Methods and systems utilizing doppler prediction to enable fusing

Abstract

A programmable circuit for controlling a detonation altitude of a radar equipped munition is provided. The circuit comprises means for calculating a velocity of the munition while the munition is operating in a pulse mode at an altitude greater than the desired detonation altitude and means, responsive to the means for calculating the velocity of the munition, for determining when the munition is at a reference altitude in order to operate the munition in a continuous wave transmission mode. The circuit further comprises means, responsive to the means for determining, for calculating a time representing when the vehicle will reach the desired detonation altitude based on the calculated velocity and the determined reference altitude, and means, responsive to the means for calculating the time representing when the vehicle will reach the desired detonation altitude, for generating a fusing signal to detonate the munition after the calculated time has passed.

1 . A programmable circuit for controlling a detonation altitude of a radar equipped munition, the circuit comprising:
 means for calculating a velocity of a radar equipped munition while the munition is operating in a pulse mode at an altitude greater than the desired detonation altitude;   means, responsive to the means for calculating the velocity of the munition, for determining when the munition is at a reference altitude in order to operate the munition in a continuous wave transmission mode;   means, responsive to the means for determining, for calculating a time representing when the vehicle will reach the desired detonation altitude based on the calculated velocity and the determined reference altitude; and   means, responsive to the means for calculating the time representing when the vehicle will reach the desired detonation altitude, for generating a fusing signal to detonate the munition after the calculated time has passed.   
   
   
       2 . The circuit of  claim 1 , wherein the means for calculating the velocity of the munition include:
 means for initiating the continuous wave transmission when a radar ground return signal occurs within a Doppler range gate;   means for discontinuing the continuous wave transmission after a preset time; and   means for utilizing radar ground returns from the continuous wave transmission to determine a Doppler frequency.   
   
   
       3 . The circuit of  claim 2 , further comprising:
 means for calculating the velocity of the munition from the Doppler frequency.   
   
   
       4 . The circuit of  claim 2 , further comprising:
 means for setting a Doppler bandwidth based on the velocity of the munition.   
   
   
       5 . The circuit of  claim 1 , wherein the means for calculating the velocity of the munition include means for operating the radar in the pulse mode with a pulse repetition frequency of at least twice a near maximum Doppler frequency. 
   
   
       6 . The circuit of  claim 1 , wherein the means for determining when the munition is at the reference altitude include:
 means for configuring the radar with a height of fuse (HOF) reference gate representative of the reference altitude; and   means for determining when radar ground return signals are coincident with the HOF reference gate.   
   
   
       7 . The circuit of  claim 1 , further comprising:
 means for receiving, at the radar, a desired detonation altitude.   
   
   
       8 . A method for controlling a detonation altitude of a radar equipped munition, the method comprising:
 calculating a velocity of a radar equipped munition while the munition is operating in a pulse mode at an altitude greater than the desired detonation altitude;   determining when the munition is at a reference altitude in order to operate the munition in a continuous wave transmission mode;   calculating a time representing when the vehicle will reach the desired detonation altitude based on the calculated velocity and determined reference altitude; and   generating a fusing signal to detonate the munition after the calculated time has passed.   
   
   
       9 . The method of  claim 8 , wherein calculating the velocity of the munition comprises:
 operating the radar in the pulse mode with a pulse repetition frequency of at least twice a near maximum Doppler frequency.   
   
   
       10 . The method of  claim 8 , wherein calculating the velocity of the munition comprises:
 initiating a continuous wave transmission when a radar ground return signal occurs within a Doppler range gate;   discontinuing the continuous wave transmission after a preset time; and   utilizing radar ground returns from the continuous wave transmission to determine a Doppler frequency.   
   
   
       11 . The method of  claim 9 , further comprising:
 calculating the velocity of the munition from the Doppler frequency.   
   
   
       12 . The method of  claim 9 , further comprising:
 setting a Doppler bandwidth based on the velocity of the munition.   
   
   
       13 . The method of  claim 8 , further comprising:
 receiving, at the radar, a desired detonation altitude.   
   
   
       14 . The method of  claim 8 , wherein determining when the munition is at the reference altitude comprises:
 configuring the radar with a height of fuse (HOF) reference gate representative of the reference altitude; and   determining when radar ground return signals are coincident with the HOF reference gate.