IPS is Indoor Positioning Syarem and Geofencing is locating where you are geographically for, say, turning on WiFi as you get near home, or turning it off as you're driving away. (It can also be used to keep the phone unlocked when you're at home, but be careful - many geofencing apps can't be set to a smaller diameter than to include your entire property (about 50-100 feet), so if you leave (or drop) the phone in your front lawn, anyone grabbing it finds it unlocked, and can reset the lock screen to None. Then go home, reflash it, and you've lost your phone.
