System for graphic representation of vessel's position on Mercator map

A system for graphic representation of a vessel's position on the Mercator map, comprising:

• a veocity and drift angle sensor having a signal generated at a first output corresponding to the speed of the vessel, and a signal generated at a second output signal corresponding to the drift angle of the vessel;
• a computer computing the longitudinal and latitudinal velocity components, and having a first input and a second input respectively connected to said first and second outputs of said velocity and drift angle sensor, a third input, and first and second outputs at which electric signals corresponding to longitudinal and latitudinal motion of the vessel are generated;
• a heading sensor having an output connected to said third input of said computer;
• a first multiplier having a first input connected to said first output of said computer, a second input and an output;
• a second multiplier having a first input connected to said second output of said computer, a second input connected to said second input of said first multiplier, and an output;
• a storage having an input and an output connected to said second inputs of said first and second multipliers;
• a first frequency divider with a controlled division coefficient and having a first input connected to said output of said first multiplier, a second input and an output;
• a second frequency divider with a controlled division coefficient and having a first input connected to said output of said first frequency divider, a second input and an output;
• a third frequency divider with a controlled division coefficient and having a first input connected to said output of said second multiplier, a second input connected to said second input of said first frequency divider, and an output;
• a fourth frequency divider with a controlled division coefficient and having a first input connected to said output of said third frequency divider, a second input connected to said second input of said second frequency divider, and an output;
• a plotter indicating the position of the vessel on the Mercator map and electrically coupled to said second frequency divider and said fourth frequency divider;
• a first integrating drive of said plotter having an input connected to said output of said second frequency divider;
• a second integrating drive of said plotter having an input connected to said output of said fourth frequency divider;
• a unit for setting the scale of the standard parallel of the Mercator map having an output connected to said second inputs of said second and fourth frequency dividers:
• a nonlinear converter reproducing an electric signal in the form of trigonometric latitude functions, and having a correction input, an information input and an output connected to said input of said storage and to said second inputs of said first and third frequency dividers;
• an adder having a first input, a second input and an output, said first input of said adder being connected to said second output of said computer and said output of said adder being connected to said information input of said nonlinear converter;
• a latitude setting unit successively setting the latitude of the standard parallel and the latitude of the initial position of the vessel, and having an output connected to said second input of said adder;
• and
• an approximator, of the correction for the meridional minute length at the location of the vessel, having an input connected to said output of said latitude setting unit and an output connected to said correction input of said nonlinear converter.