In order to keep track of your movements your VR headset needs to use some method of sensing both the headset itself as well as the controllers in your hands. The first VR headsets used what are known as lighthouses, individually placed sensors or positional trackers, which plugged into your PC.
This is the most accurate method of tracking, but is cumbersome and unless they’re permanently installed in a room you’ll need to set them up each time you want to play and that includes calibrating them anew every time.