Method, apparatus, and computer program products for alerting surface vessels to hazardous conditions

• US 6,750,815 B2
• Filed: 08/27/2002
• Issued: 06/15/2004
• Est. Priority Date: 10/05/1999
• Status: Expired due to Term

• Current Assignee: FLIR Systems Trading Belgium BVBA
• Original Assignee: Honeywell International Inc.
• Inventors: Khatwa, Ratan, Michaelson, Dave, Suchodolski, Jeanne C.
• Primary Examiner(s): PIHULIC, DANIEL T
• Application Number:
  US10/229,822
• Publication Number:
  US 20030112171A1
• Time in Patent Office: 658 Days
• Field of Search: 342/357.13, 367/909, 367/99, 367/128, 701/208
• US Class Current: 342/357.31
• CPC Class Codes: B63B 2201/26 signalling anomalies, e.g. rupture of connection
• CPC Class Codes: B63B 43/18 preventing collision or grounding; reducing collision damage reducing pollution by collision B63B25/082
• CPC Class Codes: B63B 49/00 Arrangements of nautical instruments or navigational aids nautical measuring instruments G01C; radio navigation, analogous arrangements using other waves G01S
• CPC Class Codes: B63B 79/10 using sensors, e.g. pressure sensors, strain gauges or accelerometers
• CPC Class Codes: B63B 79/20 using models or simulation, e.g. statistical models or stochastic models
• CPC Class Codes: B63G 8/38 Arrangement of visual or electronic watch equipment, e.g. of periscopes, of radar periscopes, optical aiming or sighting devices per se G02B23/00
• CPC Class Codes: G01C 13/008 measuring depth of open water
• CPC Class Codes: G01C 21/20 Instruments for performing navigational calculations G01C21/24, G01C21/26 take precedence
• CPC Class Codes: G01C 21/22 Plotting boards
• CPC Class Codes: G01C 21/3881 Tile-based structures
• CPC Class Codes: G01C 5/00 Measuring height; Measuring distances transverse to line of sight; Levelling between separated points; Surveyors' levels G01C3/20, G01C3/30 take precedence
• CPC Class Codes: G08G 3/02 Anti-collision systems
• CPC Class Codes: Y10S 367/909 Collision avoidance

Abstract

A navigational system for surface vessels that provides warning of impending grounding occurrences. A data base of bottom contours and submerged obstructions is compared to various indicators of the surface vessel'"'"'s position and motion to provide alerts and to display bottom hazards ahead of the vessel.

Claims

1. An apparatus for generating terrain proximity alerts for use in a surface marine vessel, said apparatus comprising an alert generator that:

generates a predetermined alert distance as a function of the speed of the surface marine vessel;

compares a current coordinate position of the surface marine vessel to a prestored coordinate position of terrain proximate to the surface marine vessel; and

generates an alert if the distance between the surface marine vessel and the proximate terrain is less than said predetermined alert distance.

2. An apparatus according to claim 1, wherein said alert generator further compares prestored elevations of terrain proximate to the surface marine vessel to the depth of the surface marine vessel and generates an alert if the distance between the surface marine vessel and the proximate terrain is no greater than a predetermined alert distance.

3. An apparatus according to claim 2 further comprising a memory device in electrical connection with said alert generator containing data defining tide data, wherein said alert generator compares prestored elevations of terrain proximate to the surface marine vessel to the depth to the surface marine vessel in a manner accounting for said tide data.

4. An apparatus according to claim 2 further comprising comparing prestored elevations of terrain proximate to said vessel with a height of said vessel and generating an alert if the distance between the terrain and the vessel is less than a predetermined alert distance.

5. An apparatus according to claim 1, wherein said generator generates a value indicating a depth that the surface marine vessel resides below the surface of the water.

6. An apparatus according to claim 1, wherein said alert generator generates the predetermined alert distance as a function of a distance required to stop the vessel.

7. An apparatus according to claim 1, wherein said alert generator determines performance characteristics of the marine vessel, and wherein said alert generator generates the predetermined alert as a function of a distance required to perform an evasive maneuver.

8. An apparatus according to claim 1, further comprising a memory device in electrical communication with said alert generator, wherein said memory device includes a database containing elevation data for different global coordinates of the earth, wherein said alert generator determines the current coordinate position of the surface marine vessel and searches the memory device for the prestored coordinate position of terrain proximate to the surface marine vessel and generates an alert if the distance between the surface marine vessel and the proximate terrain is less than a predetermined alert distance.

9. An apparatus according to claim 1, wherein said alert generator generates an envelope relative to at least one of the surface marine vessel and the proximate terrain, wherein said alert generator determines if the other of the surface marine vessel and the proximate terrain penetrates the envelope, and wherein said alert generator generates an alert if the envelope is penetrated.

10. An apparatus according to claim 9, wherein the surface marine vessel is traveling in a direction defining a track, and wherein said alert generator generates an envelope relative to said surface marine vessel in the direction of the track of the surface marine vessel.

11. An apparatus according to claim 10, wherein said alert generator generates an envelope relative to said surface marine vessel in the direction of the track of the surface marine vessel having side boundaries extending along the track of the surface marine vessel and spaced apart by a width perpendicular to the track.

12. An apparatus according to claim 10, wherein said alert generator generates an envelope relative to said surface marine vessel in the direction of the track of the surface marine vessel having side boundaries extending along the track of the surface marine vessel and spaced apart by a width perpendicular to the track that increases for distances further away from the surface marine vessel.

13. An apparatus according to claim 9, wherein said alert generator generates an envelope relative the surface marine vessel having a lower boundary with a depth representative of a maximum depth of the surface marine vessel and extending outwardly with respect to the surface marine vessel.

14. An apparatus according to claim 9, wherein said alert generator generates an envelope relative the surface marine vessel having a lower boundary with a depth greater than the depth of the surface marine vessel and an outward boundary positioned at an outward distance from the surface marine vessel.

15. An apparatus according to claim 14, wherein the depth of the lower boundary is a function of a distance between the current coordinate position of the surface marine vessel and a selected coordinate position.

16. An apparatus according to claim 14, wherein said alert generator generates an envelope having a lower boundary having a lower elevation than the surface marine vessel, wherein the elevation of the lower boundary is a function of a distance between the current coordinate position of the surface marine vessel and the coordinate position of a terrain feature proximate to the surface marine vessel.

17. An apparatus according to claim 14, wherein said alert generator generates an envelope having an outward boundary positioned at an outward distance from the surface marine vessel, wherein the outward distance is at least a function of a speed of the surface marine vessel.

18. An apparatus according to claim 17, wherein said alert generator determines a distance required for the surface marine vessel to stop based on a current speed of the surface marine vessel, and wherein said alert generator generates an envelope having an outward boundary positioned at the determined distance from the surface marine vessel.

19. An apparatus according to claim 17, wherein said alert generator determines a distance required for the surface marine vessel to perform an evasive maneuver at a selected turning radius based on at least a current speed of the surface marine vessel, and wherein said alert generator generates an envelope having an outward boundary positioned at the determined distance from the surface marine vessel.

20. An apparatus according to claim 17, wherein said alert generator determines a first distance equal to a distance required for the surface marine vessel to stop based on a current speed of the surface marine vessel, wherein said alert generator further determines a second distance equal to the distance required for the surface marine vessel to perform an evasive maneuver at a selected turning radius based on at least a current speed of the surface marine vessel, and wherein said alert generator generates an envelope having an outward boundary positioned at the smaller of the first and second distances from the surface marine vessel.

21. An apparatus according to claim 9, wherein said alert generator generates a caution envelope relative to the surface marine vessel indicating a first level of terrain proximity alert and a warning envelope relative to the surface operating marine vessel indicating a second level of terrain proximity alert.

22. An apparatus according to claim 21, wherein said alert generator generates the caution and warning envelopes such that they each have a lower boundary having a lower elevation than the marine vessel and an outward boundary positioned at an outward distance from the marine vessel, such that if the proximate terrain penetrates the boundaries of the caution envelope, said alert generator generates a first level of terrain proximity alert, and if the proximate terrain penetrates the boundaries of the warning envelope, said alert generator generates a second level of terrain proximity alert.

23. An apparatus according to claim 9, wherein said alert generator determines performance characteristics of the marine vessel, and wherein said alert generator generates the predetermined alert distance as a function of a distance required to perform an evasive manuever.

24. An apparatus according to claim 1 further comprising a display in electrical communication with said alert generator, wherein said display displays visual representations of the proximate terrain and colors portions of the proximate terrain if the distance between the surface marine vessel and the proximate terrain is less than the predetermined alert distance.

25. An apparatus according to claim 1, wherein said alert generator generates at least one of a visual and aural alert if the distance between the surface marine vessel and the proximate terrain is less than the predetermined alert distance.

144. The apparatus of claim 9 wherein said alert generator further includes an avoidance maneuver generator that outputs an avoidance guidance signal when the proximate terrain penetrates the envelope.

145. The apparatus of claim 144 wherein said avoidance maneuver generator prevents generation of said alerts when said avoidance guidance signal is asserted.

146. The method of claim 144 further comprising the step of outputting an avoidance guidance signal when the terrain penetrates the envelope.

147. The method of claim 146 further comprising the step of suppressing said alerts when said avoidance guidance signal is asserted.

150. The apparatus of claim 24 wherein said display displays terrain in profile view.

26. A method for generating terrain proximity alerts for use in a surface marine vessel, said method comprising the steps of:

comparing a current coordinate position of the surface marine vessel to a prestored coordinate position of terrain proximate to the surface marine vessel, wherein one of a terrain elevation data or vessel elevation data is corrected to account for tides; and

providing an alert if the distance between the surface marine vessel and the proximate terrain is less than a predetermined alert distance.

27. A method according to claim 26 further comprising the step of storing tide data.

28. A method according to claim 26 further comprising the steps of:

determining a clearance between the vessel and an overhead obstacle proximate the vessel; and

providing an alert if said clearance is less than a predetermined value.

29. A method according to claim 26, wherein said determining step comprises determining a value indicating a depth that the surface marine vessel resides below the surface of the water.

30. A method according to claim 26 further comprising the step of determining the predetermined alert distance based on at least the speed of the surface marine vessel.

31. A method according to claim 26 further comprising the step of determining the predetermined alert distance as a function of a distance required to stop the vessel.

32. A method according to claim 26 further comprising the step of determining the predetermined alert distance, wherein said determining step determines performance characteristics of the marine vessel and determines the predetermined alert distance as a function of a distance required to perform an evasive maneuver.

33. A method according to claim 26, further comprising the step of storing a database containing elevation data for different global coordinates of the earth, wherein said comparing step comprises determining the current coordinate position of the surface marine vessel and searching the memory device for the prestored coordinate position of terrain proximate to the surface marine vessel and said providing step comprises providing an alert if the distance between the surface marine vessel and the proximate terrain is less than a predetermined alert distance.

34. A method according to claim 26 further comprising the step of generating an envelope relative to at least one of the surface marine vessel and the proximate terrain, wherein said comparing step determines if the other of the surface marine vessel and the proximate terrain penetrates the envelope, and wherein said providing step provides an alert if the envelope is penetrated.

35. A method according to claim 34, wherein the surface marine vessel is traveling in a direction defining a track, and wherein said generating step generates an envelope relative to the surface marine vessel in the direction of the track of the surface marine vessel.

36. A method according to claim 35, wherein said generating step generates an envelope relative to the surface marine vessel in the direction of the track of the surface marine vessel having side boundaries extending along the track of the surface marine vessel and spaced apart by a width perpendicular to the track.

37. A method according to claim 35, wherein said generating step generates an envelope relative to the surface marine vessel in the direction of the track of the surface marine vessel having side boundaries extending along the track of the surface marine vessel and spaced apart by a width perpendicular to the track that increases for distances further away from the surface marine vessel.

38. A method according to claim 34, wherein said generating step generates an envelope relative to the surface marine vessel having a lower boundary with a depth representative of a maximum depth of the surface marine vessel and extending outwardly with respect to the surface marine vessel.

39. A method according to claim 34, wherein said generating step generates an envelope relative the surface marine vessel having a lower boundary with a depth greater than the depth of the surface marine vessel and an outward boundary positioned at an outward distance from the surface marine vessel.

40. A method according to claim 39, wherein the depth of the lower boundary is a function of a distance between the current coordinate position of the surface marine vessel and a selected coordinate position.

41. A method according to claim 39, wherein said generating step generates an envelope having a lower boundary having a lower elevation than the surface marine vessel, wherein the elevation of the lower boundary is a function of a distance between the current coordinate position of the surface marine vessel and the coordinate position of a terrain feature proximate to the surface marine vessel.

42. A method according to claim 39, wherein said generating step generates an envelope having the outward boundary positioned at an outward distance from the surface marine vessel, wherein the outward distance is at least a function of a speed of the surface marine vessel.

43. A method according to claim 42, wherein said generating step determines a distance required for the surface marine vessel to stop based on a current speed of the surface marine vessel and generates an envelope having an outward boundary positioned at the determined distance from the surface marine vessel.

44. A method according to claim 42, wherein said generating step determines a distance required for the surface marine vessel to perform an evasive maneuver at a selected turning radius based on at least a current speed of the surface marine vessel, and generates an envelope having an outward boundary positioned at the determined distance from the surface marine vessel.

45. A method according to claim 42, wherein said generating step determines a first distance equal to a distance required for the surface marine vessel to stop based on a current speed of the surface marine vessel, determines a second distance equal to the distance required for the surface marine vessel to perform an evasive maneuver at a selected turning radius based on at least a current speed of the surface marine vessel, and generates an envelope having an outward boundary positioned at the smaller of the first and second distances from the surface marine vessel.

46. A method according to claim 34, wherein said generating step generates a caution envelope relative to the surface marine vessel indicating a first level of terrain proximity alert and a warning envelope relative to the surface operating marine vessel indicating a second level of terrain proximity alert.

47. A method according to claim 46, wherein said generating step generates the caution and warning envelopes such that they each have a lower boundary having a lower elevation than the marine vessel and an outward boundary positioned at an outward distance from the marine vessel, such that if the proximate terrain penetrates the boundaries of the caution envelope, said providing step provides a first level of terrain proximity alert, and if the proximate terrain penetrates the boundaries of the warning envelope, said providing step provides a second level of terrain proximity alert.

48. A method according to claim 34, wherein said generating step determines performance characteristics of the marine vessel, and generates the predetermined alert distance, as a function of a distance required to perform an evasive maneuver.

49. A method according to claim 26 further comprising the step of displaying visual representations of the proximate terrain and colors portions of the proximate terrain if the distance between the surface marine vessel and the proximate terrain is less than the predetermined alert distance.

50. A method according to claim 26, wherein said providing step provides at least one of a visual and aural alert if the distance between the surface marine vessel and the proximate terrain is less than the predetermined alert distance.

153. The method of claim 49 wherein said step of displaying further comprises the step of displaying said visual representations of terrain in profile view.

51. A computer program product for generating terrain proximity alerts for use in a surface marine vessel, wherein the computer program product comprises:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer-readable program code means comprising;

first computer instruction means for comparing a current coordinate position of the surface marine vessel to a prestored coordinate position of terrain proximate to the surface marine vessel, wherein one of a prestored elevations of terrain proximate to the surface marine vessel or a vessel elevation data is corrected to account for tides; and

second computer instruction means for providing an alert if the distance between the surface marine vessel and the proximate terrain is no greater than a predetermined alert distance.

52. A computer program product according to claim 51 further comprising a third computer instruction means for storing tide data.

53. A computer program product according to claim 52 further comprising:

fourth computer instruction means for determining a value indicating a height that the surface marine vessel resides above the surface of the water; and

fifth computer instruction means for determining a clearance height between the vessel and an overhead obstacle proximate the vessel, and wherein said first computer instruction means for compares the height to the clearance height.

54. A computer program product according to claim 51, wherein said fourth computer instruction means determines a value indicating a depth that the surface marine vessel resides below the surface of the water.

55. A computer program product according to claim 51 further comprising third computer instruction means for determining the predetermined alert distance based on at least the speed of the surface marine vessel.

56. A computer program product according to claim 51 further comprising third computer instruction means for determining the predetermined alert distance as a function of a distance required to stop the vessel.

57. A computer program product according to claim 51 further comprising third computer instruction means for determining the predetermined alert distance, wherein said third computer instruction means determines performance characteristics of the marine vessel and determines the predetermined alert distance as a function of a distance required to perform an evasive maneuver.

58. A computer program product according to claim 51, further comprising third computer instruction means for storing a database containing elevation data for different global coordinates of the earth, wherein said first computer instruction means determines the current coordinate position of the surface marine vessel and searches the memory device for the prestored coordinate position of terrain proximate to the surface marine vessel and said second computer instruction means provides an alert if the distance between the surface marine vessel and the proximate terrain is less than a predetermined alert distance.

59. A computer program product according to claim 51 further comprising third computer instruction means for generating an envelope relative to at least one of the surface marine vessel and the proximate terrain, wherein said first computer instruction means determines if the other of the surface marine vessel and the proximate terrain penetrates the envelope, and wherein said second computer instruction means provides an alert if the envelope is penetrated.

60. A computer program instruction means according to claim 59, wherein the surface marine vessel is traveling in a direction defining a track, and wherein said third computer instruction means generates an envelope relative to the surface marine vessel in the direction of the track of the surface marine vessel.

61. A computer program product according to claim 59, wherein said third computer instruction means generates an envelope relative to the surface marine vessel in the direction of the track of the surface marine vessel having side boundaries extending along the track of the surface marine vessel and spaced apart by a width perpendicular to the track.

62. A computer program product according to claim 61, wherein said third computer instruction means generates an envelope relative to the surface marine vessel in the direction of the track of the surface marine vessel having side boundaries extending along the track of the surface marine vessel and spaced apart by a width perpendicular to the track that increases for distances further away from the surface marine vessel.

63. A computer program product according to claim 59, wherein said third computer instruction means generates an envelope relative the surface marine vessel having a lower boundary with a depth representative of a maximum depth of the surface marine vessel and extending outwardly with respect to the surface marine vessel.

64. A computer program product according to claim 59, wherein said third computer instruction means generates an envelope relative the surface marine vessel having a lower boundary with a depth greater than the depth of the surface marine vessel and an outward boundary positioned at an outward distance from the surface marine vessel.

65. A computer program product according to claim 63, wherein the depth of the lower boundary is a function of a distance between the current coordinate position of the surface marine vessel and a selected coordinate position.

66. A computer program product according to claim 60, wherein said third computer instruction means generates an envelope having a lower boundary having a lower elevation than the surface marine vessel, wherein the elevation of the lower boundary is a function of a distance between the current coordinate position of the surface marine vessel and the coordinate position of a terrain feature proximate to the surface marine vessel.

67. A computer program product according to claim 64, wherein said third computer instruction means generates an envelope having the outward boundary positioned at an outward distance from the surface marine vessel, wherein the outward distance is at least a function of a speed of the surface marine vessel.

68. A computer program product according to claim 67, wherein said third computer instruction means determines a distance required for the surface marine vessel to stop based on a current speed of the surface marine vessel and generates an envelope having an outward boundary positioned at the determined distance from the surface marine vessel.

69. A computer program product according to claim 67, wherein said third computer instruction means determines a distance required for the surface marine vessel to perform an evasive maneuver at a selected turning radius based on at least a current speed of the surface marine vessel, and generates an envelope having an outward boundary positioned at the determined distance from the surface marine vessel.

70. A computer program product according to claim 67, wherein said third computer instruction means determines a first distance equal to a distance required for the surface marine vessel to stop based on a current speed of the surface marine vessel, determines a second distance equal to the distance required for the surface marine vessel to perform an evasive maneuver at a selected turning radius based on at least a current speed of the surface marine vessel, and generates an envelope having an outward boundary positioned at the smaller of the first and second distances from the surface marine vessel.

71. A computer program product according to claim 59, wherein said third computer instruction means generates a caution envelope relative to the surface marine vessel indicating a first level of terrain proximity alert and a warning envelope relative to the surface operating marine vessel indicating a second level of terrain proximity alert.

72. A computer program product according to claim 61, wherein said third computer instruction means generates the caution and warning envelopes such that they each have a lower boundary having a lower elevation than the marine vessel and an outward boundary positioned at an outward distance from the marine vessel, such that if the proximate terrain penetrates the boundaries of the caution envelope, said second computer instruction means provides a first level of terrain proximity alert, and if the proximate terrain penetrates the boundaries of the warning envelope, said second computer instruction means provides a second level of terrain proximity alert.

73. A computer program product according to claim 59, wherein said third computer instruction means determines performance characteristics of the marine vessel, and generates the predetermined alert distance as a function of a distance required to perform an evasive maneuver.

74. A computer program product according to claim 60 further comprising fourth computer instruction means for displaying visual representations of the proximate terrain and colors portions of the proximate terrain if the distance between the surface marine vessel and the proximate terrain is less than the predetermined alert distance.

75. A computer program product according to claim 60, wherein said second computer instruction means provides at least one of a visual and aural alert if the distance between the surface marine vessel and the proximate terrain is less than the predetermined alert distance.

148. The computer program product of claim 59 further comprising a fourth computer instruction means for defining an avoidance maneuver and outputting an avoidance guidance signal when the proximate terrain penetrates the envelope.

149. The computer program product of claim 148 further comprising a fifth computer instruction means for suppressing said alerts when said avoidance guidance signal is asserted.

151. The computer program product of claim 74 wherein said fourth computer instruction means further includes means for displaying said visual representations in profile view.

76. An apparatus for alerting the crew of a surface marine vessel of proximity to terrain comprising:

an input adapted to receive signals indicative of a depth below keel;

an output; and

a signal processing device, coupled to said input and said output, for comparing a rate of change of said depth below keel with a predetermined rate and outputting an alert signal when said predetermined rate is exceeded.

77. The apparatus of claim 76 wherein said signal processing device comprises a microprocessor.

78. The apparatus of claim 76 wherein said alert signal comprises an audio alert control signal.

79. The apparatus of claim 76 wherein said alert signal comprises a video control signal useful for controlling a display.

80. The apparatus of claim 76 wherein said predetermined rate is a function of a speed of the vessel.

81. A method for alerting the crew of a surface marine vessel of proximity to terrain comprising the steps of:

(a) sensing a depth below keel;

(b) determining a rate of change of said depth below keel; and

(c) asserting an alert when said rate of change of said depth below keel exceeds a predetermined value.

82. The method of claim 81 wherein said step of asserting an alert further comprises the step of determining said predetermined value as a function of a speed of said vessel.

83. The method of claim 81 wherein said step of asserting an alert comprises the step of asserting an audible alert.

84. The method of claim 81 wherein said step of asserting an alert comprises asserting a video control signal to control a display.

85. A computer program product for alerting the crew of a surface marine vessel of proximity to terrain comprising:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer readable program code means having;

a first computer instruction means for generating a signal indicative of a rate of change of a depth below keel of the vessel;

a second computer instruction means for comparing said rate of change to a predetermined value; and

a third computer instruction means for providing alerts if said rate of change exceeds said predetermined value.

86. A system for alerting the crew of a surface vessel of a potentially hazardous condition comprising:

a terrain database having terrain data and tide data;

a signal processing device coupled to said terrain database and having;

(a) an input adapted to receive signals indicative of a depth of said vessel, a position of said vessel, terrain data, and time;

(b) an output; and

(c) wherein said signal processing device compares said depth of said vessel to terrain information and tide data information stored in said terrain data base at least in a region proximate said vessel and according to a predetermined criterion, and outputs an alert when a potentially hazardous condition is detected.

87. The system of claim 86 further comprising a display for displaying terrain proximate the vessel.

88. The system of claim 87 wherein said terrain proximate said vessel is colored in a plurality of colors according to a degree of hazard.

89. The system of claim 87 wherein a dot pattern used to represent said terrain proximate the vessel is varied in density according to a degree of hazard.

90. The system of claim 86 wherein said signal processing device compares, according to a predetermined criterion, a height of the vessel to a height to clear an obstacle stored in said terrain data base and outputs an alert signal when a potentially hazardous condition is detected.

91. The system of claim 86 wherein said signal processing device compares, according to a predetermined criterion, a height of the vessel to a height to clear an obstacle stored in said terrain data base and outputs an alert signal when a potentially hazardous condition is detected.

92. The system of claim 86 wherein said signal processing device comprises a macroprocessor.

93. The system of claim 86 further comprising:

a data base of vessel performance data; and

wherein said signal processing device compares said position, depth and terrain data according to said predetermined criterion and said vessel performance data.

94. The system of claim 93 wherein:

Said input additionally receives signals indicative of a wind strength and direction and said performance data accounts for a wind effect on vessel performance.

95. The system of claim 93 wherein said performance data includes sea keeping performance data.

96. The system of claim 86 wherein said input receives signals indicative of a depth below keel and wherein said signal processing device outputs an alert when a rate of change of said depth below keel exceeds a predetermined rate.

97. The system of claim 86 wherein said predetermined rate is a function of the speed of the vessel.

98. The system of claim 86 wherein said terrain data comprises both geographic features and man-made structures.

152. The system of claim 87 wherein said display displays said terrain in profile view.

99. A method for alerting the crew of a surface vessel of a potentially hazardous condition comprising the steps of:

(a) retrieving a clearance height value for an obstacle in a vicinity of the vessel from a terrain data base;

(b) comparing said clearance height value to a maximum vessel height according to a predetermined criterion; and

(c) outputting an alert when a potentially hazardous condition is detected in step (b).

100. The method of claim 99 further comprising the step of correcting said maximum vessel height to account for tide conditions.

101. A computer program product for alerting the crew of a surface vessel to a potentially hazardous condition, wherein the computer program product comprises:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer-readable program code means having;

a first computer instruction means for reading from a storage medium, a clearance height value for an obstacle in a vicinity of the vessel;

a second computer instruction means for comparing the said clearance height to a maximum vessel height according to a predetermined criterion; and

a third computer instruction means for providing alerts if said maximum vessel height exceeds said clearance height as defined by said predetermined criterion.

102. The computer program product of claim 101 further comprising:

a fourth computer instruction means for reading a tide data and correcting said maximum vessel height to account for said tide data.

103. A method for alerting the crew of a surface vessel to a potentially hazardous condition comprising the steps of:

(a) defining a protection envelope extending a first predetermined number of ship lengths from the vessel in a direction of travel of the vessel, having a width of a second predetermined number of ship lengths, and having a configurable vertical dimension;

(b) retrieving terrain data from a terrain data base; and

(c) comparing said terrain data to said protection envelope and outputting an alert when said terrain data penetrates said protection envelope.

104. The method of claim 103 wherein said step of retrieving terrain data further comprises the step of retrieving both geographic and man-made structures data.

105. The method of claim 103 wherein said step of defining a protection envelope further includes subdividing said protection envelope into a warning and a caution envelope wherein said warning envelope extends for a first 10 ship lengths and a caution envelope extends for a remaining 5 ship lengths.

106. The method of claim 103 wherein said first and said second predetermined numbers of ship lengths are defined by a distance required to perform a specified maneuver.

107. The method of claim 103 wherein said first predetermined distance is defined as a maximum number of ship lengths permitted for a stopping maneuver.

108. The method of claim 103 wherein said second predetermined distance is defined as a maximum number of ship lengths permitted for a turning maneuver.

109. The method of claim 105 wherein said configurable vertical dimension is approximately two feet at proximate the vessel and expands to at least 10 feet at a distance of 15 ship lengths.

110. A method for alerting the crew of a submerged vessel to a potentially hazardous condition, the method comprising the steps of:

(a) defining a protection envelope having a finite volume;

(b) retrieving terrain data from a terrain data base; and

(c) comparing said terrain data to said protection envelope and outputting an alert when said terrain data penetrates said protection envelope.

111. The method of claim 110 wherein said step of retrieving terrain data includes retrieving both geographic data and man-made structures data.

112. A method to verify points of intended movement of a surface vessel are free of potential collision hazardous comprising the steps of:

(a) identifying the points of intended movement;

(b) comparing a depth of said vessel along said points of intended movement to terrain information stored in a terrain database at least in a region proximate said points of intended movement and according to a predefined criterion;

(c) providing an alert signal when a collision hazard is identified according to said predefined criterion along said points of intended movement.

113. The method of claim 112 wherein said step of providing an alert signal further comprises the step of displaying said collision hazard along said points of intended movement on a display.

114. The method of claim 112 wherein said step of comparing further comprises the step of defining a look/ahead and look/down alert envelope extending in a direction of travel from said vessel along said points of intended movement, and wherein a collision hazard exists when said terrain information is located within the boundaries of said alert envelope.

115. The method of claim 112 wherein said step of comparing further comprises the step of defining a three dimensional uncertainty envelope about said points of intended movement and wherein a collision hazard exists when said terrain information is located within the boundaries of said uncertainty envelope.

116. The method of claim 112 further comprising the step of outputting an alternative track when said collision hazard is identified.

117. An apparatus for strategically identifying potential collision hazards along points of intended movement on a surface vessel comprising:

an input for receiving signals representative of said points of intended movement, and coupled to a data base of stored terrain information;

an output; and

a signal processing device coupled to said input and said output, for

comparing a depth of said vessel along said points of intended movement to terrain information stored in said terrain database at least in a region proximate to said points of intended movement;

determining, according to a predetermined criterion, whether a collision hazard exists along said points of intended movement; and

asserting an alert signal when said collision hazard is determined to exist.

118. The apparatus of claim 117 wherein said signal processing device comprises a microprocessor.

119. The apparatus of claim 117 wherein said signal processing device further includes means for asserting a video control signal useful for controlling display of said collision hazard along said points of intended movement on a display.

120. The apparatus of claim 117 wherein said signal processing device further comprises an avoidance logic device for determining an alternate course when said collision hazard is detected.

121. A computer program product for identifying potential collision hazards along points of intended movement of a surface vessel comprising:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer-readable program code means comprising;

first computer instruction means for receiving signals representative of points of intended movement of the vessel;

second computer instruction means for accessing a database of terrain information; and

third computer instruction means for determining, according to a predetermined criterion, whether a collision hazard exists along said points of intended movement and for asserting an alert signal when said collision hazard is determined to exist.

122. The computer program product of claim 121 further comprising a fourth computer instruction means for controlling a video display to display said collision hazard along said points of intended movement.

123. The computer program product of claim 121 further comprising a fourth computer instruction means for determining an alternate course when said collision hazard is detected.

124. A method for assisting the crew of a surface vessel in avoiding a grounding incident comprising the steps of:

accessing a database of terrain information;

receiving signals representative of a position, speed, and one of a projected track or path angle of the vessel;

defining a protection envelope with respect to the vessel;

comparing said protection envelope to terrain proximate said vessel;

determining an avoidance maneuver when said terrain penetrates said protection envelope; and

outputting an avoidance guidance signal based on said avoidance maneuver.

125. The method of claim 124 wherein said step of defining a protection envelope further comprises the step of defining a look/ahead and look/down alert envelope extending in a direction of travel from said vessel and wherein a collision hazard exists when said terrain information is located within the boundaries of said alert envelope.

126. The method of claim 124 wherein said step of comparing further comprises the step of defining a three dimensional uncertainty envelope along a projected track of the vessel and wherein a collision hazard exists when said terrain information is located within the boundaries of said uncertainty envelope.

127. The method of claim 124 wherein said step of determining an avoidance manouevre further comprises the steps of:

(a) incrementing a current vessel heading to obtain a candidate heading;

(b) comparing said protection envelope to terrain proximate said vessel along said candidate heading;

(c) repeating steps (a) and (b) when said terrain penetrates said protection envelope along said candidate heading until an avoidance heading is found wherein said terrain remains clear of said protection envelope.

128. The method of claim 127 wherein said step of determining an avoidance maneuver further comprises the step of evaluating a vessel performance maneuver.

129. The method of claim 127 wherein said step of outputting an avoidance guidance signal comprises the step of displaying an alternate course on a display.

130. The method of claim 127 wherein said step of outputting an avoidance guidance signal comprises the step of providing an audible guidance command.

131. The method of claim 127 wherein said step of outputting an avoidance guidance signal comprises the step of displaying a performance maneuver guidance command on a display.

132. An apparatus for assisting the crew of a surface vessel in avoiding a grounding incident comprising:

an input for receiving signals representative of a speed and one of a projected track or path angle of the vessel, and coupled to a data base of stored terrain information;

an output; and

a signal processing device coupled to said input and said output, for

defining a protection envelope with respect to the vessel;

comparing said protection envelope to terrain proximate said vessel;

determining an avoidance manouevre when said terrain penetrates said protection envelope; and

outputting an avoidance guidance signal based on said avoidance manouevre.

133. The apparatus of claim 132 wherein said avoidance guidance signal comprises a signal useful for controlling display of an alternate course on a display.

134. The apparatus of claim 132 wherein said avoidance guidance signal comprises a signal useful for providing an audible guidance command.

135. The apparatus of claim 132 wherein said avoidance guidance signal comprises a signal useful for controlling display of a performance maneuver guidance command on a display.

136. A computer program product for assisting the crew of a surface vessel to avoid a grounding incident comprising:

a computer readable storage medium having computer readable program code means embodied in said medium, said computer-readable program code means comprising;

first computer instruction means for accessing a database of terrain information;

a second computer instruction means for defining a protection envelope with respect to the vessel;

a fourth computer instruction means for comparing said protection envelope to terrain proximate said vessel;

a fifth computer instruction means for determining an avoidance maneuver when said terrain penetrates said protection envelope; and

a sixth computer instruction means for outputting an avoidance guidance signal based on said avoidance maneuver.

137. The computer program product of claim 136 wherein said fourth computer instruction means further comprises a seventh computer instruction means defining a protection envelope further comprises the step of defining a look/ahead and look/down alert envelop extending in a direction of travel from said vessel and wherein a collision hazard exists when said terrain information is located within the boundaries of said alert envelop.

138. The computer program product of claim 136 wherein said fourth computer instruction means further comprises a seventh computer instruction means defining a three dimensional uncertainty envelope along a projected track of the vessel and wherein a collision hazard exists when said terrain information is located within the boundaries of said uncertainty envelope.

139. The computer program product of claim 136 wherein said fifth computer instruction means further comprises:

(a) a seventh computer instruction means for incrementing a current vessel heading to obtain a candidate heading;

(b) an eighth computer instruction means for comparing said protection envelope to terrain proximate said vessel along said candidate heading;

(c) a ninth computer instruction means for repeating steps (a) and (b) when said terrain penetrates said protection envelope along said candidate heading until an avoidance heading is found wherein said terrain remains clear of said protection envelope.

140. The computer program product of claim 136 wherein said fifth computer instruction means further comprises a seventh computer instruction means for evaluating a vessel performance maneuver.

141. The computer program product of claim 136 wherein said sixth computer instruction means further comprises a seventh computer instruction means for displaying an alternate course on a display.

142. The computer program product of claim 136 wherein said sixth computer instruction means further comprises a seventh computer instruction means for providing an audible guidance command.

143. The computer program product of claim 136 wherein said sixth computer instruction means further comprises a seventh computer instruction means for displaying a performance maneuver guidance command on a display.