We need to solve the SLAM (Simultaneous Localization and Mapping) problem and find a way to construct and update a map of the unknown harbor environment (GIM-Mapper) while simultaneously keeping track of our autonomous vessel’s location within it (GIM-Locator). In this case it would mean the fusion of point-clouds provided by various sensors, such as LiDARs, radars and various types of cameras, into INS (Inertial Navigation System) and occasional GNSS provided data streams. Every man-made urban harbor has plenty of topological landmarks, which will be used as features to create the topological map. After you have done this recording once, while arriving at the harbor for the first time after the installation of the system, the map can be used for future localization. This is something we have done in our previous projects worldwide. The same approach can be applied to other locations as well, such as various waterways in the urban areas if the environment has enough features and the vessel has additional information coming from its INS system. Even sporadic GNSS fixes will be naturally useful and will be fused to limit the inherent drift of the INS system.