Nghia T Nguyen

US Patent:

44687435, Aug 28, 1984

Filed:

Apr 26, 1983

Appl. No.:

6/488674

Inventors:

Thomas J. Dunn - Ocean Bluffs MA
Donald G. Yuniskis - Arlington MA
Gabor L. Szakacs - West Roxbury MA
Nghia V. Nguyen - Westwood MA

Assignee:

EPSCO, Inc. - Westwood MA

International Classification:

G06F 1520

US Classification:

364520

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. The plotter includes a high accuracy rapid hyperbolic line drawing system utilizing a specialized approximation sequence for those charts which are not provided with hyperbolic navigation TD lines.

US Patent:

43934480, Jul 12, 1983

Filed:

Feb 15, 1980

Appl. No.:

6/121651

Inventors:

Thomas J. Dunn - Ocean Bluffs MA
Donald G. Yuniskis - Arlington MA
Gabor L. Szakacs - West Roxbury MA
Nghia V. Nguyen - Westwood MA

Assignee:

Epsco Incorporated - Westwood MA

International Classification:

G06F 1550
G01S 514

US Classification:

364449

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. The plotter includes a high accuracy rapid hyperbolic line drawing system utilizing a specialized approximation sequence for those charts which are not provided with hyperbolic navigation TD lines.