On 3/2/16 4:15 AM, Alberto di Bene wrote:
Pardon me for the OT request... I know that some of you are deeply
involved with space communication
(may be Jim Lux ?) and I am quite curious about the Forward Error
Correcting codes used in the New
Horizons probe, that as of now is beyond Pluto, and still sends correct
photos with its meager 10W
transmitter, from a distance greater that 5*10^9 km....
Does it use the k=15, rate 1/6 convolutional code, preceded by a Reed
Solomon block code, like Cassini,
or something better has been implemented ? Is there any place where I
can find information of this ?
Thanks for any answer
73 Alberto I2PHD
It's sort of tangential to time-nuts, although DSN does do a lot of
state of the art timing (all those JPL papers on measuring Allan Dev and
Phase noise) for navigation purposes. (and, in fact, there's some
experimental efforts to use the data modulation as a timing source)
New Horizon's telecom design is here:
http://www.boulder.swri.edu/~tcase/NH%20RF%20Telecom%20Sys%20ID1369%20FINAL_Deboy.pdf
They're using R=1/6 Turbo for the downlink, k=1784. (googling "new
horizons turbo coding" turns up a lot.. knowing that it's turbo helps
you get a better google result set)
CCSDS 131.0.B-2 describes the coding in detail (ccsds.org, I believe)
There's an IEEE Proceedings (2007 I think) that has a whole bunch of
papers about coding performance.
Everything you might want to know about what the Deep Space Network can
do can be found in what's called the 810-005 document
http://deepspace.jpl.nasa.gov/dsndocs/810-005/
In particular you'll want to look at module 206 which describes the
various coding schemes.
LDPC is also supported in a variety of flavors.
There's also a wealth of more general information at
http://descanso.jpl.nasa.gov/ where there's a bunch of textbooks and
reports (although since New Horizons is an APL mission, there's no
"design and performance" book for it)
The various periodic IPN (Inter-Planetary Network) Progress Reports also
have a lot of information (this is where a lot of the allan dev and
phase noise stuff was published)
http://ipnpr.jpl.nasa.gov/ It's not particularly well indexed, but
google finds most of them.
There's a handy website with the live status of all the DSN stations
https://eyes.nasa.gov/dsn/dsn.html
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