What is the secret behind Tobi's GPS-like technique?
That ability is explained in later episodes, so it will be enclosed in spoiler tags.


   When Obito crashed onto Madara's cave, he saved him by attaching a white Zetsu (who is a clone saturated with Hashirama Senju's cells). There are many white Zetsu clones spread across the land, and they can communicate with each other via the roots of trees in the earth. (Avatar: the Last airbender style). The Zetsu attached to Obito is no different. That way he can get immediate intelligence from practically anywhere, including the location of other people.


The teleportation is made using his normal space-time techniques.