Abstract: A night vision device includes an image intensifier tube for providing an intensified image of a dim or night-time scene. The night vision device also includes provision for full duplex transmission and receipt of voice audio between the user of the device and another person who is using a substantially identical device. Another provision of the device is for interrogating IFF (identify friend or foe) units worn by other personnel. The IFF units have provision for receiving a beamed interrogation signal and for transmitting a coded identification signal in response. Thus, a user of the night vision device can identify friendly personnel at a distance, as well as communicating by voice with others who are using similar night vision devices so equipped.

Abstract: Methods and apparatus for non-linearizing modulo 2 addition based encryption by block substitution techniques which allows use of the substitution scheme with relatively simple hardware and yet makes cryptanalysis more difficult. The basic block substitution, a one to one mapping of n-bit binary numbers onto themselves, is based on the fact that certain permutations of the n-bit binary numbers define linear orthomorphisms, which enable block substitution by modulo 2 addition of one permuted set of numbers to another. These equations representing the linear orthomorphism have an additive relationship when viewed as vectors, and in fact, form an additive group in the algebraic sense. The permutations of the n-bit binary numbers which define these linear orthomorphisms have the further property that any power of these permutations, that is, applying the permutations successively to the previously permuted numbers, generates a new linear orthomorphism.

Abstract: A system, which uses inertial measurement units, is shown for determining the position and orientation of a towed array of sensors used for target detection. The system uses an onboard master inertial navigation system and a relative position determination mechanism to generate a first estimated position for each inertial measurement unit within the array. Each inertial measurement unit measures force and angular change information used by an onboard computer to create a second estimated position by known methods for each inertial sensor. An error signal represented by the difference between the two estimated positions for each inertial unit is processed over time by a Kalman filter to reduce the error in the heading and attitude determined for each inertial unit to establish an accurate location for each inertial unit and, thus, the towed array of such units.

Abstract: Signals indicative of the Sagnac phase shift between counterpropagating waves in a sensing loop are combined to produce an error signal. A phase modulator is arranged to modulate the phase of optical signals that pass through the sensing loop. A phase modulator driver apparatus responsive to the error signal produces a ramp signal to drive the phase modulator to null the error signal. A reset apparatus is arranged for resetting the ramp signal to when the phase reaches a predetermined limit. The reset apparatus preferably includes a reset integrator circuit arranged to produce an output that is a ramp signal whose slope is proportional to the rotation rate of the sensing loop. A pair of comparators is arranged to determine when the reset integrator reaches one of two rollover limits. Rollover logic circuitry is connected to the pair of comparators and arranged such that when the reset integrator reaches one of the rollover limits, the integrator is forced to the other integration limit.

Abstract: According to the present invention, a high efficiency no-dropout uninterruptible power supply is presented which will provide desired UPS characteristics while reducing or eliminating undesirable characteristics. In particular, simultaneous improvements are achieved in the areas of switchover transfer response time, droop and transients, EMI generation, power efficiency and heat generation, size, weight, ease of waveshaping, and powerline frequency sensitivity. The invention utilizes dual concurrent feedback loops to control utility-backup power transfer and incorporates a novel method of synchronized AC output generation which allows zero-power switching and simple high-frequency waveshaping control.

Abstract: A method and associated structures are disclosed for locating a laser beam that has a wavelength outside of the visible portion of the electromagnetic spectrum. The method comprises positioning a sample of a polycrystalline nonlinear frequency converting compound generally linearly downstream from a laser source, and then detecting the emission from the polycrystalline frequency converting compound to thereby identify the position of the original laser beam. In preferred embodiments, the polycrystalline nonlinear frequency converting compound comprises KTP.

Abstract: A fiber optic interferometric sensor for use in a hydrophone system at high pressures includes a reference fiber wrapped around a rigid inner cylinder. A solid layer of compliant material is applied over the reference fiber. The sensing arm of the interferometer is wound over the layer of material applied over the reference fiber. The outer material is sufficiently compliant to provide acoustic sensitivity comparable to that of air-backed hydrophones.

Abstract: An electron gun for use in remediation of hazardous volatile organic compounds is provided. The electron gun comprises a cathode having a concave emitting surface and a dome-shaped focusing electrode concentrically surrounding the emitting surface. The focusing electrode has an inwardly protruding lip portion that extends at least partially into a beam focusing region defined in front of the emitting surface. A target grid is spaced from the cathode and a negative voltage is applied between the emitting surface and the target. The target grid has a surface area that is substantially larger than an associated surface area of the emitting surface. An electron beam is provided by the emitting surface in response to the negative voltage, and is focused into a broad diverging beam by the focusing electrode. The electron gun may be configured for temperature limited emission or space charge limited emission.

Abstract: An improved electron window is provided for use with a diverging electron beam for use in remediation of hazardous volatile organic compounds. The electron window comprises a support grid having a plurality of circular holes disposed in a diverging bolt circle pattern. Individual electrons of the diverging electron beam pass through respective ones of the plurality of holes. A barrier is provided on a downstream side of the support grid so that the individual electrons pass through the barrier. The circular holes are each of substantially uniform diameter. The diverging bolt circle pattern further comprises a single one of the holes substantially centered on the support grid, and a plurality of groups of the holes concentrically disposed around the single one of the holes. Each of the groups of the holes is disposed in a circular pattern.

Abstract: An improved photocathode (12) and image intensifier tube (10) are disclosed along with a method for making both the tube (10) and photocathode (12). The disclosed image intensifier tube (10) creates a visible light image (20) from an image emitting photons (22). The tube (10) comprises a photocathode (12) having an indium-gallium-arsenide active layer (26) and an aluminum-gallium-arsenide window layer (28). The photocathode (12) is operable to emit electrons (23) in response to the photons (22). A display apparatus is coupled to the photocathode (12) and is operable to transform the emitted electrons (23) into a visible light image (24). An embodiment of the invention is capable of detecting 1.06 .mu.m radiation.

Abstract: A method and apparatus for locating a pulse echo radar emitter in both angle and range using a single antenna and minimal use of the observer platform's navigation instruments are described. The emitter's rest frequency and pulse repetition frequencies are extracted. Using the emitter signal DOA and measurements of pulse TOA and emitter frequency, the observer's acceleration and velocity along the emitter DOA path are found. Combining observer velocity with the above kinematic quantities allows emitter range and bearing to be determined. No observer platform heading or angular attitude information is required.

Abstract: An apparatus for determining a spatial angular reference to an emitter of RF signals, such as direction of arrival or angle of arrival, from phase measurements made between two antennas is described. The apparatus uses at least a pair of dual polarized antennas having non-parallel boresights. Like polarized outputs from the antennas produce phase information which is stored and then summed to remove bias error in favor of the sin (AOA) component, while the phase information from the like polarized antennas is also differenced producing a signal indicative of the bias error. It is shown that the bias error can be uniquely related to emitter angle and azimuth. The latter information is obtained without the need for making emitter frequency measurements.

Abstract: A laser system includes an apparatus and method having a primary laser resonator having a laser medium therein for producing a laser beam of a first wavelength and a second laser resonator optically connected to the primary resonator to allow a portion of the laser energy from the primary laser resonator to pass into the secondary laser resonator. An optical parametric oscillator is located intracavity of the secondary laser resonator and includes a non-linear crystal for producing a laser beam of a second wavelength therefrom. A coherent beam output is coupled to the optical parametric oscillator for producing an output beam of predetermined wavelength of the second wavelength while blocking the output of the laser beam of the first wavelength so that a dual resonator combines a secondary laser cavity and an optical parametric oscillator to produce a predetermined output wavelength.

Abstract: A harmonic gyro-TWT is provided that has only one possible mode of operation. The harmonic gyro-TWT comprises a waveguide and an electron beam projected through the waveguide and encircling an axis of the waveguide. A plurality of evenly spaced electrical conductors are disposed within the waveguide parallel to the axis and spaced a fixed distance from an inner wall of the waveguide. The electrical conductors are connected together at an end of the waveguide. The electrical conductors are excited in phase with an AC signal connected between the electrical conductors and the inner wall of the waveguide. As a result, a multipole field having an order equal to twice the number of electrical conductors is defined within the waveguide. A plurality of support rails couple the inside surface of the waveguide to each respective one of the plurality of electrical conductors.

Abstract: A monolithic Coriolis rate sensor includes a first member and a vibration generator that causes the member to vibrate along a first direction. At least one other member is mechanically coupled to the first member so that orthogonal vibrational modes are coupled to the other member when the members are rotated about a rotation axis. The vibrational mode coupling occurs as a result of the Coriolis effect. A vibration sensor is used to sense the orthogonal vibrational modes, the amplitude of which determines the rate at which the members are rotated. In a preferred embodiment, a central and two transverse end members with substantially equal resonant frequencies are mechanically coupled to form an "I"-shaped structure. The center member is vibrated at its resonant frequency, and orthogonal vibrational modes are coupled to the end members when the structure is rotated about a rotational axis that is orthogonal to both vibration directions.

Abstract: A digital circuit for adapting the output of a closed-loop accelerometer to a utilization circuit where the cycle time of the rebalance loop of the accelerometer is unrelated to the cycle time of the utilization circuit. A register receives and stores a digital value representative of measured acceleration and a bank of serially-arranged divide-by-two counters accepts the output of the rebalance loop clock. A gate arrangement makes one-by-one correlations between the states of the register and the outputs of the divide-by-two counters. A trigger circuit receives the gate outputs, providing a pulse when triggered by a downgoing edge of a square wave output of the gate array. A counter receives the pulse stream and is gated, in turn, in accordance with the cycle time of the utilization circuit so that the accelerometer data employed therein is representative of the portion of the acceleration occurring during a cycle of the utilization circuit.

Abstract: An infrared sensor includes a linear array of plural photoconductive sensor elements, and a similarly linear multiplexing circuit arranged in side-by-side relation with the linear array of sensor elements. The multiplexing circuit includes a matching plurality of signal input ports, and a wirebond of plural conductors substantially in parallel conducts signals from the plural sensor elements of the array to the respective signal input ports of the multiplexer circuit. The multiplexer circuit includes a matching plurality of adaptation circuits or cells interposed between the respective sensor elements of the array and the input ports of the multiplexing circuit. Each adaptation cell includes a multi-position switch which by its position varies the transfer function of a feed back circuit of the adaptation cell. Plural modes of signal processing for each individual sensor element of the array are provided according to the positions of the multi-position switches of the plural adaptation cells.

Abstract: The present invention provides a double helix coupled vane forward wave crossed-field amplifier utilizing backwall cooling and vane channel cooling in the RF slow wave circuit. Backwall channel cooling is provided for the majority of the anode vanes. Additional cooling is provided exclusively for the output vanes via individual coolant carrying passages in each output vane. The coolant carrying passages are machined into each standard double helix coupled output vane to create a vane channel in the shape of a "U". A tube formed in a corresponding U-shape is inserted and brazed to the machined vane. The vane assembly is then attached to the anode body of which the backwall has holes formed to accept the tubes from each vane. Divided backwall coolant channels are brazed to the outside of the anode, thereby placing in fluid communication the coolant channels to the tubes.

Abstract: An optical tracking system and method are disclosed. The optical tracking system includes a scanning mirror which scans and receives images within a field of view scannable by the mirror. An optical system receives images from the scanning mirror and directs the images upon a charge coupled device (CCD) camera. An Inertial Measurement Unit (IMU) beam serves as a fixed reference point from which the position of the scanning mirror is determined and is directed upon the CCD camera. A dispersive element provides and directs a pattern of light consisting of a grid of diffracted orders upon the CCD camera. The movement of the scanning mirror provides a corresponding movement of the diffracted orders. The position of the center of any diffracted order can be determined in relation to the IMU beam by centroiding. The position of the scanning mirror is determined by correlating the position of the diffracted orders to the position of the scanning mirror.

Abstract: A fiber optic sensing coil formed in a polarization-maintaining optical fiber has two optical fiber leads extending therefrom. A multifunction integrated optics chip linearly polarizes optical signals input to the sensing coil. Fiber optic leads formed of polarization-maintaining optical fiber extend from the multifunction integrated optics chip. The fiber optic multifunction integrated optics chip leads are arranged such that the linear polarization of optical signals output from the multifunction integrated optics chip is directed along one of the principal axes of birefringence of each of the fiber optic multifunction integrated optics chip leads. Splices are formed between corresponding the first sensing coil leads and the multifunction integrated optics chip leads. The sensing coil leads and the multifunction integrated optics chip leads are arranged such that their corresponding principal axes of birefringence are at angles of approximately 45.degree. relative to one another.