I have an HTC Evo 3D from Virgin Mobile, about six months old. Until yesterday, the GPS worked great, tracking my exercise in RunKeeper very accurately.
Since yesterday, RunKeeper shows my walking route as a random zig zag line, jumping left and right of my actual location, and reports my 4 mile walk as 10 miles. This has happened three times, on trails that have always been reported accurately in the past.
In Google maps, my location also jumps around.
GPS Test showed that I could see 10/10 satelites, but the accuracy was only about 30 feet.
Any ideas what may be causing this? The phone has never been dropped or got wet.