Abstract: A moving radar (405) generates a synthetic aperture image from an incomplete sequence of periodic pulse returns. The incomplete sequence of periodic pulse returns has one or more missing pulses. The radar converts the incomplete sequence of pulse returns into a digital stream. A computer (403) processes the digital stream by computing an along track Fourier transform (402), a range compression (408), an azimuth deskew (410) and an image restoration and auto focus (412). The image restoration and autofocus (412) utilizes a low order autofocus (501), a gap interpolation using a Burg algorithm (503), and a high order autofocus (505) for generating an interpolated sequence. The interpolated sequence contains a complete sequence of periodic pulse returns with uniform spacing for generating the synthetic aperture image. The image restoration and autofocus (412) computes a linear prediction coefficients estimate using the Burg Algorithm (606).

Abstract: A multi-stage cryocooler includes a concentric second-stage pulse tube expander in which a pulse tube is located within a second-stage regenerator. In one embodiment, an inner wall of the regenerator also functions as an outer wall of the pulse tube. In another embodiment, there is an annular gap between an inner wall of the regenerator and an outer wall of the pulse tube. The gap may be maintained at a low pressure, approaching a vacuum, by placing the gap in fluid communication with an environment around the cryocooler, such as the low-pressure environment of space. The integrated second-stage structure, with the pulse tube within the annular regenerator, provides several potential advantages over prior multi-stage cryocooler systems.

Abstract: A sensor system senses a scene and includes a dual-band imaging infrared detector lying on a beam path, wherein the infrared detector detects infrared images in a first infrared wavelength band and in a second infrared wavelength band; and a two-color cold-shield filter lying on the beam path between the infrared detector and the scene. The cold-shield filter defines a first aperture size for infrared light of the first infrared wavelength band, and a second aperture size larger than the first aperture size for infrared light of the second infrared wavelength band. The first infrared wavelength band has wavelengths less than wavelengths of the second infrared wavelength band.

Abstract: A radar antenna has a reflector and maximum gain along its boresight. The reflector has a periphery, typically circular, rectangular or elliptical. A plurality of Global Positioning System (GPS) satellite signal receiving antennas are rigidly, mechanically attached to the reflector near its periphery. The plurality of GPS satellite signal receiving antennas are connected pairwise to a phase comparator for comparing a plurality of first phase differences induced by a first GPS satellite signal received concurrently between the plurality of GPS satellite signal receiving antennas. A Phase comparator measures the phase difference of the signal received at GPS satellite signal receiving antennas pairwise thus performing a differential phase measurement. This differential phase measurement is supplied to a computer for identifying an ambiguous boresight position using the phase differences measured by the phase comparator. The position of the GPS satellites is known with respect to the geo-location of the antenna.

Abstract: An antenna array is assembled by direct attaching a flip chip transmit/receive (T/R) module to an antenna circuit board. A fillet bond is applied to the circuit board and the flip chip T/R module around at least a portion of the periphery of the flip chip T/R module.

Abstract: An imaging sensor system images in two different spectral bands a light beam traveling on a light path from a target. The sensor system includes an imaging sensor operable to image light of the two different spectral bands, a common optics having at least one reflective or refractive optical element, and a wavelength-selective beamsplitter on the light path between the target and the imaging sensor. The wavelength-selective beamsplitter splits the light beam into two subbeams, one subbeam for each of the two different spectral bands, that are respectively incident upon two different locations of the imaging sensor. The imaging sensor may be used to detect buried explosive mines.

Abstract: A radar classifies an unknown target illuminated with a large bandwidth pulse. The large bandwidth pulse may be algorithmically synthesized. The target reflects the large bandwidth pulse to form a return. The return is digitized into digital samples at range bin intervals. A computer extracts unknown range and amplitude pairs descriptive of the unknown target from the digital samples. Some range and amplitude pairs are located within one range bin interval. Principle scatterers are extracted from the unknown range and amplitude pairs using Modified Forward backward linear Prediction to form an unknown feature vector for the target. A plurality of pre-stored, known feature vectors containing known range and amplitude pairs are retrieved from the computer. The known range and amplitude pairs are descriptive of known targets, and are grouped in clusters having least dispersion for each of the known targets.

Abstract: An optical system includes a primary lens group having a central beam path therethrough and including a front lens group and a rear lens group. An anamorphic lens group lies on the central beam path and is positioned between the front lens group and the rear lens group. The anamorphic lens group includes at least one optically powered anamorphic lens that has different enlargements of a light beam along different axes perpendicular to the central beam path. The anamorphic lens group may be mounted on structure that allows it to be removed from the central beam path. An image transceiver is either an image source that directs a light beam through the primary lens group and the anamorphic lens group, or is an image receiver that receives a light beam through the primary lens group and the anamorphic lens group.

Abstract: A microwave attenuator circuit is disclosed, including a combination of a plurality of quarter wave transformers and a plurality of resistive elements.

Abstract: A radar acquires a formed SAR image of radar scatterers in an area around a central reference point (CRP). Target(s) are within the area illuminated by the radar. The area covers terrain having a plurality of elevations. The radar is on a moving platform, where the moving platform is moving along an actual path. The actual path is displaced from an ideal SAR image acquisition path. The radar has a computer that divides the digital returns descriptive of the formed SAR image into multiple blocks, such as a first strip and an adjacent strip. The first strip is conveniently chosen, likely to generally align with a part of the area, at a first elevation. An adjacent strip covers a second part of the area at a second elevation. The first strip is overlapping the adjacent strip over an overlap portion. The first and second elevation are extracted from a terrain elevation database (DTED).

Abstract: A telescope has a primary light mirror structure including a central base, and a concave primary mirror having a central opening in which the central base is received and extending radially outwardly from the central opening. The concave primary mirror has an inner margin adjacent to the central opening. A secondary light mirror structure includes a secondary mirror having a center and an outer periphery. The secondary mirror faces the concave primary mirror and the central base of the primary light mirror structure. A spider support extends between the inner margin of the concave primary mirror and the center of the secondary mirror facing the central base. The spider support does not extend to the outer periphery of the secondary mirror. The spider support has openings therethrough to permit light rays to pass between the secondary mirror and the central base of the primary light mirror structure.

Abstract: A system and method for aligning an input signal (24) synchronized to a first clock signal (22) with a second clock signal (26) The invention includes a mechanism (106) for generating a third clock signal (354) and an arrangement (352) for loading the input signal (24) in accordance with the third clock signal (354) and reading out an output signal in accordance with the second clock signal (26). In an illustrative embodiment, the invention is used in a sensor system (350) to align detector input data (24), which is synchronized to a data-capture clock (22), with a signal-processing clock (26). The register (352) acts as a data path transitioning stage between the actual time the input data is sampled and the time a processing system (102) clocks in the sampled data.

Abstract: A water-stable and water-soluble ceramic precursor is provided, containing at least one Group III element. Also, a metal acid salt complex is provided comprising (1) bismuth, lanthanum, and titanium, and (2) a polyether acid. In addition, methods are provided for preparing the Group III metal acid salt complex and the Bi, La, Ti acid salt complex comprising a bismuth polyether acid salt complex, a lanthanum polyether acid salt complex, and a titanium polyether acid salt complex. Finally, devices that include lanthanum-doped bismuth titanate as the active component are provided, as well as a water-stable and water-soluble gallium polyether acid complex.

Abstract: A display device includes a lamp having an output light beam, wherein the lamp is disposed in a lamp alignment position when it projects the output light beam A spatial light modulator receives the output light beam and controllably spatially modulates the intensity of the output light beam, and an optics system that projects the spatially modulated output light beam. There is a lamp mount upon which the lamp and at least one spare lamp are supported. The lamp mount selectively and controllably moves one of the lamp and the at least one spare lamp into the lamp alignment position.

Abstract: A temperature-compensated structure includes a temperature compensator having a temperature-compensation bellows whose length is responsive to changes in temperature, and a temperature-compensation actuator that moves responsive to the length of the temperature-compensation bellows. There is a movable structure, and a mechanical force multiplier extending between the temperature-compensation actuator and the movable structure so that a force applied to the movable structure is greater than the force produced by the temperature-compensation bellows.

Abstract: In an exemplary aspect of the invention, an antenna is disclosed that includes a ground plane and a disk disposed adjacent to the ground plane. The disk has a perimeter. The antenna further includes a loading reflector having an underside. At least a portion of the underside is electrically connected to a portion of the perimeter of the disk. The loading reflector has a width at a widest point, and the width at the widest point of the loading reflector is larger than a thickness of the disk. The disk may be circular or elliptical. The ground plane may include a cavity, where the disk is disposed within an outer border of the cavity. When an elliptical disk is used, the cavity may also be elliptical. An elliptical cavity may have a parabolic surface.

Abstract: An embodiment of an electronically scanned array antenna includes an array of radiative elements having an array height. A plurality of separate subarrays of the radiative elements include a first row comprising a first plurality of subarrays, wherein subarrays of the first plurality of subarrays are horizontally non-overlapping with one another, and a second row comprising a second plurality of subarrays. The subarrays of the second row are arranged vertically adjacent to the subarrays of the first row, wherein subarrays of the second plurality of subarrays are horizontally non-overlapping with one another. The radiative elements of the separate subarrays are not shared with any other subarray. The subarrays of the radiative elements have subarray heights which are smaller than the array height.

Abstract: A regenerative refrigeration system includes one or more control devices that utilize micro electro mechanical systems (MEMS) technology. Such MEMS devices may be small in size, on a scale such that it can be introduced into a refrigeration system, such as a cryocooler, without appreciably affecting the size or mass of the refrigeration system. Through the use of MEMS devices, dynamic control of the system may be achieved without need for disassembly of the system or making the system bulky. Suitable regenerative refrigeration systems for use with the MEMS devices include pulse tube coolers, Stirling coolers, and Gifford-McMahon coolers.

Abstract: A load circuit for use with a switching mode circuit. The novel load circuit includes a series inductive-capacitive network coupled to an output of the switching mode circuit and a circuit for providing a capacitance coupled to the output of the switching mode circuit. In an illustrative embodiment, the circuit for providing capacitance includes one or more lumped capacitors adapted to compensate for an intrinsic capacitance in the switching mode circuit. The load circuit may also include a shunt inductance coupled to the output of the switching mode circuit. In an illustrative embodiment, the load circuit is adapted to provide a Class-E load to a two-stage Class-E high power amplifier. The amplifier includes a driver stage, a novel Class-E inter-stage matching network (ISMN), and a high power stage using the novel load circuit.

Abstract: A system for calibrating a sensor in a vehicle, such as a space capsule or other space borne apparatus, uses an expandable integrating sphere. A sensor in the vehicle measures the energy from an electromagnetic energy source within the integrating sphere through a calibration window. The expandable fluid impermeable integrating sphere expands when filled with a fluid, such that when filled with the fluid, its interior is viewable through the calibration window. The system includes a source of fluid to fill the integrating sphere and a fluid regulator coupled to the vehicle to determine when to supply the fluid to the integrating sphere to maintain an appropriate gas pressure level with the integrating sphere.