[ntp:questions] Start of new GPS 1024 week epoch

Magnus Danielson magnus at rubidium.dyndns.org
Fri Aug 16 17:32:46 UTC 2013


On 08/16/2013 10:36 AM, David Taylor wrote:
>
> Yes, all my receivers are very simple, consumer-level ones.  Sometimes
> I see as low as 2m "location accuracy" on the GPS 60 CSx, more likely
> 3m when walking.
>
> Thanks for the pointers to the documents.  A pity that they haven't
> been able to find two or three spare bits to reduce the 1024 week
> ambiguity to nearer a half-century or even 100 years.  Oh, well!
>
If you look at the new signals (L1C, L2C, L5), they have 13-bit Week
Number (WN) compared to the old 10-bit numbers. Adding the bits to the
traditional signal structure would be possible, but would not help if
you have not upgraded to include them. Also, the 8192 week cycle would
also loop eventually, and it would still be a multiple of 1024 weeks off
in that case. However, that's almost 157 years up in 2136/2137 shift. We
know that it's too soon for software folks to fix their code.

Cheers,
Magnus


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