FIRE CONTROL SYSTEM

• US 3,694,095 A
• Filed: 08/05/1970
• Issued: 09/26/1972
• Est. Priority Date: 08/05/1970
• Status: Expired due to Term

• Current Assignee: John D. Louthan
• Original Assignee: John D. Louthan
• Inventors: Louthan, John D.
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): McGraw, V. P.
• Application Number:
  US05/061,133
• Time in Patent Office: 783 Days
• Field of Search: 356/254,255 350/52,301,304 33/46.5,49R,49A,46AS
• US Class Current: 356/255
• CPC Class Codes: G02B 17/02 Catoptric systems, e.g. image erecting and reversing system
• CPC Class Codes: G02B 23/08 Periscopes arrangements on floating structures of underwater viewing devices B63C11/49; arrangement of visual watch equipment on submarines B63G8/38
• CPC Class Codes: G02B 23/14 Viewfinders for photographic apparatus G03B13/02

Abstract

A first, fixed mirror is placed in the path of light passing to a boresight reticle and inclined at an angle to the boresight axis. A second mirror is positioned transversely to said boresight axis and reflects the image of a target to the first mirror and thence along the boresight axis to the boresight reticle. The second mirror is rotatable about two axes, the first axis lying in the plane of the first mirror and intersecting said boresight axis at a right angle, and the second axis lying in the plane of the second mirror and parallel to the first axis. Computing means are provided to determine the desired (correct) lead angle, the actual lead angle and the lead angle error between the intercepting aircraft and the target, and to produce signals indicative of the error. Means are provided for receiving the error signals and for responding thereto to rotate said second mirror about its second axis to center the target image on the boresight reticle when the actual lead angle is equal to the correct lead angle and to rotate said second mirror about its first axis to displace the target image with respect to the boresight reticle to indicate the amount and direction of the lead angle error.

Claims

1. A system for determining the correct lead angle of an intercepting craft with respect to a target and for determining and indicating the lead angle error of said craft, the system comprising:

a boresight reticle mounted on said craft;

a first mirror positioned transversely with respect to the sighting axis of the boresight reticle, and at an inclined angle thereto, to receive the image of said target and to reflect it athwart the axis of the boresight reticle;

a second mirror positioned in the path of the axis of the boresight reticle and in the reflection path of the target image reflected from the first mirror to reflect said target image substantially along the boresight reticle axis;

means for determining and providing range and angle data indicative of the range and of the angle of said target with respect to said boresight reticle axis at a plurality of instants in time;

computing means responsive to said range and angle data to compute the actual lead angle and the correct lead angle between said boresight reticle axis and said target and to produce signals indicative of correct lead angle and of lead angle error;

mounting means connected to the first mirror for permitting the first mirror to rotate about a first axis positioned in the plane of said second mirror and lying along a line normal to the plane of the reflection path of the target image and for permitting the first mirror to rotate about a second axis positioned in the plane of the first mirror and parallel to said first axis of rotation;

mounting means connected to said second mirror for holding said second mirror in a fixed position with respect to the axis of the boresight reticle;

positioning means for receiving the correct lead angle signal and for responding thereto to rotate the first mirror about the second axis by an angular amount corresponding to a parameter of the correct lead angle signal and effective for placing the target image in the center of the boresight reticle when the intercepting craft has assumed a heading giving the correct lead angle; and

positioning means for receiving the lead angle error signal and for responding thereto to rotate the first mirror about the first axis by an angular amount corresponding to a parameter of the lead angle error signal and effective for displacing the target image away from the center of the boresight reticle in an amount and direction indicative of the size and direction of lead angle error of the intercepting craft.

2. A fire control display system for determining the correct lead angle of an attacking aircraft witH respect to a target and for determining and indicating the lead angle error of said attacking aircraft with respect to said target and comprising:

a boresight reticle mounted on said aircraft;

a first light reflecting surface positioned transversely with respect to the sighting axis of the boresight reticle, and at an inclined angle thereto, to receive the image of the target and to reflect it athwart the said axis of the boresight reticle;

a second light reflecting surface positioned in the path of the axis of the boresight reticle and in the reflection path of the reflected target image to reflect said target image substantially along the boresight reticle axis;

means for determining and providing range and angle data indicative of the range and of the angle of said target with respect to said boresight reticle axis at a plurality of instants in time;

computing means responsive to said range and angle data to compute the correct lead angle and the actual lead angle between said boresight reticle axis and said target and to produce signals indicative of correct lead angle and of lead angle error;

mounting means connected to the first light reflecting surface for permitting the first light reflecting surface to rotate about a first axis positioned in the plane of said second light reflecting surface and lying along a line normal to the plane of the reflection path of the target image and for permitting the first light reflecting surface to rotate about a second axis positioned in the plane of the first light reflecting surface and parallel to said first axis of rotation;

mounting means connected to said second light reflecting surface for holding said second light reflecting surface in a fixed position with respect to the axis of the boresight reticle;

positioning means for receiving the correct lead angle signal and for responding thereto to rotate the first light reflecting surface about the second axis by an angular amount corresponding to a parameter of the correct lead angle signal and effective for placing the target image in the center of the boresight reticle when the attacking aircraft has assumed a heading giving the correct lead angle; and

positioning means for receiving the lead angle error signal and for responding thereto to rotate the first light reflecting surface about the first axis by an angular amount corresponding to a parameter of the lead angle error signal and effective for displacing the target image away from the center of the boresight reticle in an amount and direction indicative of the size and direction of lead angle error of the attacking aircraft.

3. A system for computing the correct lead angle and for computing and indicating the lead angle error of an intercepting craft with respect to a target and comprising:

a boresight reticle mounted on said craft;

a first mirror positioned to intercept the sighting axis of said boresight reticle and lying in a plane inclined with respect to the plane normal to said boresight axis;

a second mirror positioned to reflect the image of said target onto said first mirror;

said second mirror having a first axis of rotation lying in the plane of said first mirror and lying along a line normal to the plane of the reflection path of said target image;

said second mirror having a second axis of rotation parallel to said first axis of rotation and lying in the plane of said second mirror;

computing means for calculating the range and angle of said target with respect to said intercepting craft, for calculating the actual and the correct lead angles of said interceptor craft with respect to said target, and for calculating the amount of lead angle error from the computed, correct and actual lead angles, said computing means being further operative for producing signals indicative of correct lead angle and of lead angle error;

mounting means connected to the first mirror for holding said first mirror in a fixed position with respect to the axis of the boresight reticle;

mounting means connected to said second mirror for permitting said second mirror to rotate about both the first and second axes of rotation;

positioning means for receiving the correct lead angle signal and for responding thereto to rotate the said second mirror about its second axis in order to reflect the image of said target off said first and second mirrors and along said boresight axis when the intercepting craft has assumed a heading providing the correct lead angle; and

positioning means for receiving the lead angle error signal and for responding thereto to rotate said second mirror about its first axis by an angular amount calculated to move said target image away from the center of the boresight reticle to indicate the degree and direction of error of the actual lead angle of the intercepting craft.

4. A fire control display system for determining and indicating the correct lead angle and for determining and indicating the lead angle error of an attacking craft with respect to a target and comprising:

a boresight reticle mounted on said craft;

a first image reflecting means positioned to intercept the sighting axis of said boresight reticle and lying in a plane inclined with respect to the plane normal to said boresight axis;

a second image reflecting means positioned transversely with respect to said boresight axis to reflect the image of said target onto said first image reflecting means and having a first axis of rotation lying along a line normal to the plane of the reflection path of said target image;

said second image reflecting means having a second axis of rotation parallel to said first axis of rotation and lying in the plane of said first image reflecting means;

computing means for calculating the range and angle of said target with respect to said boresight axis, the correct and actual lead angles of said attacking craft with respect to said target, and the amount of lead angle error between the correct and actual lead angles, said computing means being further operative for producing signals indicative of correct lead angle and of lead angle error;

mounting means connected to said first image reflecting means for holding said first image reflecting means in a fixed position with respect to the axis of the boresight reticle;

mounting means connected to said second image reflecting means for permitting said second image reflecting means to rotate about both the first and the second axes of rotation;

positioning means for receiving the correct lead angle signal and for responding thereto to rotate the second image reflecting means about said first axis to reflect the image of said target off said first and second image reflecting means and along said boresight axis when the attacking craft has assumed a heading providing the correct lead angle; and

positioning means for receiving the lead angle error signal and for responding thereto to rotate said second image reflecting means about its second axis by an angular amount calculated to move said target image with respect to the center of the boresight reticle to indicate the degree and direction of the lead angle error of the attacking craft.