In the framework of autonomous driving, one of the most challenging problems to be solved for an autonomous system which aims to navigate without any human support, is represented by the localization task. Considering the self-driving vehicle as a robotic system, the localization problem arises with motion in an unknown environment and relates to the capability of the autonomous system to know at each instant its own positioning with respect to a fixed reference. The knowledge of position and orientation of a mobile robot is referred to as pose and it is related to the state estimation capabilities of the control system of the robot.