[Difx-users] DiFX Software for Satellite Data Processing {External} {External}

[Leonid Petrov]

Nihao, De Wu,

   We work on support of satellites as targets in difxvtd, but similar
to difxcalc, it is still in the experimental phase and substantial 
efforts
for its testing are needed before we could consider it operational.
The principal difficulty is not in computation of path delay itself, but
in development of visibility analysis of VLBI observations of satellites 
that
is substantially different than visibility analysis of continuum 
targets.

Leonid


> On 2023-08-27 19:50, Adam Deller via Difx-users wrote:
> Hi De Wu,
> 
> The correlation code itself doesn't know or care about the nature of
> the source; it just applies delays based on the sampled polynomials it
> is given.  difxcalc is capable of generating delay models for
> near-field objects using NASA's SPICE code, however I would caution
> that this is a rarely used and hence rarely tested mode.  Some
> (minimal) documentation is given on
> https://www.atnf.csiro.au/vlbi/dokuwiki/doku.php/difx/spacecraft and
> the vex2difx page it links to, under the SOURCE block.
> 
> Cheers,
> Adam
> 
> On Fri, 25 Aug 2023 at 18:52, 深空探测 <wude7826580 at gmail.com>
> wrote:
> 
>> Dear all,
>> 
>> I am currently using DiFX-2.6.2 software for my data processing
>> needs. After employing the 'startdifx' command to generate the .im
>> files, I have noticed that the generated .im files contain delay
>> data for radio sources. However, my intention is to process data
>> from artificial satellites. Given that the positions of artificial
>> satellites change rapidly, the delay data in the .im files
>> calculated based on the radio source model might not be suitable.
>> 
>> In light of this, I am reaching out to inquire whether the DiFX
>> software includes dedicated modules for handling artificial
>> satellite data. Specifically, I am curious to know if there is a
>> provision within the software to calculate delay data in accordance
>> with the operational mode of artificial satellites. I am assuming
>> that I would be providing the known orbital data of the satellites
>> as input.
>> 
>> Your guidance and insights on this matter would be greatly
>> appreciated. Thank you in advance for your assistance.
>> 
>> Best regards,
>> 

>> De Wu
> 
> --
> 
> !=============================================================!
> Prof. Adam Deller
> Centre for Astrophysics & Supercomputing
> Swinburne University of Technology
> John St, Hawthorn VIC 3122 Australia
> phone: +61 3 9214 5307
> fax: +61 3 9214 8797
> !=============================================================!
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