[time-nuts] OT : New Horizons FEC

jimlux jimlux at earthlink.net
Wed Mar 2 10:30:49 EST 2016


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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