How does the Audi A3's Audi pre sense basic system work?

I am interested in knowing more about the Audi A3's safety features. Particularly, how does the Audi pre sense basic system work and what does it offer in terms of collision prevention?

The Audi pre sense basic system uses sensors to detect potential collisions and prepares the car by tightening seat belts, closing windows and sunroof, and pre-charging the brakes. It can also apply the brakes in certain situations to prevent or mitigate a collision.