Method and apparatus for plotting vessel position

Claim 1

Apparatus for computing and plotting the position of a vessel relative to a predetermined course comprising: a plurality of remote microwave transponders each having a known geographical location and adapted to transmit radio signals at predetermined microwave frequencies when triggered; and a pipelaying barge including: transmitter means for triggering each of said remote transponders at predetermined time intervals; receiver means for receiving the signals transmitted by said transponders; first computing means responsive to said transmitter means and said receiver means for computing the ranges from the barge to each of said transponders; means for storing data; second computing means responsive to said first computing means and said data storing means for correcting the ranges to each of said transponders for inaccuracy related to the refractivity of the atmosphere and for correcting the ranges to each of said transponders to a predetermined reference plane; third computing means responsive to said data storing means and said second computing means for computing the coordinates of said barge in a predetermined navigational coordinate system; an incremental digital plotter having an elongated chart adapted for movement along a line parallel to the longitudinal axis thereof and having a marker adapted for movement along a line perpendicular to the longitudinal axis of said chart, said chart having said predetermined course preplotted thereon as a plurality of substantially contiguous straight line segments substantially parallel to the longitudinal axis of said chart and approximately centered thereon; fourth computing means responsive to said data storing means for determining the orientation of the grid lines of a predetermined navigational coordinate system relative to each of said segments; means for positioning said marker on said chart at the coordinates of a first point on said predetermined course; fifth computing means responsive to said data storing means and said third and fourth computing means for calculation the distance along the longitudinal axis of said chart and along a line perpendicular thereto between the coordinates of said first point and the computed coordinates of said barge; means responsive to said fifth computing means and said data storing means for generating first and second groups of electrical pulses related in number to said calculated distances; and means responsive respectively to said first and second groups of pulsEs for moving said chart and said marker to position said marker at the computed coordinates of the vessel.

Claim 3

A method of determining the position of vessel means relative to a predetermined offshore course, said method comprising: providing plotter means on offshore vessel means, with said plotter means having movable marker means; providing movable chart means in said plotter means, with said chart means having a desired course preplotted thereon in the form of a plurality of substantially contiguous line segments of a desired offshore course of vessel means, said course line segments being disposed in sequence along a portion of said chart means, and a plurality of segments of grid lines separately oriented relative to at least some of said course line segments. at least one of said grid line segments being associated with at least one of said desired course line segments and being oriented in an orientation relative to said chart means different from that of another adjacent one of said grid line segments, with said different orientations of said one and other grid line segments being operable to reduce the width of said portion of said chart means having preplotted thereon said one course line segment and another course line segment associated with said other grid line segment; effecting said different orientations by orienting grid line segments associated with at least two adjacent course line segments in relative inclination, with the grid line pattern of one grid line segment associated with one of said at least two adjacent course line segments being inclined relative to the grid line pattern of another grid line segment associated with another of said at least two adjacent course line segments and being displaced from alignment with a projection of the grid line pattern of said other grid line segment; said relative inclination between said two adjacent grid line segments resulting from different orientations of said one and said other grid line segments produced by rotation of one of said one and other grid line segments relative to a projection of the other of said one and other grid line segments; arranging the course line segments of said at least two adjacent course line segments in generally end-to-end relation, extending between lateral boundaries separated by a distance less than a distance between lateral boundaries of said at least two course line segments which would result if said at least two course line segments were plotted on a grid pattern comprising said one grid line segment and a projection thereof; said lesser distance between said lateral boundaries being a consequence of said relative inclination of grid line segments associated with said at least two course line segments; and said preplotted desired course, including said at least two course line segments, more closely approaching a generally straight line configuration than would result from the plotting of said at least two course line segments on a grid line pattern corresponding to that of said one grid line segment and a projection thereof; moving said chart means and marker means to position said marker means on said chart means at coordinates of the actual positions of the vessel means in each of said one and other, differently oriented, grid line segments; and manipulating said vessel means as determined by said positioning of said marker means on said chart means in relation to said preplotted desired course, to tend to cause said actual positioning of said vessel means to tend to bear a desired coincidence with said preplotted course.

Claim 4

A method of determining the position of vessel means relative to a predetermined offshore course, said method comprising: providing plotter means on offshore vessel means, with said plotter means having movable marker means; providing movable chart means in said plotter means, with said chart means having a desired course preplotted thereon in the form of a plurality of substantially contiguous line segments of a desired offshore course of vessel means, said course line segments being disposed in sequence along a portion of said chart means, and a plurality of segments of grid lines separately oriented relative to at least some of said course line segments. at least one of said grid line segments being associated with at least one of said desired course line segments and being oriented in an orientation relative to said chart means different from that of another adjacent one of said grid line segments, with said different orientations of said one and other grid line segments being operable to reduce the width of said portion of said chart means having preplotted thereon said one course line segment and another course line segment associated with said other grid line segment; effecting said different orientations by orienting grid line segments associated with at least two adjacent course line segments in relative inclination, with the grid line pattern of one grid line segment associated with one of said at least two adjacent course line segments being inclined relative to the grid line pattern of another grid line segment associated with another of said at least two adjacent course line segments and being displaced from alignment with a projection of the grid line pattern of said other grid line segment; said relative inclination between said two adjacent grid line segments resulting from different orientations of said one and said other grid line segments produced by rotation of one of said one and other grid line segments relative to a projection of the other of said one and other grid line segments; arranging the course line segments of said at least two adjacent course line segments in generally end-to-end relation, extending between lateral boundaries separated by a distance less than a distance between lateral boundaries of said at least two course line segments which would result if said at least two course line segments were plotted on a grid pattern comprising said one grid line segment and a projection thereof; said lesser distance between said lateral boundaries being a consequence of said relative inclination of grid line segments associated with said at least two course line segments; and said preplotted desired course, including said at least two course line segments, more closely approaching a generally straight line configuration than would result from the plotting of said at least two course line segments on a grid line pattern corresponding to that of said one grid line segment and a projection thereof; moving said chart means and marker means to position said marker means on said chart means at coordinates of the actual positions of the vessel means in each of said one and other, differently oriented, grid line segments; and manipulating said vessel means as determined by said positioning of said marker means on said chart means in relation to said preplotted desired course, to tend to cause said actual positioning of said vessel means to tend to bear a desired coincidence with said preplotted course.

Claim 19

A method of plotting the position of a vessel relative to a desired course comprising the steps of: a. generating at predetermined intervals electrical signals representative of the ranges from the vessel to each of a plurality of transponders, each located at a predetermined geographical position; b. providing means for storing data; c. modifying the generated electrical signals responsively to the stored data to correct for inaccuracy related to atmospheric conditions; d. further modifying the generated electrical signals responsively to the stored data to provided electrical signals representative of the ranges in a predetermined reference plane from the vessel to each of the plurality of the transponders; e. determining the navigational coordinates of the position of the vessel responsively to the further modified generated electrical signals; f. providing a plotter having a marker movable laterally with respect to the longitudinal axis of the bed of said plotter; g. providing a chart movable longitudinally with respect to the plotter, the chart having a line representative of the desired course preplotted thereon as a plurality of contiguous straight line segments substantially parallel to the longitudinal axis of said chart and approximately centered on said chart and a plurality of grid lines separately oriented relative to each of the segments; h. translating the determined navigational coordinates into command signals relative to distance on the chart along the longitudinal and transverse axis of the plotter for a given segment of the course; and i. moving the chart and the marker responsively to the command signals.

Claim 20

A method of plotting the position of a vessel relative to a desired course comprising the steps of: a. generating at predetermined intervals electrical signals representative of the ranges from the vessel to each of a plurality of transponders, each located at a predetermined geographical position; b. providing means for storing data; c. modifying the generated electrical signals responsively to the stored data to correct for inaccuracy related to atmospheric conditions; d. further modifying the generated electrical signals responsively to the stored data to provided electrical signals representative of the ranges in a predetermined reference plane from the vessel to each of the plurality of the transponders; e. determining the navigational coordinates of the position of the vessel responsively to the further modified generated electrical signals; f. providing a plotter having a marker movable laterally with respect to the longitudinal axis of the bed of said plotter; g. providing a chart movable longitudinally with respect to the plotter, the chart having a line representative of the desired course preplotted thereon as a plurality of contiguous straight line segments substantially parallel to the longitudinal axis of said chart and approximately centered on said chart and a plurality of grid lines separately oriented relative to each of the segments; h. translating the determined navigational coordinates into command signals relative to distance on the chart along the longitudinal and transverse axis of the plotter for a given segment of the course; and i. moving the chart and the marker responsively to the command signals.

Claim 21

A method of working with a pipeline offshore, said method comprising: providing pipeline working vessel means operable to work with an at least partially submerged pipeline at an offshore location; generating electrical signals representative of the ranges from said pipeline working vessel means to each of a plurality of transponders, each located at a predetermined geographical position, providing position plotting means carried by said pipeline working vessel means and containing a preplotted course related to a predetermined position of said pipeline; determining, on said pipeline working vessel means, an actual offshore position of said pipeline working vessel means during the performing of work relating to said pipeline; said determining of an actual offshore position of said pipeline working vessel means being effected by providing means on said pipeline working vessel means for storing data, modifying said generated electrical signals on said pipeline working vessel means responsively to said stored data to correct for inaccuracy related to atmospheric conditions, further modifying said generated electrical signals on said pipeline working vessel means responsively to said stored data to provide electrical signals Representative of the ranges, in a predetermined reference plane, from the vessel means to each of said plurality of said transponders, and on said pipeline working vessel means, determining the navigational coordinates of an actual position of said pipeline working vessel means responsively to said further modified generated electrical signals; visually indicating on said plotting means an indication of said predetermined position of said pipeline relative to an actual position of said pipeline working vessel means as determined by said navigational coordinates; performing work on said pipeline from said pipeline working vessel means, with said pipeline working vessel means floating on a body of water and with at least a portion of said pipeline being disposed on a submerged location spaced from said pipeline working vessel means; and while performing work on said pipeline from said pipeline working vessel means, operating said pipeline working vessel means in accordance with said visual indication of said predetermined position of said pipeline relative to said pipeline working vessel means so as to cause the actual location of said pipeline working vessel means to tend to bear a desired coincidence with said predetermined pipeline position.

Claim 22

A method of working with a pipeline offshore, said method comprising: providing pipeline working vessel means operable to work with an at least partially submerged pipeline at an offshore location; generating electrical signals representative of the ranges from said pipeline working vessel means to each of a plurality of transponders, each located at a predetermined geographical position, providing position plotting means carried by said pipeline working vessel means and containing a preplotted course related to a predetermined position of said pipeline; determining, on said pipeline working vessel means, an actual offshore position of said pipeline working vessel means during the performing of work relating to said pipeline; said determining of an actual offshore position of said pipeline working vessel means being effected by providing means on said pipeline working vessel means for storing data, modifying said generated electrical signals on said pipeline working vessel means responsively to said stored data to correct for inaccuracy related to atmospheric conditions, further modifying said generated electrical signals on said pipeline working vessel means responsively to said stored data to provide electrical signals Representative of the ranges, in a predetermined reference plane, from the vessel means to each of said plurality of said transponders, and on said pipeline working vessel means, determining the navigational coordinates of an actual position of said pipeline working vessel means responsively to said further modified generated electrical signals; visually indicating on said plotting means an indication of said predetermined position of said pipeline relative to an actual position of said pipeline working vessel means as determined by said navigational coordinates; performing work on said pipeline from said pipeline working vessel means, with said pipeline working vessel means floating on a body of water and with at least a portion of said pipeline being disposed on a submerged location spaced from said pipeline working vessel means; and while performing work on said pipeline from said pipeline working vessel means, operating said pipeline working vessel means in accordance with said visual indication of said predetermined position of said pipeline relative to said pipeline working vessel means so as to cause the actual location of said pipeline working vessel means to tend to bear a desired coincidence with said predetermined pipeline position.