I have an old phone (ZTE Z667G) that I use as a dedicated GPS in my car. I use the offline navigation app, Sygic, because It requires no internet connection. There is no sim card in the phone. I download maps and apps at home when I can connect it to WiFi. I would like to if there is a way to use this phone as a GPS tracker so I can use my primary phone (Samsung Galaxy Express Prime) to track the location of my dedicated GPS phone (the ZTE). I figure that it must be possible, because I believe every phone has a unique GPS signature. Any ideas?