Radar Absolute Positioning †.

The General Lighthouse Authorities (GLA) R&D Directorate has, for some time, advocated that alternate position navigation and timing (PNT) systems should be established to offset critical dependency on Global Navigation Satellite Systems (GNSS), both in the maritime world and across wider industry. The maritime world already has a number of viable systems that may provide a ship's navigator with position-fixing information independent of GNSS. A promising option is radar. Depending on size, merchant vessels are required to fit radar operating in the X-band (9 GHz) and, optionally S-band (3 GHz). The radar return from the shoreline provides a unique and identifiable fingerprint that depends on the location of the vessel. GRAD has developed a number of different processes that can convert a series of images from the ship's radar into a series of output position-fixes, independent of having access to satellite (GNSS) positioning. This report describes the methods we investigated and presents the results from a number of ship trials. [ABSTRACT FROM AUTHOR]