Date: April 8, 2021
Time: 11:00 am Mountain, 1:00 pm Eastern


Microsoft Teams: Click here to join the meeting

Dial in backup method: Phone: +1 571-388-3904
Conference ID: 168 008 659#


NRAO: Jim, Walter, Abi, Justin
USNO:Bruce, David, Lucas, Nicole, Christopher, Philip, Megan
  • Welcome NRAO's Abi Smoake who is working with Mark Wainright on the USNO backup correlator software patch support.

  • Daily Observation Report (N-series)
    • No reobservations in March but N21069 had two stations unavailable (SC and MK) so was observed with HN-OV instead.
    • Missing scans - USNO reported problems with scans missing in the Xcube data, which NRAO found did get recorded to the Mark6.
      • Missing scans have happened at all three stations. It is likely that it will also be seen at other stations.
      • They appear to have recently increased in number; four observations were impacted in January, eight in February and March.
      • Are there enough missing scans that NRAO needs to work on addressing the problem?
        • Could be an issue with scans coming in without enough of a gap for the Xcube to be caught up on recording one scan and it misses the next one. USNO could try Increasing gap time between scans as a short-term fix. Replacements for the Xcubes currently on order will hopefully be fast enough to avoid the problem.
    • A five-station intensive plan is being developed that would eventually replace the N, O and F series intensives but not the P-series.
      • There will be a four month test period beginning May 1st to characterize the five-station baselines.
        • The new five station intensive will run every other day. The desired time range is 00h - 08h UT in order that USNO will be able to correlate it first thing in the morning but they will accept it being run outside that window.
        • The five station intensive will not interrupt other observing.
        • Up to three stations can be lost from an observation as long as it is not reduced to just the OV-BR baseline.
        • The N, O and F series observations will end April 30th.
        • A new project code will be needed.
      • During the test period the P-series observation will take the place of the N-series as a daily intensive run concurrent with the IVS intensive.
        • The P-series will remain 1.5 hours in duration.
        • It can interrupt other observing the way the N-series currently can.
        • Due to the longer duration the time window for the observation will increase slightly to 17h15m - 19h45m UT.
  • Other Intensive Observations
    • O-series test on HN-OV baseline
      • Will run simultaneous with the N-series observations but will not interrupt other observing.
      • Will end when the new five station intensive begins, see above.
    • F-series characterization series on six of the VLBA stations every two weeks.
      • Will end when the new five station intensive begins, see above.
    • P-series intensive observations roughly every other day on the HN-MK baseline
      • Beginning May 1st will run daily in place of the old N-series observations, see above.
    • I-series "Holiday" intensive observations at MK
      • MK will substitute for KK on federal holidays.
    • Q-series MK-WZ backup observation series
      • Involves a post-observing procedure for operators to copy the data to correlator in Japan.
      • Was restarted in late June 2020 due to the Ishioka station being unavailable, continuing through 2021 until at least mid-May when Ishioka expects to be back online.
  • Post-Monthly Report Review for March 2021
    • No backlog from February that needed to be caught up in March.
    • 'UD012' requested 16 hours in February, used none.
    • 'US005A' was added late, charged double time even though it was canceled at the last minute.
    • A last minute 'UD013A' was also scheduled, also canceled at the last minute. No time was charged for this one.
    • Sixteen P-series were requested in March, only fifteen ran.
  • Pre-monthly request for May 2021
    • Five station intensive observation replacing the N, O and F series intensives beginning May 1st, see above.
    • New project added, 14 hours at multiple bands with separate files for each band. Requests that all bands observe within a 48 hour window.
      • Not actually a new project, it is following on a project that begins in April.
    • Two additional Q-series runs for May may be added late depending on the timing of Ishioka coming back online.

  • Open issues
    • A minor 'DiFX' release went out in October (2.6.2) and will be installed on the VLBA correlator. USNO is currently using 2.6.1 on their correlator(s), waiting on internal approval to move to the new version.
      • It has been approved, not installed yet.
    • USNO emails to ut1 list are not being forwarded along to other USNO people.
      • Mail is being blocked at the Dept. of Defense level. A possible fix is being tested.
      • Occasional problems with navy.mil addresses no longer working.
    • USNO-NRAO contracts:
      • USNO renewal of MK fiber support contract currently at NAVSUP and being combined with other support contracts.
        • Follow-on contract for six months started December 2020.
        • Might be moved into operational costs/general support.
      • Networking support contract being worked on, might involve changing some dates to spread out USNO contract renewals over different times of the year.
        • Six month extension started December 2020.
      • A follow-on to the correlator support contact is in place for six months, started September 2020.
        • The end of this contract is approaching on March 22. Need to address this soon.
          • Should be something in place before it expires. NRAO response to RfP expected tomorrow.
      • Interest in merging the support contracts into the interagency agreement.
        • ACTION: USNO will bring this to NSF. No update.
    • Data ingest of IVS data to NRAO/Socorro in support of USNO backup correlator operations:
      • We will do a monthly test of the backup correlator by correlating a WZ-KK intensive. Nominally scheduled for the first Wednesday of the month.
        • Results of April 7 test - correlation delayed due to laptop problems but got done today.
      • Data copying will need to be coordinated, probably handled by VLBA operations. Instructions for the operators are pending.
        • Was done for the March 10 test, some hiccups but was ultimately successful.
        • April 7 test - an initial glitch downloading WZ, operator error, otherwise went okay.
      • Test correlator is only correlating on one node instead of four, that needs to be figured out.
        • ACTION: still an issue, NRAO to investigate.
        • Fringer and correlator can't download data directly, has to be run through gygax first.
        • Synching files also has to be side-loaded through gygax which further complicates process.T
        • The ftps download of files through gygax (above two bullet points) stopped working this week.
          • ACTION Something changed on the NRAO side, USNO will contact NRAO helpdesk.
      • A bigger test of a 24-hour R4 observation is desired, NRAO would like a requirement document to figure out what needs to be done.
        • ACTION: USNO to provide the requirements in two groups. One with the disk space details, and a second with station connection details.
          • Not ready yet.
        • ACTION: NRAO acquire additional storage capacity in support of requirement.

  • Long term issues

    • Possible issue raised with accessability of USNO data in the VLBA legacy archive. Any way to put in a request people who do access the data to properly credit USNO and limit access?
      • Probably not much can be done with legacy archive, new archive system will have more potential. Currently new data is going into both, sometime soon it will switch to only going into the new archive.
        • Requirements have been set, still several months at least until we switch to just the new archive.
    • USNO has interest in exploring the recently announced VLBA+Y3 observing mode. What would be needed to move forward on exploring this?
      • This is RSRO so an external proposal will be needed.
      • A number of scheduling and technical issues with the VLBA+Y3 concept are still being sorted out at NRAO.
      • How will this fall under the USNO's 50% VLBA time since this is not fully VLBA? Probably have to go under open skies time instead.
      • A letter to NRAO expressing interest in doing this could get the necessary discussions started.
      • Mark Claussen suggested USNO might start with VLBA+Y1 observing mode since it's an already established mode while the VLBA+Y3 is still in development
      • USNO will move ahead with the VLBA+Y1 suggestion, topic can be taken out of long-term and will be brought back once things start moving forward.
    • There's interest in having VLBA observe along with a VGOS session in "mixed-mode".
      • Heard from IVS OPC in November. First they need to move some correlation off to other correlators and then they can start considering adding more stations like VLBA to the VGOS observations. Possibly start looking into it mid 2021.
    • New IVS session code naming structure
      • There is likely to be a change to format of the IVS "session code", but maybe not until later in 2021 or 2022.
      • New IVS codes will be similar to existing codes but perhaps slightly longer, for example "NYYYYDOYNN". USNO & Goddard had a discussion about it, length will be more than six characters. NRAO has already used some seven character length codes (such as "N20014B") without it causing any problems.
      • Scheduling OMS program was tested, it will support up to at least ten characters for projects.
      • The Mark6 disk pack shipping/tracking program Packtrack has some problems with lengthy project codes but there are workarounds. This would only affect any intensives which get correlated in Socorro, something that will end when the switch to the five-station intensive observation eliminates the intensives that are correlated by NRAO instead of USNO.
      • Walter Brisken suggested running an end to end test to make sure all of the software can handle the longer names.
        • NRAO can probably do an end to end test with one of the intensives correlated by NRAO (the O, P, F-series), it will take more software work on USNO side depending on what IVS comes up with.
      • Will be discussed in the March IVS workshop.
        • There is renewed interest in doing this, possibly some action on it this year.
    • Peculiar delays - VLBA has a delay compared to Kokee that perhaps should be checked out, maybe put some VLBA stations into a KK observation as tagalongs so comparisons can be made. Walter reached out to some people, says it looks like it would be a bigger effort than anticipated and may have to wait until things return to normal after COVID.
    • 'DiFX' Workshops are happening. Walter talked about real-time VLBI Feb 18.
      • Probably will be another one later this year.

  • Fiber Status at each site:
    • 200 Mbps minimum at each site with 190 Mbps the practical limit due to required overhead.
    • 1 Gbps at PT,KP,MK
    • 2.5 Gbps at HN
    • 10 Gbps at LA

Next meeting May 13, 2021

-- JimOgle - 2021-04-05
Topic revision: r4 - 2021-04-08, JimOgle
This site is powered by FoswikiCopyright © by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding NRAO Public Wiki? Send feedback