GPS to fail with solar flares?

I just read an article on CNN talking about how solar flares might cause problems for GPS users.  I was pretty excited to read the article because GPS technology is something I'm very interested in.

But I guess I have to admit that the article left with with a "wait, what??" feeling.  I didn't get enough information from the article to really understand what was going on, only a vague feeling of "GPS might go kaputz sometime".  It boils down to a general warning that GPS may, or may not, fail for some unknown period of time, sometime in the future... I'm really hoping for more detail - when will these events occur?  How intense will they be, how long will they last, and what capabilities should I expect to lose?  Airlines, rescue squads, surveyors, and websites like geocaching.com could certainly benefit from these details.

Apparently a solar flare recently left the sun - the article gives a couple of links to some videos that are kind of interesting to view - and this flare may cause problems for all kinds of GPS devices.  The reason for this comes from research at Cornell University, where researchers detected a significant loss of signal (40-50%) during a solar flare in 2005.  The signal loss consisted of two events, one that lasted one minute, 10 seconds, and a second 40 minutes later that lasted 15 minutes.  The solar flare affected, apparently, all GPS units on the sunlit side of the Earth.  But even this article isn't clear on the implications of a 50% drop in signal for GPS users.  The CNN article also doesn't give any information about when this latest solar burp might reach Earth.

A loss of signal would certainly cause your GPS device to have a harder time calculating where you are, but what's not clear from these articles is how much of a problem this would be for ordinary GPS users.  Who needs to be concerned, and who doesn't, and when?  At one point, the author says to "have a backup navigation system handy, such as a printed map", which obviously suggests that us normal folks driving around might suddenly not be able to use our GPS units to get where we want to go.  Yet the Cornell Univ. research  quoted from 2006 states that "if you're driving to the beach using your car's navigation system, you'll be OK."  So should folks expect that they will need a map, or should they expect that their car GPS will be just fine?

Obviously it will also depend on the size of the solar flare; another point of the articles is that 2011 and 2012 are years where we expect some long, intense solar flares, due to the solar maximum.  These flares, according to the Cornell Univ. researchers, could be expected to result in a 90% loss of signal that could last for a couple of hours.  Now that sounds pretty serious and an event like that deserves some further investigation.  If that kind of signal loss is really to be expected, then specific warnings for certain time periods when such flares are expected to strike Earth are needed - now who's in charge of that one?  People rely on GPS a lot these days, for good reason - it's amazing tech!  I would hope for specific warnings when such signal loss should be reasonably expected; a generic one is somewhat useful but not as empowering to users.