We distill the GPS broadcast ephemerides and almanacs from the
navigation message received by our vast ground network, weeding out
bit errors and data errors with strong majority voting schemes.
Both the broadcast ephemerides and the broadcast almanacs for each
GPS satellite are available in a RINEX-like file format. We include
the "Klobuchar" ionosphere correction parameters in the broadcast
ephemeris files. The full resolution broadcast ephemerides are also
available in a streaming socket format.
The almanac is also available in Yuma file format.
Additional broadcast parameters needed for some A-GPS protocols, but
that are not part of the RINEX standard, are provided in a separate
'delta' file. We also embed in these 'delta' files real-time URE
performance metrics from the GDGPS orbit determination process, for
actual, up to the minute satellite performance status.
The RINEX broadcast ephemeris files are updated every 5 minutes. The
ephemeris 'delta' files are updated every minute. The almanac files,
in both the RINEX-like format and Yuma format are updated every 12.5
minutes. The broadcast ephemeris (with the parameters of the RINEX
file) is also available as a continuous UDP data stream.
Access to all these products is available concurrently from multiple
redundant data centers for optimal reliability.