A system that uses what a camera sees to find a device's place and direction.
It is like finding your car in a giant parking lot. You spot the red diner sign. Now you know which way to walk.
VPS matches camera views with real places. AR maps and robots use it to stay lined up with the world.
SLAM
SLAM can build and update maps that VPS matches against.
Computer Vision
Computer Vision finds landmarks in the camera view.
3D Reconstruction
3D Reconstruction can make scene models for VPS to match.