Patents by Inventor Xen Price
Xen Price 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: 9108748Abstract: Apparatus and methods for raising the orbit of a satellite having electric propulsion thrusters, an Earth sensor and an inertial reference sensor such as a gyro. A satellite positioning system generates orbital data and a profile generator generates an ideal electric orbit raising profile of the satellite. The ideal profile is one that the satellite must follow so that the perigee, apogee and inclination of the satellite can be adjusted simultaneously in a mass-efficient manner. A state machine processes the ideal profile and a true anomaly to generate a desired electric orbit raising profile. Steering apparatus generates signals that are used to control the attitude of the satellite to follow the desired profile.Type: GrantFiled: October 20, 2010Date of Patent: August 18, 2015Assignee: Space Systems/Loral, LLCInventors: Saghir Munir, Darren Stratemeier, Xen Price, Yassir Azziz, Jorge Delgado, Justo Jacinto
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Patent number: 9045239Abstract: Spacecraft payload orientation steering is provided for an orbiting spacecraft in motion along an orbit track around a celestial body, the orbit track having a nominal inclination with respect to an equatorial orbit, a substantial eccentricity, and a drift angle with respect to the nominal inclination. Coordinates of an optimal payload target location as a function of a spacecraft position along the orbit track are determined, the target location being on the surface of the celestial body and having a substantial motion with respect to the surface and with respect to a spacecraft nadir. A payload of the spacecraft is substantially aligned with the determined coordinates by steering the satellite body to correct for at least one of the inclination drift angle, and the eccentricity, thereby adjusting the spacecraft orientation as a function of the spacecraft position along the orbit track.Type: GrantFiled: December 2, 2009Date of Patent: June 2, 2015Assignee: Space Systems/Loral, LLCInventors: Saghir Munir, Xen Price, Matthew Machlis
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Patent number: 8179313Abstract: Estimation of a desired antenna tracking profile is provided for a radio frequency autotracked (RFAT) antenna in the absence of a ground reference. A first RFAT antenna subsystem has a first antenna and a first antenna positioning mechanism (APM), each mounted on a vehicle, and a first ground-based RF beacon; a second RFAT antenna subsystem has a second antenna and a second APM, each mounted on the vehicle, and a second ground-based RF beacon. A controller stores an accumulated record of actuations of the second APM as a function of time under normal operation, calculates a desired antenna tracking profile for the second antenna, from a first ground-based RF beacon and from the accumulated record, excluding any real-time data from the second ground-based RF beacon, and transmits actuation commands to the second APM so as to cause the second antenna to track the desired antenna tracking profile.Type: GrantFiled: May 13, 2010Date of Patent: May 15, 2012Assignee: Space Systems/Loral, Inc.Inventors: Yassir Azziz, Alicia Kavelaars, Xen Price, David Cielaszyk, Rob Schwarz
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Publication number: 20120097796Abstract: Apparatus and methods for raising the orbit of a satellite having electric propulsion thrusters, an Earth sensor and an inertial reference sensor such as a gyro. A satellite positioning system generates orbital data and a profile generator generates an ideal electric orbit raising profile of the satellite. The ideal profile is one that the satellite must follow so that the perigee, apogee and inclination of the satellite can be adjusted simultaneously in a mass-efficient manner. A state machine processes the ideal profile and a true anomaly to generate a desired electric orbit raising profile. Steering apparatus generates signals that are used to control the attitude of the satellite to follow the desired profile.Type: ApplicationFiled: October 20, 2010Publication date: April 26, 2012Inventors: Saghir Munir, Darren Stratemeier, Xen Price, Yassir Azziz, Jorge Delgado, Justo Jacinto
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Publication number: 20100179711Abstract: Spacecraft payload orientation steering is provided for an orbiting spacecraft in motion along an orbit track around a celestial body, the orbit track having a nominal inclination with respect to an equatorial orbit, a substantial eccentricity, and a drift angle with respect to the nominal inclination. Coordinates of an optimal payload target location as a function of a spacecraft position along the orbit track are determined, the target location being on the surface of the celestial body and having a substantial motion with respect to the surface and with respect to a spacecraft nadir. A payload of the spacecraft is substantially aligned with the determined coordinates by steering the satellite body to correct for at least one of the inclination drift angle, and the eccentricity, thereby adjusting the spacecraft orientation as a function of the spacecraft position along the orbit track.Type: ApplicationFiled: December 2, 2009Publication date: July 15, 2010Inventors: Saghir Munir, Xen Price, Matthew Machlis
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Patent number: 6672544Abstract: A spacecraft embedded in a reference frame rotating relative to inertial space. The spacecraft generally includes actuators for maneuvering the spacecraft with respect to the reference frame, an attitude measurement device that measures the pitch and roll attitude of the spacecraft with respect to the reference frame, a control device adapted to keep the roll and pitch angles of the spacecraft close to the commanded roll and pitch angles, and a harmonic torque estimator adapted to read the commanded angular velocity of the spacecraft relative to an inertial frame, read momentum wheel speeds, read known predicted external torques and combine angular velocity, measured wheel speed and known external torque to produce an estimated observable periodic torque.Type: GrantFiled: March 1, 2002Date of Patent: January 6, 2004Assignee: Space Systems/LoralInventors: Lawrence McGovern, Xen Price
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Publication number: 20030164429Abstract: A spacecraft embedded in a reference frame rotating relative to inertial space. The spacecraft generally includes actuators for maneuvering the spacecraft with respect to the reference frame, an attitude measurement device that measures the pitch and roll attitude of the spacecraft with respect to the reference frame, a control device adapted to keep the roll and pitch angles of the spacecraft close to the commanded roll and pitch angles, and a harmonic torque estimator adapted to read the commanded angular velocity of the spacecraft relative to an inertial frame, read momentum wheel speeds, read known predicted external torques and combines angular velocity, measured wheel speed and known external torque to produce an estimated observable periodic torque.Type: ApplicationFiled: March 1, 2002Publication date: September 4, 2003Inventors: Lawrence McGovern, Xen Price
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Patent number: 6053455Abstract: A spacecraft, such as a geosynchronous weather or communications satellite, is constructed to include a plurality of low thrust thrusters mounted at predetermined locations on at least one of a spacecraft appendage or a spacecraft bus. The plurality of low thrust thrusters are fired in pairs for at least one of removing a disturbance torque or providing fine pointing attitude control. In one embodiment the low thrust thrusters are mounted on a solar array panel, thereby increasing the moment arm and enhancing the thrust output of the low thrust thrusters. In one embodiment a spacecraft has a plurality of low thrust thrusters arranged as at least two sets of two low thrust thrusters, individual ones of the low thrust thrusters of a set being disposed in a V-configuration and mounted at predetermined locations on at least one of a spacecraft appendage or a spacecraft bus. The plurality of low thrust thrusters are selectively fired for achieving control of 3-axes of spacecraft attitude or momentum.Type: GrantFiled: January 22, 1998Date of Patent: April 25, 2000Assignee: Space Systems/Loral, Inc.Inventors: Xen Price, Thomas Randolph, Kam K. Chan, Ahmed Kamel
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Patent number: 6000661Abstract: A feedback motion compensation (FMC) component for use in a spacecraft having a payload. The FMC component includes a controller having sensor data inputs and an open loop dynamics model that is driven by actuator commands to produce a high accuracy attitude estimate suitable for payload motion compensation.Type: GrantFiled: September 22, 1997Date of Patent: December 14, 1999Assignee: Space Systems/Loral, Inc.Inventors: Xen Price, Kam Chan, Jeffery Stoen
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Patent number: 5996942Abstract: A method in accordance with this invention for maintaining a spacecraft in a desired orbital configuration, comprises the steps of: (a) recording a history of yaw momentum stored in momentum wheels; (b) estimating an average inertial torque and momentum over a previous time interval (such as one day); (c) determining a desired change in inertial torques using PID control law; (d) commanding a change in satellite trim tab and solar array position from a desired change in solar torque; and (e) slewing the trim tab and solar array a desired amount.Type: GrantFiled: September 22, 1997Date of Patent: December 7, 1999Assignee: Space Systems/Loral, Inc.Inventors: Xen Price, Kam Chan