초록 ▼

A hostile missile is identified as being of a type which maneuvers aerodynamically within the atmosphere when it performs an exoatmospheric maneuver which significantly changes its specific energy. When the determination is made that the hostile missile is an atmospheric maneuvering missile, the hos

A hostile missile is identified as being of a type which maneuvers aerodynamically within the atmosphere when it performs an exoatmospheric maneuver which significantly changes its specific energy. When the determination is made that the hostile missile is an atmospheric maneuvering missile, the hostile missile is engaged with an interceptor which is guided toward a predicted intercept point (PIP) assuming horizontal hostile missile flight at an altitude above a specified minimum altitude.

대표청구항 ▼

1. A method for engaging a ballistic missile target, said method comprising the steps of: sensing a ballistic target, measuring its position, and determining its velocity;determining specific energy of said target;processing a current determination of specific energy with that of a previous determin

1. A method for engaging a ballistic missile target, said method comprising the steps of: sensing a ballistic target, measuring its position, and determining its velocity;determining specific energy of said target;processing a current determination of specific energy with that of a previous determination to generate a specific energy difference;comparing said specific energy difference with a threshold energy;if said difference is below said threshold, repeating said steps of determining, processing, and comparing;if said difference is greater than said threshold, deeming said target to be maneuvering and to be of a type of target which transitions from exoatmospheric ballistic motion to aerodynamic flight;determining an expected intercept point within the atmosphere; andguiding an interceptor missile toward said expected intercept point. 2. A method according to claim 1, wherein said step of determining an expected intercept point includes the steps of: determining a ballistic intercept point assuming that the target follows a ballistic trajectory; andmodifying said ballistic intercept point to account for aerodynamic flight. 3. A method according to claim 2 wherein said step of modifying the ballistic intercept point comprises the step of maintaining a predicted altitude of intercept above a threshold altitude. 4. A method according to claim 1, wherein said step of determining an expected intercept point within the atmosphere comprises the steps of: taking a difference between a current altitude of said target and a threshold value of altitude;determining a time-to-go for said target to reach said threshold value of altitude;determining a speed ratio related to an absolute velocity of said target and a horizontal velocity of said target;determining horizontal pseudocomponents of velocity of said target in horizontal flight by multiplying horizontal components of said target velocity by said speed ratio; anddetermining pseudo-horizontal-position of said target by adding a current horizontal position of said target to the quotient of (a) a difference between said pseudocomponents and said target velocity components (b) divided by said time-to-go. 5. A method according to claim 1, wherein said step of sensing a ballistic target comprises the step of illuminating said target with a radar system. 6. A method according to claim 1, wherein said step of sensing a ballistic target comprises illuminating the target using an infrared system. 7. A method according to claim 1, wherein said step of determining specific energy of said target is performed repeatedly at periodic intervals. 8. A method according to claim 1, wherein if said difference is less than said threshold, deeming said target to be a ballistic type of target; and initializing an interceptor missile for a ballistic target mode. 9. A method for engaging a target missile, said method comprising the steps of: tracking said target missile with a sensor, and computing a sensor-to-target range, a target velocity, and an interceptor-to-target range;computing an interceptor average velocity;computing a target missile relative heading to intercept assuming ballistic motion of said target missile;computing an interceptor relative heading to intercept assuming ballistic motion of said target missile;computing an interceptor time-to-go to intercept assuming ballistic motion of said target missile;computing a predicted intercept point assuming ballistic motion of said target missile;determining if (a) said predicted intercept point assuming ballistic motion is less than a threshold altitude and (b) said target missile is capable of aerodynamic flight;if (a) said predicted intercept point is less than a threshold altitude and (b) said target missile is capable of aerodynamic flight, adjusting kinetic parameters of said target missile to reflect horizontal motion at said threshold altitude; computing said target missile relative heading to intercept assuming adjusted motion of said target missile;computing said interceptor relative heading to intercept assuming adjusted motion of said target missile;computing said interceptor time-to-go to intercept assuming adjusted motion of said target missile;computing said predicted intercept point assuming adjusted motion of said target missile;computing an interceptor range-to-go to intercept point; andcomputing an interceptor heading error to the intercept point and applying said heading error to guide said interceptor. 10. A method according to claim 9, wherein said step of determining if (b) said target missile is capable of aerodynamic flight comprises the steps of: determining an exoatmospheric specific energy of said target missile;comparing the exoatmospheric specific energy of said target missile during successive determinations, to establish a magnitude of specific energy changes;comparing said magnitude of specific energy changes with a threshold energy; andif said specific energy changes exceed said threshold energy, deeming said target missile to be capable of aerodynamic flight. 11. A method according to claim 10, wherein said successive determinations are immediately successive determinations. 12. A method according to claim 9, wherein said step of computing said predicted intercept point includes the steps of: determining a ballistic intercept point assuming that the target follows a ballistic trajectory; andmodifying said ballistic intercept point to account for aerodynamic flight. 13. A method according to claim 12, wherein said step of modifying said ballistic intercept point comprises the step of maintaining a predicted altitude of intercept above a threshold altitude. 14. A method according to claim 9, wherein said step of computing a predicted intercept point includes the steps of: taking a difference between a current altitude of said target missile and a threshold value of altitude;determining a time-to-go for said target missile to reach said threshold value of altitude;determining a speed ratio related to an absolute velocity of said target missile and a horizontal velocity of said target missile;determining horizontal pseudocomponents of velocity of said target missile in horizontal flight by multiplying horizontal components of said target velocity by said speed ratio; anddetermining pseudo-horizontal-position of said target missile by adding a current horizontal position of said target missile to the quotient of (a) a difference between said pseudocomponents and said target velocity components (b) divided by said time-to-go. 15. A method according to claim 9, wherein said step of tracking said target missile with a sensor comprises the step of illuminating said target with a radar system. 16. A system for engaging a target missile following a track which transitions from exoatmospheric to atmospheric, said system comprising: a radar system for tracking said target missile, and for measuring its position and velocity;a specific energy sensor coupled to said radar system for determining a specific energy of said target missile;a first processor coupled to said specific energy sensor, for taking the difference between a current determination of specific energy with that of a previous determination to generate a specific energy difference;a comparator for comparing said specific energy difference with a threshold energy;a second processor coupled to said comparator, for, in response to said specific energy difference being greater than said threshold while said target is exoatmospheric, deeming said target to be maneuvering and to be of a type which transitions from exoatmospheric ballistic motion to aerodynamic flight;determining a predicted intercept point within the atmosphere and at a predetermined altitude; andguiding an interceptor missile horizontally toward said predicted intercept point. 17. A system according to claim 16, wherein said step of determining a predicted intercept point includes the steps of: determining a ballistic intercept point assuming that the target missile follows a ballistic trajectory; andmodifying said ballistic intercept point to account for aerodynamic flight. 18. A system according to claim 17, wherein said step of modifying the ballistic intercept point comprises the step of maintaining a predicted altitude of intercept above a threshold altitude. 19. A system according to claim 16, wherein said step of determining a predicted intercept point comprises the steps of: taking a difference between a current altitude of said target missile and a threshold value of altitude;determining a time-to-go for said target missile to reach said threshold value of altitude;determining a speed ratio related to an absolute velocity of said target missile and a horizontal velocity of said target missile;determining horizontal pseudocomponents of velocity of said target missile in horizontal flight by multiplying horizontal components of said target velocity by said speed ratio; anddetermining pseudo-horizontal-position of said target missile by adding a current horizontal position of said target missile to the quotient of (a) a difference between said pseudocomponents and said target velocity components (b) divided by said time-to-go. 20. A system according to claim 16, wherein said first processor coupled to said specific energy sensor and said second processor coupled to said comparator are the same processor.