Time-to-go missile guidance method and system
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
F41G-007/00
F42B-015/01
G06F-017/10
F42B-015/00
출원번호
US-0683652
(2007-03-08)
등록번호
US-8378276
(2013-02-19)
발명자
/ 주소
Lam, Vincent C.
출원인 / 주소
Lockheed Martin Corp
인용정보
피인용 횟수 :
1인용 특허 :
19
초록▼
A method and apparatus for guiding a vehicle to intercept a target is described. The method iteratively estimates a time-to-go until target intercept and modifies an acceleration command based upon the revised time-to-go estimate. The time-to-go estimate depends upon the position, the velocity, and
A method and apparatus for guiding a vehicle to intercept a target is described. The method iteratively estimates a time-to-go until target intercept and modifies an acceleration command based upon the revised time-to-go estimate. The time-to-go estimate depends upon the position, the velocity, and the actual or real time acceleration of both the vehicle and the target. By more accurately estimating the time-to-go, the method is especially useful for applications employing a warhead designed to detonate in close proximity to the target. The method may also be used in vehicle accident avoidance and vehicle guidance applications.
대표청구항▼
1. A non-transitory computer readable medium encoded with computer executable code capable of being run on a computer for guiding a vehicle to a target, the computer executable code comprising: computer executable code for determining a vehicle-to-target position vector r; computer executable code f
1. A non-transitory computer readable medium encoded with computer executable code capable of being run on a computer for guiding a vehicle to a target, the computer executable code comprising: computer executable code for determining a vehicle-to-target position vector r; computer executable code for determining a net vehicle-to-target velocity v; computer executable code for determining a net vehicle-to-target acceleration a; computer executable code for determining the time-to-go τ according to a first equation: 12a·aτ3+32a·vτ2+(a·r+v·v)τ+v·r=0;computer executable code for determining an acceleration command A according to a second equation: A=rτ2+vτ+12a; and computer executable code for generating control signals based upon the thus calculated acceleration command A. 2. A non-transitory computer readable medium in accordance with claim 1, wherein a time-to-go solution to the first equation is approximated by the equation: τ=(-e2+e24+d327)13+(-e2-e24+d327)13-v_cosγ, wherein: d=2( r cos β+ v2)−3 v2 cos 2 γ,e=2 v3 cos 3 γ−2 v cos γ( r cos β+ v2)+2 vr cos α,v=v/a,cos γ=a·v/av,r=r/a,cos β=a·r/ar,cos α=v·r/vr,a=|a|, a≠0,v=|v|, andr=|r|. 3. A non-transitory computer readable medium in accordance with claim 1, wherein a time-to-go solution to the first equation is approximated by the equation: τ=2-d3cos{13cos-1(-e2-d3/27+φ)}-v_cosγ, wherein: d=2( r cos β+ v2)−3 v2 cos2 γ,e=2 v3 cos 3 γ−2 v cos γ( r cos β+ v2)+2 vr cos α,φ=0, 2π/3, or 4π/3,v=v/a,cos γ=a·v/av,r=r/a,cos β=a·r/ar,cos α=v·r/vr,a=|a|, a≠0,v=|v|, andr=|r|. 4. A non-transitory computer readable medium in accordance with claim 1, wherein a time-to-go solution to the first equation is approximated by the equation: τ=(r0/v0)f(N, α0), wherein: r0 is an initial vehicle-to-target distance,v0 is an initial net vehicle-to-target speed, cosα0=r.0v0, and N is a proportional navigation constant. 5. A non-transitory computer readable medium in accordance with claim 4, wherein f(N, α0) is approximated by: f(N,α0)=secα0∫01ⅆr_1+tan2α0N-1(r_2N-2-1),andr_=rr0. 6. A non-transitory computer readable medium in accordance with claim 4, wherein f(N, α0) is approximated by: f(N, α0)≈[1+p1(N)α0+p2(N)α02+p3(N)α03+p4(N)α04+p5(N)α05], and p1(N), p2(N), p3(N), p4(N), and p5(N) are polynomials of N. 7. A non-transitory computer readable medium in accordance with claim 4, wherein f(N, α0) is approximated by: f(N,α0)≈secα0{1-tan2α0N-1}-12{1-tan2α02(2N-1)[(N-1)-tan2α0]}. 8. A non-transitory computer readable medium in accordance with claim 7, wherein τ tan 2 α02. 10. A non-transitory computer readable medium in accordance with claim 4, wherein N is one of 3, 4, and 5. 11. The non-transitory computer readable medium of claim 10, wherein N is one of 3, 4, and 5. 12. A non-transitory computer readable medium including computer executable code capable of being run on a computer for guiding a vehicle to avoid an obstacle, the computer executable code comprising: computer executable code for determining a vehicle-to-obstacle position vector r; computer executable code for determining a net vehicle-to-obstacle velocity v;computer executable code for determining a net vehicle-to-obstacle acceleration a; computer executable code for determining the time-to-go τ between a current vehicle position and an obstacle position according to a first equation: 12a·aτ3+32a·vτ2+(a·r+v·v)τ+v·r=0;computer executable code for determining an offset vector Ψto avoid an obstacle; computer executable code for determining an acceleration command A according to a second equation: A=rτ2+vτ+12a+ψ; and computer executable code for generating a guidance signal based upon the thus determined acceleration command A. 13. A non-transitory computer readable medium in accordance with claim 12, wherein the guidance signal is at least one of an audible warning and a visual warning. 14. A non-transitory computer readable medium in accordance with claim 12, wherein the guidance signal is a braking command. 15. A method, comprising: estimating a time-to-go to a target from a vehicle on a course to the target, the target having an actual acceleration;adjusting the estimated time-to-go for the actual acceleration of the target; andmodifying the course of the vehicle responsive to the acceleration adjusted estimated time-to-go. 16. The method of claim 15, wherein: estimating the time-to-go includes determining a zero-effort-miss estimate; andadjusting for the actual acceleration results in zero-effort-miss with acceleration compensation guidance estimate. 17. The method of claim 15, wherein: estimating the time-to-go includes determining a true proportional navigation estimate; andadjusting for the actual acceleration results in an augmented proportional navigation estimate. 18. The method of claim 15, further comprising acquiring the information from which the time-to-go is estimated. 19. The method of claim 18, wherein acquiring the information includes acquiring the vehicle-to-target vector, the vehicle-to-target velocity, and the vehicle-to-target acceleration. 20. The method of claim 18, wherein acquiring the information includes determining the information from a RADAR return signal or an optical return signal. 21. The method of claim 18, wherein acquiring the information includes receiving information from an external source. 22. The method of claim 18, wherein acquiring the information includes accessing at least a portion of the information from a memory. 23. The method of claim 15, wherein modifying the course of the vehicle includes modifying the course so that the vehicle intercepts the target. 24. The method of claim 15, wherein modifying the course of the vehicle includes modifying the course so that the vehicle avoids colliding with the target. 25. The method of claim 24, wherein modifying the course includes applying a minimum margin offset. 26. The method of claim 24, wherein modifying the course includes maintaining a safe distance relative to surrounding vehicles to avoid accidents. 27. The method of claim 24, wherein modifying the course includes maintaining an intercept course. 28. A non-transitory computer readable medium encoded with a instructions that, when executed by a processor, perform a method, the method comprising: estimating a time-to-go from a vehicle to a target, the target having an actual acceleration; andadjusting the estimated time-to-go for the actual acceleration of the target. 29. The non-transitory computer readable medium of claim 28, wherein, in the method: estimating the time-to-go includes determining a zero-effort-miss estimate; andadjusting for the actual acceleration results in zero-effort-miss with acceleration compensation guidance estimate. 30. The non-transitory computer readable medium of claim 28, wherein, in the method: estimating the time-to-go includes determining a true proportional navigation estimate; andadjusting for the actual acceleration results in an augmented proportional navigation estimate. 31. The non-transitory computer readable medium of claim 28, wherein the method further comprises modifying the course of the vehicle responsive to the acceleration adjusted estimated time-to-go. 32. The non-transitory computer readable medium of claim 31, wherein modifying the course of the vehicle in the method includes modifying the course so that the vehicle intercepts the target. 33. The non-transitory computer readable medium of claim 31, wherein modifying the course of the vehicle in the method includes modifying the course so that the vehicle avoids colliding with the target. 34. The non-transitory computer readable medium of claim 31, wherein modifying the course in the method includes applying a minimum margin offset. 35. The non-transitory computer readable medium of claim 31, wherein modifying the course in the method includes maintaining a safe distance relative to surrounding vehicles to avoid accidents. 36. The non-transitory computer readable medium of claim 31, wherein modifying the course in the method includes maintaining an intercept course. 37. The non-transit readable medium of claim 28, wherein the target is an obstacle. 38. An apparatus, comprising: a processor;software that, when executed by the processor, performs a method comprising: estimating a time-to-go from a vehicle to a target, the target having an actual acceleration;adjusting the estimated time-to-go for the actual acceleration of the target; anditerating the estimating and adjusting over time. 39. The apparatus of claim 38, wherein, in the method: estimating the time-to-go includes determining a zero-effort-miss estimate; andadjusting for the actual acceleration results in zero-effort-miss with acceleration compensation guidance estimate. 40. The apparatus of claim 38, wherein, in the method: estimating the time-to-go includes determining a true proportional navigation estimate; andadjusting for the actual acceleration results in an augmented proportional navigation estimate. 41. The apparatus of claim 38, wherein the method further comprises modifying the course of the vehicle responsive to the acceleration adjusted estimated time-to-go. 42. The apparatus of claim 41, wherein modifying the course of the vehicle in the method includes modifying the course so that the vehicle intercepts the target. 43. The apparatus of claim 41, wherein modifying the course of the vehicle in the method includes modifying the course so that the vehicle avoids colliding with the target. 44. The apparatus of claim 41, wherein modifying the course in the method includes applying a minimum margin offset. 45. The apparatus of claim 41, wherein modifying the course in the method includes maintaining a safe distance relative to surrounding vehicles to avoid accidents. 46. The apparatus of claim 41, wherein modifying the course in the method includes maintaining an intercept course. 47. The apparatus of claim 38, wherein the target is an obstacle. 48. The apparatus of claim 38, further comprising an on-board RADAR sensor and in which the method further comprises acquiring data through the RADAR sensor on which the estimating and adjusting are performed. 49. The apparatus of claim 38, wherein the method further comprises acquiring data on which the estimating and adjusting are performed from an external source. 50. The apparatus of claim 38, wherein the method further comprises acquiring data on which the estimating and adjusting are performed from an on-board memory.
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이 특허에 인용된 특허 (19)
Waymeyer Walter K. (La Verne CA), Advanced homing guidance system and method.
Yueh William R. (Claremont CA), Fourth order predictive, augmented proportional navigation system terminal guidance design with missile/target decouplin.
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