Patents Represented by Attorney, Agent or Law Firm Terje Gudmestad
  • Antenna configuration for low and medium earth orbit satellites
    Patent number: 6184838
    Abstract: An antenna configuration suitable for LEO/MEO satellites includes a plurality of lenses whereby each lens has a plurality of feed horns positioned with respect to the lens. The lens has a first surface and a second surface. The plurality of feed horns is disposed upon a curved surface. Each of the plurality of feed horns generates a beam that has a phase distribution. The phase distributions have a predetermined phase relationship with the first surface and preferably the second surface. This allows the lens to transmit and receive a signal with desired phase distribution across a cross-section of the beam. The beams from the plurality of lenses are inter-leaved on the ground to form a contiguous coverage with multiple overlapping spot-beams.
    Type: Grant
    Filed: November 20, 1998
    Date of Patent: February 6, 2001
    Assignee: Hughes Electronics Corporation
    Inventors: Sudhakar K. Rao, Philip H. Law
  • Reflective waveguide variable power divider/combiner
    Patent number: 6181221
    Abstract: A reflective waveguide variable power divider/combiner comprises an orthomode tee section, which includes a section of cylindrical waveguide and a rotatable reflective phase shifter section. The rotatable reflective phase shifter section is rotatably connected to the orthomode tee section by a cylindrical choke joint. The orthomode tee section includes a single orthomode tee unit. The reflective waveguide variable power divider/combiner terminates at a short circuit that separates a motor from the rotatable reflective phase shifter section. The motor is configured to rotate the rotatable reflective phase shifter section relative to the orthomode tee section.
    Type: Grant
    Filed: October 6, 1998
    Date of Patent: January 30, 2001
    Assignee: Hughes Electronics Corporation
    Inventors: Rolf Kich, James M. Barker
  • Multiple output power supply circuit for an ion engine with shared upper inverter
    Patent number: 6181585
    Abstract: A power supply circuit for an ion engine suitable for a spacecraft is coupled to a bus having a bus input and a bus return. The power supply circuit has a first primary winding of a first transformer. An upper inverter circuit is coupled to the bus input and the first primary winding. The power supply circuit further includes a first lower inverter circuit coupled to the bus return and the first primary winding. The second primary winding of a second transformer is coupled to the upper inverter circuit. A second lower inverter circuit is coupled to the bus return and the second primary winding.
    Type: Grant
    Filed: July 12, 1999
    Date of Patent: January 30, 2001
    Assignee: Hughes Electronics Corporation
    Inventors: Gilbert I. Cardwell, Jr., Thomas K. Phelps
  • Large signal gain modifier circuit
    Patent number: 6177784
    Abstract: A diode-resistor network for modifying the gain/bandwidth of the feedback loop. The feedback loop gain modifier circuit comprises two (2) diodes and a resistor coupled and parallel with a resistor in the AC feedback path of an amplifier. The diodes are connected such that one diode conducts on a voltage bus overshoot and the other diode conducts on a voltage bus undershoot. In this manner, during large step load transients, one of the gain modifier circuits diodes conducts thereby coupling the resistors in parallel resulting in a modified the gain/bandwidth of the feedback loop. In this way, the feedback gain modifier circuit does not affect the small signal feedback loop stability because it is only activated when a large transient is present.
    Type: Grant
    Filed: August 19, 1999
    Date of Patent: January 23, 2001
    Assignee: Hughes Electronics Corporation
    Inventor: Winnie W. Choy
  • Radiator using thermal control coating
    Patent number: 6176453
    Abstract: A spacecraft has internal structure which generates heat, and a radiator element in thermal communication with the spacecraft internal structure. The radiator element has a radiating surface and a coating on the radiating surface including a white thermal control paint. The paint has an initial solar absorptance of not greater than 0.16 and an initial infrared emittance of not less than about 0.80. The standard end-of-life projected solar absorptance is not more than about 0.33 for a paint with an inorganic binder, and the standard end-of-life projected solar absorptance is not more than about 0.6 for a paint with an organic binder.
    Type: Grant
    Filed: December 11, 1998
    Date of Patent: January 23, 2001
    Assignee: Hughes Electronics Corporation
    Inventors: Lynn E. Long, James R. Denman
  • Method and apparatus for spacecraft amplification of multi-channel signals
    Patent number: 6173155
    Abstract: The number of high power amplifiers required for multi-channel satellite communications is reduced by a high power amplification of selected sets of signals in respective common amplifiers, with each set of combined signals consisting of channels whose frequency bands are mutually discrete and sufficiently separated in frequency that their third order intermodulation products do not substantially overlap in frequency with any of the channels in the same set. The signals can be separated out again after amplification and transmitted as downlink signals, either individually from a dedicated downlink antenna or in combination with other channels in a common downlink antenna.
    Type: Grant
    Filed: September 25, 1998
    Date of Patent: January 9, 2001
    Assignee: Hughes Electronics Corporation
    Inventor: John L. Norin
  • Closed microwave device with externally mounted thermal expansion compensation element
    Patent number: 6169468
    Abstract: The thermal expansion of a microwave device such as a microwave resonator is partially or completely compensated by an externally mounted thermal expansion element. The microwave device includes a sidewall and an endwall affixed at its periphery to the sidewall. The thermal expansion compensation element is disposed external to the microwave device, between the endwall of the microwave device and a rigid external support. As the sidewall lengthens with increasing temperature, the thermal expansion compensation element expands to flex the endwall in the opposite direction to the growth in length of the sidewall, so that the central portion of the endwall remains in approximately the same position regardless of the temperature change.
    Type: Grant
    Filed: January 19, 1999
    Date of Patent: January 2, 2001
    Assignee: Hughes Electronics Corporation
    Inventor: John T. Chavez
  • Fast, highly accurate frequency measurement technique
    Patent number: 6169760
    Abstract: The frequency of a signal is determined using a signal filter having a signal filter skirt band frequency range wherein an intermediate fraction of an initial amplitude of an introduced signal passes through the signal filter. The magnitude of the transmitted intermediate fraction varies with the frequency of the introduced signal. A test applied signal having a frequency which lies within the signal filter skirt band frequency range is introduced into the signal filter. The transmitted amplitude of the test applied signal is measured after the test applied signal has passed through the signal filter. The transmitted amplitude is utilized as an indicator of the frequency of the test applied signal, either directly or through a calibration relation for amplitude as a function of frequency in the signal filter skirt band frequency range.
    Type: Grant
    Filed: March 19, 1998
    Date of Patent: January 2, 2001
    Assignee: Hughes Electronics Corporation
    Inventor: Clark D. Brenneise
  • Integrated reconfigurable polarizer
    Patent number: 6166610
    Abstract: A tunable polarizer having a 90 degree phase shift section and two adjustable, or rotatable, 45 degree phase shift sections. Each section is separated by spacer to maintain independence and avoid interaction. When the two 45 degree phase shift sections and are orthogonal to each other, the polarization detected is determined by the 90 degree phase shift section which provides compatibility with circularly polarized signal. When the two 45 degree phase shift sections and are aligned, the polarizer is in a linear polarization compatibility mode.
    Type: Grant
    Filed: February 22, 1999
    Date of Patent: December 26, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: Parthasarathy Ramanujam, Alan R. Keith
  • Balanced vibratory gyroscope and amplitude control for same
    Patent number: 6164134
    Abstract: A balanced vibratory micro-gyroscope having an electrode pattern having four inner drive electrodes and four outer sense electrodes for providing balanced push-pull control of a cloverleaf micro-gyroscope. A control circuit utilizes equal and opposite input signals to the drive electrodes and processes output signals from the sense electrodes to precisely control the drive electrodes. Capacitance is added between opposing drive and sense electrodes pattern in order to null capacitive coupling effects between adjacent drive and sense electrodes. The control circuit linearizes the force on the micro-gyroscope thereby improving performance. Advantage is taken of Coulomb's Law to eliminate an electronic multiplier in the vibration amplitude control loop. A simplified full-wave rectifier further enhances the control circuit and operation of the micro-gyroscope.
    Type: Grant
    Filed: January 29, 1999
    Date of Patent: December 26, 2000
    Assignee: Hughes Electronics Corporation
    Inventor: Donald R. Cargille
  • Temperature compensation of the pressure cutoff of charging of a pressurized-gas storage battery
    Patent number: 6163134
    Abstract: A pressurized-gas battery, such as a nickel-hydrogen battery, is rapidly charged at a high charging rate until the measured pressure reaches a high-pressure limit, and thereafter slowly charged at a reduced charging rate as the measured pressure falls toward a low-pressure limit. The high-pressure limit and the low-pressure limit each decrease with increasing temperature.
    Type: Grant
    Filed: January 27, 2000
    Date of Patent: December 19, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: Allen R. Powers, Steven J. Stadnick
  • Method for in-orbit multiple receive antenna pattern testing
    Patent number: 6157817
    Abstract: A method of testing in-orbit communications satellite receive antennas from a single ground test station. The ground test station transmits an uplink test signal to the orbiting satellite. Telemetry circuitry onboard the satellite measures the power level of the uplink signal received and converts it to a corresponding digital value. The satellite's position is slewed over angles approximately covering the receive antenna areas of reception. The power level of the received uplink test signal and satellite orientation information are transmitted to the ground test station in the satellite's telemetry data stream. A computer at the ground test station plots the power level with respect to the satellite's corresponding orientation to map the receive antenna pattern. In an alternative embodiment, a plurality of receive antennas are tested simultaneously.
    Type: Grant
    Filed: February 4, 1999
    Date of Patent: December 5, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: John L. Norin, Andrew B. Kopito
  • Method and apparatus for testing photovoltaic solar cells using multiple pulsed light sources
    Patent number: 6154034
    Abstract: A method and apparatus for testing photovoltaic solar cells using multiple flashlamps is disclosed. The method comprises steps of providing a plurality of flashlamps, pulsing the flashlamps to expose the solar cell to light for a short period of time, preferably less than about 100 milliseconds, and measuring a characteristic of the photovoltaic solar cell in response to the radiation emitted by the flashlamps. In a preferred embodiment of the invention, for use in testing triple junction solar cells, the apparatus includes six flashlamps: one flashlamp tailored to emit light in a portion of the light spectrum for stimulating each of the three junctions, and three additional flashlamps for conducting specialized testing.
    Type: Grant
    Filed: October 20, 1998
    Date of Patent: November 28, 2000
    Inventors: James N. Lovelady, Shawn A. Mitschelen
  • Dual spin zero momentum satellite system
    Patent number: 6152402
    Abstract: An attitude control system for a spacecraft which includes a bearing power and transfer assembly. The bearing power and transfer assembly is disposed between a first body and a second body. The first body and the second body are counter-rotated with respect to each other by the bearing and power transfer assembly such that the overall spacecraft momentum about the spin axis of the bearing and power transfer assembly is nominally zero.
    Type: Grant
    Filed: April 7, 1999
    Date of Patent: November 28, 2000
    Assignee: Hughes Electronics Corporation
    Inventor: David L. Augenstein
  • Method for reducing cross-polar degradation in multi-feed dual offset reflector antennas
    Patent number: 6150990
    Abstract: A unique feed structure for improving the cross-polarization performance of a reflector antenna system is disclosed. According to the present invention, the feed structure is an array including a number of feeds, which are rotated in a predetermined fashion to yield superior cross polarization performance of the antenna system. The array feed in the center of the feed structure is positioned approximately in the focus of the antenna reflector. The array feeds located on the y-axis are slightly rotated in either a clockwise or a counter-clockwise manner. The magnitude of the rotation is proportional to the distance of the feeds from the x-axis along the y-axis. The rotation of the feeds yields significant performance in cross polarization performance, while having little or no co-polarization effect.
    Type: Grant
    Filed: July 20, 1998
    Date of Patent: November 21, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: Parthasarathy Ramanujam, Philip H. Law, Louis R. Fermelia
  • Free return lunar flyby transfer method for geosynchronous satellites havint multiple perilune stages
    Patent number: 6149103
    Abstract: A method is provided for using at least two lunar flyby maneuvers to transfer a satellite from a quasi-geosynchronous transfer orbit having a high inclination to a final geosynchronous orbit having a low inclination. The invention may be used to take the inclination of a final geosynchronous orbit of a satellite to zero, through the use of a first leading-edge lunar flyby and subsequent successive leading or trailing edge lunar flybys resulting in a geostationary orbit.
    Type: Grant
    Filed: May 15, 1998
    Date of Patent: November 21, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: Jeremiah O. Salvatore, Cesar A. Ocampo
  • Attitude determination system and method
    Patent number: 6145790
    Abstract: An attitude sensing system utilizing simplified techniques and apparatus includes a spacecraft control processor which receives signals from an inertial measurement unit and two attitude sensors. The spacecraft control processor calculates a time-varying gain matrix for estimating attitude errors and gyroscope drifts corresponding to the axes of the inertial measurement unit. In special cases where the separation angle between the attitude sensor vectors is less than approximately 10 degrees, the time-varying gain matrix is computed as a fixed gain matrix and a corresponding desensitizing factor.
    Type: Grant
    Filed: September 22, 1998
    Date of Patent: November 14, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: Garry Didinsky, Yeong-Wei Andy Wu
  • Rocket engine with combustion chamber step structure insert, and its fabrication
    Patent number: 6138451
    Abstract: A rocket engine has a combustion chamber formed of an annular wall made of an annular wall material, and an annular insert made of an annular insert material that is of substantially the same thermal expansion coefficient as the annular wall material. The annular insert has an insert outer surface sized to fit within and contact the wall inner surface along less than the wall length. The annular wall and the annular insert are welded together. There is further an attachment between the combustion chamber and an injector. The attachment includes an annular metallic deposit bonded to the combustion chamber, an annular adaptor ring, a weld joint between the adaptor ring and the metallic deposit, and a joint between the adaptor ring and the injector.
    Type: Grant
    Filed: May 11, 1998
    Date of Patent: October 31, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: Kurt Kreiner, David Bronson
  • Yb-doped fiber laser operating near EDFA absorption band
    Patent number: 6137813
    Abstract: A Yb-doped fiber laser uses a homogeneously-broadened material. The disclosed laser design is particularly advantageous for operating the fiber laser between 970-980 nm and using this output as a pump for an Er-doped fiber amplifier (EDFA) having an absorption band between 970-990 nm. Using a homogeneously-broadened host glass, for example alumino-germano-silicate or fluoride glass, significantly reduces the inefficiency that can result from the three-level nature of Yb-doped fiber laser transitions that are required for operating it at approximately 976 nm.
    Type: Grant
    Filed: April 10, 1998
    Date of Patent: October 24, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: Stanislav I. Ionov, Dennis C. Jones
  • (Zinc, cadmium, magnesium) aluminate-gallate-containing organic-binder paint and film articles
    Patent number: 6124378
    Abstract: An article is a liquid or solid mixture of a plurality of particles and a binder. The article may be a paint or a freestanding film. The particles have a composition A[xAl(1-x)Ga].sub.2 O.sub.4+.gamma. (.delta.In), wherein A is zinc, magnesium, and/or cadmium, the value of x is from 0 to 1, the value of .delta. is from 0 to about 0.2, and the value of .gamma. is less than about 0.2. In the liquid paint mixture, a paint vehicle is also typically present to impart the desired fluidity to the mixture. The solid paint or film made using this material is white, has very low solar absorptance, and may be made electrically conductive by doping the particles with indium or other appropriate dopant.
    Type: Grant
    Filed: September 2, 1998
    Date of Patent: September 26, 2000
    Assignee: Hughes Electronics Corporation
    Inventors: James F. Cordaro, Lynn E. Long