Raw observations from RIMS network
The data collected by the RIMS network includes dual-frequency GPS data, GLONASS L1, and EGNOS Geostationary Signal in Space (SIS). For each RIMS, and each satellite tracked a set of observables is provided. Therefore at any one time information from each RIMS will be provided with a set of observables from visible satellites. The raw data can be provided in both ASN.1 and RTCM format. This data is provided by EDAS in real-time with an update rate of one second. Each message contains a variable number of sections (depending on the number of tracked satellites). The summary table below lists all the raw observables provided from the RIMS network, described in the map below:
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 defined precisely 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 formed of a number of distinct message types containing various aspects of the overall augmentation message. The message types provided are summarised in the table below. The EGNOS augmentation message is transmitted per second and each message is 250 bits long. In an EDAS message, the previous four augmentation messages transmitted are also provided.
| 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 |
RIMS Antenna Phase Centre Coordinates
The Antenna Phase Centre Coordinates of all RIMS stations are provided in a dedicated message. The coordinates are expressed as Earth-Centered, Earth-Fixed (ECEF) Cartesian coordinates in the World Geodetic System 1984 (WGS84) reference system. This data therefore consists of a set of WGS84 coordinates for 34 RIMS stations.
