[Difx-users] Question - correlate near field sources ie Spacecraft

Thu Feb 27 18:58:02 EST 2020

Hi Stuart,

I think if the vex file is wrong (it says Mark5B for a couple of stations
when they were actually VDIF) you might need to actually update the vex
file.  Can you do that, or is that a bit beyond your vex hacking skills?

Cheers,
Adam

On Fri, 28 Feb 2020 at 10:26, Stuart Weston via Difx-users <
difx-users at listmgr.nrao.edu> wrote:

> >> Which in v2d would translate to "format=VDIFL/8016/2"
>
>
>
> So the vex file has MARK5B, but two stations recorded VDIF. Drudg knowing
> the station setup has put the appropriate commands in the prc file to
> record VDIF.
>
>
>
> Anyway I ran through the setup and tried to run it and “errmon” tells me
> for these files:
>
>
>
> This does not look like a valid Mark5B data.
>
>
>
> Fair enough, I see its trying to use “format=Mark8-128-2-2” and it should
> be “format=VDIF_8000-128-2-2” (if I use m5spec on the vdif files).
>
>
>
> So I try the above line in the v2d files "format=VDIFL/8016/2" for the
> appropriate stations, and now when I run vex2difx I get :
>
>
>
> Error: cannot change format to VDIF from any other non-VDIF format
> (antenna WA) with the .v2d file.  You need to change the .vex file.
>
>
>
> Hummm, a bit of a catch 22 here ?
>
>
>
> Stuart Weston
>
>
>
> Mobile: 021 713062
>
> Skype: stuart.d.weston
> Email:  stuart.weston at aut.ac.nz
>
> http://www.atnf.csiro.au/people/Stuart.Weston/index.html
>
> Software Engineer
> Institute for Radio Astronomy & Space Research (IRASR)
> School of Engineering, Computer and Mathematical Sciences
> Faculty of Design and Creative Technologies
> Auckland University of Technology, New Zealand.
>
> http://www.irasr.aut.ac.nz/
>
>
>
> *From:* Jan Wagner <jwagner105 at googlemail.com>
> *Sent:* Thursday, 27 February 2020 11:58 PM
> *To:* Stuart Weston <stuart.weston at aut.ac.nz>
> *Subject:* Re: [Difx-users] Question - correlate near field sources ie
> Spacecraft
>
>
>
> Hi Stuart,
>
>
>
> due to the strange VDIF format error you could use DiFX utility
> "printVDIFheader" to verify what the headers of vygr2_wa_no0108 actually
> say.
>
>
>
> Maybe the "legacy" flag is set ('L' column in printVDIFheader output would
> be all '1').
>
>
>
> In that case the frame header size would then be 16 instead of 32 bytes,
> and format VDIFL instead of VDIF, with a format string *possibly* of
> "VDIFL_8000-128-2-2". Which in v2d would translate to "format=VDIFL/8016/2".
>
>
>
> And as Simone already pointed out, "vsum -s <vdif files>" could be a more
> convenient way of generating a file list for a set of VDIF files. Vsum
> autodetects the nasty details of the VDIF format.
>
>
>
> Good luck!
>
>
>
> Jan
>
>
>
> Am 27.02.2020 um 04:05 schrieb Stuart Weston via Difx-users:
>
> Well two of you asked for updates �� Progress so far …
>
>
>
> *directory2filelist:*
>
>
>
> First issue, directory2filelist doesn’t like VDIF files (Which I have for
> Wa and Ti) :
>
>
>
> oper at ww-flexbuf-01 DiFX-2.5.2 vygr2> directory2filelist
> /raid0/etransfer/wa/vygr2_wa_no0108 VDIF_8000-128-2-2
>
> VDIF Warning: Changing frameheadersize from 32 to 16
>
> VDIF Warning: Changing databytesperpacket from 8000 to 124473216
>
> Segmentation fault
>
>
>
> It is even more unhappy with “vbs_fs” for merging jive5ab vdif chunks into
> one logical file at the fuse mount point (PS: I now use “vbs_fs” for DSPSR
> with Williem for VDIF Single Dish pulsar data).
>
>
>
> *v2d :*
>
>
>
> Also for v2d ephemFile has to be either tle (Two-Line elements) or bsp
> (which I assume means BaryCenter on 399 Earth, our observing platform). Now
> NASA HORIZONS doesn’t seem to produce a valid file acceptable to SPICE. So
> goto NASA NAIF which has some “old” archived bsp files but nothing current.
>
>
>
> I was trying to use the HORIZONS ID “Voyager_2” , that didn’t work :
>
>
>
>
> ================================================================================
>
>
>
> Toolkit version: N0066
>
>
>
> SPICE(IDCODENOTFOUND) --
>
>
>
> The target, 'Voyager_2', is not a recognized name for an ephemeris object.
> The
>
> cause of this problem may be that you need an updated version of the SPICE
>
> Toolkit. Alternatively you may call SPKEZ directly if you know the SPICE ID
>
> codes for both 'Voyager_2' and '399'
>
>
>
> A traceback follows.  The name of the highest level module is first.
>
> spkezr_c --> SPKEZR
>
>
>
> Oh, by the way:  The SPICELIB error handling actions are USER-TAILORABLE.
> You
>
> can choose whether the Toolkit aborts or continues when errors occur, which
>
> error messages to output, and where to send the output.  Please read the
> ERROR
>
> "Required Reading" file, or see the routines ERRACT, ERRDEV, and ERRPRT.
>
>
>
>
>
>
>
> Anyway under the NAIF archive there is a
> “voyager_2.ST+1992_m05208u.merged.bsp” which goes to “2021 JAN05”. Now you
> need NAIF ID 3 for the Earth Barycenter (our observation platform) and NAIF
> ID -32 for Voyager 2
>
>
>
> SOURCE VGR2 {
>
> ephemObject = -32
>
> ephemFile   = voyager_2.ST+1992_m05208u.merged.bsp
>
> }
>
>
>
> Now v2d works, there are some warnings about stop/start times for the vdif
> files.
>
>
>
> oper at ww-flexbuf-01 DiFX-2.5.2 vygr2> vex2difx --force vygr2.v2d
>
> Warning: Filelist file vygr_atca.filelist was a listing with no start/stop
> times.
>
> Note: Future versions of vex2difx may stop allowing file lists without
> start/stop times.  Filelists for VDIF and Mark5B files with start/stop
> times can be generated with "vsum -s" and "m5bsum -s" respectively.  These
> times allow vex2difx to properly assign data to jobs and is especially
> important in cases where multiple jobs are generated per project.
>
> Warning: Filelist file vygr_dss.filelist was a listing with no start/stop
> times.
>
> Warning: Filelist file vygr_wa.filelist was a listing with no start/stop
> times.
>
> start date: 2020y015d08h00m00s
>
> stop date: 2020y015d12h00m00s
>
> Warning: no clock values for antenna AT .
>
> Warning: no clock values for antenna WA .
>
> Warning: no clock values for antenna TI .
>
> Note: Proceeding even though there were 3 warnings.
>
> Warning: Job vygr2 1: no clock offsets being applied to antenna AT
>
>           Unless this is intentional, your results will suffer!
>
> Warning: Job vygr2 1: no clock offsets being applied to antenna TI
>
>           Unless this is intentional, your results will suffer!
>
> Warning: Job vygr2 1: no clock offsets being applied to antenna WA
>
>           Unless this is intentional, your results will suffer!
>
> Warning: Job vygr2 2: no clock offsets being applied to antenna AT
>
>           Unless this is intentional, your results will suffer!
>
> Warning: Job vygr2 2: no clock offsets being applied to antenna TI
>
>           Unless this is intentional, your results will suffer!
>
> Warning: Job vygr2 2: no clock offsets being applied to antenna WA
>
>           Unless this is intentional, your results will suffer!
>
>
>
> 2 job(s) created.
>
>
>
> I’ll come back to the *clock offsets* next as I do have those to add,
> I’ll append a $CLOCK section shortly.
>
>
>
> I am just working my way through step by step, where each step will have
> several iterations to sort things out.
>
>
>
> Stuart Weston
>
>
>
> Mobile: 021 713062
>
> Skype: stuart.d.weston
> Email:  stuart.weston at aut.ac.nz
>
> http://www.atnf.csiro.au/people/Stuart.Weston/index.html
>
> Software Engineer
> Institute for Radio Astronomy & Space Research (IRASR)
> School of Engineering, Computer and Mathematical Sciences
> Faculty of Design and Creative Technologies
> Auckland University of Technology, New Zealand.
>
> http://www.irasr.aut.ac.nz/
>
>
>
> *From:* Stuart Weston
> *Sent:* Thursday, 27 February 2020 1:51 PM
> *To:* difx-users at listmgr.nrao.edu
> *Cc:* Oleg Titov <Oleg.Titov at ga.gov.au> <Oleg.Titov at ga.gov.au>
> *Subject:* Question - correlate near field sources ie Spacecraft
>
>
>
> I have some VLBI on Voyager to correlate.
>
>
>
> So had a read of :
>
>
>
> https://www.atnf.csiro.au/vlbi/dokuwiki/doku.php/difx/spacecraft
>
>
>
> I have setup SPICE
>
>
>
> Anyone done this before and any tip’s, help or suggestions ?
>
>
>
> The ephemFile as that as obtained say from
> https://ssd.jpl.nasa.gov/horizons.cgi ?
>
>
>
> Stuart Weston
>
>
>
> Mobile: 021 713062
>
> Skype: stuart.d.weston
> Email:  stuart.weston at aut.ac.nz
>
> http://www.atnf.csiro.au/people/Stuart.Weston/index.html
>
> Software Engineer
> Institute for Radio Astronomy & Space Research (IRASR)
> School of Engineering, Computer and Mathematical Sciences
> Faculty of Design and Creative Technologies
> Auckland University of Technology, New Zealand.
>
> http://www.irasr.aut.ac.nz/
>
>
>
>
>
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>
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>
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>
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-- 
!=============================================================!
A/Prof. Adam Deller
ARC Future Fellow
Centre for Astrophysics & Supercomputing
Swinburne University of Technology
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phone: +61 3 9214 5307
fax: +61 3 9214 8797

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