IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0760189
(2013-02-06)
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등록번호 |
US-8571727
(2013-10-29)
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발명자
/ 주소 |
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출원인 / 주소 |
- The Aerospace Corporation
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대리인 / 주소 |
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인용정보 |
피인용 횟수 :
0 인용 특허 :
3 |
초록
▼
An improved method for launch vehicle guidance is disclosed. A pre-computed energy-angular momentum (E-J) curve to place a launch vehicle into a target orbit is received and stored. An energy, angular momentum, radial distance, velocity magnitude, and flight path angle of the launch vehicle are comp
An improved method for launch vehicle guidance is disclosed. A pre-computed energy-angular momentum (E-J) curve to place a launch vehicle into a target orbit is received and stored. An energy, angular momentum, radial distance, velocity magnitude, and flight path angle of the launch vehicle are computed from state vector data while the launch vehicle is traveling to the target orbit. The pre-computed E-J curve and the computed energy, angular momentum, radial distance, velocity magnitude, and flight path angle of the launch vehicle are used to determine pitch and pitch rate of the launch vehicle.
대표청구항
▼
1. A computer program embodied on a computer-readable storage medium, the computer program configured to cause at least one processor to: receive and store a pre-computed energy-angular momentum (E-J) curve to place a launch vehicle into a target orbit;compute an energy, angular momentum, radial dis
1. A computer program embodied on a computer-readable storage medium, the computer program configured to cause at least one processor to: receive and store a pre-computed energy-angular momentum (E-J) curve to place a launch vehicle into a target orbit;compute an energy, angular momentum, radial distance, velocity magnitude, and flight path angle of the launch vehicle from state vector data while the launch vehicle is traveling to the target orbit; anduse the pre-computed E-J curve and the computed energy, angular momentum, radial distance, velocity magnitude, and flight path angle of the launch vehicle to determine pitch and pitch rate of the launch vehicle. 2. The computer program of claim 1, wherein when the launch vehicle deviates from the E-J curve, the program is further configured to cause the at least one processor to engage one or more motors of the launch vehicle to alter a pitch of the launch vehicle to a corrected slope to steer out energy deviations and return the launch vehicle to the E-J curve. 3. The computer program of claim 2, wherein the program is configured to cause the at least one processor to determine the corrected slope by δ(J)=(B)ΔE(1+ɛ)Jf-Jwhere B is a constant gain or a function of J whose value can be adjusted as needed to ensure satisfactory performance, ΔE is a difference between actual vehicle energy and energy prescribed by the E-J curve, Jf refers to final angular momentum at orbit injection, and constant ε is a small positive non-dimensional number that ensures that a denominator of the equation does not become zero. 4. The computer program of claim 1, wherein the program is further configured to cause the at least one processor to receive and store a pre-computed inclination versus angular momentum (I-J) curve. 5. The computer program of claim 4, wherein when the launch vehicle deviates from the I-J curve, the program is further configured to cause the at least one processor to engage one or more motors of the launch vehicle to perform yaw corrections to steer out deviations from a desired inclination. 6. The computer program of claim 5, wherein the program is configured to cause the at least one processor to determine the yaw corrections by δθ=-ΔIJB1Jfarcos(ϕ)(Jf(1+ɛ1)-J)where ΔI is a change in inclination, J is angular momentum, Jf is angular momentum at orbit injection, B1 is a constant gain or a function of J, ε1 is a constant, r is a distance to a center of Earth or gravitational field, a is an acceleration, and φ is an argument of latitude. 7. The computer program of claim 1, wherein the E-J curve represents an optimum trajectory to reach the target orbit. 8. The computer program of claim 7, wherein the optimum trajectory is configured to deliver a largest mass to the target orbit with a smallest amount of fuel for the launch vehicle. 9. The computer program of claim 1, wherein the program is further configured to cause the at least one processor to continuously check for deviations by the launch vehicle from the E-J and I-J curves from launch of the launch vehicle until the launch vehicle reaches the target orbit. 10. The computer program of claim 1, wherein the program is further configured to cause the at least one processor to calculate inclination dispersions by taking a difference between pre-flight trajectory angular momentum and vehicle trajectory angular momentum and drive the difference to zero. 11. A computer-implemented method, comprising: receiving and storing a pre-computed energy-angular momentum (E-J) curve to place a launch vehicle into a target orbit;computing an energy, angular momentum, radial distance, velocity magnitude, and flight path angle of the launch vehicle from state vector data while the launch vehicle is traveling to the target orbit; andusing the pre-computed E-J curve and the computed energy, angular momentum, radial distance, velocity magnitude, and flight path angle of the launch vehicle to determine pitch and pitch rate of the launch vehicle. 12. The computer-implemented method of claim 11, wherein when the launch vehicle deviates from the E-J curve, the method further comprises engaging one or more motors of the launch vehicle to alter a pitch of the launch vehicle to a corrected slope to steer out energy deviations and return the launch vehicle to the desired E-J curve. 13. The computer-implemented method of claim 12, the corrected slope is determined by δ(J)=(B)ΔE(1+ɛ)Jf-Jwhere B is a constant gain or a function of J whose value can be adjusted as needed to ensure satisfactory performance, ΔE is a difference between actual vehicle energy and energy prescribed by the E-J curve, Jf refers to final angular momentum at orbit injection, and constant ε is a small positive non-dimensional number that ensures that a denominator of the equation does not become zero. 14. The computer-implemented method of claim 11, further comprising: receiving and storing a pre-computed inclination versus angular momentum (I-J) curve. 15. The computer-implemented method of claim 14, wherein when the launch vehicle deviates from the I-J curve, the method further comprises engaging one or more motors of the launch vehicle to perform yaw corrections to steer out deviations from a desired inclination. 16. The computer program of claim 15, wherein the yaw corrections are determined by δθ=-ΔIJB1Jfarcos(ϕ)(Jf(1+ɛ1)-J)where ΔI is a change in inclination, J is angular momentum, Jf is angular momentum at orbit injection, B1 is a constant gain or a function of J, ε1 is a constant, r is a distance to a center of Earth or gravitational field, a is an acceleration, and φ is an argument of latitude. 17. The computer-implemented method of claim 11, wherein the E-J curve represents an optimum trajectory to reach the target orbit. 18. The computer-implemented method of claim 17, wherein the optimum trajectory is configured to deliver a largest mass to the target orbit with a smallest amount of fuel for the launch vehicle. 19. The computer-implemented method of claim 11, further comprising: continuously checking for deviations by the launch vehicle from the E-J and I-J curves from launch of the launch vehicle until the launch vehicle reaches the target orbit. 20. The computer-implemented method of claim 11, further comprising: calculating inclination dispersions by taking a difference between pre-flight trajectory angular momentum and vehicle trajectory angular momentum; anddriving the difference to zero. 21. An apparatus, comprising: physical memory comprising computer program instructions; andat least one processor configured to execute the computer program instructions, the at least one processor configured to: receive and store a pre-computed energy-angular momentum (E-J) curve to place a launch vehicle into a target orbit;compute an energy, angular momentum, radial distance, velocity magnitude, and flight path angle of the launch vehicle from state vector data while the launch vehicle is traveling to the target orbit; anduse the pre-computed E-J curve and the computed energy, angular momentum, radial distance, velocity magnitude, and flight path angle of the launch vehicle to determine pitch and pitch rate of the launch vehicle. 22. The apparatus of claim 21, wherein when the launch vehicle deviates from the E-J curve, the at least one processor is further configured to engage one or more motors of the launch vehicle to alter a pitch of the launch vehicle to a corrected slope to steer out energy deviations and return the launch vehicle to the E-J curve. 23. The apparatus of claim 22, wherein the at least one processor is configured to determine the corrected slope by δ(J)=(B)ΔE(1+ɛ)Jf-Jwhere B is a constant gain or a function of J whose value can be adjusted as needed to ensure satisfactory performance, ΔE is a difference between actual vehicle energy and energy prescribed by the E-J curve, Jf refers to final angular momentum at orbit injection, and constant ε is a small positive non-dimensional number that ensures that a denominator of the equation does not become zero. 24. The apparatus of claim 21, wherein the at least one processor is further configured to receive and store a pre-computed inclination versus angular momentum (I-J) curve. 25. The apparatus of claim 24, wherein when the launch vehicle deviates from the I-J curve, the at least one processor is further configured to engage one or more motors of the launch vehicle to perform yaw corrections to steer out deviations from a desired inclination. 26. The apparatus of claim 25, wherein the at least one processor is configured to determine the yaw corrections by δθ=-ΔIJB1Jfarcos(ϕ)(Jf(1+ɛ1)-J)where ΔI is a change in inclination, J is angular momentum, Jf is angular momentum at orbit injection, B1 is a constant gain or a function of J, ε1 is a constant, r is a distance to a center of Earth or gravitational field, a is an acceleration, and φ is an argument of latitude. 27. The apparatus of claim 21, wherein the E-J curve represents an optimum trajectory to reach the target orbit. 28. The apparatus of claim 27, wherein the optimum trajectory is configured to deliver a largest mass to the target orbit with a smallest amount of fuel for the launch vehicle. 29. The apparatus of claim 21, wherein the at least one processor is further configured to continuously check for deviations by the launch vehicle from the E-J and I-J curves from launch of the launch vehicle until the launch vehicle reaches the target orbit. 30. The apparatus of claim 21, wherein the at least one processor is further configured to calculate inclination dispersions by taking a difference between pre-flight trajectory angular momentum and vehicle trajectory angular momentum and drive the difference to zero.
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