Abstract: Disclosed is a dither spring structure and method of dither spring manufacture. The dither spring structure includes a central hub, an outer toroidal rim, a plurality of flexible reeds and a plurality of lobes. The reeds extend between the hub and the rim, and one of the lobes is positioned between each pair of adjacent reeds. The rim is defined by a plurality of spaced arcuate segments with one of the segments at a radial outward end of each of the reeds. Each arcuate segment has first and second wing elements extending transversely to each side of its respective reed, and a free end of the first wing element of one reed is spaced from a free end of the second wing element of an adjacent reed to produce thermal stress relief. The dither spring structure can be manufactured via electro-discharge machining (EDM) using a single continuous pass of an EDM cutting element.

Abstract: An apparatus for eliminating or reducing vibration-induced errors due to vibration rectification by applying a variable weighting function at the demodulator or analog-to-digital converter by changing the size of the demodulator reference signal or the converter gain, respectively. The changing is performed within the frequency spectrum of the vibration. Sampling of the detector output may be utilized and the samples are accumulated and processed to remove the variations due to vibration, and the rotation rate is recovered by digital demodulation.

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 protective headgear for an aviator. The headgear includes a helmet adapted to be worn by the aviator, a visor and a mechanism for mounting the visor to the helmet. The mounting mechanism is defined by a pair of gear train assemblies, one of which is mounted to each side of the helmet adjacent to a helmet front opening. Each gear train assembly includes multiple gears that allow the visor to be manually moved between a deployed position wherein the visor covers a portion of the helmet front opening to protect the aviator's face and eyes, and a stowed position wherein the visor is completely clear of the helmet front opening so as to not obstruct the forward view of the aviator.

Abstract: Disclosed is a vibration isolator system for mounting an inertial sensor assembly (ISA) to a support that is subject to shock and vibration. The vibration isolator system includes a ring shaped elastomeric member, and ring shaped outer and inner members. Both the outer and inner members are fixed to the elastomeric member. In addition, the outer member is secured to the support and the inner member is secured to the ISA. The elastomeric member isolates the ISA from shock and vibration that may otherwise be transmitted from the support to the ISA.

Abstract: A method performed during the processing of a ring laser gyro (RLG) will produce a long life in the RLG. The method includes filling the RLG with a gas mixture. A current is discharged within the RLG which will create certain reactions to condition the RLG for a long life.

Abstract: Disclosed is a mounting mechanism and method for accurately securing and uniformly bonding piezoelectric transducers (PZT's) to a dither spring. The dither spring includes a central hub, an outer toroidal rim, a plurality of flexible reeds and a plurality of lobes. The reeds extend between the hub and the rim, and one of the lobes is positioned between each pair of adjacent reeds. A mounting mechanism includes locating channels on the lobes sized to receive mounting inserts that hold the PZT's during assembly. The mounting mechanism accurately positions and provides a uniform bonding force to the PZT's to precisely and firmly secure the PZT's on the dither spring reeds.

Abstract: A substrate holder and mask system for depositing curved films and mirrors on flat mirror substrates. A spherical mask is held in close proximity to a substrate by a support structure to intercept a fraction of vapor from a distant source. The film deposited on the substrate behind the mask has a spherically symmetric curvature when the source has a large area. The cross section of the mask support structure is made as small as possible to minimize irregularities in the spherical figure. A mirror is subsequently deposited on said curved substrate after removing said mask.

Abstract: A head mounted display which utilizes a flat image source, an optical system including a reflecting filter and a Mangin mirror having at least one curved surface, operable to make the flat image compatible with the flat image source, and provide an undistorted image to be viewed by the eye of a viewer.

Abstract: Disclosed is a path length control apparatus (PLC) for an optical device. The optical device, such as a ring laser gyroscope, is of the type that includes a block having an internal optical cavity that defines a closed optical path. A light source directs a light beam into the optical path, and a plurality of mirrors reflect the light beam about the path. The PLC includes a piezoelectric transducer (PZT) and a wireboard element. The PZT is mounted to one of the mirrors and alters, in response to a control voltage, the position of the mirror relative to the optical cavity to maintain a constant optical path length for the light beam. An adhesive having a ring shaped bonding pattern partially mechanically couples the wireboard element to the PZT so as to permit operation of the PZT free of resistance from the wireboard element.

Abstract: Mirrors are tested separately at different distances to plasma in separate ring laser gyros. Testing mirrors a predetermined distance away from plasma in the gyros allows accelerated testing of the environment of the mirrors in gyros. The test results are graphed to also allow prediction of ring laser gyro life.

Abstract: Disclosed is a hermetically sealed housing assembly for protecting electrical equipment. The housing assembly includes a hermetically sealed housing member having an exterior wall and an interior region for containing the electrical equipment. A flex tape electrical signal conductor extends through an opening in the exterior wall, and transmits electrical signals between the electrical equipment in the interior region and electrical components in a region exterior to the housing member. The flex tape signal conductor is hermetically sealed to the exterior wall of the housing member at the opening to maintain the integrity of the hermetic seal of the housing member even after temperature-cycling for a period of time.

Abstract: A radar altimeter system uses a microprocessor-based subsystem to process radar signals in software. The subsystem includes a track loop and a verify loop for digital signal processing of the radar signals. The track loop generates a gate pulse and integrates a radar return signal over the time window defined by the gate pulse in order to determine the leading edge of the return pulse. The verify loop positions the gate pulse for maximum overlap with the return pulse and integrates the return pulse over the gate pulse to determine the maximum signal strength of the radar return signal.

Abstract: A laser gyro lifetime prediction method incorporates a memory model that stores a worst case performance parameter for a readout intensity, a laser intensity and a derived quantity known as volts per mode for a laser gyro. A microprocessor based life prediction method utilizes a predetermined failure criteria to judge a estimate of laser gyro life based on historic performance of laser gyro operating parameters. The prediction is based on a linear quadratic or higher order fit of lifetime data for critical temperatures. The performance data is stored in a memory model for each critical temperature and parameter. The laser gyro reports eminent failures to the inertial navigation system or a host controller. Routine scheduled maintenance of the laser gyro is enhanced by knowing its lifetime.

Abstract: The compact brouting switch allows communication between external systems with differing or same protocols. The compact brouting switch includes switch ports which receive and transfer data between the external systems. A processor in the switch controls the movement of data within the switch and assigns data to specific switch ports to transfer data to specific external systems. However, the switch ports also have the capability of directly transferring data from one external system to another external system bypassing the processor.

Abstract: A low-cost portable handheld still-frame thermal camera for capture of calibrated digital thermographic infrared images having a lens assembly, a slideable linear array of uncooled 8-12 um thermal IR sensors, a slider actuation mechanism, and associated digital processing capability for calibrating, displaying, and storing images captured by the camera. The sensors are preferably thermoelectric sensors. The lens passes infrared radiation, the array is contained in an evacuated chamber, and operates at room temperature. The thermographic images may be displayed immediately or remotely or may be printed by conventional techniques.

Abstract: Disclosed is a fault-tolerant and/or fail-safe information processing system architecture for handling information from a plurality of independent subsystems which provide information related to selected input quantities, and which includes a plurality of redundant information processors for deriving specific processor output data as a function of the selected subsystem input quantities.