Abstract: A three state EM motor/damper used in a ground-based or space-based Stirling refrigerator expander mechanism provides multiple states of operation to obtain fail safe performance during assembly, launch (space based refrigerators), and operation. The device is attached to the expander's reciprocating displacer to enable actuation during assembly, provide maximum damping during launch, and provide attenuated damping to control displacer motion during operation as a refrigerator. The motor/damper is a linearly actuated "voice coil" device employing a moving coil wound on an electrically conductive bobbin and oscillating within a permanent magnet/back iron field assembly. The electrically conductive bobbin internally generates and dissipates eddy currents when moved through the magnetic field. The bobbin acts as a coil of one turn, shorted to itself. This mechanism transforms kinetic energy to electrical energy, which then dissipates as heat. In this manner, mechanical energy is removed from the system.

Abstract: A portable lens measuring device (10) comprises a plurality of optical fibers (23) and a lamp (18) for providing light to a common end. The portable lens measuring device (10) includes a sensor (32) for detecting light from the common end through the second arm, the light sensor (32) generating a signal responsive to the amount of light detected, and a lens assembly (25), the lens assembly being connected to the common end and having a fixed focal point. The portable lens measuring device (10) includes a controller (12) for controlling the lens assembly (25), for regulating the lamp and for receiving the signal generated by the detector. The portable lens measuring device (10) also includes a sensor motor (14) for moving the lens assembly (25) across a first and second surfaces of the lens to provide a value of the center thickness of the lens.

Abstract: An autocalibration system is provided for a back-scanning, gimbal-mounted step and stare imaging system. The step and stare imaging system effects step and stare performance even though the gimbal mounted platform upon which the system telescope is mounted rotates at a constant rate. The autocalibration system calibrates the system's static line of sight positioning and the system's rotational, or angular rate line of sight positioning.

Abstract: A computer aided system design tool which enables the user to define the system functionally by defining functional program requirements (28) and defining preliminary system requirements (30). After the program requirements (28) and preliminary system requirements (30) have been defined, an automated reuse tool (38) selects particular implementations for each of the functions specified by the user when defining the functional program requirements (28). The automated reuse tool (38) also partitions the system constrains defined by the preliminary system requirements (30) over the system by proper selection of particular implementations for each design. The resulting reuse design database (40) may then be simulated (42) to verify proper operation of the system.

Abstract: A FLIR boresight alignment system (52) for aligning a sensor pod LOS associated with a weapons pod of a fighter aircraft to a navigation reference frame. A pod inertial navigation and global positioning system (62) provides position, velocity and attitude of a sensor (58) within the pod. An aircraft inertial navigation and/or global positioning system (68) provides position, velocity and attitude of the aircraft. The sensor position and velocity and the aircraft position and velocity are applied to a transfer alignment filter (64) that utilizes Kalman filtering. An output of the transfer alignment filter (64) is applied to a sensor inertial navigation system to correct the pod LOS relative to the navigation reference frame. Alternately, the transfer alignment filter (64) may operate directly upon the pseudo ranges and delta pseudo ranges to satellites being tracked by the GPS receiver.

Abstract: A thermal imaging device (10) provides for its use with a variety of accessory telescopic lenses (12). Each of the accessory telescopic lenses (12) and the thermal imaging device (10) include cooperating physical features allowing the lenses (12) to be mated with the device (10) in a single relative position. Each lens (12) also carries a uniquely positioned magnet (176), and the thermal imaging device (10) includes a plurality of magnetically-responsive sensors (178) responding to the magnets (176) of the various lenses (12) to identify which (if any) of the accessory lens (12) is installed on the device (10). Some of the accessory lenses (12) also include a variable-power feature. These variable-power lenses (12) have an additional magnet (182) moving between an effective position and an ineffective position in response to a user-selected power setting for the lens (12).

Abstract: Shaft rotation sensor, including: two directional magnetic sensors disposed with respect rotating magnetic source, to sense magnetic field vector component generated by magnetic source; the magnetic sensors being disposed to provide output signals, having a sineosine relationship, representing magnitude of magnetic field vector component. In another aspect of the invention, a shaft rotation sensor, including: first and second directional magnetic sensors disposed with respect to rotating magnetic source, such that first sensor senses, and provides first output representing, magnitude of first magnetic field component and second sensor senses, and provides second output representing, magnitude of second magnetic field component orthogonal to first magnetic field component; and first and second outputs being electrically connected in series to provide first output channel.

Abstract: A system and technique for directing intensity modulated electromagnetic energy. The inventive system (10) includes an intensity modulated source of electromagnetic energy (12). Individual elements (22) in an array of energy directing elements (15) are activated in sync with the modulation of the energy source (12). In a particular implementation, the source (12) is a laser. The intensity of the laser is reduced during each successive field per frame. The energy directing elements (15), in this case, light directing elements, are implemented with an array of digital micromirrors. The light source (12) is modulated in intensity in accordance with a fixed modulation scheme. The mirrors (22) are selectively activated relative to the light source modulation scheme. Hence, the invention provides a gray scale output while allowing the time between mirror flips to be constant.

Abstract: A thermal weapon sight employs a rotating multifaceted scan mirror (22) to reflect infrared light (14) from an object to a bank of CCD detectors (50) of which the output is multiplexed (80) and compensated for overall and individual sensor deviations. The compensated output, after suitable signal processing (86), is employed to drive an LED array (62) that projects visible light to different facets of the same scanning mirror (22) to provide a visible output (14') representing the infrared input obtained from the object being viewed. A compensation circuit includes a series of digital analog converters (208a-208m) having a bank of switched capacitors (234a-234m) for which a voltage reference is provided by a CMOS voltage buffer (220) having fast recovery time, and which is able to drive the large capacitative load.

Abstract: A video camera (28) is provided including an image receiving surface (30). A monitor (36) is operably coupled to the video camera (28) to display an image (34) received at the image receiving surface (30). A reference reflector (24) is secured to the alignment camera (28) such that a reference portion (40) of the image receiving surface (30) is located at the optical center of curvature (32) of the reference reflector (24). An alignment mark (44) is coordinately positioned with the reference portion (40) on the monitor (36). The video camera (28) and the reference reflector (24) are movable as a unit to position the optical center of curvature (32) of the reference reflector (24) coincident with the focal point 22 of an element or optical system to be tested (18).

Abstract: An imaging system (10) contains a diffractive optic lens (14) which allows for a relatively accurate representation of objects within a field of view. These objects are associated with light rays (20, 22 and 24) which are made to impinge upon the diffractive optic lens (14) and thereafter are made to be received by an imaging surface (12) at a receiving angle which may be determined by the structure of the diffractive optic lens (14). The diffractive optic lens (14) may be placed within the typical dewar (16) of the image acquisition system (10), may be removable deployed over the imaging surface (12), or alternatively, the diffractive optic lens may be etched upon the front side of the imaging surface (12) by the use of standard etching techniques such as lithography, diamond turning and the like.

Abstract: A system for producing a high quality scene image in a thermal imaging system by electronically compensating for variations in the imaging system imager focal length. The system includes optics (16, 18) for detecting a scene (14), a detector assembly (27) being responsive to energy from the detected scene; and an imager (25) for imaging the energy from the detected scene onto the detector assembly (27). The imager (25) includes a temperature sensor (25b) for sensing imager lens temperature. The detector assembly (27) outputs electric signals in response to the energy from the detected scene at a first clock sample rate. The system further includes a processor (84) for controlling the first clock sample rate of the detector assembly to maximize detected scene image quality through variation of the first clock sample rate to automatically compensate for imager lens focal length variation due to ambient temperature changes in the imager lens (25a) and due to inherent manufacturing tolerances.

Abstract: The present system provides a thermal imaging device including a detector array responsive to thermal infrared radiation. The detector array has a linearly-arrayed plurality of spaced-apart detector elements defining cooperatively a length dimension for the detector array. Each of the plurality of detector elements provides a corresponding individual electrical signal indicative of the thermal infrared radiation incident thereon. The detector elements vary from one another in the plurality of detector elements, and the thermal imaging device responsively provides a visible-light image replicating a viewed scene. The thermal imaging device includes a scanning device scanning the viewed scene across the plurality of detector elements in a direction generally perpendicular to the length dimension.

Abstract: A device and method for receiving a radio signal transmitted over a channel, selecting and deselecting an equalizer, and balancing processing in response to such selection. A radio frequency signal is received from a transmission channel into a receive path, and delay spread in the radio frequency signal is estimated using an analysis circuit. The analysis circuit also determines a threshold delay spread. In the event the estimated delay spread exceeds the threshold delay spread, an equalizer is selected, otherwise the equalizer is deselected. Similarly, in the event the estimated delay spread does not exceed the threshold delay spread, a high complexity processor is selected, otherwise a low complexity processor is selected. If the low complexity processor is selected, an output signal is generated using the low complexity processor, and if the high complexity processor is selected, the output signal is generated using the high complexity processor.

Abstract: A self-cooling Stirling cycle cooler (1). The cooler (1) includes a conduit (20) for transporting thermal energy from a first location to a second location. The conduit is a closed loop having first and second ends terminating in a first chamber (29). A pump (14) is mounted in the first chamber (29) for moving the heat energy therein from the first location to the second location. The pump (14) includes a piston (40) which reciprocates in the first chamber (29). A first valve (42) is provided for controlling the direction of a flow of fluid in the conduit (20) into the first chamber (29) and a second valve (46) for controlling the flow of the fluid in the conduit (20) out of the first chamber (29). In a Stirling cycle cooler, the balancer mass is used as the pump piston to facilitate the movement of fluid in the conduit. By utilizing the balancer mass of a Stirling cycle cooler, self-cooling is effected with minimal additional hardware, weight and cost.

Abstract: According to the present invention, light is provided to an elliptical optical surface (102) separating first and second homogeneous optical media (104), (106) that cause collimated light (108) originating in one of the media to be perfectly focussed either at a primary focus within the second medium or at a virtual focus within the first medium (110). For example, a collimated beam (510) is expanded by refraction in an immersion refractive confocal ellipsoid optic (502) having an input optical surface (504) and output optical surface (506). Further, the elliptical optical surface is used in combination with a second optical surface such that both surfaces share a common optic axis and are separated by an optically transmissive medium such as glass and spaced such that the optical focal points of both surfaces are common to create an immersion optical beam expander.

Abstract: A closed-loop missile tracking system (10) employs a missile (12) with a thermal beacon (22) and an optical beacon (24). A target designator (40) defines a boresight from a missile firing location, such as an aircraft, to a target. The closed-loop missile tracking system (10) employs a first tracker (48) and a second tracker (64) with a forward looking infrared (FLIR) sensor (52) to track the displacement of the optical beacon (22) and thermal beacon (24) from the boresight. The first tracker (48) generates a first set of azimuth and elevation error signals. The second tracker (64) further includes a video demultiplexing interface (70) which transforms serial multiplexed video signals, which are output by the FLIR sensor (52) and contain a field with M rows and L columns of pixels, into a demultiplexed parallel video signal. A video thermal tracker (VTT) (58) selects the N adjacent horizontal rows of pixels and generates a second set of azimuth and elevation error signals therefrom.

Abstract: A line spectral frequency (LSF) vector quantizer, having particular application in digital cellular networks (DCN), is provided for code excited linear predictive (CELP) speech encoders. The LSF vector quantizer is efficient in terms of bits employed, robust and effective in terms of performance across speakers and handsets, moderate in terms of complexity, and accommodates effective and simple built-in transmission error detection schemes. The LSF vector quantizer employs a minimum number of bits, is of moderate complexity and incorporates built-in error detection capability in order to combat transmission errors. The LSF vector quantizer classifies unquantized line spectral frequencies into four categories, employing different vector quantization tables for each category. Each quantization table is optimized for particular types of vectors. For each category, three split vector codebooks are used with a simplified error measure to find three candidate split quantized vectors.

Abstract: A high-speed data register for storing a series of data values received at a high-speed clock rate and including a first set of pipelined latches and a second set of pipelined latches. Control circuitry loads the received data values alternately into said first set of latches and said second set of latches from an input or "last" register, which stores the last data value received by the data register. Data values thus enter the last register at the high-speed clock rate but are loaded into each of the first and second set of pipelined latches at one-half that rate.