Abstract: A solar cell assembly wherein a solar cell is provided with electrical layer contacts for both the p-type semiconductor layer and the n-type semiconductor layer which are exposed on a top side of the solar cell, so that electrical contact to both layers can be made from the top side of the cell, and a glass cover overlying the solar cell includes a pair of U-shaped electrical cell contacts extending over the sides of the glass cover so that one leg of each U makes contact with one of the layer contacts and the other leg is accessible from the top of the cover glass. External electrical contact to the cell is easily and conveniently made, and cells can be electrically joined to adjacent cells in an array using a connector bar. The glass cover also supports the solar cell so that excess material on the substrate of the solar cell can be etched away to reduce the weight of the solar cell assembly.

Abstract: A layer of material having relatively low light sensitivity is interposed between a substrate and a light sensitive recording medium during recording of a slant fringe hologram. The layer frees the ends of the fringes from the substrate to permit greater expansion during a subsequent chemical swelling process, thereby resulting in a slant fringe hologram having improved efficiency. In one embodiment, a separate layer of light insensitive material is applied to the substrate prior to application of the recording medium. In another embodiment, a separate layer of light sensitive material is applied to the substrate and is then desensitized by exposure to incoherent light or by heat treatment prior to application of the recording medium.

Abstract: A spacecraft (100) such as a satellite, is shaped roughly in the form of a cup with a hollow inner cavity (106) such that a plurality of such spacecraft may be stowed for launch in a nested stack (204), thereby enabling a greater number of satellites to be launched simultaneously with a single launch vehicle (201). The cup-shaped configuration results from the satellite having a base member (105) with panels or side walls (101a, 101b, 101c) extending from portions of the perimeter of the base member at a non-zero angle thereto.

Abstract: An anti-skid braking system control method determines the brake torque on a wheel of a road vehicle to prevent wheel lock-up while retaining braking force. The method utilizes a wheel slip-wheel acceleration phase plane (400), which is divided into at least three and preferably four wedge-shaped sectors (401, 402, 403, 404) meeting at a central point (440), each sector representing one of three available brake control actions (A, H, R) to be taken. The vehicle's wheel slip and wheel acceleration are estimated, a representation of the phase plane is used to determine in which sector the slip/acceleration coordinate lies, and a control command is output to the system for effecting the desired control action in accordance with the sector determined. The control method is adaptive to vehicle speed.

Abstract: A method of manufacturing optical elements, such as for head-up displays, from holographically recorded interference patterns in a dichromatic gelatin is disclosed. The exposed hologram pattern is developed through hydration, the hydrated hologram gelatin is dehydrated by contacting the hydrated gelatin with a mixture of isopropyl alcohol and an inert anhydrous fluid, such as a liquid fluorinated hydrocarbon solution. The dehydrated hologram pattern can then be subsequently stabilized, for example, by baking.

Abstract: A method for cancelling azimuth, i.e., doppler ambiguity, in a SAR receiver on board a moving craft, e.g., an aircraft, which permits a lower PRF, without causing range ambiguity. Radar returns are received on board the craft with an antenna having first and second apertures to produce corresponding first and second return signals. The first return signal is processed over a given time period to generate a first series of component SAR signals representing radar returns from respective cells of an azimuth-range grid. The second return signal is processed over the given time period to generate a second series of component SAR signals representing radar returns from the respective cells of the azimuth-range grid. The component signals, individually weighted, are additively combined to produce a third series of resultant SAR signals representing the radar returns from the respective cells of the azimuty-range grid.

Abstract: A method and apparatus are disclosed for providing a laser beam that is automatically aligned with a substantially rigid, stabilized platform or frame that can be oriented over a wide angular range, such as by the gimbals of a laser pointing and tracking system. A single-transverse-mode master laser oscillator 12 is mounted on the stabilized platform 13 which is part of the inner gimbal, which can be rotated about an elevation axis 16, and a multipass laser amplifier 21 with a phase conjugation mirror 22 and an optional nonlinear frequency-conversion device 20 are located off the inner gimbal. An outer gimbal or pedestal mount permits rotation about an azimuthal axis 17. The laser oscillator 12 and laser amplifier 21 are coupled by means of a beamsplitter 15 and two reflecting elements 18 and 19. The laser media used for the oscillator 12 and amplifier 21 are either the same, or compatible media having the same wavelength.

Abstract: U-shaped heater (42) carries busses (22, 24) which are electrically connected to supply heating power. Heated tip (58) is secured to the front of the heater and is as wide as is necessary to at the same time reach all of the leads to be soldered. The heater and busses rock on a pivot provided by pin (18) close to the heated tip so that rocking causes little lateral dfisplacement. Rocking in the single plane is limited by the busses engaging on the back of body (12) and the thermocouple connector body engaging on the front of the body, both in sliding engagement. Spring (62) holds the movable parts on the pivot pin and centers the heater.

Abstract: The system for sensing ions in aqueous solution such as an electroplating bath includes a light source (18) which delivers light including a selected wavelength through a series of optical fibers (20, 24, 26, 32) to probe (14). The probe is partially immersed in the solution (12) and the light is delivered through the solution in the space (94) between prisms (82, 92). The return light is conducted by optical fibers (32,38) to detector or opto-electronic transducer (44). A portion of the original light is diverted by splitter (22) through fiber (42) to opto-electronic transducer (46) so that a comparison of the signals determines the amount of light in selected wavelength which is absorbed in the solution due to ions thereon. The signal processing unit (40) is preferably enclosed in an electromagnetic protected area (16) to avoid the adverse EMI and corrosive atmosphere effects near the electroplating tank (10).

Abstract: An electrically scanned phased array with low sidelobes and tapered aperture illumination is disclosed. The array is fed by a uniform corporate feed network (55) and includes a main array aperture formed by main radiating elements (72-75) and first and second ancillary arrays formed by ancillary radiating elements (70-71) and (76-77). For a linear aperture, the outputs from the feed network (55) are phase shifted to steer the beam to one of the available beam locations, and coupled to corresponding ones of the main array radiating elements (72-75) and the ancillary array radiating elements (70-71or 76-77). The beam steering phase shifts invoke uniform phase gradients between the elements of the respective array, and bi-state phase correctors (85-88) are provided to correct for phase gradient discontinuities across the main and ancillary array apertures.

Abstract: Apparatus and method are disclosed for providing a variable lens and birefringence compensator (10) adapted to be used within the resonator cavity of a repetitively pulsed, variable rate, solid state laser. A cylindrical body of optical material (12) having a temperature dependent index of refraction is thermally coupled to heat exchange means (14) surrounded by potting material (16) and a heat sink (18) which adds heat to or extracts heat from the exterior surface of the cylindrical body in order to establish radially dependent thermal and stress gradients within the body. The heat exchange means is supplied power through leads (20) from the same source (22) which excites the excitation mechanism of the solid state laser. Heat is infused into or extracted from the compensator body at the same rate at which the flashtube stimulates the laser rod (24) within the laser cavity defined by resonator mirrors (26, 28).

Abstract: Point and area target tracking are employed by a dual mode video tracker which includes both a correlation processor (30) and a centroid processor (32) for processing incoming video signals representing the target scene (20) and for generating tracking error signals over an entire video frame. A microcomputer (26) controls the operation of the correlation and centroid processors, as well as a preprocessor (28) which preconditions the incoming video signals. The tracker operates in any of several modes in which the correlation and centroid processors function either independently or cooperatively with each other. The correlation processor generates a reference map in pixel format which is used to produce azimuth and elevation optimal weighting values for each pixel in the field-of-view. The reference map is recursively updated. The track gate for the correlation processor is automatically sized using a gradient function derived from the optimal weighting values.

Abstract: Two-state, bilateral, single-pole, double-throw, half-bridge power-switching apparatus capable of high speed, high current switching over a duty factor range of zero percent to 100% includes a single-wire connector to a source of switching signals, a first FET whose gate is connected to the single-wire connector, and a second FET having its gate connected to the drain of the first FET and its source connected to the drain of the first FET through a device for preventing, in part, cross-current from the first FET to the second FET and for permitting the gate voltage on the second FET to be raised sufficiently high to turn on the second FET. The apparatus also includes a system for delivering on/off signals to the second FET and for holding the second FET on or off in response to switching signals having a duty factor in the range of zero percent to 100%.

Abstract: A solar cell assembly wherein a solar cell is provided with electrical layer contacts for both the p-type semiconductor layer and the n-type semiconductor layer which are exposed on a top side of the solar cell, so that electrical contact to both layers can be made from the top side of the cell, and a glass cover overlying the solar cell includes a pair of U-shaped electrical cell contacts extending over the sides of the glass cover so that one leg of each U makes contact with one of the layer contacts and the other leg is accessible from the top of the cover glass. External electrical contact to the cell is easily and conveniently made, and cells can be electrically joined to adjacent cells in an array using a connector bar. The glass cover also supports the solar cell so that excess material on the substrate of the solar cell can be etched away to reduce the weight of the solar cell assembly.

Abstract: A plurality of pursuers or defensive missiles which are self-guided and self-propelled individually assign themselves to one of a plurality of targets or incoming offensive missiles in such a manner that the probability is substantially increased that more targets will be selected by at least one pursuer and that fewer targets will be selected by more than one pursuer.

Abstract: Fluxing station (34) has a flux dispenser (52) where liquid flux cascades down steps (88, 90). Circulating pump (46) draws liquid flux from a reservoir (54) below the steps and recirculates it to cascade down the steps. There is provision to add makeup flux from reservoir (38) or supply a cleaning liquid such as alcohol from reservoir (37) to clean the circulating system. A drain (62) is provided. Electrical components can be positioned with their leads on the steps so that liquid flux cascades thereover for accurately fluxing only the ends of the leads. Two or more pairs of steps, with different spacing, may be provided to accommodate components of different lengths.

Abstract: A cryogenic refrigerator is disclosed having a displacer with a regenerator therein. The regenerator opens at one end to a warm volume and at the other end to a cold volume. The opening at the cold volume includes an end hole and a plurality of radial holes. The radial holes serve as secondary passageways should the end hole become blocked with contaminants. The life of the cryogenic refrigerator is thereby greatly enchanced.

Abstract: Fine single crystals of low-melting point materials are prepared by slowly withdrawing a glass crystal growth capillary tube containing the material from a heating apparatus which precisely maintains the molten material at a temperature just above its melting point. Temperature control of the molten material in the crystal growth tube, prior to solidification, is attained by enclosing the crystal growth tube in a temperature control tube containing the molten material being solidified. Preferably, the inside diameter of the temperature control tube is slightly larger than the outside diameter of the crystal growth tube, and both tubes reach into a reservoir of the molten material to be grown as a crystal, so that the molten material is drawn upwardly into the crystal growth tube and the space between the crystal growth tube and the temperature control tube by capillary action.

Abstract: A system (20) for diagnosing defects in electronic assemblies is disclosed. The system (20) comprises a knowledge base (26) for storing information regarding the electronic assembly for receiving current test failure data regarding an electronic assembly (12). The system further comprises a pattern search section (36) for comparing current test failure data to information stored in the knowledge base (26). A voting section (40) is also provided for generating a recommended repair procedure to eliminate the defect in the electronic assembly (12). Finally, the system (20) further comprises a historical pattern generation section (46) which updates the knowledge base (26) with information regarding whether the recommended repair procedure eliminated the defect.

Abstract: A modified printed wiring board for reducing the cracking of solder joints used to attach ceramic leadless chip carriers to the surface of the printed wiring board. A relatively thin expansion layer is provided on top of the conventional printed wiring board. This expansion layer is bonded to the printed wiring board except at locations underneath the footprint of the chip carrier and solder joints. This expansion layer reduces the stress on solder joints between the ceramic leadless chip carrier and the printed wiring board due to thermal expansion mismatch, to thereby reduce cracking of the solder joint. Prevention of bonding underneath the chip carrier footprint is provided by a thin layer of polytetrafluoroethylene (PTFE). Methods for applying ther PTFE layer are disclosed.