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Re: [pilc] OT - CCSDS Proximity-1 Help Req'd
Darren: Greg Kazz, chairman of the CCSDS Space Link Protocols Working
Group, will be happy to answer your questions. I've CC'd him and he will
answer you directly.
I have also copied Matt Cosby of QinetiQ and Dai Stanton of Keltik (both in
the UK), who implemented Prox-1 onboard the British 'Beagle' lander that is
scheduled to touch down on the surface of Mars on Christmas day. They
should be able to give you local advice.
Prox-1 will be the primary communications link for Beagle to transfer data
to and from Earth via the European 'Mars Express' orbiting communications
relay, and the US 'Mars Odyssey' orbiting relay. The two US Mars rovers
'Spirit' and 'Opportunity' (respectively scheduled to land on Mars January
3 and January 24, PST) will also each use Prox-1 for communicating via
these two orbiting Mars relays. The US 'Mars Reconnaissance Orbiter'
(http://mars.jpl.nasa.gov/mro/mission/tl_relay.html) will join the
international fleet of Prox-1 based Mars communications relays when it
arrives at the planet in March 2006.
All of these proximity communications occur in the UHF band.
Best regards
Adrian J. Hooke
Chairman, CCSDS Engineering Steering Group (CESG)
NASA Jet Propulsion Laboratory,
Interplanetary Network Directorate
Pasadena, California 91109-8099, USA
+1.818.354.3063
http://www.ccsds.org
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
At 03:43 AM 12/19/2003, Long, Darren wrote:
Hi,
Sorry for being a bit off topic, but wondered if anyone can provide a bit
of guidance w.r.t. the CCSDS Proximity-1 Link Protocol. I can't think of
anywhere else to ask.
The specification for the Proximity-1 Physical Layer (211.1-B.1) on Page
3.9, section 3.5.1 "Delivered Bit/Symbol Stream Error Rate mentions links
where Reed Solomon coding in the data-link layer. So far (and I admit
that I haven't read every word of the Proximity-1 documents) I can't find
any reference to use of an RS code in any of the three newly restructured
documents.
I am interested in using an off-the-shelf protocol for a narrow band
half-duplex ground-to-air UHF data-link and have been wondering about
adopting elements of Proximity-1. Currently I'm in favour of a
concatenated RCPC,RS combination, similar to that described by TM Sync &
Coding, for both uplink and downlink ), but Proximity-1 only seems to
support the convolutional codes.
Obviously I don't need to be compliant with the standard, and can tailor
as needed, I'm just curious about the reference to the RS code and wonder
if it could be an error.
If responding direct, and not via the list, please send to both of my
email addresses.
darren.long@uk.thalesgroup.com
darren.long@bluescreenofdeath.net
Thanks for any help you can give...
Darren Long
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