The GPS part is just the tiles talking to any tile-enabled phone. The GPS is only in the phones, like: Any tile-enabled phone -> sees a tile -> sends a packet

The GPS part is just the tiles talking to any tile-enabled phone. The GPS is only in the phones, like: Any tile-enabled phone -> sees a tile -> sends a packet to the Tile mothership with the tile UUID + phone location. (Plus perhaps some nuances like guessing a more specific location for the tag based on bluetooth radio data)