The EPN Central Bureau monitors regularly the content and latency of the RTCM 3 real-time data streams provided by the EPN station through the three regional EPN broadcasters.

Results

The individual station web pages (e.g. Data Provided section in BRUX00BEL) shows the results of the monitoring for a specific EPN station. A summary can be found below:

The EPN CB ftp site also contains a directory ftp://www.epncb.eu/pub/station/real-time/ with the results of the monitoring for each broadcaster. Background information is provided below and in the README file available from the ftp.

More details

Verification of Message Types (files: monitor_BBB.str)

The RTCM 3 message types included in the stream are identified as well as their sampling rate. For ephemeris messages, the sampling rates are not computed. For the sake of completeness, these message types are compared to the message types indicated in the sourcetable of each broadcaster.

Verification of Satellite Constellations (files: monitor_BBB.const)

The RTCM 3 message types

  • RTCM 3.0/1: 1004 (GPS) and 1012 (GLONASS)
  • RTCM 3.2/3: 1071-1077 (GPS), 1081-1087 (GLONASS), 1091-1097 (Galileo), 1100-1107 (SBAS), 1111-1117 (QZSS), and 1121-1127 (BeiDou)

are used to identify for which satellite constellations observations are included in each real-time stream. In addition, if applicable, the MSM version is identified. A comparison with the constellations indicated in the source table and the site log is also provided.

Verification of Antenna/Radome Type and Serial Number (files: monitor_BBB.ant)

The RTCM 3 message types

  • 1007: Antenna and radome type
  • 1008: Antenna and radome type, and antenna serial number
  • 1033: Receiver and radome type, and antenna serial number

are used to verify the agreement of the antenna/radome information contained in each real-time stream with the site log.

Verification of Receiver Type, Firmware and Serial Number (files: monitor_BBB.rec)

The RTCM 3 message type

  • 1033: Receiver type, firmware, and serial number

is used to verify the agreement of the receiver information contained in each real-time stream with the site log.

Verification of Station Coordinates and Antenna Height (files: monitor_BBB.coord)

The RTCM 3 message types

  • 1005: (X,Y,Z) coordinates of the Antenna Reference Point (ARP)
  • 1006: (X,Y,Z) coordinates of the Antenna Reference Point (ARP) and height of the ARP above the marker (MRK->ARP)

are used to verify the agreement of the coordinates included in each real-time stream with respect to the best ETRS89 coordinates EUREF has for this station. These coordinates are available from RTCM.CRD (coordinates of the station marker) or RTCM-ARP.CRD (coordinates of the ARP). The height of the Antenna Phase Center above the Antenna Reference Point is extracted from https://files.igscb.org/pub/station/general/igs14.atx, containing the antenna calibrations

Computation of the Stream Latency (files: monitor_BBB.latency)

The stream latency is computed as the average of the differences between the reception time of an observable on the EPN CB server (converted to GPS time) and the GPS time of the observation. Although the measured latency depends partly on local network traffic, it provides a reliable idea of significant delays.