Alignment, code and power test of airborne laser designators

• US 5,734,466 A
• Filed: 09/27/1995
• Issued: 03/31/1998
• Est. Priority Date: 09/27/1995
• Status: Expired due to Fees

• Current Assignee: The United States of America As Represented By The Secretary of Agriculture
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: George, Edwin B., Marlow, Steven A.
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/534,798
• Time in Patent Office: 916 Days
• Field of Search: 356/141.1, 356/138, 250/342
• US Class Current: 356/141.3
• CPC Class Codes: F41G 1/35 for illuminating the target , e.g. flash lights
• CPC Class Codes: F41G 3/326 for checking the angle between the axis of the gun sighting device and an auxiliary measuring device F41G3/323 takes precedence
• CPC Class Codes: F41G 7/226 Semi-active homing systems, i.e. comprising a receiver and involving auxiliary illuminating means, e.g. using auxiliary guiding missiles
• CPC Class Codes: F41G 7/2293 using electromagnetic waves other than radio waves
• CPC Class Codes: F42B 15/01 Arrangements thereon for guidance or control steering arrangements F42B10/60; aircraft flight control B64C; guidance systems other than those installed aboard F41G7/00, F41G9/00; locating by use of radio or other waves G01S; flight control in general G05D1/00; computer aspects G06]
• CPC Class Codes: G01B 11/27 for testing the alignment of axes means for centering or aligning a light guide within a ferrule G02B6/3834
• CPC Class Codes: G01J 1/0266 Field-of-view determination; Aiming or pointing of a photometer; Adjusting alignment; Encoding angular position; Size of the measurement area; Position tracking; Photodetection involving different fields of view for a single detector

Abstract

This invention relates to laser guided weapon systems and in particular to boresighting a designator laser to a forward looking infrared (FLIR) sighting system that is at a wavelength other than that of the laser with sufficient accuracy, confirming adequate power level available for designation and that the proper pulse rate code has been selected and is being transmitted. Due to the nature of the designation laser being at a different bandwidth than the FLIR, the positioning of the laser spot is not visible to the targeting system and the initial system alignment is depended on for accuracy and precision. This invention presents a way of addressing three aspects of laser designation prior to weapon use. This is achieved through the use of a beamsplitter and thermal resistor that appear to be at the same point of space to the targeting system. The offsets are measured and then used to correct the misalignment.

Claims

1. An apparatus for testing and aligning a laser target designator, said laser target designator including a laser for radiating a laser beam along a beam optical axis, a target image detector for viewing an image in a field of view which contains the target and into which said laser beam extends along said beam optical axis, servo means for moving said laser and target image detector together as well as a means to make alignment adjustments between said laser and said target image detector, along with image processing for tracking said servo means to a target in said field of view, said apparatus for field testing and alignment comprising:

an optical assembly containing an aperture that will both focus the incoming laser light and limit laser energy passing through the optical assembly so that a maximum will be achieved when the laser beam is centered on the aperture;

a beam splitter assembly optically positioned so that a laser detector assembly, positioned at the split optical focus, will detect maximum energy when the beam is fully on the optical assembly while the remaining energy is focused at a thermal resistor assembly all optically positioned so that both the laser detector assembly and the thermal resistor assembly appear at the same point in space in the view of the said laser target designator image processing;

said thermal resistor assembly positioned at the focus of the beam passing through the beam splitter; and

a signal processing assembly to provide designation intensity, determine laser designation code, and misalignment between said laser and said target image detector.

2. The apparatus of claim 1 wherein said signal processing assembly provides a means of centering the said laser beam through use of said laser servo on the said detector assembly resulting in azimuth and elevation corrections in the two dimensional said laser target designator image plane that can be used as correction angles for the laser pointing since the resistor assembly that is visible to the said laser target designator and appears at the same point in space through which the laser beam passes.

3. The apparatus of claim 1 signal processing assembly further consists of a means of determining said laser intensity, interpretation of the said designation code, and a means of centering the said laser beam on the said optical assembly through the use of said servo.

4. The said means of centering the laser on the said optical assembly as recited by claim 3 with consisting of means to command said laser servo so that said signal processing detects changes of intensity to generate sensitivities or gradients that will lead to maximization of the laser energy on the said detector assembly and result in the said azimuth and elevation corrections required for said correction of said laser beam pointing.

5. The apparatus of claim 1 including means to integrate the device into an aircraft in view of the targeting pod for in-flight calibration and alignment of the said laser target designator or used as a ground test device prior to flight or for periodic test and alignment of the said laser target designator.