[Sis-ams] Time Tag - CCSDS Time

[Scott Burleigh]

Ray, Timothy J. (GSFC-583.0) wrote:
>
> Sounds good Pat.
>
>  
>
> Just out of curiosity, is there some advantage to using the older epoch?
>
The 1958 epoch is the only one that is documented in the Blue Book for 
CCSDS time code formats.  If we want to standardize on some other epoch, 
we will either need to do so informally in the interoperability test 
plan (which is how I understand Pat's suggestion) or else define it 
formally in the AMS spec.  I think we would run into some resistance if 
we strayed from what's currently in the spec for this field, since it 
took quite a bit of back-and-forth with other CCSDS folks to arrive at 
the current text.

Scott
> ------------------------------------------------------------------------
>
> *From:* sis-ams-bounces at mailman.ccsds.org 
> [mailto:sis-ams-bounces at mailman.ccsds.org] *On Behalf Of *Donahue, Pat
> *Sent:* Wednesday, August 20, 2008 12:35 PM
> *To:* sis-ams at mailman.ccsds.org
> *Subject:* [Sis-ams] Time Tag - CCSDS Time
>
>  
>
> For interoperability sake, just like we have agreed to an 
> "Unsegmented" CCSDS format, I suggest that we also agree to all use 
> the 1958 epoch as our basis, and 4 bytes of course time (since you 
> need that many bytes to properly contain the number of seconds since 
> Jan 1, 1958).
>
>  
>
> By the way, if you are working with the Jan 1, 1970 epoch in Unix just 
> add 378691200 and you will have the number of seconds since Jan 1, 
> 1958.  Correct me if I am wrong.
>
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