Here's the deal with GPS, not the XF system specifically, just GPS systems in general. The way GPS works is by triangulating the distance from your car to 3 GPS satellites that are in geosynchronous or ab orbit that leaves them in a fixed position above the earth. It only needs 3 sats to work. The system uses GPS, compass, gyroscopes, and vehicle speed sensor to accurately plot your position and direction. As for the GPS antenna, they all have a standard connection, but the plastic housing may be a little different around the connector. The antenna can be underneath anything BUT metal. if there is any metal object, or very thick plastics, the antenna will not be able to receive the signal from the sats. This means it can be mounted directly under the dash if it is plastic, and mounting it on some kind of metal plate is ideal to boost the reception. as long as there is power to the radio, is will find your position. After full power up, the system will take some time to calibrate its self using the movement of the vehicle. this can take a long time depending on the system for it to be truly accurate. when you turn the ignition off, the memory power will allow the system to remember your last position, and power up in that position. If the car is towed, it will need to find its new location which takes about a minute of driving. This explanation applies to all modern GPS systems. I personally thing the XF one is a waste of money since it has a terrible user interface, with a very small dot-matrix b&w screen. But if you get one at a great deal, the fit and finish is of course perfect. But as a dealer option, very bad deal.