Abstract: A high-temperature (10 K) superconductive integrated circuit has a ground plane (2), an interlevel dielectric (6), and a low value resistor (18) to provide conductive paths to reduce parasitic circuit inductances, thereby increasing the speed and performance of the integrated circuit. The circuit also includes a high value resistor (20) connected between interconnect wires (34) to produce a desired resistance with a short distance between the interconnect wires (34), thereby significantly reducing the circuit area.

Abstract: A method for reducing smear in video images generated by a frame transfer CCD imaging system having an array of charge coupled devices. The video images comprise successive image frames, each frame including an array of image pixels corresponding to the array of charge coupled devices. The pixel array has a plurality of rows and columns. Each frame is temporally separated from a next successive frame by an integration time interval during which light falling upon the array of charge coupled devices is integrated to produce integrated charge samples representative of image frame pixel values, and by a transfer interval during which the charge samples are transferred from an imaging area to a storage area.

Abstract: A method and apparatus for monitoring the quality of a laser process such as a welding process comprises monitoring the light emitted from the weld plasma above the surface of the workpiece being irradiated by the laser beam. The size of the plasma is determined from the light emission and compared to a predetermined value of the size as determined under process and workpiece conditions that produce welds of acceptable quality. Variations of the monitored plasma size greater than a preselected value can represent unacceptable welds. Such variations can be caused by changes in the laser beam power, the workpiece speed, laser focusing problems, insufficient shield gas flow, workpiece deformation and weld contamination. The process monitors the light emission from a selected range of wavelengths that correspond to the major emission peaks of the light spectrum. The process enables in-process control.

Abstract: A process for designing and producing spacecraft more efficiently, without the excessive time, complexity and expense usually associated with spacecraft design. The process moves the design complexity usually associated with spacecraft design to payload modules whose designs are potentially reusable in other spacecraft missions. Each module is designed to be largely independent of a parent spacecraft structure, the design of which can be simplified to accommodate multiple modules that connect to the parent structure through a standardized backbone interface. Each module is designed for independent structural integrity, and to provide its own thermal management. Modules may also provide their own power regulation and, optionally, their own power storage and generation capabilities. Modules may also provide their own attitude control systems. Attachment of modules to the parent structure is simplified because of the modules' independence.

Abstract: A method that allows a space vehicle to determine navigation information represented by the contents of a state vector. The method includes the steps of intermittently receiving navigation signals, initializing the state vector with an estimate of the navigation information, and generating a predicted state vector that represents the predicted values for the navigation information after a predetermined time increment in the future. The method further determines whether a navigation signal has been received within a predetermined window of time from a navigation beacon. If a navigation signal has been received, the method updates the state vector and the contents of the state vector are propagated forward in time to provide an estimate of the navigation information after a predetermined time increment. In some instances, however, a navigation signal is not received within the predetermined window of time.

Abstract: A frequency selective medium that is adapted to receive an incident electromagnetic radiation at an angle of incidence of about 45.degree. has two arrays of conductive elements on opposite parallel surfaces (20, 22) of a dielectric substrate. In one embodiment, the conductive elements are cross-dipoles (6) each having a horizontal dipole (10) and a vertical dipole (8) of different lengths and widths. In another embodiment, the conductive elements comprise a plurality of conductive gridded rectangular loops (40). The frequency selective medium allows incident waves that are within a passband of transmit frequencies to transmit through the medium, and reflects waves at frequencies within a stopband adjacent the passband. In other embodiments, meanderline polarizers (28) are added to cross-dipole and gridded rectangular loop frequency selective media to circularly or dual-linearly polarize incident linearly polarized waves.

Abstract: A non-imaging laser-based tracking system for tracking the position of a targeted moving object. The tracking system includes two lasers: a reference laser and a slave laser. Each laser is a weapon, and when locked on a target, single laser effectiveness may be doubled without a thermal blooming performance loss associated with a single laser operating at twice the power. The slave laser beam is dithered relative to the reference laser beam in a direction along the longitudinal axis of the target. The system includes an optical receiver for repetitively scanning the irradiance profile reflected by the target. Since the slave laser beam is dithered relative to the reference laser beam, both laser beams will jitter and drift together providing a gain factor of two in average irradiance on the moving target.

Abstract: A pair of serially connected electrically operated computer controlled gas valves combine with a pressure sensor to output pressure regulated low pressure gas dispensed from a high pressure gas source and define a pressure regulation system of relatively simple construction, great versatility and of heretofore unknown flexibility, well suited to remote control. The computer controlled valve controller selectively operates the valves in any and all of three operational modes, including the familiar Bang-Bang mode in which both valves operate simultaneously, a Bang-Wait mode in which both valves operate simultaneously for a precise time interval and thereafter close while the outlet gas pressure is checked, and a newly defined Burp mode. In the novel Burp mode, the valve closest to the high pressure gas source is first opened and closed to admit and capture a small volume of gas within inter-valve piping. Thereafter only the outlet valve is opened and closed to release that small volume of captured gas.

Abstract: A relatively narrow fractional bandwidth saw filter formed on a standard ST cut of quartz. The electrode pattern is modified in order to eliminate distortion. In particular, the overlap pattern is formed with one or less active overlaps per wavelength in those regions of the SAW filter where the weighing function is maximum. A plurality of six finger/.lambda. electrode patterns with two active overlaps per wavelength is also provided.

Abstract: The present invention provides a modeforming circuit (100). The modeforming circuit (100) includes a first matrix circuit (102) comprising an interconnected network of transmission lines (208-212) and phase shifters (216-218) that implement at least one N/2.times.N/2 identity matrix and at least one N/2.times.N/2 phase shift matrix. The first matrix circuit (102) is connected in series to a second matrix circuit (104). The second matrix circuit (104) includes an interconnected network of phase shifters that implements at least one N/2.times.N/2 phase shift matrix. The modeforming circuit (100) may further include a third matrix circuit (106) connected in series with the second matrix circuit (104). The third matrix circuit (106) includes a network of transmission lines (220-230) that reorder N inputs to N mode outputs. The first matrix circuit (102) may be implemented as a first matrix sub-circuit (108) connected in series with a second matrix sub-circuit (110) to provide even further reduced complexity.

Abstract: An autonomous control system supports autonomous operation of the a spacecraft in carrying out mission objective commands. The control system also provides autonomous fault detection, isolation and recovery. Performance problems and anomalies are detected and accounted for in the carrying out mission objectives. A mission manager module analyzes all incoming mission objective commands to verify that sufficient system resources are available and not already dedicated to other pending mission objective commands. A command processor is included to translate acceptable mission objective commands into lower level command sequences for delivery to a flight manager controlling the underlying spacecraft systems. The mission manager reanalyzes all pending mission objective commands whenever unexpected performance or fault conditions are detected. The mission objective commands can be constructed in a hierarchical fashion, with many sequences predefined within the spacecraft.

Abstract: A frequency selective surface filter (20 or 50) particularly useful in connection with a transmit antenna (10) for passing and rejecting signals in multiple frequency bands. According to one embodiment, the frequency selective surface filter (20) has a single conductive screen (24) disposed on a dielectric medium (22). The single-conductive screen (24) includes an array of parallel intersecting lines (26) and (28) providing low frequency filtering. The single-conductive screen (24) also includes an array of double-loop conductive elements each made up of an inner conductive loop (32) and an outer conductive loop (30). According to a second embodiment, the frequency selective surface filter (50) contains two dielectrically separated conductive layers including a first conductive layer (52) having an array of double-slots made up of an inner slot (64) and an outer slot (66). The double-slot configuration further includes a second conductive layer (60) made up of an array of single conductive loops (62).

Abstract: There is provided an optically pumped laser apparatus 10 which includes a heat conductive assembly 14 which is affixed to a solidstate yag laser crystal medium for generating a laser beam 49 within the laser crystal medium 12. The heat conductive assembly 14 comprises a heat diffusing element 32 which serves to diffuse the heat that is generated through the cooling surfaces 24 and 26. It includes a heat discharging structure 33 for removing the heat from the system. The efficiency of the laser system is improved by the geometry of pumping the crystal laser medium along the paths shown by the arrow 40 and to directing heat removed by the heat conductive assembly along the arrows 42, which paths are normal to one another and which provide an effective geometry that minimizes temperature variations within the laser crystal 12 to provide a low value for the OPD of the system.

Abstract: The system and method are set forth for photoacoustical analysis of isotope and other compounds having telltale absorption wavelenghths between 1700-2500 nm. The system and method includes a Co:Mg F.sub.2, optical parametric oscillator (OPO) or diode laser tunable between 1700-2500 nm which is directed into a sample at energies sufficient to generate detectable acoustical emissions. A microphone detects the emissions for processing and analysis. The system and method is adapted to detect stable isotope compounds such as .sup.13 CO.sub.2 as well as other chemical compounds. For non-gaseous compounds, a CO.sub.2 or diode laser is used to photoablate the gaseous sample containing the suspected compound.

Abstract: A method and apparatus for noninvasively measuring blood glucose levels provides an indirect, reagentless, differential, photoacoustic technique which responds to absorption in a thin surface layer. An excitation source provides electromagnetic energy which is utilized to irradiate the tissue, such as skin. The output of the radiation of the excitation source at the desired wavelength is coupled through a transmission device, such as a fiber optic bundle, which irradiates the electromagnetic energy onto the body surface. Upon irradiation, acoustic energy is generated by the absorption of the electromagnetic energy in a relatively thin layer of the sample to be measured, characterized by a heat-diffusing length. The acoustic energy is detected by the probe which includes a measuring cell, reference cell, window and differential microphone. Absorption of the light beam results in periodic heating of the tissue, at and near the tissue surface.

Abstract: A correlated superconductor single flux quantum oscillator-counter analog-to-digital (A/D) converter has a superconducting quantum interference device (SQUID) quantizer 20 with two Josephson junctions 24 and 26, each connected to a digital sampling and counting circuit with synchronized timing to increase the sampling rate or the bit resolution of the A/D converter. In a preferred embodiment, a plurality of SQUID quantizers 60 . . . 72 each with two Josephson junctions 74 . . . 88 are connected to a counter structure with precisely synchronized timing to further increase the sampling frequency and/or the bit resolution. A counter structure preferably comprises multiple rows 218, 240, 254 of single flux quantum flip-flops 220 . . . 234, 242 . . . 248, 256, 258 and parallel-serial converter/shift registers 236 250, 260 to produce an output digital data stream in serial form.

Abstract: A rotating mirror drum radiometer imaging apparatus. The apparatus generally comprises a two-sided mirror, a drum for securely supporting the two-sided mirror therein at an angle of preferably about 45 degrees relative to a longitudinal axis of symmetry extending through the drum, support walls for supporting the drum for rotational movement, and a motor and drive wheel for rotationally driving the drum. In one embodiment the drum includes first and second cut-outs in a side surface thereof. The cut-outs are further spaced preferably about 180 degrees from each other about the longitudinal axis of symmetry and enable a transmitted signal to be alternately received therethrough by first and second sides of the two-sided mirror as the drum and mirror are concurrently rotated by the motor and drive wheel. A first antenna is disposed adjacent a first end of the drum and a second antenna is disposed adjacent a second end of the drum.

Abstract: A high contrast imaging system (10) having an adaptive focal plane (52). The system (10) includes receiver optics (32) that receive radiation (30) from both a detected target (16) and a laser beam (14) incident thereon, and a polarizing beam splitter (44) that splits the radiation into a first beam of reflected laser radiation and a second beam of radiation (46). The polarizing beam splitter (44) linearly polarizes the second beam of detected target radiation (46). A beam polarizer (48) circularly polarizes the second beam of detected target radiation (46). An adaptive focal plane or micromirror array (52) reflects the circularly polarized detected target radiation back through the beam polarizer (48) to linearly polarize the reflected, second beam of radiation (46). A detector array (56) detects the reflected, second beam of radiation (62) and outputs a signal to tracker electronics (22) in accordance with the intensity of radiation.

Abstract: A digital audio radio system that employs transmitting multiple time-separated versions or legs of the same or substantially the same source signal to accommodate signal blockage problems while using no or little additional bit data rate. In one embodiment, a first leg transmits only right channel data and a second leg transmits only left channel data when no blockage occurs, the two legs can be combined to provide a complete signal and perfect reception. If one of the legs is blocked, then a cloning technique is used to clone the existing channel as the non-existing channel to provide either a combination of two right channels or two left channels. In another embodiment, a first leg transmits a sequence of the even frames including both right and left channel data and leaves the odd frames blank, and a second leg transmits a sequence of the odd frames including both the right and left channel data and leaves the even frames blank.

Abstract: A high-speed receiver is disclosed for gathering data from an information signal carried on a superconducting transmission line. The high-speed receiver includes triggers that carry trigger pulses, and a plurality of superconducting sensors magnetically coupled to the transmission line. The sensors respond to the trigger pulses by capturing data from the information signal. The sensors may operate in a variety of capacities, including comparators, A to D converters, and logic functions.