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

• US 6,734,808 B1
• Filed: 06/26/2000
• Issued: 05/11/2004
• 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): TWEEL JR, JOHN ALEXANDER
• Application Number:
  US09/606,766
• Time in Patent Office: 1,415 Days
• Field of Search: 340/984, 342/357.13, 367/909, 367/99, 367/128, 701/208
• US Class Current: 340/984
• 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 79/20 using models or simulation, e.g. statistical models or stochastic models
• CPC Class Codes: B63B 79/30 for diagnosing, testing or predicting the integrity or performance of vessels
• 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 21/22 Plotting boards
• 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: Y10S 367/909 Collision avoidance

Abstract

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

Claims

1. An apparatus for alerting the crew of a submerged vessel of proximity to terrain, said apparatus comprising:

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

an output; and

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

defining a look ahead distance as a function of the speed of the vessel;

defining a first alert envelope indicative of a first level of terrain proximity alert, wherein boundaries of the first alert envelope are determined as a first function of the position path angle, and look ahead distance;

defining a second alert envelope indicative of a second level of terrain proximity alert, wherein boundaries of the second alert envelope are determined as a second function of the position path angle, and look ahead distance; and

outputting an alert signal when a subset of the stored terrain information is located within the boundaries of at least one of the first and second alert envelopes.

2. An apparatus according to claim 1, wherein said signal processing device defines at least one of the first and second envelopes to be bounded by a cutoff envelope.

3. An apparatus according to claim 1, wherein said signal processing device further defines at least one of the first and second envelopes as a function of a configurable datum.

4. An apparatus according to claim 1, wherein said signal processing device further defines at least one of the first and second envelopes to include a subset of alert envelopes representing various severities of hazard to the vessel.

5. An apparatus according to claim 1, wherein said signal processing device comprises a microprocessor.

6. An apparatus according to claim 1, wherein said signal processing device device comprises a means for outputting the alert signal as a video control signal, wherein the video control signal is useful for controlling representations of terrain on a video display in various colors according to a degree of terrain threat.

7. An apparatus according to claim 1 further comprising a aural warning generator coupled to said signal processing device, and wherein the alert signal output from said signal processing device comprises an audio control signal to command said aural warning generator to output an aural alert.

86. The apparatus of claim 1 where said signal processing device determines an avoidance maneuver and outputs an avoidance guidance signal when said subset of terrain information is located within the boundaries of said first or said second alert envelopes.

96. The apparatus of claim 6 wherein said video control signal is useful for controlling said representations of terrain in profile view.

8. A method for alerting the crew of a submerged vessel of proximity to terrain comprising the steps of:

accessing a database of terrain information;

receiving signals representative of a position, speed, and a path angle of the vessel;

defining a look ahead distance as a function of the speed of the vessel;

defining a first alert envelope indicative of a first level of terrain proximity alert, wherein boundaries of the first alert envelope are determined as a first function of the position path angle, and look ahead distance;

defining a second alert envelope indicative of a second level of terrain proximity alert, wherein boundaries of the second alert envelope are determined as a second function of the path angle, look ahead distance, and the terrain floor boundary; and

outputting an alert signal when a subset of the stored terrain information is located within the boundaries of at least one of the first and second alert envelopes.

9. A method according of claim 8, wherein said step of outputting an alert signal further comprises the step of outputting a video control signal to control display of terrain on a display device.

10. A method according to claim 8 further comprising the step of defining a cut off envelope to form a boundary of at least one of the first and second alert envelopes.

11. A method according to claim 8, wherein said outputting step comprises outputting an audio control signal to generate an aural alarm.

12. A method according to claim 8, wherein at least one of said defining an alert envelope steps comprises defining at least one of the first and second envelopes as a function of a configurable datum.

13. A method according to claim 8, wherein at least one of said defining an alert envelope steps comprises defining at least one of the first and second envelopes to include a subset of alert envelopes representing various severities of hazard to the marine vessel.

87. The method of claim 8 further comprising the step of outputting an avoidance guidance signal when said terrain information is located within the boundaries of said first or said second alert envelopes.

97. The method of claim 8 wherein said step of outputting a video control signal includes a signal to display terrain in profile view.

14. A computer program product for alerting the crew of a submerged vessel of proximity to terrain, 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 accessing a database of terrain information;

second computer instruction means for receiving signals representative of a position, speed, and a path angle of the vessel;

third computer instruction means for defining a look ahead distance as a function of the speed of the vessel;

fourth computer instruction means for defining a first alert envelope indicative of a first level of terrain proximity alert, wherein boundaries of the first alert envelope are determined as a first function of the position path angle, and look ahead distance;

fifth computer instruction means for defining a second alert envelope indicative of a second level of terrain proximity alert, wherein boundaries of the second alert envelope are determined as a second function of the position path angle, and look ahead distance; and

sixth computer instruction means for outputting an alert signal when a subset of the stored terrain information is located within the boundaries of at least one of the first and second alert envelopes.

15. A computer program product according to claim 14, wherein said sixth computer instruction means further outputs a video control signal to control display of terrain on a display device.

16. A computer program product according to claim 14, further comprising seventh computer instruction means for defining a cut off envelope to form a boundary of at least one of the first and second alert envelopes.

17. A computer program product according to claim 14, wherein said sixth computer instruction means further outputs an audio control signal to generate an aural alarm.

18. A computer program product according to claim 14, wherein said at least one of said fourth and fifth computer instruction means defines at least one of the first and second envelopes as a function of a configurable datum.

19. A computer program product according to claim 14, wherein said at least one of said fourth and fifth computer instruction means defines at least one of the first and second envelopes to include a subset of alert envelopes representing various severities of hazard to the vessel.

88. The computer program product of claim 14 further comprising a seventh computer instruction means for defining an avoidance maneuver and outputting an avoidance guidance signal when said stored terrain information is located within the boundaries of at least one of said first or said second alert envelopes.

89. The computer program product of claim 88 further comprising an eighth computer instruction means for preventing output of said alert signal when said avoidance guidance signal is output.

98. The computer program product of claim 15 wherein said video control signal includes a signal to display said terrain in profile view.

20. An apparatus for generating terrain proximity alerts for use in a submerged vessel, said apparatus comprising an alert generator that generates an envelope with respect to the vessel and having a lower boundary based on a depth of said vessel and extending outwardly along a path vector of the vessel, wherein said alert generator compares the envelope to terrain proximate to the vessel and generates alerts if the proximate terrain penetrates the envelope.

21. An apparatus according to claim 20, wherein said alert generator compares prestored elevations of terrain proximate to the vessel to the elevation of the lower boundary of the envelope and generates an alert if the elevation of the terrain is at least as great as the elevation of the lower boundary of the envelope.

22. An apparatus according to claim 20, wherein said alert generator generates an envelope relative to the vessel having a lower boundary with a depth greater than the vessel and an outer boundary positioned at an outward distance from the marine vessel.

23. An apparatus according to claim 22, wherein said alert generator generates the outer distance of the outward boundary based on at least the speed of the vessel.

24. An apparatus according to claim 22, wherein said alert generator generates the outer boundary as a function of the performance characteristics of the vessel.

25. An apparatus according to claim 22, wherein said alert generator determines the outer boundary as a function of a distance required for the vessel to stop based on a current speed of the marine vessel.

26. An apparatus according to claim 22, wherein said alert generator determines the outer distance as a function of a distance required for the vessel to perform an evasive maneuver.

27. An apparatus according to claim 22, wherein said alert generator determines a first distance equal to a distance required for the vessel to stop based on a current speed of the vessel, wherein said alert generator further determines a second distance equal to the distance required for the vessel to perform an evasive maneuver at a selected turning radius based on at least a current speed of the vessel, and wherein said alert generator generates an envelope having an outer boundary positioned at an outward that is the smaller of the first and second distances.

28. An apparatus according to claim 20, wherein the vessel is traveling in a direction defining a track, and wherein said alert generator generates an envelope relative to the vessel in the direction of the track of the vessel.

29. An apparatus according to claim 28, wherein said alert generator generates an envelope relative to the vessel in the direction of the track of the vessel and having side boundaries extending along the track of the vessel and spaced apart by a width perpendicular to the track.

30. An apparatus according to claim 28, wherein said alert generator generates an envelope relative to the vessel in the direction of the track of the marine having side boundaries extending along the track of the vessel and spaced apart by a width perpendicular to the track that increases for distances further away from the vessel.

31. An apparatus according to claim 20, wherein said alert generator generates a caution envelope relative to the vessel indicating a first level of terrain proximity alert and a warning envelope relative to the vessel indicating a second level of terrain proximity alert.

32. An apparatus according to claim 31, wherein said alert generator generates the caution and warning envelopes such that they each have a lower boundary having a lower elevation than the vessel and an outward boundary positioned at an outward distance from the 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.

33. An apparatus according to claim 20 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 according to a degree of hazard to the vessel.

34. An apparatus according to claim 20, wherein said alert generator generates at least one of a visual and aural alert if the proximate terrain penetrates the envelope.

90. The apparatus of claim 20 wherein said alert generator further includes an avoidance maneuver generator that outputs an avoidance guidance signal when the proximate terrain penetrates the envelope.

91. The apparatus of claim 90 wherein said avoidance maneuver generator prevents generation of said alerts when said avoidance guidance signal is asserted.

99. The apparatus of claim 33 wherein said display displays terrain in profile view.

35. A method for generating terrain proximity alerts for use in a submerged vessel, said method comprising the steps of:

generating an envelope with respect to the vessel wherein said envelope has a volume and has a lower boundary based on a depth of said vessel and extends outwardly along a path vector of said vessel;

comparing the envelope to terrain proximate to the vessel; and

providing alerts if the proximate terrain penetrates the envelope.

36. A method according to claim 35, wherein said comparing step compares prestored elevations of terrain proximate to the vessel to the elevation of the lower boundary of the envelope and said providing step provides an alert if the elevation of the terrain is at least as great as the elevation of the lower boundary of the envelope.

37. A method according to claim 35, wherein said generating step generates an envelope relative to the vessel having a lower boundary with a lower depth greater than the vessel and an outer boundary positioned at an outward distance from the vessel.

38. A method according to claim 37, wherein said generating step generates the outward distance of the outward boundary based on at least the speed of the vessel.

39. A method according to claim 37, wherein said generating step generates the outer distance of the outward boundary based on the performance characteristics of the vessel.

40. A method according to claim 37, wherein said generating step determines the outward distance as a distance required for the vessel to stop based on a current speed of the vessel.

41. A method according to claim 37, wherein said generating step determines the outer distance as a distance required for the vessel to perform an evasive maneuver.

42. A method according to claim 37, wherein said generating step determines a first distance equal to a distance required for the vessel to stop based on a current speed of the vessel, wherein said generating step further determines a second distance equal to the distance required for the vessel to perform an evasive maneuver at a selected turning radius based on at least a current speed of the vessel, and wherein said generating step generates an envelope having an outer boundary positioned at the smaller of the first and second distances.

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

44. A method according to claim 43, wherein said generating step generates an envelope relative to the vessel in the direction of the track of the vessel having side boundaries extending along the track of the vessel and spaced apart by a width perpendicular to the track.

45. A method according to claim 43, wherein said generating step generates an envelope relative to the vessel in the direction of the track of the vessel and having side boundaries extending along the track of the vessel and spaced apart by a width perpendicular to the track that increases for distances further away from the vessel.

46. A method according to claim 35, wherein said generating step generates a caution envelope relative to the vessel indicating a first level of terrain proximity alert and a warning envelope relative to the 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 vessel and an outward boundary positioned at an outward distance from the 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 35 further comprising the step of displaying visual representations of the proximate terrain and colors portions of the proximate terrain if the proximate terrain penetrates the envelope.

49. A method according to claim 35, wherein said providing step provides at least one of a visual and aural alert if the proximate terrain penetrates the envelope.

92. The method of claim 35 further comprising the step of outputting an avoidance guidance signal when the terrain penetrates the envelope.

93. The method of claim 92 further comprising the step of suppressing said alerts when said avoidance guidance signal is asserted.

50. A computer program product for generating terrain proximity alerts for use in a submerged 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 generating an envelope with respect to the vessel having a lower boundary extending outwardly along a path vector of the vessel;

second computer instruction means for comparing the envelope to terrain proximate to the vessel; and

third computer instruction means for providing alerts if the proximate terrain penetrates the envelope.

51. A computer program product according to claim 50, wherein said second computer instruction means compares prestored depths of terrain proximate to the vessel to a depth of the lower boundary of the envelope and said third computer instruction means provides an alert if the depth of the terrain is less than or equal to the depth of the lower boundary of the envelope.

52. A computer program product according to claim 50, wherein said first computer instruction means generates an envelope relative to the vessel having a lower boundary with a lower depth greater than the vessel and an outer boundary positioned at an outward distance from the vessel.

53. A computer program product according to claim 52, wherein said first computer instruction means generates the outer distance of the outward boundary based on at least the speed of the vessel.

54. A computer program product according to claim 52, wherein said first computer instruction means generates the outer distance of the outward boundary based on performance characteristics of the vessel.

55. A computer program product according to claim 52, wherein said first computer instruction means determines the outer distance as a function of distance required for the vessel to stop.

56. A computer program product according to claim 52, wherein said first computer instruction means determines the outer distance as a distance required for the vessel to perform an evasive maneuver.

57. A computer program product according to claim 52, wherein said first computer instruction means determines a first distance equal to a distance required for the vessel to stop based on a current speed of the vessel, wherein said first computer instruction means further determines a second distance equal to the distance required for the vessel to perform an evasive maneuver at a selected turning radius based on at least a current speed of the vessel, and wherein said first computer instruction means generates an envelope having an outward boundary positioned at the smaller of the first and second distances.

58. A computer program product according to claim 50, wherein the vessel is traveling in a direction defining a track, and wherein said first computer instruction means generates an envelope relative to the vessel in the direction of the track of the vessel.

59. A computer program product according to claim 58, wherein said first computer instruction means generates an envelope relative to the vessel in the direction of the track of the vessel having side boundaries extending along the track of the vessel and spaced apart by a width perpendicular to the track.

60. A computer program product according to claim 58, wherein said first computer instruction means generates an envelope relative to the vessel in the direction of the track of the vessel having side boundaries extending along the track of the vessel and spaced apart by a width perpendicular to the track that increases for distances further away from the vessel.

61. A computer program product according to claim 50, wherein said first computer instruction means generates a caution envelope relative to the vessel indicating a first level of terrain proximity alert and a warning envelope relative to the vessel indicating a second level of terrain proximity alert.

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

63. A computer program product according to claim 50 further comprising the fourth computer instruction means for displaying visual representations of the proximate terrain and colors portions of the proximate terrain if the proximate terrain penetrates the envelope.

64. A computer program product according to claim 50, wherein said third computer instruction means provides at least one of a visual and aural alert if the proximate terrain penetrates the envelope.

94. The computer program product of claim 50 further comprising a fourth computer instruction means for defining and avoidance maneuver and outputting an avoidance guidance signal when the proximate terrain penetrates the envelope.

95. The computer program product of claim 94 further comprising a fifth computer instruction means for suppressing said alerts when said avoidance guidance signal is asserted.

100. The computer program product of claim 63 wherein said fourth computer instruction means further includes means for displaying said visual representations in profile view.

65. An apparatus for alerting the crew of a submerged 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.

66. The apparatus of claim 65 wherein said signal processing device comprises a microprocessor.

67. The apparatus of claim 65 wherein said alert signal comprises an audio alert control signal.

68. The apparatus of claim 65 wherein said alert signal comprises a video control signal useful for controlling a display.

69. The apparatus of claim 65 wherein said predetermined rate is a function of a speed of the vessel.

70. A method for alerting the crew of a submerged 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.

71. The method of claim 70 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.

72. The method of claim 70 wherein said step of asserting an alert comprises the step of asserting an audible alert.

73. The method of claim 70 wherein said step of asserting an alert comprises asserting a video control signal to control a display.

74. A computer program product for alerting the crew of a submerged 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.

75. A system for alerting the crew of a submersed vessel of a potentially hazardous condition comprising:

a terrain database;

a signal processing device coupled to said terrain data base and having;

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

(b) an output;

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

(d) wherein said signal processing device outputs an alert when a rate of change of said depth exceeds a predetermined rate.

76. The system of claim 75 further comprising a display for displaying terrain proximate the vessel.

77. The system of claim 76 wherein said terrain proximate said vessel is colored in a plurality of colors according to a degree of hazard.

78. The system of claim 76 wherein a dot pattern used to represent said terrain proximate the vessel is varied in density according to a degree of hazard.

79. The system of claim 76 wherein said display displays terrain proximate the vessel in profile view.

80. The system of claim 75 wherein said signal processing device comprises a microprocessor.

81. The system of claim 75 wherein said signal processing device determines an avoidance maneuver and outputs an avoidance guidance signal when said potentially hazardous condition is detected.

82. The system of claim 75 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.

83. The system of claim 75 wherein said predetermined rate is a function of the speed of the vessel.

84. The system of claim 75 wherein said terrain data comprises both geographic features and man-made structures.

101. The system of claim 76 wherein said display displays said terrain in profile view.

85. 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.

102. A method to verify points of intended movement of a submerged 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.

103. The method of claim 102 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.

104. The method of claim 102 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.

105. The method of claim 102 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.

106. The method of claim 102 further comprising the step of outputting an alternative track when said collision hazard is identified.

107. An apparatus for strategically identifying potential collision hazards along points of intended movement on a submerged 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.

108. The apparatus of claim 107 wherein said signal processing device comprises a microprocessor.

109. The apparatus of claim 107 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.

110. The apparatus of claim 107 wherein said signal processing device further comprises an avoidance logic device for determining an alternate course when said collision hazard is detected.

111. A computer program product for identifying potential collision hazards along points of intended movement of a submerged 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.

112. The computer program product of claim 111 further comprising a fourth computer instruction means for controlling a video display to display said collision hazard along said points of intended movement.

113. The computer program product of claim 111 further comprising a fourth computer instruction means for determining an alternate course when said collision hazard is detected.

114. A method for assisting the crew of a submerged 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 an said avoidance maneuver.

115. The method of claim 114 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.

116. The method of claim 114 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.

117. The method of claim 114 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.

118. The method of claim 117 wherein said step of determining an avoidance maneuver further comprises the step of evaluating a vessel performance maneuver.

119. The method of claim 117 wherein said step of outputting an avoidance guidance signal comprises the step of displaying an alternate course on a display.

120. The method of claim 117 wherein said step of outputting an avoidance guidance signal comprises the step of providing an audible guidance command.

121. The method of claim 117 wherein said step of outputting an avoidance guidance signal comprises the step of displaying a performance manouevre guidance command on a display.

122. An apparatus for assisting the crew of a submerged 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 maneuver when said terrain penetrates said protection envelope; and

outputting an avoidance guidance signal based on said avoidance maneuver.

123. The apparatus of claim 122 wherein said avoidance guidance signal comprises a signal useful for controlling display of an alternate course on a display.

124. The apparatus of claim 122 wherein said avoidance guidance signal comprises a signal useful for providing an audible guidance command.

125. The apparatus of claim 122 wherein said avoidance guidance signal comprises a signal useful for controlling display of a performance maneuver guidance command on a display.

126. A computer program product for assisting the crew of a submerged 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 third computer instruction means for comparing said protection envelope to terrain proximate said vessel;

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

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

127. The computer program product of claim 126 wherein said third computer instruction means further comprises a sixth computer instruction means 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.

128. The computer program product of claim 126 wherein said third computer instruction means further comprises a sixth 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.

129. The computer program product of claim 126 wherein said fourth computer instruction means further comprises:

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

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

(c) an eighth 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.

130. The computer program product of claim 126 wherein said fourth computer instruction means further comprises a sixth computer instruction means for evaluating a vessel performance maneuver.

131. The computer program product of claim 126 wherein said fifth computer instruction means further comprises a sixth computer instruction means for displaying an alternate course on a display.

132. The computer program product of claim 126 wherein said fifth computer instruction means further comprises a sixth computer instruction means for providing an audible guidance command.

133. The computer program product of claim 126 wherein said fifth computer instruction means further comprises a sixth computer instruction means for displaying a performance maneuver guidance command on a display.