I think for most people who play Pokemon Go, the real fun in the game is getting out and enjoying the world as you catch virtual creatures. Some folks just don’t want to put that much effort into the game and look for other ways to catch them all. One person took their need to catch all the Pokemon to the next level with an intricate cheat that spoofs GPS to their smartphone and allows them to walk around the Pokemon virtual world using a joystick, never leaving the house.
This hack is able to broadcast fake GPS signals to the phone by transmitting radio signals. The hackers are using an RF Shield box that has a GPS antenna on it, presumably to avoid affecting other GPS devices in the vicinity but I am no engineer. The phone is placed inside said box and connected to a signal generator and GPS emulator hardware.
Google Earth is the nav interface for the system and the joystick is used to trick the game into thinking that the player is moving around the environment. Coordinates are converted to GPS signals that are then transmitted inside the box for the phone to receive. One issue with the hack pointed out by Hackaday is that with the lid of the shield box open the spoofed GPS signals do escape.
The lid was opened to allow the hackers to get at the touchscreen on the smartphone. There is some question as to whether Niantic might be able to match up accelerometer data from the phone with the GPS data and realize the phone isn’t actually moving. This seems like a lot of trouble to go through to get out of walking around outside to play a game as it’s meant to be played.