So, the Iranians are now claiming to have tricked that UAV into landing on its own. On the face of it, seems reasonable enough. However, drones don't have to rely on GPS for navigation, and likely don't. The ability to navigate precisely without outside reference has been in the US toolkit since ALCMs (nuclear cruise missiles) went operational in the 70s. I'm thinking a bug or an operator failure caused the drone to accidentally rely only on GPS, and after who knows how many tries the Iranians managed to make their neat trick work. In other words, assuming the story is true at all, the Iranians used a bit of skill and a great big pot of dumb luck to succeed.
Assuming it's true at all. I've always thought that drone was a really weird color, very different from the various camouflage schemes I've seen in the past. I would not be surprised if it turns out the thing is made of paper mache and tin.