[Sls-slp] Repeating TC's / SLS-SLP Presentation to SLS area Plenary

[Greg Kazz]

G.P.

NASA/JPL does not implement COP-1, however it does implement the 
FARM. We send our command loads back to back meaning for a given 
sequence of TC frames 1,2,3,4,5... the sequence of CLTUs is 
duplicated once and the frame sequence numbers are transmitted 
as:  1,2,3,4,5...1,2,3,4,5...

We view this approach as compliant with the telecommand standard. We 
view being able to retransmit collections of frames be they 
"cyclical" i.e., 1,2,3,4,5,1,2,3,4,5 or "hammer": 1122334455 as being 
an implementation issue within the existing standards.

Greg


At 01:58 AM 7/18/2008, Gian.Paolo.Calzolari at esa.int wrote:

>Takahiro,
>         thank you for your input.
>Do you investigate at CLTU level whether the CLTU you transmit 
>several times was generated by an AD, BD or BC frame?
>
>Ed, Greg,
>         any details on the NASA/JPL implementation of this feature?
>
>
>Ciao
>
>Gian Paolo
>----- Forwarded by Gian Paolo Calzolari/esoc/ESA on 18/07/2008 10:56 -----
>Gian Paolo Calzolari/esoc/ESA
>
>16/06/2008 18:13
>To
>Takahiro Yamada <tyamada at pub.isas.jaxa.jp>
>cc
>Edward.Greenberg at jpl.nasa.gov, "Greg J. Kazz" 
><Greg.J.Kazz at jpl.nasa.gov>, Jean-Luc.Gerner at esa.int, 
>sls-slp at mailman.ccsds.org, sls-slp-bounces at mailman.ccsds.org
>Subject
>Re: [Sls-slp] SLS-SLP Presentation to SLS area 
>Plenary<Notes:///C125639C0053C39E/DABA975B9FB113EB852564B5001283EA/2FE80B53432485F0C125746A00551E14>Link 
>
>
>
>
>
>
>sls-slp-bounces at mailman.ccsds.org wrote on 16/06/2008 17:27:54:
>
> > Gian Paolo,
> >
> > > We would really appreciate knowing some details on the NASA/JPL (Ed?
> > > Greg?) and JAXA (Takahiro?) implementations of this feature also to
> > > understand how much those implementations are within the line of the
> > > current standards.
> >
> > For deep space missions, we send each command frame (actually, it is a
> > CLTU) multiple times in order to decrease the probability of
> > retransmission. For example, if we are to send command frames #1, #2,
> > #3, and #4, we send #1, #1, #2, #2, #3, #3, #4, and #4. This is a case
> > in which we send the same command twice and this is what we use for our
> > asteroid mission, but we can send the same command any number of times.
>
>Takahiro,
>         thank you for your input.
>Do you investigate at CLTU level whether the CLTU you transmit 
>several times was generated by an AD, BD or BC frame?
>
>Ciao
>
>Gian Paolo
>
>
> >
> > For doing retransmission, we use COP-1 as specified by CCSDS.
> >
> > I'm not sure if this violates the specification of COP-1 but I will
> > check it when I have time.
> >
> > Best regards,
> > Takahiro Yamada.
> >
> >
> > _______________________________________________
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