System and methods for simultaneous momentum dumping and orbit control
원문보기
IPC분류정보
국가/구분
United States(US) Patent
등록
국제특허분류(IPC7판)
B64G-001/26
B64G-001/10
출원번호
US-0141832
(2008-06-18)
등록번호
US-8439312
(2013-05-14)
발명자
/ 주소
Ho, Yiu-Hung M.
Kurland, Jeffrey A.
Uetrecht, David S.
출원인 / 주소
The Boeing Company
대리인 / 주소
Yee & Associates, P.C.
인용정보
피인용 횟수 :
4인용 특허 :
13
초록▼
The present system and methods enable simultaneous momentum dumping and orbit control of a spacecraft, such as a geostationary satellite. Control equations according to the present system and methods generate accurate station-keeping commands quickly and efficiently, reducing the number of maneuvers
The present system and methods enable simultaneous momentum dumping and orbit control of a spacecraft, such as a geostationary satellite. Control equations according to the present system and methods generate accurate station-keeping commands quickly and efficiently, reducing the number of maneuvers needed to maintain station and allowing station-keeping maneuvers to be performed with a single burn. Additional benefits include increased efficiency in propellant usage, and extension of the satellite's lifespan. The present system and methods also enable tighter orbit control, reduction in transients and number of station-keeping thrusters aboard the satellite. The present methods also eliminate the need for the thrusters to point through the center of mass of the satellite, which in turn reduces the need for dedicated station-keeping thrusters. The present methods also facilitate completely autonomous orbit control and angular momentum control using.
대표청구항▼
1. A method of simultaneous orbit control and momentum dumping in a spacecraft in an orbit, the spacecraft including a plurality of north/south thrusters, the method comprising the steps of: generating a set of firing commands for the north/south thrusters from solutions to inclination control and r
1. A method of simultaneous orbit control and momentum dumping in a spacecraft in an orbit, the spacecraft including a plurality of north/south thrusters, the method comprising the steps of: generating a set of firing commands for the north/south thrusters from solutions to inclination control and roll/yaw momentum dumping equations; andfiring the north/south thrusters according to the firing commands so that control of an inclination of the orbit and a roll/yaw momentum dumping are achieved simultaneously using only the north/south thrusters. 2. The method of claim 1, wherein the inclination control and roll/yaw momentum dumping equations comprise exactly three equations. 3. The method of claim 2, wherein the inclination control and roll/yaw momentum dumping equations are defined as ∑i=1,3finormalΔti=ΔPI∑i=1,3(ri2fi3-ri3fi2)Δti=ΔHroll∑i=1,3(ri3fi1-ri1fi3)Δti=ΔHyawwhere ΔPI=spacecraft mass X minimum delta velocity required to control mean inclinationΔHroll=roll momentum dumping requirement in orbit frameΔHyaw=yaw momentum dumping requirement in orbit framefitangential=fi1=tangential component for the ith thrusterfiradial=fi2=radial component for the ith thrusterfinormal=fi3=normal component for the ith thrusterri1=x component of the lever arm for the ith thrusterri2=y component of the lever arm for the ith thrusterri3=Z component of the lever arm for the ith thrusterΔti=on time for the ith thruster. 4. The method of claim 1, wherein the spacecraft includes a plurality of east/west thrusters, the firing commands for the north/south thrusters are a first set of firing commands, and further comprising the steps of: generating a second set of firing commands for the east/west thrusters from solutions to drift and eccentricity control and pitch momentum dumping equations; andfiring the east/west thrusters according to the second set of firing commands so that a drift and an eccentricity control of the orbit and a pitch momentum dumping are achieved simultaneously using only the east/west thrusters. 5. The method of claim 4, wherein the drift and eccentricity control and pitch momentum dumping equations are defined as ∑i=1,2fitangentialΔti=ΔPDrift∑i=1,2(ri1fi2-ri2fi1)Δti=ΔHpitchwhere ΔPDrift=spacecraft mass X minimum delta velocity required to control mean longitudinal driftΔHpitch=pitch momentum dumping requirement in orbit framefitangential=fi1=tangential component for the ith thrusterfiradial=fi2=radial component for the ith thrusterfinormal=fi3=normal component for the ith thrusterri1=x component of the lever arm for the ith thrusterri2=y component of the lever arm for the ith thruster. 6. The method of claim 1, wherein the thrusters have fixed orientations relative to the spacecraft, such that the thrusters cannot pivot with respect to the spacecraft. 7. The method of claim 1, wherein when each thruster is fired it applies a force to the spacecraft, and none of said forces points through the center of mass of the spacecraft. 8. A method of simultaneous orbit control and momentum dumping in a spacecraft, the spacecraft including a plurality of east/west thrusters, the method comprising the steps of: generating a set of firing commands for the east/west thrusters from solutions to drift and eccentricity control and pitch momentum dumping equations; andfiring the east/west thrusters according to the firing commands so that a drift and an eccentricity control of the orbit and a pitch momentum dumping are achieved simultaneously using only the east/west thrusters. 9. The method of claim 8, wherein the drift and eccentricity control and pitch momentum dumping equations comprise exactly two equations. 10. The method of claim 9, wherein the drift and eccentricity control and pitch momentum dumping equations are defined as ∑i=1,2fitangentialΔti=ΔPDrift∑i=1,2(ri1fi2-ri2fi1)Δti=ΔHpitchwhere ΔPDrift=spacecraft mass X minimum delta velocity required to control mean longitudinal driftΔHpitch=pitch momentum dumping requirement in orbit framefitangential=fi1=tangential component for the ith thrusterfiradial=fi2=radial component for the ith thrusterfinormal=fi3=normal component for the ith thrusterri1=x component of the lever arm for the ith thrusterri2=y component of the lever arm for the ith thruster. 11. The method of claim 8, wherein the thrusters have fixed orientations relative to the spacecraft, such that the thrusters cannot pivot with respect to the spacecraft. 12. The method of claim 8, wherein when each thruster is fired it applies a force to the spacecraft, and none of said forces points through the center of mass of the spacecraft. 13. A system for simultaneous orbit control and momentum dumping of a spacecraft in an orbit, comprising: a plurality of north/south thrusters affixed to the spacecraft; andmeans for generating a set of firing commands for the north/south thrusters from solutions to inclination control and roll/yaw momentum dumping equations so that control of an inclination of the orbit and a roll/yaw momentum dumping are achieved simultaneously using only the north/south thrusters. 14. The system of claim 13, wherein the inclination control and roll/yaw momentum dumping equations comprise exactly three equations. 15. The system of claim 14, wherein the inclination control and roll/yaw momentum dumping equations are defined as ∑i=1,3finormalΔti=ΔPI∑i=1,3(ri2fi3-ri3fi2)Δti=ΔHroll∑i=1,3(ri3fi1-ri1fi3)Δti=ΔHyawwhere ΔPI=spacecraft mass X minimum delta velocity required to control mean inclinationΔHroll=roll momentum dumping requirement in orbit frameΔHyaw=yaw momentum dumping requirement in orbit framefitangential=fi1=tangential component for the ith thrusterfiradial=fi2=radial component for the ith thrusterfinormal=fi3=normal component for the ith thrusterri1=x component of the lever arm for the ith thrusterri2=y component of the lever arm for the ith thrusterri3=Z component of the lever arm for the ith thrusterΔti=on time for the ith thruster. 16. The system of claim 13, wherein the spacecraft includes a plurality of east/west thrusters, and further comprising means for generating a set of firing commands for the east/west thrusters from solutions to drift and eccentricity control and pitch momentum dumping equations so that a drift and an eccentricity control of the orbit and a pitch momentum dumping are achieved simultaneously using only the east/west thrusters. 17. The system of claim 16, wherein the drift and eccentricity control and pitch momentum dumping equations are defined as ∑i=1,2fitangentialΔti=ΔPDrift∑i=1,2(ri1fi2-ri2fi1)Δti=ΔHpitchwhere ΔPDrift=spacecraft mass X minimum delta velocity required to control mean longitudinal driftΔHpitch=pitch momentum dumping requirement in orbit framefitangential=fi1=tangential component for the ith thrusterfiradial=fi2=radial component for the ith thrusterfinormal=fi3=normal component for the ith thrusterri1=x component of the lever arm for the ith thrusterri2=y component of the lever arm for the ith thruster. 18. A spacecraft configured to orbit Earth in a geostationary orbit, and further configured to autonomously control a position of the spacecraft relative to a fixed point on Earth, comprising: a spacecraft body; anda plurality of north/south thrusters associated with the spacecraft body, the north/south thrusters;wherein the spacecraft generates a set of firing commands for the north/south thrusters from solutions to inclination control and roll/yaw momentum dumping equations, and the spacecraft fires the thrusters according to the firing commands so that control of an inclination of the orbit and a roll/yaw momentum dumping are achieved simultaneously using only the north/south thrusters. 19. The spacecraft of claim 18, wherein the inclination control and roll/yaw momentum dumping equations comprise exactly three equations. 20. The spacecraft of claim 19, wherein the inclination control and roll/yaw momentum dumping equations are defined as ∑i=1,3finormalΔti=ΔPI∑i=1,3(ri2fi3-ri3fi2)Δti=ΔHroll∑i=1,3(ri3fi1-ri1fi3)Δti=ΔHyawwhere ΔPI=spacecraft mass X minimum delta velocity required to control mean inclinationΔHroll=roll momentum dumping requirement in orbit frameΔHyaw=yaw momentum dumping requirement in orbit framefitangential=fi1=tangential component for the ith thrusterfiradial=fi2=radial component for the ith thrusterfinormal=fi3=normal component for the ith thrusterri1=x component of the lever arm for the ith thrusterri2=y component of the lever arm for the ith thrusterri3=Z component of the lever arm for the ith thrusterΔti=on time for the ith thruster. 21. The spacecraft of claim 18, wherein the spacecraft includes a plurality of east/west thrusters, and further comprising means for generating a set of firing commands for the east/west thrusters from solutions to drift and eccentricity control and pitch momentum dumping equations so that a drift and an eccentricity control of the orbit and a pitch momentum dumping are achieved simultaneously using only the east/west thrusters. 22. The spacecraft of claim 21, wherein the drift and eccentricity control and pitch momentum dumping equations are defined as ∑i=1,2fitangentialΔti=ΔPDrift∑i=1,2(ri1fi2-ri2fi1)Δti=ΔHpitchwhere ΔPDrift=spacecraft mass X minimum delta velocity required to control mean longitudinal driftΔHpitch=pitch momentum dumping requirement in orbit framefitangential=fi1=tangential component for the ith thrusterfiradial=fi2=radial component for the ith thrusterfinormal=fi3=normal component for the ith thrusterri1=x component of the lever arm for the ith thrusterri2=y component of the lever arm for the ith thruster.
Michael F. Barsky ; Thomas M. Tanner ; Loren I. Slafer ; Paul D. Williams ; George B. Semeniuk ; Joseph M. Allard GB, Stationkeeping method utilizing open-loop thruster pulses and closed-loop authority limited momentum storage devices.
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