[time-nuts] Question re neutrinos and GPS

[Magnus Danielson]

Antonio,

On 01/07/2012 12:20 AM, iovane at inwind.it wrote:
> So far it seemed to me that the overall standpoint of the authoritative time-
> nuts list is that the GPS timing and geografical survey of the OPERA experiment
> are good (and hence experimental errors or artifacts, if any, should be
> searched for elsewhere).
>
> I myself, not being a deep GPS expert, joined this standpoint with confidence
> (but indeed I could have been affected by a sentimental bias).
>
> Now I read on another list, in which the subject is not timekeeping and from a
> respectable author, that:
>
> "The GPS is very unlikely to give an accurate speed for anything near the
> speed of light - for there are many known effects not taken into account by the
> GPS protocol.
> In the end the OPERA experiment may alert people to the assumptions and
> approximations implicit in the GPS."
>
> This wrongfooted me. So please, does the above quoted statement have any
> meaning for time-nuts? Don't answer "ask the author of the statement" please, I
> would like to hear the opinion of time-nuts.

It's a lot of hand-waving going around in that statement.

Let's recall some facts:

1) GPS is not used itself to measure the speed of neutrinos. It is used 
to provide the timing of the two labs. See the OPERA article.

2) A number of relativistic effects is being compensated for in the GPS 
system, of which many is not seen to the ordinary user at first glaze. 
See the ICD GPS 200D.

3) Beyond those belonging to the GPS system, the experiment includes 
further compensations according to the state of the art for this level 
of time calibration. See the PTB test report.

Additional references can be given at need.

People have been attacking the GPS time-transfer, but quite few have 
been looking into the local time-transfer within the sites. I have 
naturally asked some questions about that and got some calibration 
reports in my hand.

Another issue would be the interpretation of the detector signals. I 
doubt it could source that level of bias thought.

Maybe a more detailed analysis should be written up in a paper. There is 
a fair bit of orientation in the time-transfer over GPS field which 
people would need. Since they don't see the same things as the pro:s, it 
looks like the biggest source of uncertainty.

Cheers,
Magnus