Patents by Inventor David S. Uetrecht
David S. Uetrecht has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 8439312Abstract: 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.Type: GrantFiled: June 18, 2008Date of Patent: May 14, 2013Assignee: The Boeing CompanyInventors: Yiu-Hung M. Ho, Jeffrey A. Kurland, David S. Uetrecht
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Patent number: 8265804Abstract: A method for controlling a vehicle may include sensing a position of each of a plurality of stars relative to the vehicle. The method may also include determining an attitude of the vehicle using the sensed positions of the plurality of stars, and the attitude may be determined either with or without using information from a gyro or sensor for measuring angular velocity. The method may additionally include implementing a set of strategies to optimize determination of the attitude of the vehicle when using only the sensed positions of the plurality of stars, without information from the sensor for measuring angular velocity. The method may further include controlling the vehicle based on the determined attitude of the vehicle.Type: GrantFiled: May 29, 2009Date of Patent: September 11, 2012Assignee: The Boeing CompanyInventors: David S. Uetrecht, David D. Needelman, Tung-Ching Tsao
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Publication number: 20090078829Abstract: 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.Type: ApplicationFiled: June 18, 2008Publication date: March 26, 2009Inventors: Yiu-Hung M. Ho, Jeffrey A. Kurland, David S. Uetrecht
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Patent number: 6681159Abstract: Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Kalman filter is temporarily replaced with a substantially greater interim process-noise covariance Q. This replacement increases the weight given to the most recent attitude measurements and hastens the reduction of attitude errors and gyroscope bias errors. The error effect of the substituted gyroscopes is reduced and the absolute-attitude sensors are not driven out of their capture range. In another method embodiment, this replacement is preceded by the temporary replacement of an operational measurement-noise variance R with a substantially larger interim measurement-noise variance R to reduce transients during the gyroscope substitutions.Type: GrantFiled: October 28, 2001Date of Patent: January 20, 2004Assignee: The Boeing CompanyInventors: Rongsheng Li, Jeffrey A. Kurland, Alec M. Dawson, Yeong-Wei A. Wu, David S. Uetrecht
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Publication number: 20030171855Abstract: Methods and structures are provided that enhance attitude control during gyroscope substitutions by insuring that a spacecraft's attitude control system does not drive its absolute-attitude sensors out of their capture ranges. In a method embodiment, an operational process-noise covariance Q of a Kalman filter is temporarily replaced with a substantially greater interim process-noise covariance Q. This replacement increases the weight given to the most recent attitude measurements and hastens the reduction of attitude errors and gyroscope bias errors. The error effect of the substituted gyroscopes is reduced and the absolute-attitude sensors are not driven out of their capture range. In another method embodiment, this replacement is preceded by the temporary replacement of an operational measurement-noise variance R with a substantially larger interim measurement-noise variance R to reduce transients during the gyroscope substitutions.Type: ApplicationFiled: October 28, 2001Publication date: September 11, 2003Applicant: BOEING COMPANYInventors: Rongsheng Li, Jeffrey A. Kurland, Alec M. Dawson, Yeong-Wei A. Wu, David S. Uetrecht
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Patent number: 6339734Abstract: A method, apparatus, article of manufacture, and a memory structure for compensating for instrument induced spacecraft jitter is disclosed. The apparatus comprises a spacecraft control processor for producing an actuator command signal, a signal generator, for producing a cancellation signal having at least one harmonic having a frequency and an amplitude substantially equal to that of a disturbance harmonic interacting with a spacecraft structural resonance and a phase substantially out of phase with the disturbance harmonic interacting with the spacecraft structural resonance, and at least one spacecraft control actuator, communicatively coupled to the spacecraft control processor and the signal generator for inducing satellite motion according to the actuator command signal and the cancellation signal.Type: GrantFiled: February 22, 2000Date of Patent: January 15, 2002Assignee: Hughes Electronics CorporationInventors: Ketao Liu, David S. Uetrecht
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Patent number: 6282467Abstract: A system and method for determining the attitude in an inertial frame of a spacecraft spinning about an axis in a body frame including determining momentum vector direction in the inertial frame; determining momentum vector direction in the body frame; acquiring information from an at least single-axis sensor; obtaining reference information on the at least single-axis sensor; updating the attitude in the inertial reference frame using the momentum vector direction in the inertial frame, the momentum vector direction in the body frame, the output of the at least single-axis sensor, and the reference information on the at least single-axis sensor; and propagating the attitude using data from one or more inertial sensors.Type: GrantFiled: October 14, 1997Date of Patent: August 28, 2001Assignee: The Boeing CompanyInventors: Piyush R. Shah, Garry Didinsky, David S. Uetrecht
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Patent number: 6076772Abstract: Attitude-control methods are provided which eliminate or reduce structural resonances in spacecraft that are excited by momentum wheel imperfections. The methods are preferably practiced with an over-determined attitude-control system which is typically available because spacecraft often carry backup momentum wheels to insure against failure of primary momentum wheels. In a method embodiment, a set of angular-velocity waveforms is selected that substantially realizes a commanded momentum vector when applied to a corresponding set of momentum wheels wherein none of the selected angular-velocity waveforms dwells at a resonant frequency of the spacecraft. The angular velocity of the corresponding set of momentum wheels is then conformed to the selected set of angular-velocity waveforms to realize a spacecraft attitude that corresponds to the commanded momentum vector without exciting the resonance.Type: GrantFiled: December 15, 1997Date of Patent: June 20, 2000Assignee: Hughes Electronics CorporationInventors: Bruce N. Eyerly, David S. Uetrecht
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Patent number: 6003818Abstract: A system and method for slewing a spacecraft with a reaction wheel system including determining initial total momentum, determining maximum forward and reverse rates that can be realized within the reaction wheel system maximum storage capacity, determining a slew rate and slew direction from the maximum forward and reverse rates so as to minimize slew time for known slew angles or maximize slew rate for arbitrary slew angles, and slewing the spacecraft.Type: GrantFiled: March 11, 1998Date of Patent: December 21, 1999Assignee: Hughes Electronics CorporationInventors: Piyush R. Shah, Douglas J. Bender, David S. Uetrecht
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Patent number: 5098041Abstract: An attitude and nutation control system (30) for a momentum-biased vehicle (10) having roll, pitch, and yaw axes which employs a normal mode estimator (32) which predicts steady-state values for roll attitude, roll rate, and yaw rate. The normal mode estimator (32) receives instantaneous roll attitude information from an earth sensor (34) and optionally receives roll and/or yaw rate information from roll gyro (35a) and yaw gyro (35b). A logic circuit (36) coupled to the normal mode estimator (32) generates correction signals when the steady-state values for roll attitude, roll rate, and yaw rate are outside predetermined limits. A plurality of thrusters (14a-d) produce torque for bringing the steady-state values for roll attitude, roll rate, and yaw rate within predetermined limits.Type: GrantFiled: June 7, 1990Date of Patent: March 24, 1992Assignee: Hughes Aircraft CompanyInventor: David S. Uetrecht