Abstract: Disclosed is a bearing assembly with thermal compensation. The bearing assembly includes a bearing mechanism defined by a pair of races and a plurality of bearing elements. The races are manufactured from a material having a coefficient of thermal expansion that is substantially different than the coefficient of thermal expansion of the material from which the bearing elements are manufactured. A thermal compensation mechanism of the bearing assembly is contiguous with the races. The thermal compensation mechanism permits movement of the races relative to the bearing elements in a direction parallel the rotational axis of the bearing mechanism as a result of the effect of temperature variations on the materials of the races and bearing elements.

Abstract: A missile guidance system employs a strap down inertial measurement unit with a separate accelerometer and star sensor that are moved for preflight accelerometer initialization. During flight, light is directed on the accelerometer and inertial measurement unit to produce on the star sensor images of the light source, the accelerometer and the inertial measurement unit. The location of these images, which manifest the acceleration and position of the inertial measurement unit relative to the vehicle, are used to improve the accuracy of the inertial measurement unit data for vehicle guidance.

Abstract: A system for avoiding singularities in a control moment gyro (CMG) array of a satellite uses closed and open loop control of the CMGs for reorientation of the satellite. A control system detects when closed loop control according to pseudo inverse rules will cause a singularity and issues a signal. The CMGs are then controlled open loop to avoid the singularity. The pseudo inverse singularity problem arises where there are more actuators than dimensions in the controlled space. Accordingly, the invention may also be used in a robotic arm manipulator.

Abstract: Control moment gyros in an array are rotated to reorient a satellite. Gyro angle is selected from one of three values based upon whether the stored angular momentum for the desired angle is below a singularity free value, greater than the singularity free value or is greater than the maximum available stored angular momentum.

Abstract: A method for visualizing time-varying data from one or more data streams at a different interval than the interval between acquisition of the individual data items in the data stream. Data received is combined, or aggregated, between updates of a display to retain some information from each element. The aggregated data is then displayed at the next update of the display in a number of display elements. The characteristics of the display elements, and the organization of the elements represent changes in the data streams.

Abstract: In an ring laser gyro, a path length modulation signal is applied to an amplifier with two gain levels and the amplifier's output is added to a path length transducer drive signal that changes the gyro's path length. When a path length reset signal is produced, the higher gain signal is selected and maintained for a short interval after the reset signal.

Abstract: Control moment gyros in an array are rotated to reorient a satellite by an attitude signal. If the signal causes a gyro to have position that will produce a singularity in attitude control, a disturbance is introduced into the signal to avoid the singularity.

Abstract: Control moment gyros in an array are rotated to reorient a satellite. A pseudo inverse control is employed that adds a term to a Moore-Penrose pseudo inverse to prevent a singularity.

Abstract: The attitude (yaw, pitch and roll) of a home satellite is determined using position signals, derived from a GPS receiver on the home satellite and GPS receiver on other satellites, that are transmitted between the home satellite and the other satellites by an intersatellite communications link using gimbaled transceivers on the satellites. The home satellite determines its attitude from the gimbal elevation and azimuth and the position vectors between the satellites.

Abstract: Satellites are launched to a first orbit on a launch rocket. The satellites are connected together, forming a satellite cluster, that is propelled from the first orbit to a higher mission orbit by thrustors on each satellite. The satellite cluster is formed so that satellite cluster rotation from aerodynamic drag on the individual satellites is minimized. The thrustors are sequenced to control satellite cluster attitude during the transition to the second altitude. At the second altitude, the satellites are separated from the satellite cluster and propelled to their mission orbits using their own thrustors and attitude system.

Abstract: A output mirror with a substrate that is doped with a radiation stabilizing material is used to reduce the adverse effects of long periods of exposure to radiation. The output mirror is capable of maintaining its transmissive characteristics when exposed to radiation and is used in radiation environments.

Abstract: Disclosed is a method of forming a primer coating and an opaque coating on an integrated circuit or multichip module. First a primer coating composition is applied to a surface of the integrated circuit device or multichip module to form a primer coating that increases the resistance of the surface to thermal and mechanical damage that may occur as a result of the application of the opaque coating. An opaque coating composition is then heated to a molten state and the molten opaque coating composition is applied over the primer coating to form an opaque coating that overlies active circuitry on the surface, to prevent optical and radiation based inspection and reverse engineering of the active circuitry.

Abstract: A reaction wheel assembly (RWA) is constructed by placing the electronics on a base and installing on the base a cover that contains the reaction wheel rotor and motor. As the cover in placed over the base, a connector on the cover mates with a connector on the base. The base contains a retractable input plug which is retracted on the base as the cover is installed and then extended from the retracted position through an aperture in the cover and fastened in place. The cover contains filtered vent holes in a wall that separates the base and cover, and evacuation ports are provided on the base and cover to create a vacuum in the RWA to test the electronics.

Abstract: Stacked die that are separated by an overlaying chip capacitor with a plate bonded to the bottom of the top die with a conductive adhesive and the capacitor shell bonded to the top of the lower die with a non-conductive adhesive. The lower die is attached to a substrate using a conductive adhesive. Conductors extend from edge terminals on the substrate to edge terminals on the lower die, and conductors extend from the lower die terminals to the capacitor that are tiered to provide space between the die for the wires and connections. A second overlaying capacitor is attached to the top of the upper die with non-conducive adhesive. Pads on the capacitor are connected by conductors to edge pads on the die and conductors extend from the pads to pads on the substrate.

Abstract: The compressor shaft in a gas turbine engine is supported on a bearing having four independently hydraulically pressurized cells. The pressure in the cells is controlled by a signal processor based on engine operating parameters, including stall margin and blade tip to compressor case clearance.

Abstract: In a fiber optic gyro (FOG) with a photo-diode phase detector that produces a detector signal that is supplied to an A/D converter to generate a FOG information signal for use in a signal processor to produce a FOG control signal based on FOG controller equations, the photo-diode out is summed with a feedback signal from the signal processor to reduce a DC offset in the input to the A/D converter.

Abstract: Pressure sensors are placed at axial locations in the isolator of a scramjet or ramjet. An engine fuel control produces calculated pressure values for the those locations from a stored function. As the engine operates, the pressure signals from the pressure sensors are compared with those pressure values for each sensor location and the stored function is adjusted so that the curve of the calculated pressures closely matches the measured pressures within stored upper and lower pressure limits for each pressure sensor location. From the adjusted function. the shock system is located. Fuel flow is controlled to maintain the shock system at a desired location in the isolator. Faulty pressure sensors are detected from a signal that manifests the difference between calculated and actual pressure at each pressure sensor.

Abstract: A multichip module is attached to a printed wire circuit board using three conductive mounting feet that are vapor phase soldered to conductive feet on the module's substrate and to conductive feet on the printed wiring circuit board that are connected to a ground plane on the board.

Abstract: An integrator in a ring laser gyro that produces an output for changing the path length is reset synchronously with a gyro dither signal to reduce gyro errors from the dithering operation during the reset.

Abstract: A rate mode robotic control system in which displacement of a hand-control element from a null position generates a robotic control signal to command acceleration and/or velocity of a controlled element. A force generator urges the hand-control element to the null position with a force proportional to the displacement of the hand-control element from the null position. A reflected force feedback signal increases or decreases the force urging the hand-control to the null position as a function of the resistance encountered by the controlled element.