Real-time Data Transmission

Observers have the option of requesting that their data be transferred directly to the correlator for near real-time correlation.  This capability must be requested as part of the observing proposal.

The current limitations on this capability are:

  • A maximum per-station data rate of 512 Mbps (maximum total bandwidth of 128 MHz), when using all ten stations.
  • Only a single observing setup can be used within a given scheduling block; i.e., the number of data channels and their bandwidth do not change in a given observing session, but tuning or band changes are supported.
  • Raw data transferred in real-time will not be saved, but it will be recorded to the Mark6 disk packs as normal
  • Spectral resolution for the real-time correlated data is fixed (it cannot be re-correlated to different spectral resolutions until the disk packs arrive)
  • Clock model problems may prevent some antennas from correlating in real-time

 It is possible to get per-station data rates higher than 512 Mbps, but only by excluding some stations from the observation.  The total data rate from all stations cannot exceed 6 Gbps.

Station Data Rate Limitations

Station

Maximum Data Rate

Saint Croix

600 Mbps

Hancock

5 Gbps

North Liberty

1 Gbps

Fort Davis

1 Gbps

Los Alamos

10 Gbps

Pie Town

1 Gbps

Kitt Peak

1 Gbps

Owens Valley

1 Gbps

Brewster

10 Gbps

Mauna Kea

10 Gbps

 

Note: The practical station link capacity due to overhead and other traffic is at most 85% of the reported link speed.

Connect with NRAO

The NSF National Radio Astronomy Observatory and NSF Green Bank Observatory are facilities of the U.S. National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Founded in 1956, the NSF NRAO provides state-of-the-art radio telescope facilities for use by the international scientific community. NSF NRAO telescopes are open to all astronomers regardless of institutional or national affiliation. Observing time on NSF NRAO telescopes is available on a competitive basis to qualified scientists after evaluation of research proposals on the basis of scientific merit, the capability of the instruments to do the work, and the availability of the telescope during the requested time. NSF NRAO also provides both formal and informal programs in education and public outreach for teachers, students, the general public, and the media.

The U.S. National Science Foundation (U.S. NSF) is an independent federal agency created by Congress in 1950 "to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense..."

AUI collaborates with the scientific community and research sponsors to plan, build, and operate cutting-edge facilities. We cultivate excellence, deliver value, enhance education, and engage the public.