The EPN Central Bureau permanently monitors the three regional EPN broadcasters by checking stream latency and comparing the stream meta-data with the station meta-data provided in the station log files. The verification is done each 6 hours and all results are available from : ftp://epncb.oma.be/epncb/station/real_time .
The EPN Central Bureau checks the latency of the GNSS observables in the data streams as they are received at the EPN CB, located at Brussels, Belgium. This latency is the 20-sec average obtained by comparing the GPS time of the received observation with the UTC time of the EPN CB server (corrected for leap seconds). The measured latency depends partly on local network traffic. The latency checks are performed with an interval of about 6 hours and are available for the ASI, BKG, and ROB broadcasters.
Summary Files by Stream
The stream-specific summary files give an overview of the meta-data and constellations tracked in each stream as well as the detected meta-data inconsistencies:
Summary of the Stream Meta-data Inconsistencies by Broadcaster
Antenna Type and Serial Number
The agreement of the antenna/radome information contained in the streams with the site log information for the ASI, BKG, and ROB broadcasters (streams with errors are indicated by "*"). The following Message Types are checked:
- RTCM 2.X: Message Type 23: Antenna and radome type
- RTCM 3.X: Message Type 1007/1008/1033: Antenna and radome type + (optional) antenna serial number
Receiver Type, Firmware and Serial Number
The agreement of the receiver information contained in the streams with the site log information for the ASI, BKG, and ROB broadcasters (streams with errors are indicated by "*"). The following Message Types are checked:
- For RTCM 3.X: Message Type 1033: Receiver type + receiver serial number + firmware version
Station Coordinates and Antenna Height
The comparison of the coordinate and antenna height information contained in the stream (STR) with the official EPN coordinates (REF) for the
and ROB broadcasters (streams with errors are indicated by "*" and all values are given in meters).
APC: Coordinates refer to Antenna Phase Centre
ARP: Coordinates refer to Antenna Reference Point
The following Message Types are checked:
For RTCM 2.X:
- Message Type 3: (X,Y,Z) coordinates of the Antenna Phase Center (APC), with cm-precision
- Message Type 22: (dX,dY,dZ) corrections to message 3 to achieve mm-precision for L1 and L2 APC + Heigth of the APC above the Marker: MRK->APC (optional)
- Message Type 24: (X,Y,Z) coordinates of the Antenna Reference Point (ARP)
For RTCM 3.X:
- Message Type 1005: (X,Y,Z) coordinates of the Antenna Reference Point (ARP)
- Message Type 1006: (X,Y,Z) coordinates of the Antenna Reference Point (ARP) + (optional) Height of the ARP above the Marker (MRK->ARP)
The checks read the following RTCM Message Types:
- RTCM 3.0/1: Message Types 1004/1012
- RTCM 3.2: Message Types 1071-1077/1081-1087/1091-1097/1111-1117/1121-1127, only MSM7 observables are considered as usefull
- Antenna and radome type (including serial numbers and antenna height) and receiver type (including firmware and serial number) are extracted from the station log files available from ftp://epncb.oma.be/epncb/station/log.
- Station coordinates are extracted form ftp://epncb.oma.be/epncb/station/coord/EPN/RTCM.CRD
- Antenna phase center height above antenna reference point from ftp://igscb.jpl.nasa.gov/pub/station/general/igs08.atx, containing the antenna calibrations
More details on the verifications that are performed are given in the following README.TXT file.