GPS Airborne target geolocating method

Abstract

A geolocation method is applied for accurate targeting of a target using an airborne beacon as a pseudo star generated by a high altitude vehicle, and using optical sensors by a low altitude vehicle for imaging the beacon and target for generating accurate relative GPS positioning of the target for improved the geolocation of the target preferably for precise delivery of a payload to the target. The method is applicable to military and civilian needs for accurate delivery of a payload to a target, such as for precise delivery of humanitarian aid or weapon munitions.

1. A method for determining a target location of a target, the method comprising the steps of,
 sensor determining a first GPS position of a sensor platform, the first GPS position having GPS positioning errors,    beacon determining a second GPS position of a beacon platform, the second GPS position having GPS positioning errors, the first and second GPS positions having relative errors less than the GPS positioning errors,    beacon measuring a beacon offset angle,    target measuring a target offset angle, and    computing the target location of the target from the first and second GPS positions and the beacon offset angle and the target offset angle.    
     
     
       2. The method of  claim 1  further comprising the steps of,
 determining a third GPS position of a maneuvering payload,    communicating the target location of the target to the maneuvering payload, and    maneuvering payload toward the target location.    
     
     
       3. The method of  claim 1  further comprising the steps of,
 determining a third GPS position of a maneuvering payload,    communicating the target location of the target to the maneuvering payload,    maneuvering payload toward the target location, and    repeating all of the steps for repetitively communicating the target location of the target to the maneuvering payload while the maneuvering payload maneuvers along a payload track towards the target.    
     
     
       4. The method of  claim 1  wherein,
 the first GPS position has a y 1  altitude and an x 1  and a z 1  horizontal position, the second GPS position has a y 2  altitude and an x 2  and a z 2  horizontal position,    the beacon offset angle comprises the angle of φ x  and φ z ,    the target offset angle comprises the angles of θ x  and θ z , and    the target location is a horizontal location at x 3  and z 3 .    
     
     
       5. The method of  claim 1  wherein,
 the first GPS position has a Y 1  altitude and an x 1  horizontal position, the second GPS position has a Y 2  altitude and an x 2  horizontal position,    the beacon offset angle comprises the angle of φ x ,    the target offset angle comprises the angles of θ x , and    the target location is a horizontal location at x 3 , where x 3 y 1  tan[θ x +φ x −α x ] where α x =arctan(x 2 /(y 2 −y 1 )).    
     
     
       6. The method of  claim 1  wherein the beacon measuring step comprises the step of,
 calibrating a focal plane of a beacon sensor of the sensor platform for measuring the beacon offset angle.    
     
     
       7. The method of  claim 1  wherein the target measuring step comprises the step of,
 calibrating a focal plane of a target sensor of the sensor platform for measuring the target offset angle.    
     
     
       8. The method of  claim 1  wherein,
 the beacon measuring step comprises the step of calibrating a beacon focal plane of a beacon sensor of the sensor platform for measuring the beacon offset angle,    the target measuring step comprises the step of calibrating a target focal plane of a target sensor of the sensor platform for measuring the target offset angle, and    the calibrating of the beacon and target focal plane is relative to respective fields of view of a common boresight.    
     
     
       9. A method for delivering a payload to a target location of a target, the method comprising the steps of,
 determining a first GPS position of a sensor platform,    determining a second GPS position of a beacon platform, the first and second GPS positions having relative errors,    measuring a beacon offset angle,    measuring a target offset angle,    computing the target location of the target from the first and second GPS position and beacon offset angle and target offset angle,    determining a third GPS position of a maneuvering payload,    communicating the target location to the maneuvering payload, and    maneuvering payload toward to the target location for delivering the payload to the target location.    
     
     
       10. The method of  claim 9  wherein maneuvering payload is a smart bomb comprising GPS navigation, guide communications, and a munitions payload. 
     
     
       11. A system for determining a target location of a target, comprising:
   an acquisition airborne vehicle configured to act as a sensor platform; and        a beacon airborne vehicle configured to act as a beacon platform, wherein said beacon airborne vehicle is configured to direct a beacon to said acquisition airborne vehicle that is used in determining an offset angle of a beacon image.     
     
     
       12. The system of  claim 11 , wherein said acquisition airborne vehicle comprises a target sensor, a beacon sensor, a GPS receiver, and two- way communications equipment.   
     
     
       13. The system of  claim 12 , wherein the target sensor is downwardly pointing and the beacon sensor is upwardly pointing. 
     
     
       14. The system of  claim 12 , wherein the target sensor comprises at least one of a visible sensor, an ultraviolet sensor, and an infrared sensor. 
     
     
       15. The system of  claim 12 , wherein the beacon sensor and the target sensor have a common boresight reference. 
     
     
       16. The system of  claim 12 , wherein the beacon sensor is gimbaled with respect to the target sensor. 
     
     
       17. The system of  claim 11 , wherein said beacon airborne vehicle comprises a steerable beacon generator, a GPS receiver, and two- way communications equipment.   
     
     
       18. The system of  claim 11 , wherein said acquisition airborne vehicle is configured to determine a location of the acquisition airborne vehicle by GPS navigation. 
     
     
       19. The system of  claim 11 , wherein said beacon airborne vehicle is configured to determine a location of the beacon airborne vehicle by GPS navigation. 
     
     
       20. The system of  claim 11 , wherein the beacon is encrypted. 
     
     
       21. The system of  claim 11 , wherein the beacon airborne vehicle is configured to relay data to one or more ground locations. 
     
     
       22. The system of  claim 12 , wherein the acquisition airborne vehicle is configured to use the beacon sensor to form the beacon image within a field of view of the target sensor. 
     
     
       23. A system for delivering a payload to a target, comprising:
   a beacon airborne vehicle configured to act as a beacon platform;        an acquisition airborne vehicle acting as a sensor platform comprising a computing device, wherein said beacon airborne vehicle is configured to direct a beacon to said acquisition airborne vehicle that is used in determining an offset angle of a beacon image; and        a maneuvering payload for delivering the payload to the target, wherein the computing device on said acquisition airborne vehicle is configured to relay location information of the target to said maneuvering payload.     
     
     
       24. The system of  claim 23 , wherein the computing device continuously computes coordinates of the target as the location information and continuously relays the coordinates to said maneuvering payload. 
     
     
       25. The system of  claim 23 , wherein said maneuvering payload comprises a humanitarian payload. 
     
     
       26. The system of  claim 23 , wherein said maneuvering payload comprises a smart bomb. 
     
     
       27. The system of  claim 26 , wherein the smart bomb comprises GPS navigation, guide communications, and a munitions payload. 
     
     
       28. The system of  claim 26 , wherein the smart bomb is a miniature precision- guided smart bomb.   
     
     
       29. The system of  claim 23 , wherein said acquisition airborne vehicle can support a plurality of maneuvering payloads. 
     
     
       30. The system of  claim 23 , wherein the location information is related to a three dimensional map. 
     
     
       31. A computer system, comprising:
   means for determining a first GPS position of a sensor platform;        means for determining a second GPS position of a beacon platform;        means for determining a beacon offset angle;        means for determining a target offset angle; and        means for determining a target location from at least the first and second GPS positions and the beacon offset angle and the target offset angle.     
     
     
       32. The computer system of  claim 31 , further comprising:
   means for determining a third GPS position of a maneuvering payload; and        means for communicating the target location to the maneuvering payload.