I wasn't aware there of existence GPS blackout areas anywhere, esp. in the continental United States. Do you have more information that would support your statement?

For what it's worth, GPS seems to work fine for a lot of people around Lompoc, CA: http://www.strava.com/rides-by-country/united-states/califor...

The evidence is personal experience. The blackout only affects a certain radius of Vandenberg which only covers a part of Lompoc.

So, what exactly happens there? Your device stops seeing satellites (loses lock)? Or does the reported uncertainty become on the order of hundreds of meters? Or does it simply give you confused directions when you're driving?

Searching for combinations of terms like "GPS, blackout, airforce base, lompoc" only brings up this thread. I find it hard to believe that if it were a real occurrence no one else would notice and write/complain about it.

GLONASS uses nearly the same frequency range as GPS, so the answer is no.

Tangentially related - IIRC GLONASS also happens to have an almost identical frame structure to GPS. Very peculiar fact given the context.