Recommend me a GPS unit!

[Skvez]

Be aware that GPS phones are more likely to stop working in “an event” than a true handheld GPS. Also given the transmitting nature of the phone it can be used to track you. A dedicated GPS receiver only receives, it can’t track you (unless someone gets physical access to the unit) and can’t be turned off or blocked remotely without also turning off / blocking all the other GPS receivers in your area.