Accuracy fuze for airburst cargo delivery projectiles

Abstract

In one aspect, an artillery projectile apparatus is provided that includes a carrier projectile containing a payload, and a fuze disposed at an ogive of the projectile and which is configured to eject the payload when the fuze is detonated. The fuze includes a receiver configured to receive location information from a radionavigation source and a processor configured to acquire position data from the receiver. The processor is also configured to estimate a projectile flight path using the position data, to determine intercept parameters of the artillery projectile relative to an ejection plane of its payload cargo, and to adjust an ejection event initiation command time of the payload in accordance with the determined intercept parameters. In some configurations, the present invention dramatically decreases range errors typically associated with delivering artillery payloads to specific targets.

1 . A method for delivering an artillery projectile payload to a target, said method comprising:
 determining a cargo ejection plane between a gun firing the artillery projectile and the target and a nominal ejection event initiation command time to deliver the artillery projectile payload to the target;   firing the artillery projectile at the target;   acquiring, at the artillery projectile after firing, position and time of flight data of said projectile;   using derived position data and time of flight data to predict a time of intercept and altitude; and   adjusting, at the artillery projectile after firing, ejection event initiation command time of the artillery projectile payload in accordance with the acquired position and time data.   
   
   
       2 . A method in accordance with  claim 1 , wherein said acquiring position and time data comprises receiving global positioning satellite (GPS) data using a receiver located at the artillery projectile. 
   
   
       3 . A method in accordance with  claim 1 , further comprising sampling said GPS data at a variable rate during flight. 
   
   
       4 . A method in accordance with  claim 1 , wherein said receiving GPS data further comprises utilizing an antenna for a high-spin-rate projectile. 
   
   
       5 . A method in accordance with  claim 1 , wherein said adjusting ejection event initiation command time comprises adjusting the ejection event initiation command time utilizing a processor at the artillery projectile. 
   
   
       6 . A method in accordance with  claim 1 , further comprising updating nominal ejection plane intercept parameters following acquisition of a GPS data set. 
   
   
       7 . A method in accordance with  claim 6 , further comprising performing convergence tests on the updated ejection plane intercept parameters following acquisition of a GPS data set. 
   
   
       8 . A method in accordance with  claim 7 , further comprising conditioning said adjusting the ejection event initiation command time upon results of the convergence tests, and utilizing a default ejection event initiation command time in the event that the convergence tests indicate a GPS anomaly. 
   
   
       9 . A method in accordance with  claim 1 , wherein said adjusting ejection event initiation command time of the artillery projectile payload comprises predicting an elevation and time for the artillery projectile to intercept the ejection plane and reducing said predicted time if an ejection plane interception point is higher than a determined nominal intercept point, and increasing said predicted time if the ejection plane interception point is lower than the determined nominal intercept point.