A Georeferencing Approach to Real-time Virtual Aid to Navigation Verification

The safe and economic movement of commercial and military vessel traffic and cargo of strategic military importance is dependent upon a short range Aids to Navigation (AtoN) system designed to enable navigators to accurately determine their position, plot a safe course, and be warned of dangers and obstructions that exist along their route of transit. A new type of short range AtoN being introduced is the electronic aid to navigation (eAtoN) capable of providing a virtual presence that may or may not be associated with a real, physical AtoN. This paper describes research to verify the performance of virtual eAtoN to ensure they are watching properly through the use of georeferencing to bottom features and characteristics obtained through Electronic Nautical Chart (ENC) models compared to live echosounder readings using running averages and derivative trend information. This approach also provides a means to attach tangible physical attributes and characteristics to a virtual data object that has no other physical presence. This is especially important in an era when both the Automated Identification System (AIS) and the Global Navigation Satellite System (GNSS) on which precise positioning is based are subject to spoofing, aliasing, jamming and denial of service attacks that threaten to render eAtoN useless or even pose a hazard to navigation. AIS and non-AIS eAtoN are described along with their place in the overall AtoN system, their unique capabilities and methods of deployment and use. Differences and distinctions between physical and electronic AtoN are identified, along with their characteristics and the challenges encountered to verify their proper deployment. A new and comprehensive verification approach is then described that considers environmental, physical and electronic characteristics; performance requirements, and database representations for eAtoN. This approach forms the basis for a strategy to overcome vulnerabilities of such devices through the introduction of georeferencing.