On 11/03/2013, at 11:11 AM, Nathan Ward <nznog@daork.net> wrote:

> On 11/03/2013, at 10:47 AM, Jay Daley <jay@nzrs.net.nz> wrote:
>
>> - Currently each server independently takes its reference time from differential GPS, which is very slightly different from official NZ time. �We spoken to the people from IRL responsible for official NZ time and we have agreed a long term plan that will see the differences between GPS and NZ time sent directly to our servers from the IRL atomic clocks, which will condition our servers very close to official NZ time.
>
> Does this mean that these NTP servers won't serve up UTC, but rather UTC +/- some delta so that when offset by 12/13 hours it is in line with NZT?
> If so, is that commonly done elsewhere?
> What's the offset likely to be?

The NTP servers will continue to serve UTC but a corrected version of it that eliminates errors caused in the way we receive the time signal.

According to the IRL people (who run the atomic clocks), the big issue is variable atmospheric delay of the GPS signals. �It is that error that we want to compensate for. �Again I don't have the figures to hand but Wikipedia may:

� � � � http://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_System

> They work well for me in their current state, and I appreciate the service.
> I generally use these plus some pool.ntp.org servers to ensure accurate time when there's a failure/maintenance on one of your clocks.

thanks
Jay

>
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--
Jay Daley
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.nz Registry Services (New Zealand Domain Name Registry Limited)
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