  This paper explores the state of the art on to methods to verify and validate
navigation algorithms for autonomous surface ships. We perform a systematic
mapping study to find research works published in the last 10 years proposing
new algorithms for autonomous navigation and collision avoidance and we have
extracted what verification and validation approaches have been applied on
these algorithms. We observe that most research works use simulations to
validate their algorithms. However, these simulations often involve just a few
scenarios designed manually. This raises the question if the algorithms have
been validated properly. To remedy this, we propose the use of a systematic
scenario-based testing approach to validate navigation algorithms extensively.
