[time-nuts] Timing between two GPS PPS outputs.
gsricalde at gmail.com
Sun Dec 30 08:36:08 UTC 2012
Some tests of timing receivers' PPS:
http://www.cnssys.com/files/PTTI/PTTI_2002_CNS_Testbed.pdf (Motorola M12M)
Non-timing receivers could be unsuitable for your requirements, as
some of us have discovered:
On Sat, Dec 29, 2012 at 3:49 AM, Dan Kemppainen <dan at irtelemetrics.com> wrote:
> Hi all,
> I've been following this list with some interest, and have a question about
> two individual timing GPS units PPS outputs. Let's assume that the timing
> GPS units are identical units, say two SSR-6t's for example.
> If I take these two units and fire them up next to each other off of the
> same antenna one would expect the PPS signals to be very similar to each
> other. If the unit specifies 20nS, I would expect at most, say, 40nS Error
> between the two PPS signals. (Maybe this is not correct, by all means
> discussion is welcome).
> Now, lets say we fire these units up on different antennas at the same
> location. For the purpose of this discussion let's assume the antennas are
> identical or as identical as reasonably possible. (Same make, mode, cable
> length, etc). Will they still be within the specified errors or each other?
> Now, lets say we move them some distance apart say 500meters (or yards if
> you prefer). Do they still maintain the same relative error between them?
> The reason for this question is two fold. I have a personal project in mind
> where I'd like to time stamp two events within several tens of hundreds of
> nS if possible, over some distance without cabling. Also, as I started
> thinking of this application, I realized my understanding of the details of
> GPS timing is a little weak. I figured this would be a good place to ask.
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