Abstract: A rotation sensor for sensing rotation, particularly about an axis of a coiled optical fiber, wherein the coiled optical fiber has with light waves propagating in opposite directions in the coiled optical fiber, the phase relationship of the counter-propagating light waves providing a basis for indicating rotation of the sensor. A portion of the coiled optical fiber is a part of and affected by a bias optical phase modulator which causes a varying phase relationship between the light waves at a fundamental frequency. However, the varying phase relation ship has at least one harmonic which is due to mechanical vibration of the optical fiber that is a part of the modulator. This harmonic contributes to an erroneous indication of rotation. The amplitude of such harmonic is reduced by lowering the Q of the resonating fiber. This is effected by applying a damping material to the optical fiber and a portion of the modulator.

Abstract: A HIGFET having a gate with a pad which is isolated from the FET heterostructure wafer by a dielectric layer to minimize leakage current between the gate and the wafer. The method of production of this device involves application of the gate metal only over the active area of the FET and a photo resist covering on the gate metal. The wafer, including the area covered by the photo resist, is covered with the dielectric layer. The photo resist layer is removed along with the dielectric layer from over the gate metal. Another layer of gate metal is formed on the preexisting gate metal including a gate pad on part of the remaining dielectric layer.

Abstract: A process for fabricating a flow control device which includes a housing with separate main flow and flow control (servo) passages between an inlet port and an exit port. A control chamber in the housing is in fluid communication with the servo passage. A flexible membrane forms a partition between the main flow passage and the control chamber. The servo passage includes a variable servo orifice upstream of the control chamber and a fixed orifice downstream of the chamber. When the servo valve is open to permit passage of fluid into the control chamber, the resultant pressure on the membrane maintains the main valve closed. The main valve opens in response to closing the servo valve. The fixed orifice has a profile sufficiently small to provide for an acceptable leak or continuous fluid flow through the device when the servo valve is open, and further provides for a soft start when the servo valve is closed to open the main valve.

Abstract: A multi-band high-speed videometric head tracking system having a gradient reflector array attached to a helmet on a person's head, ultraviolet light source emitting light which is reflected by the reflector array to a video camera which provides an image to a spot location estimator providing accurate locations of spots in the image representing the reflectors' reflecting light to image location accuracies within a pixel of the image. The location information from the spot location estimator goes to a track point 3-D location and helmet LOS estimator that provides location and orientation information to a Kalman Filter that accurately estimates and predicts the helmet position at faster rates than would be possible for a process that uses just the image-based measurements of the helmet.

Abstract: A retroreflective array projection screen for displaying virtual images wherein the apparent distances from the observer to the viewed subject is greater than the distance from the observer to the retroreflective screen. Real images from a source are collimated and then partially reflected onto the retroreflective array. Virtual images are reflected from the array through the beamsplitter onto an observer at an exit pupil.

Abstract: A light source with wavelength compensation for a fiber optic rotation sensor includes a light source to provide light for input to the fiber optic rotation sensor. A source control circuit generates a source control signal representative of the temperature of the light source. A driver generates a drive signal as a function of the source control signal to drive the light source. One of a plurality of scale factors for the fiber optic rotation sensor is generated also as a function of the source control signal over a predetermined temperature range. The source control circuit includes a temperature sensor which provides a current signal representative of the temperature of the light source and a buffer network for sinking the current signal and for generating a source control voltage as the source control signal.

Abstract: A control loop for controlling a process or plant which controls the process or plant via an actuator. The control loop receives from the process or plant a signal representative of the process or plant output. The loop includes a nominal controller that generates a control signal for the actuator which is used only in the absence of a predicted disturbance to the process or plant signal from a disturbance mode controller unit having a neural network conditioned for predicting and indicating a disturbance.

Abstract: A light source device having a controlled current source that maintains a constant intensity of light from the source during changes in light source temperature, particularly at warm-up. The light source is heated to speed up warm-up and to maintain constant temperature of the source during operation under varying ambient temperatures. Control of the current to the light source is determined by the temperature profile circuit with signals via a temperature signal conditioner from a temperature sensor proximate to the light source. Control of the heater is ultimately dictated by temperature sensor signals.

Abstract: A multiple-fail-operational fault-tolerant clock having a plurality of interconnected and identical clock modules, that provides a fault tolerant clock signal despite some clock module failures. The clock incorporates fault-tolerant operational diagnostics so that a working clock module may be voted for supplying the output clock signal.

Abstract: An uncooled IR array, in conjunction with an array of binary optical microlenses, having a large effective fill factor.

Abstract: In a combustion system, fuel flow and fuel composition are sensed, and energy flow in the combustion system is determined based on the fuel flow and the fuel composition. Air flow of combustion air is also sensed. The fuel-to-air ratio in the combustion system is controlled as a function of the energy or oxygen demand flow determined and the air flow sensed.

Abstract: A silicon accelerometer includes several silicon layers. The silicon layers form two silicon beams supported by flexure members. An acceleration responsive silicon mass is arranged to bend the flexure members in response to accelerations. The silicon beams are vibrated in vacuum chambers and gas damping is provided for the acceleration responsive mass and the flexure members. Sensing electronics detect vibration of the two silicon beams.

Abstract: PID controllers form a large proportion of controllers in use in many controlled systems today. This application describes how to use a neural network which receives PID inputs to be a controller and operate as a PID controller to save on retraining and provide other efficiencies in control. Also shown is the user selectability between PID conventional controllers and Neural Network controllers.

Abstract: Windshear detector using Rayleigh-backscattered light and a molecular filter for optical discrimination, and frequency locking of a laser, to detect windshear. The windshear detector has a pulsed ring laser that transmits a signal out of the detector and receives reflected backscatter of the transmitted signal. The ring laser is driven with an injection laser. Both lasers are ultimately keyed to the molecular transmission or absorption filter with locking electronics. The received reflected backscatter is detected and processed into a signal that indicates whether there is windshear or turbulence.

Abstract: An indicating system for measuring movement of a material, having a magnetic pickup device, waveform conditioning circuit and light signal emitter functioning under the system's own self-made power, having a light waveguide or optic fiber connecting the light signal emitter to a light signal receiver which in turn is connected to a signal processor for outputting information such as speed, acceleration and/or position of the material.

Abstract: An amplitude reset controller for a resonator fiber optic gyroscope using a feedback loop and modulation to control amplitudes of a serrodyne waveform provided by a serrodyne signal generator at an operation frequency depending on resonance conditions in the resonator. The controller with a single serrodyne signal generator switches between such control at greater rotation rates and the removal of such control at smaller rotation rates, using instead a reference command. Also, a blanking operation mode can be additionally used to eliminate signals controlling the controlled frequency adjustment signal generator operation frequency during phase resets in its output serrodyne signal.

Abstract: A spectrum stabilizer for stabilizing the wavelength of light emitted by a source for use in an optical system where the source can have that wavelength altered by varying one or more source parameters, such as source current, temperature and/or alignment of the output end of the source with an optical fiber of the optical system, and wherein light from a selected point in the optical system is coupled to a double mode waveguide for wavelength sensing.

Abstract: A fault-tolerant clock having at least four channels, each providing its own clock output, and yet all clock output signals of all functioning channels being coherent with one another. One clock functions as a master with the other clocks of the remaining channels slaving themselves to that one clock. In view of a failure of the master, another clock reigns as the master clock to slave the remaining clocks. If the next master clock fails, then still another clock becomes a master to slave the remaining clock or clocks. The clocks are independently powered such that complete failure of one clock, including its power, does not necessarily prevent the other clocks from providing coherent outputs.

Abstract: An optical fiber rotation sensor having an ordinary single mode fiber coil with a depolarizer in series therewith configured with component optical path lengths therein and birefringent axes relationships therein chosen with respect to the source autocorrelation. Amplitude related phase errors due to polarization mode coupling can be eliminated or reduced economically, and signal fading can be substantially prevented.

Abstract: A low cost fiber optic gyro includes a Sagnac interferometer configured in a minimum reciprocal configuration and modified to use a 0.8 micron wavelength laser diode as the interferometer light source and 1.3 micron, single-mode fiber for the sensing coil.