Where did you get the understanding that you need GPS or that you need to maintain eye contact?
You are supposed to be able to walk around and it will follow you and remain within 5m distance.
Considering this kit costs $399 USD, I am almost certain the tracking technology will detect the persons face for the selfie aspect, but will also be able to track the whole body so it knows who to follow. Tracking technology isn't exactly new for cameras, it's relatively simple. It's just not used in practice because there's not many products which need this feature.
