Abstract: In a gyroscope including a rotor spinning about a spin axis, the rotor gimballed about two mutually perpendicular axes and including cross coupled closed loops operative on the two mutually perpendicular axes so as to be able to detect rates about said two axes, a feedback loop is provided to cause the gyroscope spin axis to nutate in a cone about its nominal, blind, spin axis at a controlled amplitude and at a frequency which is at least close to the natural nutation frequency of the gyro and the nutation detected and changes in the nutation amplitude or frequency used as a measure of the rate about the blind axis.

Abstract: A self-calibrating star tracker in which a light signal source located on the detector is reflected into the optics and redirected from the optics back onto the detector. In this manner, movement of the detector or optics from a known position can be sensed and calibration of the instrument can be conducted at any time (i.e., pre-flight or during the mission). The star tracker is contemplated to be used with an inertial guidance system and comprises a detector and optics.

Abstract: A modular electronic system having cooling means has a plurality of stacked electronic circuit units. Each stackable circuit unit has a rectangular frame having a pair of end members which support a plurality of spaced-apart, cooling channels. A cooling passageway extends through each channel along the length thereof and communicates with a cavity in each end member. The cavities form integral entrance and exit plenums for a fluid coolant when a plurality of the circuit units are stacked and aligned. A plurality of dual in line packages or other discrete electronic circuit packages are thermally coupled to one side of the channels with the leads from the packages extending between the channels to the other side thereof where they are connected by wave soldering to a printed circuit board. The individual circuit units are electrically interconnected by male contacts on a transverse member of the frame which cooperate with female contacts on electrical connection boards.

Abstract: Conventional first and second Schuler tuned inertial platforms, that are physically displaced from each other by a predetermined distance, are employed in an inertial system to reduce navigation errors caused by the uncertainty in the earth's gravitational field. In addition to the two Schuler tuned platforms, a conventional velocity measuring instrument is employed to provide damping to the inertial system. The invention takes advantage of the fact that for a pair of ideal platforms if the relative velocity between them as displaced sensors can be measured with moderate accuracy then performance rivaling that obtainable with a gradiometer aided inertial platform can be achieved.

Abstract: High accuracy distance measurements are achieved with a low accuracy Tacan set by utilizing signals available within the Tacan set at a point of sufficient accuracy to provide accurate distance measurements to be made and thus upgrade an en-route navigation aid to higher accuracy for use in a precision landing system.

Abstract: A low cost system using passive radiometry or active radar for the detection of a target and providing discrimination between desired targets and false targets. The device may be mounted on a drone aircraft or other vehicle and comprises a detecting sensor having a fixed antenna system whose function is to detect the presence and direction to a target in airframe coordinates. The sensor provides means for generating a broad fan beam containing a plurality of closely spaced interference lobes spaced so as to encompass a predetermined target size. The interference lobes are continuously swept across the line of travel and the receiving circuitry provides means for detecting a desired target within the interference lobes. The system also provides a pre-programmed means, initiated by the target sensor, designed to aim the aircraft at the target and a target tracker or homing means having a fixed antenna directed along the heading axis of the drone aircraft and used to "home" the aircraft into the target.

Abstract: A Doppler radar employing a common antenna for transmitting and receiving. A single sideband modulator (SSBM) is employed in the transmitting circuit to offset the rf reference frequency during transmit time and to discontinue offset during receiver ON time. Through a coupler and isolators an attenuated portion of the rf reference signal is applied to the receiver mixer at gated intervals. The output of the mixer are signals which are free of undesired reflected transmitter signals.

Abstract: A piezoelectric actuator for use in controlling the path length in a ring laser is made up of a plurality of piezoelectric discs which have a different polarity in their central area than at their circumference so as to result in exerting a pushpull effect on the mirror which they control permitting fewer discs to be used, a lighter structure and a structure which is stiffer and has a more rectilinear motion without deleterious rotation.

Abstract: A method for providing at room temperature a hermetic bonded seal between the surfaces of glass, ceramics, metals or any combination of these. The method comprises the steps of polishing the surfaces to be bonded and then plasma cleaning the surfaces. Next, a chemically cleaned bonding material such as indium is applied to the surfaces and a force is applied to the surfaces to be sealed at room temperature for a limited period of time to affect the bonded seal.

Abstract: A Doppler radar having a single sense Doppler signal from the rf mixer. A single sideband modulator in a common antenna system for transmitting and receiving shifts the fore and aft beams to achieve a single sense Doppler signal. The use of the single sideband modulator results in a differential Doppler shift between fore and aft beams of only a few hundred knots, thereby permitting use of low cost components. A single sense Doppler also reduces the Doppler passband by a 2:1 factor which permits the power supply frequency to operate at a higher frequency than the receiver.

Abstract: In a digital to synchro/resolver converter which has an intrinsic transformation ratio variation with respect to input angle greater than desired in a given application, the intrinsic variation is corrected by applying a correction to the reference voltage used in carrying out the digital to synchro conversion.

Abstract: A measuring system for a ring laser mirror, or the like, is provided, whereby the mirror can be quickly scanned and the backscatter levels measured and presented in the form of a map which directly indicates the spots of the mirror where acceptable backscatter levels exist. When such a spot has been identified, the system of the invention is also capable of measuring the reflectivity of the spot, which normally must be approximately 99.7% to be acceptable. The system of the invention has the capability of measuring the reflectivity of the mirror in addition to measuring the backscatter in a single set-up, and without having to manipulate the mirror.

Abstract: A temperature compensation mechanism for a vibrating beam accelerometer comprising first and second bridge circuits. A quadrature signal is applied to the first bridge circuit containing the quartz crystal which pulls the resonant frequency of the quartz oscillator up or down depending upon the frequency shift caused by temperature variations.

Abstract: A gyro seeker which is capable of use in a cannon launched missile. The gyro seeker is enclosed in a housing mounted in the nose section of the missile. The platform of the gyro seeker supports an optical assembly, a detector, a gyro assembly, and a cryostat for cooling the detector. Means are provided on the outer gimbal of the platform for withstanding the extreme acceleration induced by cannon launching. The platform is torqueable along two axes by a plurality of pole pieces located around its base. A platform caging device is provided to cage the platform during transport and serves a dual function as a means to furnish spin-up gas to the gyro element and cooling gas to the cryostat.

Abstract: A method of forming a hard vacuum seal for use in a gas laser but not limited thereto. The method comprising the steps of polishing the surfaces to be joined together and then cleaning the surfaces with a plasma cleaner. Next, a force is applied to hold the surfaces in contact and then molten indium is applied onto the adjoining surface and allowed to cool in order to set the seal. In the method of forming the gas laser seal for fine alignment of the mirror surfaces, the seal is reheated, the mirrors realigned by sliding across the laser cavity while the laser is operative and the laser output is measured for maximum laser output. Then the seal is allowed to reset.

Abstract: A digitally responsive electrostatic accelerometer having a pendulum pivotally movable about a hinge. A pair of torquer electrodes mounted on opposite sides of the pendulum are connected to a source of constant current. As the pendulum moves from its null position under the influence of acceleration forces, the displacement from null position is indicated by an increase in charge on the electrode which is in closer proximity to the pendulum. Electronic circuit means are provided to detect the direction of displacement of the pendulum from null and to apply a charge to the proper torquer electrode to force the pendulum back to null position. The principle of operation of the device is based upon the fact that the magnitude of the voltage on the torquer electrodes when charged from a constant current source contains information indicative of the position of the pendulum from null.

Abstract: A device employing the inherent self-torquing properties of a torque repeater to position its rotor. In the present invention, the torque repeater or synchro may have three stator windings and an output rotor. It is contemplated that the electrical input to the device will be digital signals. However, the invention will perform equally well with time varying or analogue input signals. A plurality of electronic switching means are connected to the stator terminals of the synchro converter and they operate under the control of a programmable switch control to short-circuit predetermined stator windings to provide the desired positional output signals. A sectant detector connected to the stator windings detects signals on the stator windings and determines the present position of the rotor. From this information, the desired positioning of the rotor is attained from the signals from the sectant detector.

Abstract: A combined angular displacement measuring and multiplier system is provided which finds particular application in heading reference units for navigational purposes, but which has general utility, as will become apparent as the description proceeds. The system of the invention includes a bubble tilt or level sensor which measures angular displacements and which, in accordance with the present invention, also serves as a multiplier for a second term, such as azimuth rate (AZ).

Abstract: An instrument which performs with precision either as a pickoff or torquer and which is not subject to geometrical errors due to the electrodes going out of round. The pickoff electrodes of the instrument are mounted adjacent the end of the movable element instead of being concentric to it. Because of the location of the pickoff electrodes relative to the movable element, the device is a variable area pickoff rather than a variable gap pickoff. This provides the advantages of obtaining outputs from the X and Y axes which are a linear function of the motion of the movable element and, therefore, the displacement angle, as determined by the ratio of X and Y outputs, is independent of the amplitude of motion.

Abstract: An ellipticity control system for controlling the elliptical deviation of the vibratory element of a displacement sensor. The apparatus incorporates a plurality of drive electrodes, at least six in number, mounted concentrically along the longitudinal axis of the elongated vibratory element. Each drive electrode is formed in pairs oriented along separate axes. A pair of X-axis pickoffs and a pair of Y-axis pickoffs axially spaced from the drive electrodes are also mounted concentrically of the vibratory element to sense the deviation of the vibratory element from null and to provide control signals by way of circuit means to the drive electrodes.