Ccsds frame decoding

[Mark Doyle]

Specifically for Johannes.

The code for the frame decoder [1] doesn't seem to do anything with the transfer frame version number. I assume this is so because it's not worth supporting? I think there is only one version of the standard anyway, right?

[1] https://github.com/JohannesKlug/hbird/blob/master/src/transport/protocols/src/main/java/org/hbird/transport/protocols/ccsds/transferframe/CcsdsFrameDecoder.java

[Johannes Klug]

You are correct. Section 4.1.2.2.2 of the Space Data Link Protocol says
that the Transfer Frame Version Number shall be set to "0" (both bits set
to 0). Of course we could read those two bits and check whether they
actually are 00!

[Mark Doyle]

I suppose the only reason to check is to support multiple CCSDS frame standards which will probably never be necessary.

[Johannes Klug]

On Mon, December 5, 2011 14:26, Mark Doyle wrote:
> I suppose the only reason to check is to support multiple CCSDS frame
> standards which will probably never be necessary.

We could also use it to detect errors in the header - if these bits were
found to be different from 00, something must be wrong, either on-board or
the data was corrupted in flight.

[Mark Doyle]

Yeah, I originally thought the same thing but then assumed it would be a redundant check once we implement the actual error checking.