This is an interesting article about the effects of Space weather on the accuracy of GPS positioning data.  Apologies if you have read, or if this has been posted before.

http://www.swpc.noaa.gov/impacts/space-weather-and-gps-systems

Cheers.

Jason

Your dead right on this!!!  And here is a site with daily reports as this is a serious factor to consider when flying daily...

http://www.spaceweather.com/

example today:


SPACE WEATHER
NOAA Forecasts






Updated at: 2015 Mar 27 2200 UTC  



FLARE

0-24 hr

24-48 hr


CLASS M

25 %

25 %


CLASS X

05 %

05 %





Geomagnetic Storms:
Probabilities for significant disturbances in Earth's magnetic field are given for three activity levels: active, minor storm, severe storm

Updated at: 2015 Mar 27 2200 UTC  

Mid-latitudes  


0-24 hr

24-48 hr


ACTIVE

40 %

40 %


MINOR

25 %

25 %


SEVERE

05 %

05 %



High latitudes  


0-24 hr

24-48 hr


ACTIVE

10 %

10 %


MINOR

25 %

25 %


SEVERE

60 %

60 %

   

How often do we get space weather storms bad enough to effect our GPS position, any ideas? I have been out in the boat on several occasions when I have noticed the GPS was out more than 100m. With the inspire this could be a serious problem.

Mark.  A geomagnetic storm (KP of 5 or above) is actually not that common and will continue to be less common as we start to enter a quiet period in our suns activity known as 'the minimum'.  This is actually an 11 year cycle and is almost as regular as clockwork.
The problems with a high KP index is the 'rippling' effect it can create in the ionosphere, which can introduce a very perceptable and constantly changing error in the distance/ time calculations made by the GPS receiver.

Youtube channel SuspiciousObservers do a daily report on current solar conditions and it's effect on the earth as well as a wealth of other solar and terrestrial data.   

Another Inspire user has also uploaded a video  looking at the potential effects on KP index and it's effects on flight.  

I hope this helps.

Cheers

Jason