Is there an app for scrambling GPS? I'm looking for an app or at least a method that would run on background and keep scrambling GPS to appear weaker (not fake gps!). Needed for debugging of my other app. My only current option is periodical manual turning off-and-back-on location, which is not very handy as I need to leave tested app to enter location settings.
I don't know about apps, but you could buy a gps jammer. But remember to check the law. In Britain it's legal to own one, but it's a crime to actually turn it on (don't ask).

Also there's a very broad price range, so you'll have to do a bit of research to find out whether what you'd need is affordable.