Abstract: An improved navigational plotting system having convenient initialization and the ability to compute and superimpose hyperbolic time difference lines on a chart includes an X-Y plotter for plotting the position and course of a vessel on a navigational chart or a plain piece of paper, dictated by the reception of hyperbolic navigation signals. Ambiguity-free conversion to latitude and longitude is done automatically without the necessity of manually entering the initial latitude and longitude of the vessel. Remote initialization is established by placing the pen of the plotter on a known point or position on the chart and entering the latitude and longitude of this known position or its hyperbolic navigation coordinates, with all subsequent plot locations being referenced to this point on the chart. A set of default pre-stored conditions are utilized in the initialization procedure in which preset scale size and hyperbolic line parameters are assumed, with convenient override sequences being provided.

Abstract: An improved navigational plotting system having convenient initialization and the ability to compute and superimpose hyperbolic time difference lines on a chart includes an X-Y plotter for plotting the position and course of a vessel on a navigational chart or a plain piece of paper, dictated by the reception of hyperbolic navigation signals. Ambiguity-free conversion to latitude and longitude is done automatically without the necessity of manually entering the initial latitude and longitude of the vessel. Remote initialization is established by placing the pen of the plotter on a known point or position on the chart and entering the latitude and longitude of this known position or its hyperbolic navigation coordinates, with all subsequent plot locations being referenced to this point on the chart. A set of default pre-stored conditions are utilized in the initialization procedure in which preset scale size and hyperbolic line parameters are assumed, with convenient override sequences being provided.