Apparatus for correcting ballistic errors using laser induced fluorescent (strobe) tracers

Abstract

A system for correcting the aim of a weapon which is operative to launch a projectile from a barrel on a ballistic path toward a target. A rear surface of the projectile is coated with a fluorescent dye that re-emits radiation when excited by laser radiation. The system includes a source of laser radiation (strobe) pulses that form a cone of light intersecting the ballistic path of the projectile. The strobe pulses are emitted at predetermined times (T 1, T 2, T 3, . . . Tn) following firing of the projectile (at time T 0 ). An optical detector receives the radiation re-emitted by a the fluorescent dye at the rear of the projectile at times (T 1 z, T 2 z, T 3 z, . . . Tnz) producing measurable location signals allowing the system to measure the vertical and lateral positions of the projectile at said times, where “z” is a re-emission delay and T 1 z, T 2 z, T 3 z, . . . Tnz are the respective times T 1, T 2 , T 3, . . . Tn each delayed by amount z.

1 . System for correcting the aim of a weapon which is operative to launch a projectile from a barrel on a ballistic path toward a target, the projectile having an elongate housing with a rear end and fluorescent dye material disposed on the rear end that produces radiation at a first frequency when excited by receipt of radiation at a second frequency, said aim correcting system comprising, in combination;
 (1) a radiation source of pulsed light at said first frequency directed toward the ballistic path of the projectile and emitted at predetermined times (T 1 , T 2 , T 3  . . . ) following firing of the projectile (at time T 0 );   (2) a radiation detector at the location of the weapon for receiving light radiation signals re-emitted by the fluorescent dye on the projectile at times (T 1   z,  T 2   z,  T 3   z  . . . Tnz) and producing electronic signals representing the vertical and lateral positions of the projectile at said times (T 1   z,  T 2   z,  T 3   z,  . . . Tnz), where “z” is a re-emission delay and T 1   z,  T 2   z,  T 3   z  . . . are the respective times T 1 , T 2 , T 3 , . . . Tn each delayed by amount z;   (3) a signal processor, coupled, to the radiation detector, for processing said electronic signals to determine the spatial (X and Y) coordinates of the projectile at said times (T 1   z,  T 2   z,  T 3   z,  . . . Tz) during flight;   (4) a computer, coupled to the processor, for calculating a lateral correction and a vertical correction in the aim of the weapon; and   (5) an output device, coupled to the computer, for facilitating an adjustment in the aim of the weapon toward the target, prior to firing the next projectile;   wherein said aim of the weapon may be adjusted after launch of the projectile to compensate for errors prior to launch of another projectile.   
     
     
         2 . The system defined in  claim 1 , wherein one of the signal processor and the computer calculates the lateral drift and the vertical drop of the projectile at said predetermined times. 
     
     
         3 . The system defined in  claim 1 , wherein said radiation source is laser source, configured to be affixed to the weapon so that a cone of illumination of the laser source intersects with the ballistic path of the projectile and excites the fluorescent dye material. 
     
     
         4 . The system defined in  claim 3 , wherein said laser source transmits light through a narrow band-pass filter so that the cone of illumination in a narrow frequency range intersects the ballistic path of the projectile and excites the fluorescent dye material. 
     
     
         5 . The system defined in  claim 1 , wherein the radiation detector is a digital camera for producing an image of the ballistic path of the projectile. 
     
     
         6 . The system defined in  claim 1 , wherein the radiation detector includes a narrow band-pass filter, allowing re-emitted light from the fluorescent dye material to be selectively received and other light excluded. 
     
     
         7 . The system defined is  claim 4 , wherein said fluorescent dye on the rear surface of the projectile responds preferentially to the laser light illumination in the narrow frequency range. 
     
     
         8 . The system defined in  claim 1 , wherein said fluorescent dye on the rear of the projectile has a protective transparent coating. 
     
     
         9 . The system defined in  claim 1 , wherein said first frequency is in one of the UV, visual and IR spectral bands. 
     
     
         10 . The system defined in  claim 1 , wherein said output device is a display. 
     
     
         11 . The system defined in  claim 10 , wherein said output device includes a aiming device allowing an operator to adjust the aim of the weapon. 
     
     
         12 . The system defined in  claim 1 , wherein the signal processor determines the time duration of the radiation signals received at said second frequency in response to radiation pulses emitted at said first frequency, and wherein said computer distinguishes the signals received from each projectile from among signals received from other, successively fired projectiles in dependence upon said time duration. 
     
     
         13 . An ammunition projectile configured to be fired from a weapon, said projectile having an elongate housing and a photo-luminescent material, disposed on a rear surface of the housing, that re-emits radiation at when excited by receipt of radiation from a radiation source. 
     
     
         14 . The ammunition projectile defined in  claim 13 , wherein said photo-luminesccnt material is a fluorescent dye that forms a coating on the rear surface of the projectile. 
     
     
         15 . The ammunition projectile defined in  claim 13 , wherein said photo-luminescent material is a fluorescent dye that forms a coating on a rear component of the projectile, and said projectile includes a transparent window on said rear component adjacent and covering said fluorescent dye. 
     
     
         16 . The ammunition projectile defined in  claim 15 , wherein said fluorescent dye forms a coating on an inside surface of said transparent window.