In the navigation system architecture shown in Fig. 1, the user
sends commands to the navigation module through the user interface.
The navigation module generates the control variables
and the control module translates these control variables in the
low level commands for the actuators of the driving wheels. The
main component of the whole guidance system is the navigation
module. The following section will give some details of the
sonar map of the environment and of the autonomy levels which
constitute the main elements of the navigation module.