Does anyone have experience with the "Ghost Radar" app?

My oldest daughter’s s/o has an iphone and she keeps telling me some amazing stories about things that happen with this app. (Sheesh, I can’t believe I’m using that term!) When she first told me something about it, I told her that it must be some VERY clever software. I still hold to that, I don’t for a minute believe that there is anything supernatural about it. I just wondered if anybody knew what type of technology is used. It made me think of the Furbies from a few years ago. I know that a lot of military places didn’t allow them on board because they somehow recorded stuff. Can anyone explain this to me?