A robot vacuum with a navigation system moves through your house in a logical manner. That way, you're sure that it won't miss any spots or keeps cleaning the same spot again and again. There are various navigation methods. There are robots that chart the room using an invisible laser. There are also robot vacuums with ceiling recognition, which have a camera that films the ceiling, so it knows exactly what the room looks like. A robot vacuum with systematic navigation has smart software to find its way around your house.