[ntp:questions] GPS and the December 5/6 Solar Flare

Hans Jørgen Jakobsen hjj at wheel.dk
Fri Apr 6 17:53:36 UTC 2007


On Fri, 6 Apr 2007 16:50:47 GMT, John Ackermann N8UR wrote:
> David J Taylor wrote:
>> John Ackermann N8UR wrote:
>>> David J Taylor said the following on 04/06/2007 02:26 AM:
>>>> John Ackermann N8UR wrote:
>>>>>> Further to the news today that the solar flare on Dec. 5/6, 2006
>>>>>> caused GPS disruption, it just so happens I was logging the signal
>>>>>> strength (average of all satellites tracked) of an M12+T timing
>>>>>> receiver at that time.  For what it's worth, the attached plot
>>>>>> shows what I saw.  This was the only significant signal strength
>>>>>> anomaly in over one year of data capture.
>>>>>>
>>>>>> John
>>>> Could you please provide a URL for the plot, John?
>>>> Attachments are not allowed in the text newsgroup.
>>> It's at http://www.febo.com/pages/gps_solar_flare .  As of now there's
>>> just an directory listing with the plot file, but I'll add a real
>>> index page with some content when I get a chance.
>>>
>>> John
>> 
>> Many thanks, John.  That's quite surprising (although I don't plot any GPS 
>> strength as a matter of routine so I'm not really in a position to 
>> comment).  I presume this affect is simply within the earth's atmosphere, 
>> rather than being any drop in ERP from the satellites themselves?
>
> I suspect it's atmospheric or some ionization effect, and not an actual
> change in the birds.  If I have the time/energy, I may do some more
> analysis.  The data I logged includes the signal strength of each SV
> being tracked, but unfortunately doesn't include the SV numbers.  So, I
> can look to see if one or more birds were affected more than others, but
> I can't link it back to individual orbits without the SV numbers.
>
I have clockstats files(+loopstats and peerstats) for the days. Its a
Trimble Acutime 2000 with the ripencc driver(43).

Slightly mangled sample below:
54075 69833.663 127.127.43.0 U1 6.12.2006 19:23:53 13 01
54075 69833.784 127.127.43.0 C1 06122006 192353 6 -111411 110.2 677 6.7 14 56xx.x76732 N 10xx.x60707 E 118  14 17 20 28 1 0 11 19
54075 69833.834 127.127.43.0 S1 14 1 1 02 56.5  52.2 34.5
54075 69833.864 127.127.43.0 S1 17 2 1 02 56.2 311.0 28.5
54075 69833.904 127.127.43.0 S1 20 3 1 02 59.1 240.5 47.7
54075 69833.924 127.127.43.0 S1 28 4 1 02 49.9 266.0 10.3
54075 69833.964 127.127.43.0 S1 01 5 1 02 60.2 116.5 54.0
54075 69833.994 127.127.43.0 S1 11 7 1 02 55.8 186.8 74.6
54075 69834.023 127.127.43.0 S1 19 8 1 02 51.0 171.0 11.6

Raw data could be made available if someone would like to make analysis.
/hjj




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