Abstract: A pulse tube expander includes a regenerator, a pulse tube, a porous plug phase shifter, and a surge tank, in series gaseous communication with each other. The porous plug phase shifter is made of a porous material such as a sintered mass or a packed solid bed of distinct, free-flowing bodies. The porous plug phase shifter introduces a phase shift between the pressure wave and the mass flow rate in the pulse tube expander. The porous plug phase shifter is resistant to clogging due to contamination that may be present in the system.

Abstract: A point-to-point radio frequency unit/antenna has a flat antenna, preferably a continuous transverse stub antenna, integrated into the housing of the microwave unit. The radio frequency unit/antenna includes a housing having an exterior wall, a microwave radio frequency transceiver electronics package within the housing and having an antenna connection, and a flat antenna affixed to one face of the exterior wall of the housing. A microwave radio frequency feed communicates between the flat antenna and the antenna connection of the microwave transceiver electronics package. There is preferably a bracket structure on another face of the housing to affix the housing to a support.

Abstract: A continuous time Bandpass Delta Sigma (&Dgr;&Sgr;) Modulator architecture with feedforward and feedback coefficients to completely specify both the signal transfer function (STF) and the noise transfer function (NTF) for a stable modulator ADC system.

Abstract: A cost-effective packaging system (10) for ultra high density input/output (integrated circuits (14). The packaging system includes a first circuit chip (14) that has a first pattern of contacts (16) distributed across a surface area of the chip (14). The first pattern of contacts (16) represents input/output connections (16). A three-dimensional circuit (18) is disposed spatially parallel with respect to the first circuit chip (14) and organizes the input/output connections (16) into a second pattern of contacts (24, 30) suitable for connection to a second circuit (22). In a specific embodiment, the three-dimensional circuit (18) is a double sided DECAL (18). The double-sided DECAL (18) includes a substrate (18) having a first circuit pattern (28) spatially parallel with a second circuit pattern (30) on or in the substrate (18). The first and second circuit patterns (28 and 30) are interconnected.

Abstract: An optical system has an extended boresight source including a boresight light source that produces a light beam, a condenser lens that receives the light beam from the boresight light source, a spatial light integrator that receives the light beam from the condenser and mixes the light beam to reduce its spatial inhomogeneities, a constriction through which the light beam from the spatial light integrator is directed, and a collimator that receives the light beam which passes through the constriction and outputs a boresight light beam. The boresight light beam is typically provided to a sensor imager that uses the boresight light beam to establish its centroid.

Abstract: A passive proximity fuze. The inventive fuze (10) is adapted to be mounted on a munition (11) and includes a receiver (16) adapted to lock on to a signal transmitted by a target transmitter (12). The receiver (16) detects a Doppler shift in the signal as the munition approaches the target. When a closest point of approach is reached the Doppler shift changes from increasing to decreasing. The inventive fuze (10) includes a mechanism for detecting this change in the Doppler shift and provides a detonation signal in response thereto. In the illustrative embodiment, the receiver (16) is an FM receiver. The mechanism for detecting a change in the Doppler shift may be implemented with discrete analog circuitry or digital circuitry. In an illustrative analog implementation, first and second resistive/capacitive networks (R1C1 and R2C2) are employed to compute a second derivative of the Doppler shift signal output by the receiver (16).

Abstract: A multi-resolution feature extraction method and apparatus. In the illustrative embodiment, the feature extractor includes circuitry for receiving and transforming a time variant data signal into a multi-resolution data signal. The multi-resolution data signal is compared to each of a plurality of object templates. The system then generates a feature vector based on a correlation of the multi-resolution data signal to one of the object templates. The multi-resolution feature extraction method employs object templates formed by transforming time variant image data for each of a plurality of objects into a respective multi-resolution template and averaging all templates for each respective object. The method includes steps for transforming an incoming time variant data signal into a multi-resolution data signal, comparing the multi-resolution data signal to each of the object templates, and generating a feature vector when the multi-resolution data signal correlates to one of the object templates.

Abstract: A bistatic passive radar system is used in conjunction with a host transmitter that is a determinable distance D from the radar system for determining the distance D and for displaying video images of a selected target, the position of the radar system and the position of the transmitter on a display. The invention is characterized by a system and method of using the display to determine the slant range S and the altitude H of the selected target relative to the position of the radar system. Three alternative embodiments of the invention are disclosed.

Abstract: An automated simulator for radar and sonar applications. The inventive simulator is implemented in hardware and generates current parameters with respect to a simulated target in response to a plurality of initial values with respect thereto. In the illustrative embodiment, the initial values include range, velocity, and acceleration and are stored in first, second and third register respectively. In the best mode, the invention is implemented in a field-programmable gate array. The inventive target simulator also includes a range delay circuit for generating a simulated return from the simulated target. The range delay circuit includes logic for determining whether a simulated pulse train to be received is ambiguous or unambiguous and adjusting the pulse repetition rate of the pulse train accordingly. The range delay circuit calculates die initial time that a packet needs to make the trip to and from the target.

Abstract: A control system for a rolling missile that has a seeker head including an optical system and a heat detector assembly. The optical system including a primary reflector, a secondary reflector, a reticle/lens assembly, and a fiber optics assembly operatively associated with the reticle/lens assembly. The fiber optics assembly is constructed so as to translate images appearing near the optical axis of the optical system to a radially displaced point on the reticle/lens assembly to provide a more efficient chopping of the image by the reticle/lens assembly thus providing continuous pulses to the heat sensitive detector assembly.

Abstract: Self aligning, blind mating connector bodies are provided for connecting to mating connector bodies. One embodiment of the connector body has an annular housing with two slots disposed 180 degrees apart. An inner body has two dowel pins disposed at locations corresponding to the slots in the annular housing. A compliant O-ring is disposed between and is resiliently coupled to the inner body and the annular housing. The inner body is free to rotate relative to the annular housing about an axis defined by the dowel pins to provide single axis gimbal motion. Another embodiment of the connector body has an annular housing with two holes disposed 180 degrees apart. An inner body has two dowel pins disposed at locations corresponding to the holes in the annular housing. An external housing ring is connected to the annular housing using a second pair of dowel pins located 180 degrees apart that are disposed at 90 degrees with respect to the first set of dowel pins.

Abstract: An architecture for processing time-critical real-time control messages in a large real-time processing system. Control messages are separated from block data transfers and identical but separate links are used to transfer the block data and control messages. One embodiment of the architecture 30 has one control link shared by multiple processing nodes while each node 10 has a separate high bandwidth data link.

Abstract: An RF interconnect between an airline circuit including a dielectric substrate having a conductor trace formed on a first substrate surface and an RF circuit separated from the airline circuit by a separation distance. The RF interconnect includes a compressible conductor structure having an uncompressed length exceeding the separation distance, and a dielectric sleeve structure surrounding at least a portion of the uncompressed length of the compressible conductor structure. The RF interconnect structure is disposed between the substrate and the RF circuit such that the compressible conductor is placed under compression between the substrate and the RF circuit. Examples of the RF circuit include a vertical coaxial transmission line or a grounded coplanar waveguide circuit disposed in parallel with the airline circuit.

Abstract: A phase-stabilized adaptive array system with a moving antenna array and a plurality of signal channels coupled to the antenna array, each for producing a channel signal. Each channel has adaptive signal weighting apparatus for weighting the channel signal by a channel weight. The system includes combining apparatus for combining the weighted channel signals to form a beam signal, and phase compensation apparatus for applying phase compensation weights to the array signals or the beam signal which vary in dependence on the array position such that the response to a signal at a known direction is held substantially constant while the antenna is moved, or as the weights are updated.

Abstract: An RF interconnect between a rectangular coaxial transmission line including a coaxial center conductor and a dielectric structure with a rectilinear cross-sectional configuration fitted around the coaxial center conductor and an RF circuit separated from the airline circuit by a separation distance. The RF interconnect includes a compressible conductor structure having an uncompressed length exceeding the separation distance, and a dielectric sleeve structure surrounding at least a portion of the uncompressed length of the compressible conductor structure. The RF interconnect structure is disposed between the rectangular coaxial transmission line and the RF circuit such that the compressible conductor is placed under compression between the substrate and the RF circuit. Examples of the RF circuit include a vertical coaxial transmission line or a grounded coplanar waveguide circuit disposed in parallel with the center conductor of the rectangular coaxial transmission line.

Abstract: An optical system includes a window, an optical corrector formed of a curved piece of a transparent material having a front surface and a back surface, and a sensor system with a sensor positioned such that the optical corrector is between the window and the sensor. At least one of the front surface and the back surface of the optical corrector is a segment of a convex aspheric curve rotated about a center, otherwise known as a torus.

Abstract: A system and method of finding a detection threshold that separates real scene objects seen through an optical system from sensor fixed artifacts. The inventive system continuously scans the sensor so that objects in the scene move in an inverse sense relative to the scanning motion while fixed frame artifacts remain fixed in focal plane coordinate system. The difference in temporal behavior is used to discriminate against fixed frame artifacts. The inventive system finds a detection threshold that maximizes the portion of a target that may be segmented while avoiding setting the threshold so low that it merges spatially adjacent artifacts in with the target.

Abstract: A dual cavity multifunction laser comprising a diode-pumped, contact cooled, slab laser head that supports two different length unstable resonators. The laser produces short (<8 ns), low energy 1 &mgr;m pulses or long (>15 ns), higher energy 1 &mgr;m pulses from the same laser system at different repetition rates, if desired. The output from each resonator can be separately optimized for different operating modes such as target designation and target profiling. The unstable resonators use independently optimized super Gaussian output couplers to generate high quality beams for each of the high and low pulse energy modes. The resonators also share a common bounce path to minimize intracavity losses and thermally induced birefringence for both resonators.

Abstract: A soiled piece of fabric is cleaned by mechanical agitation while the fabric is simultaneously subjected to acoustic energy in a gaseous environment wherein the piece of fabric is not immersed in a liquid cleaning medium. Mechanical agitation may be by gas jet action and/or by tumbling. The acoustic energy vibrates the fibers of the fabric to enhance the cleaning action. The piece of fabric may be chemically treated to mobilize the soil.

Abstract: A software-based resolver-to-digital converter (RDC) (80) for computing an angle of rotation &THgr; of gimbal-mounted instrumentation (16) in a gimbal system. The RDC (80) computes the angle of rotation of the instrumentation using parameter signals received from a resolver (32) in the system. The parameter signals, along with a resolver reference signal are input into a multiplexor (60) and are multiplexed. The signals are then fed to an analog to digital converter (38) and converted to digital form. The digital signals are then input into a processor (36) associated with the system. This processor, in addition to performing numerous system computations, is programmed through appropriate software to filter the digital signals received, compute the value for the angle of rotation &THgr; and output the computed value to system circuitry (31) for processing to enhance system operation.