[time-nuts] GPS jump

Magnus Danielson magnus at rubidium.dyndns.org
Sun Oct 12 05:04:11 EDT 2014


To me it doesn't look like a real jump but rather a result of aggregated 
systematics. I think it is related to satellite orbits and how they 
provide number of birds or lack of good symmetry, or both.

Both september 28th and 29th have equivalently large jumps as october 9th.

Cheers,
Magnus

On 10/11/2014 02:24 PM, Jim Palfreyman wrote:
> http://users.on.net/~cdadsl/
>
> Is a web page with all our different sites on it.
>
> Hobart 26m seems to be the only exception but I did make an adjustment on
> that day. But the adjustment didn't appear.
>
> All sites are collected and analysed separately with their own GPS clock.
> Some are old TACs and most are CNS mark II.
>
> It could be a fluke, but it does seem weird. And as was pointed out - this
> happened last year at around the same time. Well spotted Mike Cook!
>
>
>
> On 11 October 2014 09:54, Tom Van Baak <tvb at leapsecond.com> wrote:
>
>> Hi Jim,
>>
>> Can you tell me more about your configuration? What GPS receiver / antenna
>> system do you use; L1 or L1/L2? Is this live 1PPS data, or post-processed
>> from RINEX, etc. Is the data analysis done separately in 5 locations or is
>> the raw data collected and processed together.
>>
>> Through IGS and NASA and BIPM there's GPS and maser data from all over the
>> world so it should be possible to track this down. I can ask people I know
>> too. But can you clarify how much the "downward turn" is? Is that ps/day,
>> or ns/day, or what.
>>
>> Thanks,
>> /tvb
>>
>> ----- Original Message -----
>> From: "Jim Palfreyman" <jim77742 at gmail.com>
>> To: "Discussion of precise time and frequency measurement" <
>> time-nuts at febo.com>
>> Sent: Thursday, October 09, 2014 4:43 PM
>> Subject: [time-nuts] GPS jump
>>
>>
>>> Folks,
>>>
>>> We look after 5 separate hydrogen masers spread all over Australia and we
>>> collect tic phases between the masers and the GPS.
>>>
>>> On around ~Oct 7 we have noticed that the normal steady straight line
>> (with
>>> standard daily noise) took a noticeable downward turn - on all 5 masers.
>>>
>>> Did anyone else who tracks H-masers notice this as well?
>>>
>>> Is it JPL making corrections?
>>>
>>>
>>> Jim Palfreyman
>>> _______________________________________________
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>>
>>
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