Contact-analog headup display method and apparatus

• US 5,072,218 A
• Filed: 02/24/1988
• Issued: 12/10/1991
• Est. Priority Date: 02/24/1988
• Status: Expired due to Term

• Current Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: United Technologies Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Stiles, Lorren, Kass, Robert C., Spero, Robert E., Wright, Thomas E., Harper, Howard P., Licari, James J., Hamilton, Bruce E.
• Primary Examiner(s): Crosland, Donnie L.
• Assistant Examiner(s): Swarthout, Brent A.
• Application Number:
  US07/160,222
• Time in Patent Office: 1,385 Days
• Field of Search: 340/971, 340/980, 340/705, 340/721, 350/174, 434/44, 73/178 R, 358/103, 358/250, 364/432, 364/439, 364/441, 364/443, 364/444, 364/448, 364/457, 364/460, 364/462
• US Class Current: 340/980
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 2027/014 comprising information/image processing systems
• CPC Class Codes: G02B 2027/0187 slaved to motion of at least a part of the body of the user, e.g. head, eye
• CPC Class Codes: G02B 2027/0198 System for aligning or maintaining alignment of an image in a predetermined direction
• CPC Class Codes: G02B 27/017 Head mounted

Abstract

Images are provided to a pilot in an aircraft overflying the earth by means of a helmet mounted display system. The position and attitude of the aircraft with respect to the earth and the attitude of the helmet with respect to the aircraft are monitored in order to convert a plurality of stored earth position signals into helmet coordinates. Earth points which are viewable by the pilot are displayed using symbolic images thereof such that the symbolic images coincide, from the pilot'"'"'s point of view, with the actual positions of the viewable points on the earth.

Claims

1. A method for providing, within a helmet, symbolic images to a pilot in an aircraft, comprising the steps of:

sensing the position and attitude of the aircraft with respect to the earth and providing an aircraft position signal and an aircraft attitude signal respectively indicative thereof;

sensing the attitude of the helmet with respect to the aircraft and providing a helmet attitude signal indicative thereof;

determining, in response to said aircraft position signal, said aircraft attitude signal and said helmet attitude signal, the position and attitude of the helmet with respect to the each and respectively providing a helmet position signal and a transformed helmet attitude signal indicative thereof;

storing a plurality of earth position signals indicative of a sequence of waypoint position signals indicative of the positions of waypoints in a selected flight path with respect to the earth;

retrieving from storage, in response to said aircraft position signal, a current waypoint position signal indicative of the position of the current waypoint in the flight path;

determining, in response to said helmet position and transformed helmet attitude signals and said current waypoint position signal, the position of said current waypoint with respect to the helmet and providing a helmet-oriented current waypoint position signal indicative thereof;

ascertaining, in response to said helmet-oriented current waypoint position signal and said transformed helmet attitude signal, whether the position of the current waypoint is within the pilot'"'"'s field of view and, if so,

retrieving from storage, one or more symbolic image signals corresponding to said retrieved current waypoint position signal;

providing, in response to said helmet-oriented current waypoint position signal and said retrieved symbolic image signals, one or more symbolic images indicative of said current waypoint so as to coincide, from the point of view of the pilot, with the actual position of the current waypoint on the earth; and

wherein if it were determined in said ascertaining step that the position of the current waypoint is not within the pilot'"'"'s field of view, performing the further step of providing an image of a symbol indicative of the direction in which the pilot'"'"'s head or aircraft may be turned in order to bring a symbolic image of the current waypoint within the pilot'"'"'s field of view.

2. A method for providing, within a helmet, symbolic images to a pilot in an aircraft, comprising the steps of:

sensing the position and attitude of the aircraft with respect to the earth and providing an aircraft position signal and an aircraft attitude signal respectively indicative thereof;

sensing the attitude of the helmet with respect to the aircraft and providing a helmet attitude signal indicative thereof;

determining, in response to said aircraft position signal, said aircraft attitude signal and said helmet attitude signal, the position and attitude of the helmet with respect to the earth and respectively providing a helmet position signal and a transformed helmet attitude signal indicative thereof;

storing a plurality of earth position signal indicative of a sequence of waypoint position signals indicative of the positions of waypoints in a selected flight path with respect to the earth;

retrieving from storage, in response to said aircraft position signal, a current waypoint position signal indicative of the position of the current waypoint in the flight path;

determining, in response to said helmet position and transformed helmet attitude signals and said current waypoint position signal, the position of said current waypoint with respect to the helmet and providing a helmet-oriented current waypoint position signal indicative thereof;

ascertaining, in response to said helmet-oriented current waypoint position signal and said transformed helmet attitude signal, whether the position of the current waypoint is within the pilot'"'"'s field of view and, if so,

retrieving from storage, one or more symbolic image signals corresponding to said retrieved current waypoint position signal;

providing, in response to said helmet-oriented current waypoint position signal and said retrieved symbolic image signals, one or more symbolic images indicative of said current waypoint so as to coincide, from the point of view of the pilot, with the actual position of the current waypoint on the earth; and

wherein said step of retrieving a current waypoint position signal comprises the steps of;

retrieving a first waypoint position signal from said stored sequence of waypoint position signals and identifying said first retrieved signal as said current waypoint position signal;

retrieving a second waypoint position signal stored sequentially after said first waypoint position signal and identifying said second retrieved signal as a next waypoint position signal indicative of the position of the next waypoint in said selected flight path after said current waypoint;

determining, in response to said helmet position signal and said current waypoint position signal, whether the distance between the helmet and the current waypoint is less than a first selected distance and, if so, identifying said second retrieved waypoint position signal as indicative of the current waypoint and, if not,

determining, in response to said helmet position signal and said next waypoint position signal, whether the distance between the helmet and the current waypoint is less than a second selected distance (which is greater than said first selected distance) and, if so, determining whether both the distance between the current aircraft position and the current waypoint is increasing and the distance between the current aircraft position and the next waypoint is decreasing and, if both are so, identifying said second retrieved waypoint position signal as indicative of the current waypoint.

3. A method for providing, within a helmet, symbolic images to a pilot in an aircraft, comprising the steps of:

sensing the position and attitude of the aircraft with respect to the earth and providing an aircraft position signal and an aircraft attitude signal respectively indicative thereof;

sensing the attitude of the helmet with respect to the aircraft and providing a helmet attitude signal indicative thereof;

determining, in response to said aircraft position signal, said aircraft attitude signal and said helmet attitude signal, the position and attitude of the helmet with respect to the earth and respectively providing a helmet position signal and a transformed helmet attitude signal indicative thereof;

storing a plurality of earth position signals indicative of a sequence of waypoint position signals indicative of the positions of waypoints in a selected flight path with respect to the earth;

retrieving from storage, in response to said aircraft position signal, a current waypoint position signal indicative of the position of the current waypoint in the flight path;

determining, in response to said helmet position and transformed helmet attitude signals and said current waypoint position signal, the position of said current waypoint with respect to the helmet and providing a helmet-oriented current waypoint position signal indicative thereof;

ascertaining, in response to said helmet-oriented current waypoint position signal and said transformed helmet attitude signal, whether the position of the current waypoint is within the pilot'"'"'s field of view and, is so,

retrieving from storage, one or more symbolic image signals corresponding to said retrieved current waypoint position signal;

providing, in response to said helmet-oriented current waypoint position signal and said retrieved symbolic image signals, one or more symbolic images indicative of said current waypoint so as to coincide, from the point of view of the pilot, with the actual position of the current waypoint on the earth; and

wherein said step of retrieving a current waypoint position signal also retrieves a last waypoint position signal stored just preceding said current waypoint position signal and a next waypoint position signal stored just subsequent to said current waypoint position signal, and further comprising the steps of;

determining, in response to said aircraft position signal and said last waypoint position signal and said current waypoint position signal, an angle (A) between a line from the current aircraft position to the current waypoint and a current flight leg line from the last waypoint to the current waypoint, and providing a first angle signal having a magnitude indicative of the magnitude of angle (A);

determining, in response to said first angle signal, an angle (B) equal to the arctangent of a constant (K) times the tangent of angle A and providing a second angle signal having a magnitude indicative of the magnitude of angle (B); and

wherein said step of providing one or more stored symbolic images further comprises the step of providing an image of a steering cue offset from said image of said current waypoint by an angle defined by the relation {180-[(180-B)+A]} between a line from said current aircraft position to said current waypoint and a line intersecting said current aircraft position and said current flight leg line.