Patents by Inventor Yiu-Hung M. Ho

Yiu-Hung M. Ho 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).

  • Patent number: 9309010
    Abstract: A first inclination vector associated with a first satellite of the plurality of satellites is established. A second inclination vector associated with a second satellite of the plurality of satellites is established. The first satellite and the second satellite are controlled, such that the first satellite and the second satellite are synchronized with a node.
    Type: Grant
    Filed: January 10, 2014
    Date of Patent: April 12, 2016
    Assignee: The Boeing Company
    Inventor: Yiu-hung M. Ho
  • Publication number: 20150197350
    Abstract: A first inclination vector associated with a first satellite of the plurality of satellites is established. A second inclination vector associated with a second satellite of the plurality of satellites is established. The first satellite and the second satellite are controlled, such that the first satellite and the second satellite are synchronized with a node.
    Type: Application
    Filed: January 10, 2014
    Publication date: July 16, 2015
    Applicant: The Boeing Company
    Inventor: Yiu-hung M. Ho
  • Patent number: 8930048
    Abstract: The disclosed method involves calculating, with at least one processor, a desired orbit for the spacecraft. The method further involves calculating a velocity change required to achieve an orbit eccentricity, a velocity change required to achieve a semi-major axis, and a velocity change required to achieve an orbit inclination; all of which correspond to the desired orbit for the spacecraft. Also, the method involves calculating the direction of the vector sum of the velocity change required to achieve the orbit eccentricity, the velocity change required to achieve the semi-major axis, and the velocity change required to achieve the orbit inclination. Further, the method involves activating at least one propulsion device of the spacecraft in the direction of the vector sum in order to change the current orbit of the spacecraft to the desired orbit for the spacecraft, thereby changing the orbit eccentricity, the semi-major axis, and the orbit inclination simultaneously.
    Type: Grant
    Filed: October 23, 2012
    Date of Patent: January 6, 2015
    Assignee: The Boeing Company
    Inventors: Fawwad M. Batla, Yiu-hung M. Ho
  • Patent number: 8457810
    Abstract: A method and system for application of a compound steering law for efficient low thrust transfer orbit trajectory for a spacecraft are disclosed. The method involves calculating, with at least one processor, a desired orbit for the spacecraft. The method further involves calculating a velocity change required to achieve an orbit eccentricity and a velocity change required to achieve a semi-major axis, both of which correspond to the desired orbit for the spacecraft. Also, the method involves calculating the direction of the vector sum of the velocity change required to achieve the orbit eccentricity and the velocity change required to achieve the semi-major axis. Further, the method involves firing at least one thruster of the spacecraft in the direction of the vector sum in order to change the current orbit of the spacecraft to the desired orbit for the spacecraft, thereby changing the orbit eccentricity and the semi-major axis simultaneously.
    Type: Grant
    Filed: April 14, 2011
    Date of Patent: June 4, 2013
    Assignee: The Boeing Company
    Inventors: Fawwad M. Batla, Yiu-Hung M. Ho
  • Patent number: 8439312
    Abstract: 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: Grant
    Filed: June 18, 2008
    Date of Patent: May 14, 2013
    Assignee: The Boeing Company
    Inventors: Yiu-Hung M. Ho, Jeffrey A. Kurland, David S. Uetrecht
  • Patent number: 8282043
    Abstract: 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 control using Attitude Control Systems (ACS).
    Type: Grant
    Filed: February 23, 2011
    Date of Patent: October 9, 2012
    Assignee: The Boeing Company
    Inventor: Yiu-Hung M. Ho
  • Patent number: 8205839
    Abstract: A method for performing east-west station keeping for a satellite in an inclined synchronous orbit is described. The method includes averaging a value of a right ascension of the ascending node for an inclination vector associated with the satellite over a period of the control cycle, and managing corrections for the satellite such that an eccentricity vector, directed at perigee, is substantially collinear with the inclination vector.
    Type: Grant
    Filed: November 6, 2006
    Date of Patent: June 26, 2012
    Assignee: The Boeing Company
    Inventors: Bernard M. Anzel, Yiu-Hung M. Ho
  • Publication number: 20110144835
    Abstract: 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 control using Attitude Control Systems (ACS).
    Type: Application
    Filed: February 23, 2011
    Publication date: June 16, 2011
    Applicant: THE BOEING COMPANY
    Inventor: Yiu-Hung M. Ho
  • Patent number: 7918420
    Abstract: 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 control using Attitude Control Systems (ACS).
    Type: Grant
    Filed: July 17, 2007
    Date of Patent: April 5, 2011
    Assignee: The Boeing Company
    Inventor: Yiu-Hung M. Ho
  • Patent number: 7823836
    Abstract: A method and apparatus for maneuvering a satellite in orbit to alternately optimize the collection of solar energy and to take sensor data of terrestrial objects is disclosed The longitudinal axis of a large payload package is oriented perpendicular to the orbital plane to minimize the disturbance torque due to gravity gradient, and to allow simple rotation about the axis for attitude change between optimal Sun and optimal ground coverage.
    Type: Grant
    Filed: December 4, 2006
    Date of Patent: November 2, 2010
    Assignee: The Boeing Company
    Inventors: Yiu-Hung M. Ho, John Y. Liu
  • Publication number: 20090078829
    Abstract: 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: Application
    Filed: June 18, 2008
    Publication date: March 26, 2009
    Inventors: Yiu-Hung M. Ho, Jeffrey A. Kurland, David S. Uetrecht
  • Publication number: 20090020650
    Abstract: 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 control using Attitude Control Systems (ACS).
    Type: Application
    Filed: July 17, 2007
    Publication date: January 22, 2009
    Inventor: Yiu-Hung M. Ho
  • Publication number: 20080128559
    Abstract: A method and apparatus for maneuvering a satellite in orbit to alternately optimize the collection of solar energy and to take sensor data of terrestrial objects is disclosed The longitudinal axis of a large payload package is oriented perpendicular to the orbital plane to minimize the disturbance torque due to gravity gradient, and to allow simple rotation about the axis for attitude change between optimal Sun and optimal ground coverage.
    Type: Application
    Filed: December 4, 2006
    Publication date: June 5, 2008
    Inventors: Yiu-Hung M. Ho, John Y. Liu
  • Publication number: 20080105788
    Abstract: A method for performing east-west station keeping for a satellite in an inclined synchronous orbit is described. The method includes averaging a value of a right ascension of the ascending node for an inclination vector associated with the satellite over a period of the control cycle, and managing corrections for the satellite such that an eccentricity vector, directed at perigee, is substantially collinear with the inclination vector.
    Type: Application
    Filed: November 6, 2006
    Publication date: May 8, 2008
    Inventors: Bernard M. Anzel, Yiu-Hung M. Ho
  • Patent number: 6015116
    Abstract: Satellite stationkeeping and momentum-dumping methods are facilitated by the use of diagonally-arranged thruster pairs which are positioned on a selected one of a nadir and an antinadir satellite face. A first one of the thruster pairs is directed so that its thruster forces are spaced by moment arms from the satellite's center of mass. Firings of this thruster pair are separated by a momentum-dumping right ascension difference that is chosen to enhance momentum authority. These firings generate momentum-dumping torques and contribute to stationkeeping velocity changes. A second one of the thruster pairs is directed so that its thruster forces substantially pass through the center of mass. Firings of this thruster pair are separated by a stationkeeping right ascension difference chosen to minimize fuel consumption while providing a major portion of stationkeeping velocity changes.
    Type: Grant
    Filed: December 11, 1997
    Date of Patent: January 18, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: Bernard M. Anzel, Yiu-Hung M. Ho, Richard A. Noyola