Project Tango technology gives a mobile device the ability to navigate the physical world similar to how we do as humans. Project Tango brings a new kind of spatial perception to the Android device platform by adding advanced computer vision, image processing, and special vision sensors.
Motion tracking allows a device to understand position and orientation using Project Tango's custom sensors. This gives you real-time information about the 3D motion of a device.
Depth sensors can tell you the shape of the world around you. Understanding depth lets your virtual world interact with the real world in new ways.
Project Tango devices can use visual cues to help recognize the world around them. They can self-correct errors in motion tracking and relocalize in areas they've seen before.