If your I pad is cellular capable, than a GPS is built in to the I Pad. Not the case with the WiFi only pads. The Jepp FD pro software allows use of GPS functions of the I pad (when able) and can be toggled on and off. From my experience, the GPS within the I pad will not work (receive a usable signal) within transport airplanes, but will do so in GA types. An external antenna may not be necessary but you won't know until to fly in your particular aircraft.