Method and apparatus for laser return characterization in a countermeasures system

1. A method for determining laser return characteristics in a DIRCM system having a gimbal carrying an image mirror and a tracking camera, comprising the step of:

locating a single IR detector in an aperture in the image mirror; and,

using the output from the single infrared detector for at least one of countermeasure effectiveness, missile range measurement, or missile classification determination, or for automatic gain control of the tracking camera.

2. The method of claim 1 , wherein the gimbal has an elevation arm and wherein the image mirror is located on the elevation arm.

3. The method of claim 1 , wherein the image mirror is used in a shared path system.

4. The method of claim 1 , wherein the image mirror is used in a split path system.

5. The method of claim 1 , wherein the single IR detector is provided with thermo-electric cooling.

6. The method of claim 1 , wherein the single IR detector is a staring detector.

7. Apparatus for the improvement of laser return characterization in a DIRCM system having a laser, a tracking camera, a gimbal and an elevation arm mounted in said gimbal, comprising:

an mirror having an aperture therethrough;

a single infrared detector mounted so as to be exposed to radiation passing through said aperture; and,

a countermeasure effectiveness module coupled to the output of said single infrared detector for ascertaining when radiation indicative of a return from the reticle of a missile is present and for when said radiation is not present thereafter, whereby a detector output indicative of no laser return radiation after the previous presence thereof is indicative of the employment of an effective countermeasure.

8. The apparatus of claim 7 , and further including a missile characteristic determination module coupled to the output of said single infrared detector for deriving a characteristic of said missile based on the output from said single infrared detector.

9. The apparatus of claim 7 , and further including a missile range determination unit coupled to the output of said single infrared detector and responsive to the firing of said laser for measuring the time difference between the firing and detected return for determining range of said missile.

10. The apparatus of claim 7 , and further including an automatic gain control circuit coupled to the output of said single infrared detector for generating a gain control signal adapted to be applied to said tracking camera for the control of the gain thereof.

11. The apparatus of claim 7 , wherein said single infrared detector is made from indium phosphide.

12. The apparatus of claim 7 , and further including a thereto-electric cooling unit in contact with said single infrared detector for the removal of thermal noise therefrom.

13. A method for eliminating the burden on a tracking camera used in a DIRCM system to be able to ascertain at least one of countermeasure effectiveness, missile range measurement, and missile classification, or to provide automatic gain control of the tracking camera used by the DIRCM system, comprising the steps of:

providing the DIRCM system with a gimbal that employs an image mirror; and,

locating a single infrared detector at said image mirror so as to collect a portion of the energy returned to said DIRCM system due to the reflection of countermeasure radiation by the reticle of a missile, whereby the output of said single infrared detector may be used without affecting the operation of the tracking camera, thereby to unload the tracking camera from activities unrelated to tracking.

14. The method of claim 13 , wherein the activities unrelated to tracking include at least one of countermeasure effectiveness, missile range measurement, missile classification determinations, or as an automatic gain control, of the camera.