Fire control method and system

Abstract

A method of aiming a gun ( 14 ) that is mounted on a platform ( 12 ) and that has fired projectile at a target, the firing of the gun ( 14 ) causing the platform ( 12 ) to vibrato. The method includes tracking the projectile and the target, using a tracking device ( 20 ) and inferring an aim error vector from the tracking.

What claimed is:  
     
         1 . A method of aiming a gun that is mounted on a platform and that has fired a projectile at a target, the firing of the gun causing the platform to vibrate, comprising the steps of: 
 (a) tracking the projectile and the target, using a tracking device, at least a portion whereof is operationally connected to the platform; and    (b) inferring an aim error vector from said tracking.    
     
     
         2 . The method of  claim 1 , wherein said portion of said tracking device is rigidly mounted on the platform.  
     
     
         3 . The method of  claim 1 , wherein said tracking is begun after the vibration of the platform has substantially stopped.  
     
     
         4 . The method of  claim 1 , wherein said aim error vector includes an azimuth error and an elevation error.  
     
     
         5 . The method of  claim 1 , further comprising the step of: 
 (c) moving the gun to compensate for said aim error vector.    
     
     
         6 . The method of  claim 1 , wherein said tracking device includes radar.  
     
     
         7 . The method of  claim 6 , wherein said portion of said tracing device that is operationally connected to the platform includes an antenna.  
     
     
         8 . The method of  claim 6 , wherein said tracking is effected by steps including: 
 (i) transmitting a plurality of projectile-tracking RF pulses towards the projectile;    (ii) for each said projectile-tracking RF pulse, receiving an echo of said projectile-tracking RF pulse from the projectile;    (iii) transmitting a plurality of target-tracking RF pulses towards the target; and    (iv) for each said target-tracking RF pulse, receiving an echo of said target-tracking RF pulse from the target.    
     
     
         9 . The method of  claim 8 , wherein said projectile-tracking RF pulses are Doppler pulses.  
     
     
         10 . The method of  claim 8 , wherein said target-tracking RF pulses are linear frequency modulated pulses.  
     
     
         11 . The method of  claim 8 , wherein said transmitting of said projectile-tracking RF pulses alternates in time with said transmitting of said target-tracking RF pulses.  
     
     
         12 . The method of  claim 8 , wherein said receiving of said echoes of said projectile-tracking RF pulses from the projectile includes the step of discriminating between: 
 (A) said echoes of said projectile-tracking RF pulses from the projectile and    (B) clutter echoes of said projectile-tracking RF pulses.    
     
     
         13 . The method of  claim 12 , wherein said discriminating is effected using a CFAR method.  
     
     
         14 . The method of  claim 8 , wherein said receiving of said echoes of said target-tracking RF pulses from the target includes the step of discriminating between: 
 (A) said echoes of said target-tracking RF pulses form the target and    (B) clutter echoes of said target-tracking RF pulses.    
     
     
         15 . The method of  claim 14 , wherein said discriminating is effected using a CFAR method.  
     
     
         16 . The method of  claim 8 , wherein said tracking further includes the step of: 
 (v) processing said received echoes of said projectile-tracking RF pulses from the projectile to provide, for each said received echo of said projectile-tracking RF pulse from the projectile, a projectile measurement vector.    
     
     
         17 . The method of  claim 16 , wherein said projectile measurement vector includes: 
 (A) a measured range to the projectile;    (B) a measured projectile azimuth;    (C) a measured projectile elevation; and    (D) a measured projectile velocity vector.    
     
     
         18 . The method of  claim 16 , wherein said tracking further includes the step of: 
 (vi) updating an estimate of a projectile state vector, based on said projectile measurement vector.    
     
     
         19 . The method of  claim 18 , wherein said projectile state vector includes: 
 (A) a range to the projectile;    (B) a projectile azimuth;    (C) a projectile elevation; and    (D) a projectile velocity vector.    
     
     
         20 . The method of  claim 19 , wherein said updating is effected using a Kalman filter.  
     
     
         21 . The method of  claim 8 , wherein said tracking further includes the step of: 
 (v) processing said received echoes of said target-tracking RF pulses from the target to provide, for each said received echo of said target-tracking RF pulse from the target, a target measurement vector.    
     
     
         22 . The method of  claim 21 , wherein said target measurement vector includes: 
 (A) a measured range to the target;    (B) a measured target azimuth; and    (C) a measured target elevation.    
     
     
         23 . The method of  claim 22 , wherein said target measurement vector further includes: 
 (D) a measured target velocity vector.    
     
     
         24 . The method of  claim 21 , wherein said tracking further includes the step of: 
 (vi) updating an estimate of a target state vector, based on said target measurement vector.    
     
     
         25 . The method of  claim 24 , wherein said target state vector includes: 
 (A) a range to the target;    (B) a target azimuth; and    (C) a target elevation.    
     
     
         26 . The method of  claim 25 , wherein said target state vector further includes: 
 (D) a target velocity vector.    
     
     
         27 . The method of  claim 24 , wherein said updating is effected using a Kalman filter.  
     
     
         28 . A fire control system for a gun that is mounted on a platform and that fires a projectile at a target, conspiring: 
 (a) an antenna that is operationally connected to the platform;    (b) a transmitter for transmitting projectile-tracking RF pulses and target-tracking RF pulses via said antenna;    (c) a receiver for receiving echoes of said RF pulses via said antenna; and    (d) a signal processor for receiving signals, representative of said echoes, from said receiver and transforming said signals into measurement vectors for the projectile and the target.    
     
     
         29 . The fire control system of  claim 28 , wherein said antenna is rigidly mounted on the platform.  
     
     
         30 . The fire control system of  claim 28 , wherein said antenna is a two-way monopulse antenna.  
     
     
         31 . The fire control system of  claim 28 , wherein said projectile-tracking RF pulses are Doppler pulses.  
     
     
         32 . The fire control system of  claim 28 , wherein said target-tracking RF pulses are linear frequency modulated pulses.  
     
     
         33 . The fire control system of  claim 28 , wherein said signals include Σ signals, Δ Az  signals and Δ El  signals.  
     
     
         34 . The fire control system of  claim 28 , further comprising: 
 (e) a synchronizer for synchronizing said transmitting of said RF pulses and said receiving of said echoes of said RF pulses.    
     
     
         35 . The fire control system of  claim 28 , further comprising: 
 (e) a post-processor for updating state vectors of the projectile and the target, based on said measurement vectors.    
     
     
         36 . The fire control system of  claim 35 , wherein said updating is effected using a Kalman filter.  
     
     
         37 . The fire control system of  claim 35 , wherein said post-processor is further operative to transform said state vectors into an aim error vector.