RV133 (Astrometric/Geodetic VLBA-133)
2019 JAN 07 17:00 DOY 007
Notes prepared by
David Gordon, Ed Himwich and John Gipson
NVI/GSFC
Special notes for this experiment
=================================
This session will use the RDBE/DDC/Mark5C system at the VLBA sites, as
in previous RV sessions. The X-band frequencies are: 8365.75, 8445.75,
8805.75, and 8925.75 MHz, and now span 560 MHz. The S-band frequencies
are being shifted up by 8 MHz from the last few RV's to try to avoid
RFI in the third S-band channel (2352.75-2360.75 MHZ) at five VLBA stations.
The S-band frquencies for this session will be: 2240.75, 2270.75, 2360.75
and 2380.75 MHz. The ending in .75 MHz is necessary at the VLBA stations.
Therefore it will not be possible to monitor phase cals using the 10
kHz filters.
This session will record 8 8-MHz bandwidth channels using 2-bit sampling,
as in previous RDV's. The bit rate will be 256 Mbits/sec. The data will be
correlated at the VLBA using the VLBA DiFX software correlator.
There are 4 non-VLBA stations scheduled - HARTRAO, NYALES20, ONSALA60 and
WETTZELL. These stations should see the "Special operations notes for
non-VLBA stations" section below for special instructions.
To facilitate fringe-finding, there are some long scans on fairly strong
sources with most antennas at the beginning and near the end of the schedule.
All stations please try to be onsource and recording data for these scans.
These scans are:
Source Start DURATIONS
name yyddd-hhmmss Br Fd Hh Hn Kp La Mk Nl Ny On Ov Pt Sc Wz
1726+455 19007-170000| 300 310 309 314 300 330 309 367 367 322 302 338 353|
3C446 19007-170744| 365 300 364 365 364 365 359 357|
2000+472 19008-163555| 300 480 300 310 480 311 300 305 300 337 375|
0017+200 19008-164306| 300 300 300 369 353 320 369|
We are again using the new 'Fill' scheduling option. 'Fill' is run after a
schedule is finished in the normal manner. It increases the scan times at
stations, when possible, based on how much idle time each station has before
its next scan. We used a 'FILL_OFF' margin of 5 seconds. Using 'Fill' on the
original schedule the average observing time increased from 54% to 65%, and
the average idle time decreased from 21% to 10%. The observing time increases
most at the faster antennas and least at the slower antennas.
Purpose
=======
This is the first of six coordinated astrometric/geodetic sessions in 2019
that use the full 10-station VLBA plus several geodetic stations capable of
recording VLBA modes. This year's series is a continuation of the highly
successful RDV series begun in 1997. These are now being run under the USNO's
VLBA time allocation.
These experiments are being coordinated by the geodetic/astrometric VLBI
programs of USNO, NASA, and NRAO. The experiments have been designed so that
the same data set may be used by each agency for its particular goals.
USNO and Bordeaux Observatory will perform imaging and correction for source
structure. These sources will establish a set of core reference sources with
known structure and precisely known positions. These data will provide the
basis for evaluating the long term stability of the radio reference frame and
the ultimate accuracy of wide angle astrometric measurements of extragalactic
radio sources using VLBI.
NASA and USNO will analyze this data to determine and maintain high accuracy
terrestrial reference and celestial reference frames. The data will
incorporate the VLBA stations into the VLBI reference frame through the
inclusion of other geodetic stations for which we have long histories. This
data will also produce highly accurate Earth orientation results and
possibly the best nutation results ever produced.
NASA and NRAO will use these sessions to provide a service to users who
require high quality positions for a small number of sources. While the
quality of these results will be high, the observing and data reduction
overhead required will be minimal because a small number of such sources can
be incorporated into a session of the regular geodetic observations, instead
of requiring special observations.
Sources for this series of experiments will be selected using the proposed
approach. For each experiment we will select a set of ~60 sources from the
pool of geodetic, astrometric, and monitoring sources. About 20-30 of these
will remain the same from experiment to experiment and will be chosen to
optimize the goals of the three groups. A number of poorly observed and/or
new requested sources will also be included to obtain or improve their
positions.
Schedule information
====================
This is a new schedule generated by David Gordon at GSFC using sked.
Schedule file name: rv133.skd
At the IVS Data Center (ftp://cddisa.gsfc.nasa.gov/vlbi/ivsdata/aux/2019/rv133):
Sked file: rv133.skd
Text file: rv133.txt
At the NRAO/VLBA:
VLBA Pointing files:
rv133crd.br rv133crd.fd rv133crd.hn rv133crd.kp rv133crd.la
rv133crd.mk rv133crd.nl rv133crd.ov rv133crd.pt rv133crd.sc
Summary file: rv133.sksum
Sked file: rv133.skd
Text file: rv133.txt
Vex file: rv133.vex
This experiment uses the 10 VLBA stations and 4 IVS stations. The IVS stations
are: HARTRAO, NYALES20, ONSALA60 and WETTZELL. Below is the sked summary.
Br=BR-VLBA Fd=FD-VLBA Hh=HARTRAO Hn=HN-VLBA Kp=KP-VLBA
La=LA-VLBA Mk=MK-VLBA Nl=NL-VLBA Ny=NYALES20 On=ONSALA60
Ov=OV-VLBA Pt=PIETOWN Sc=SC-VLBA Wz=WETTZELL
Br Fd Hh Hn Kp La Mk Nl Ny On Ov Pt Sc Wz Avg
% obs. time: 63 66 60 67 65 65 52 66 66 68 63 65 65 72 65
% cal. time: 5 5 2 4 5 5 4 5 3 3 5 5 4 3 4
% slew time: 24 23 30 22 23 23 20 22 14 13 24 24 21 9 21
% idle time: 7 5 7 6 6 6 22 6 16 14 7 5 9 15 10
total # scans: 431 431 205 371 442 436 356 411 290 253 439 442 358 288 368
# scans/hour : 18 18 9 15 18 18 15 17 12 11 18 18 15 12 15
Avg scan (sec): 127 132 251 156 127 129 127 139 196 233 125 127 157 215 159
# data tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16
# Mk5 tracks: 16 16 16 16 16 16 16 16 16 16 16 16 16 16
Total TB(M5): 1.75 1.82 1.65 1.85 1.79 1.80 1.45 1.83 1.81 1.89 1.75 1.80 1.80 1.98 1.78
# OF OBSERVATIONS BY BASELINE
| Br Fd Hh Hn Kp La Mk Nl Ny On Ov Pt Sc Wz Total
--------------------------------------------------------------------------------
Br| 306 12 229 342 321 306 288 112 37 381 334 202 41 2911
Fd| 33 275 384 408 246 349 75 34 322 406 271 43 3152
Hh| 62 20 27 0 39 107 175 8 23 69 183 758
Hn| 243 267 150 310 123 70 212 260 310 98 2609
Kp| 395 291 327 75 29 374 418 238 32 3168
La| 258 357 79 34 339 419 264 42 3210
Mk| 214 63 18 332 270 144 15 2307
Nl| 103 45 286 344 297 63 3022
Ny| 153 92 80 90 173 1325
On| 27 32 63 212 929
Ov| 355 199 29 2956
Pt| 253 37 3231
Sc| 91 2491
Wz| 1059
Number of 3-station scans: 243
Number of 4-station scans: 122
Number of 5-station scans: 52
Number of 6-station scans: 52
Number of 7-station scans: 71
Number of 8-station scans: 74
Number of 9-station scans: 66
Number of 10-station scans: 128
Number of 11-station scans: 22
Number of 12-station scans: 10
Number of 13-station scans: 3
Total number of scans: 843
Total number of obs: 16564
INTENSIVE BREAKS
================
There is an IVS INT01 Intensive session scheduled during RV133. Wettzell
will drop out from ~18:15 - 19:45 on DOY 007 for this Intensive. There
will also be a USNO/NRAO UT1 Intensive session, scheduled to start at
~06:30 UTC (+/- 4 hrs) on DOY 008, using Pietown and MK-VLBA, so these
stations will drop out for about 100 minutes. The exact time is not fixed,
so it is not scheduled in, but the loss of these two antennas for a short
period should have only a minimal effect.
SOURCE SELECTION
================
There are a total of 79 sources scheduled in this session. Among them, 60
are from the geodetic source list, and 19 are sources with few or no previous
observions in IVS sessions.
SCHEDULING ALGORITHMS
=====================
This schedule uses the "SRCEVN SQRT" mode of Sked. In the absence of any
constraints, Sked will preferentially observe strong sources that have
high visibility. This mode attempts to smooth out the number of observations
per source.
RECORDING MODE and FREQUENCIES
==============================
The data will be recorded using the following setup:
8 channels
1:2 fan-out
16 MHz sample rate
2-bit sampling
This recording mode is designated 256-8(RDV). There is no correlator
speed-up factor.
The frequency sequence covers 560 MHz at X-band and 140 MHz at S-band
using 4 channels in each band. At the VLBA, the X-band uses two LO's in
order to fit into the VLBA 512 MHz passband. At the Mark4 stations, the
X-band uses both the high and low parts of the geodetic receivers. Because
only 8 channels are available when observing with the VLBA/RDBE/DDC systems,
a wider spanned bandwidth is not advisable.
The following tables list the setup for the VLBA stations and the
geodetic stations with DBBC, Mark IV, Mark 5, and VLBA5 back ends.
VLBA | HARTRAO
Chan Sky Tracks LO IF BBC | LO IF BBC BBC#
1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8080.0 A1 285.75 3
2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 A1 365.75 4
3 X 8805.75 18,20,22,24 9600 D 794.25| 8080.0 B2 725.75 5
4 X 8925.75 26,28,30,32 9600 D 674.25| 8080.0 B2 845.75 6
5 S 2240.75 3, 5, 7, 9 3100 A 859.25| 2020.0 C1 220.75 9
6 S 2270.75 11,13,15,17 3100 A 829.25| 2020.0 C1 250.75 10
7 S 2360.75 19,21,23,25 3100 A 739.25| 2020.0 C1 340.75 13
8 S 2380.75 27,29,31,33 3100 A 719.25| 2020.0 C1 360.75 14
VLBA | NYALES20
Chan Sky Tracks LO IF BBC | LO IF BBC BBC#
1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8080.0 1N 285.75 3
2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 1N 365.75 4
3 X 8805.75 18,20,22,24 9600 D 794.25| 8580.1 3N 225.65 5
4 X 8925.75 26,28,30,32 9600 D 674.25| 8580.1 3N 345.65 6
5 S 2240.75 3, 5, 7, 9 3100 A 859.25| 2020.0 2N 220.75 9
6 S 2270.75 11,13,15,17 3100 A 829.25| 2020.0 2N 250.75 10
7 S 2360.75 19,21,23,25 3100 A 739.25| 2020.0 2N 340.75 13
8 S 2380.75 27,29,31,33 3100 A 719.25| 2020.0 2N 360.75 14
VLBA | ONSALA60, WETTZELL
Chan Sky Tracks LO IF BBC | LO IF BBC BBC#
1 X 8365.75 2, 4, 6, 8 7600 B 765.75| 8080.0 A1 285.75 3
2 X 8445.75 10,12,14,16 7600 B 845.75| 8080.0 A1 365.75 4
3 X 8805.75 18,20,22,24 9600 D 794.25| 8080.0 B1 725.75 5
4 X 8925.75 26,28,30,32 9600 D 674.25| 8080.0 B1 845.75 6
5 S 2240.75 3, 5, 7, 9 3100 A 859.25| 2020.0 C1 220.75 9
6 S 2270.75 11,13,15,17 3100 A 829.25| 2020.0 C1 250.75 10
7 S 2360.75 19,21,23,25 3100 A 739.25| 2020.0 D1 340.75 13
8 S 2380.75 27,29,31,33 3100 A 719.25| 2020.0 D1 360.75 14
Special operations for non-VLBA stations:
=========================================
All non-VLBA stations:
Please note that due to the frequency sequence, phase-cal will not
be visible with a 10 kHz viewing filter in the USB channels. If you
have another means to verify phase-cal, please use it. If you have a
Mark IV Decoder, please contact Ed.Himwich@nasa.gov if you would like
advice on how to set it up to check phase-cal for this frequency sequence.
HARTRAO:
This station uses a DBBC rack.
Please use the procedures generated by DRUDG. BBCs 3 & 4 are used at
X-band with IF A, input 1. BBCs 5 & 6 are used at X-band with IF B,
input 2. BBCs 9, 10, 13 & 14 are used for S-band with IF C, input 1.
NYALES20 and WETTZELL:
These stations have Mark IV or Mark 5 racks.
Please use the procedures generated by DRUDG. VCs 3 & 4 are used at
X-band with IF 1. VCs 5 & 6 are used at X-band with IF 3. VCs 9, 10,
13 & 14 are used at S-band with IF 2.
ONSALA60:
This station uses a DBBC rack.
Please use the procedures generated by DRUDG. BBCs 3 & 4 are used at
X-band with IF A, input 1. BBCs 5 & 6 are used at X-band with IF B,
input 1. BBCs 9 & 10 are used for S-band with IF C, input 1. BBCs 13
& 14 are used at S-band with IF D, input 1.
The IF3 command in the procedure IFDSX assumes that VC3 and VC10
will be patched to High. Please verify that the switches for your
IF3 module are wired this way, and if they are not please edit the
IF3 command to change the switches. The standard wiring is described
in "help=if3". If you have questions about the wiring, please
contact Brian Corey at Haystack.
If you wish to record back-up channels, please add appropriate
valo=..., va=... vblo=... and vb=... commands in the VCSX8
procedure.
CHECKLIST for non-VLBA stations
===============================
Please follow the checklist below to ensure you have done all the
necessary steps for this experiment:
1. Make .prc file with DRUDG and check them out, or use the procedures
from the last RV session. Check out parity check procedures.
2. Make the .snp file with DRUDG.
3. Set up your system to monitor the clocks with the "gps-fmout" or
"fmout-gps" commands. If you have questions about this, please
contact Ed Himwich as soon as possible.
4. Send a "ready" message an hour or so before the experiment to the
ivs-ops mail list. Copy analysts@nrao.edu on your ready message.
5. Send a "start" message soon after you have started recording.
Copy analysts@nrao.edu on the message.
6. At the end of the experiment, send a "finish" message summarizing
how the experiment was conducted. Copy analysts@nrao.edu on
your message.
7. Transfer your log file to your normal IVS data center.
The directories for the IVS servers are listed below:
ftp cddisin.gsfc.nasa.gov/ivsincoming
ftp ivsopar.obspm.fr/ivsincoming
ftp ivs.bkg.bund.de/ivsincoming
Correlation
===========
This experiment will be correlated at the NRAO/VLBA on the VLBA DiFX software
correlator. Most of the Mark4 stations are now E-transfering their data
to Haystack, where it will be copied and shipped to the VLBA in Socorro,
New Mexico. These stations will need to coordinate this with Haystack
Observatory (contact: Jason SooHoo at jsoohoo@haystack.mit.edu). The
VLBA needs to process the session at their correlator as soon as possible
because of limited media. So please try to set up the E-transfer as
soon as possible after the session ends.
If you need to ship the media instead, please ship it to Socorro as soon
after the experiment as is practical. It should be shipped to the following
address:
Socorro address for media shipping:
VLBA Array Operations Center
National Radio Astronomy Observatory
Attn: Juan Cordova
1003 Lopezville Road
Socorro, NM 87801
U.S.A.
Phone: 575-835-7000
Shipping and VLBA contact information is also given at:
https://science.nrao.edu/facilities/vlba/contact/shipping_information.
Please use one of the recommended shipping companies (FedEx, UPS,
DHL, TNT). Please ship your media to the VLBA the same day the session
ends or the next business day (just like the R1/R4 media is shipped).
If you know that there is going to be a problem sending your media to
the VLBA the same day the session ends or the next business day, please
let us (David.Gordon-1@nasa.gov) know as soon as possible so that we,
along with the VLBA, can determine the best course of action. If you
have any questions or comments, please let us know.