Abstract: A low profile, compact microstrip-to-waveguide or stripline-to-waveguide transition. The end of the waveguide is terminated in a cavity backed slot defined in a groundplane formed on a dielectric substrate. The slot is excited by a microstrip or stripline conductor defined on the opposite side of the substrate. The conductor is terminated in a T-shaped junction including two opposed arms extending along the slot, each having a length equal to one-quarter wavelength at the center frequency of operation. A cavity covers the substrate on the conductor side, and is sized so that no cavity modes resonate in the frequency band of operation. The transition is matched by appropriate selection of the length of the slot and the length and position of the microstrip.

Abstract: An optical device comprising a glass prism that functions as a 180.degree. fold prism and a quarter-wave retarder. The optical device comprises a 180.degree. folding glass prism having first and second total internal reflecting surfaces that provides a 90.degree. phase shift of laser energy at a plurality of wavelengths propagating therethrough. The composition of the glass prism is selected so that its refractive index provides a 45.degree. shift at each of first and second total internal reflecting surfaces. Dispersion in the glass is chosen to be small enough so that the phase shift of the energy propagating therethrough is relatively insensitive to wavelength. Consequently, the prism also functions as a quarter-wave retarder at the plurality of wavelengths.

Abstract: A method to organize, store and retrieve information in a database to facilitate rapid object identification. An interval set is defined as an interval on a number line. The database is built from a list of interval sets as input sets. The method organizes the interval sets such that a binary search may be used to quickly locate all interval sets of which a value is a member, i.e., given a value, all sets that contain the element value are quickly identified. The solution sets are pre-stored or sorted on-the-fly into bins. Bins are created by superimposing all interval set boundaries onto one number line. Two successive boundaries on the number line constitute a bin. All sets which share the interval expressed by a bin are named within a bin. A binary search technique is used to search the bins, given a value, to locate an output set of the intervals which share the value. The method can be nested to accommodate any number of parameters, and can be modified to balance memory versus CPU resource utilization.

Abstract: A precision direction finding system for making precision angle of arrival estimates for a signal received through two antenna elements separated in space. Phase interferometry is used to determine a precise angle of arrival, with multiple ambiguities due to the periodic nature of the phase difference related to geometric angle. The interferometric ambiguities are resolved using the time difference of arrival (TDOA) of the signal at the two antenna elements. TDOA is measured using leading edge envelope detection for simple pulsed signals, and predetection correlation for phase and frequency modulated signals.

Abstract: An improved broad band "Y" junction isolator/circulator at V-Band is disclosed. A "star"-shaped ferrite structure is positioned in the isolator housing. The ferrite structure comprises two triangular-shaped ferrite members positioned 180.degree. from each other and bonded together.

Abstract: A phase shifter employing a voltage variable dielectric material to add controlled phase delay in a ridged-waveguide section. The dielectric material has the property that its dielectric constant varies with changing electric field applied to the material. The dielectric material fills the ridge gap between the two waveguide ridges. An electrode is disposed within the dielectric material, and is connected to a variable voltage source to establish a transverse electrical field within the dielectric material. By varying the voltage, the magnitude of the field is varied, thereby allowing the phase delay of electromagnetic signals propagating through the waveguide section to be changed.

Abstract: A low profile, compact microstrip-to-waveguide transition which utilizes electromagnetic coupling instead of direct coupling. The end of the waveguide is terminated in a cavity backed slot defined in a groundplane formed on a dielectric substrate. The slot is excited by a microstrip line defined on the opposite side of the substrate, offset from the slot centerline. A cavity covers the substrate on the microstrip side, and is sized so that no cavity modes resonate in the frequency band of operation. The transition is matched by appropriate selection of the length of the slot and the length and position of the microstrip.

Abstract: A laser system includes a laser resonator cavity having a resonant path and an Er,Yb:glass lasing element with an output of from about 1.5 to about 1.6 micrometers within the laser resonator cavity. A diode array optically pumps the lasing element to emit light. A Q-switch lies along the resonant path within the laser resonator cavity. The Q-switch is formed of a host material having a concentration of uranium ions therein, so as to be a saturable absorber of the light emitted by the lasing element. The Q-switch is preferably a uranium-doped fluoride such as U:CaF.sub.2, U:SrF.sub.2, or U:BaF.sub.2.

Abstract: A near field planar wavefront generation method that uses a relatively small number (three to five) of transmitting antennas disposed a predetermined distance from an antenna array having a multi-wavelength aperture that is part of a system under test. The method creates a synthesized one-dimensional linear planar wavefront of radiation over at least ten wavelengths for testing the antenna array of the system under test. The planar wavefront is formed at a specific frequency and at predetermined distance from the transmitting antennas, typically in the range of from 100 to 200 feet. The transmitting antennas synthesize a plane wave with linear phase progression to simulate tilt variations. To achieve this, electromagnetic energy signals emitted by the respective transmitting antennas are amplitude and phase weighted to synthesize the one dimensional linear plane wave to produce a combined wavefront having a linear phase front across the aperture of the antenna array of the system under test.

Abstract: A liquid crystal display comprising a four-layer holographic filter that projects up to 100 percent of incident white light while providing improved color purity. The four-layer holographic filter processes normal incidence collimated white light derived from a projector and focuses red, green, and blue components of the collimated white light into separate spatial locations of a liquid crystal layer. The four-layer holographic filter includes a large spectral bandwidth volume transmission grating layer that diffracts incident collimated white light off-axis, followed by an off-axis holographic color filter comprising three separate hologram layers that include an array of off-axis volume transmission hologram lenslets designed to diffract the respective blue, green and red components of the off-axis white light back on axis and focus them onto locations of blue, green and red pixels, respectively, of the liquid crystal display layer.

Abstract: A nonuniformity correction processor (30) adapted for use with a focal plane array of detectors. The inventive processor (30) includes a nonuniformity correction circuit (32, 38, 42, 53, 54, 56, 58) for generating current nonuniformity correction terms (32) and applying the terms to information (26) received from the scene via the focal plane array of detectors. A triggering circuit (44) selectively enables the nonuniformity correction circuit (32, 38, 42, 53, 54, 56, 58) in response to a motion signal (50) from a motion detector (40, 46, 48, 52). In a specific embodiment, the nonuniformity correction circuit (32, 38, 42, 53, 54, 56, 58) further includes a filtering circuit (38) for generating intermediate nonuniformity correction terms (42, 53) in response to the scene information (26) received from the focal plane array of detectors.

Abstract: A support and adjustment system includes a supported structure, a support base, three supports extending between the supported structure and the support base. Each support includes a hinge pin fixed to the supported structure, a leg, a hinge swivel dimensioned to engage the hinge pin at the first end of the leg, and a spherical ball at the second end of the leg. A socket member includes a first end having a socket dimensioned to receive the spherical ball therein and further includes a second end. The second end of the socket member is adjustably supported from the support base.

Abstract: A method is provided for removing metal oxide debris from various types of surfaces, both metallic and nonmetallic. Specifically, the surface to be cleaned is treated (preferably by immersion) with a preheated solution of 65 to 71 wt % (55.3 to 62.0 vol %) nitric acid, which is roughly equivalent to reagent grade nitric acid. The temperature of the solution is within the range of about 160.degree. to 175.degree. F. (71.degree. to 79.degree. C.). The preheated solution dissolves any metal oxide debris present on the surface, which may then be rinsed away following treatment. The method effects the removal of metal oxide residue from surfaces without further degrading the surfaces being cleaned. Further, the method is capable of cleaning internal surfaces of components without requiring disassembly of sealed or welded components, since all that is needed to effect cleaning is contact between the surface to be cleaned and the preheated solution.

Abstract: An optical fiber having a conductive layer disposed therearound has sections removed therefrom that form gaps that expose the underlying optical fiber. Light manifolds are formed at each gap, such as are provided by Bragg gratings photoinduced in the core at each gap, and photoconductive material is disposed at each of the gaps. An opaque coating may optionally be disposed over the outside of the photoconductive material to ensure that it is activated by light propagating within the optical fiber. Light transmitted down the fiber may be controllably coupled output of the fiber at each of the gaps. The optical fiber thus provides multiple functions including electrical conductor, light manifold, and substrate on which the photoconductive material is deposited.

Abstract: An apparatus and method for translating a spacecraft (102, 108) from an injection orbit (114) about a central body (100) to synchronous orbit (122) in a time efficient manner. The spacecraft (102, 108) includes propulsion thrusters (50) which are fired in predetermined timing sequences controlled by a controller (64) in relation to the apogee (118) and perigee (120) of the injection orbit (114) and successive transfer orbits (114). During transfer orbit, the spacecraft's inertial attitude is adjusted to track sun movement. The spacecraft is injected into a particular injection orbit that offsets moments created by tracking sun movement to maintain stable transfer orbits.

Abstract: The composition of an electrically conductive mixture, preferably a mixture of gasoline and alcohol, is measured using a single measurement cell having a first electrode and a second electrode with a measurement space therebetween for receiving a specimen of the mixture. With a specimen of the mixture in the measurement space, the first electrode is alternatively connected to a reference discharge voltage, preferably ground, and to a feedback control voltage. A first operational state encompasses the period when the first electrode is connected to the reference discharge voltage and a second operational state encompasses the period when the first electrode is connected to the feedback control voltage. A first operational state peak voltage is measured during the first operational state, and a peak second operational state voltage is measured during the second operational state.

Abstract: A system (10) for providing ephemeris data of a medium to high orbit satellite (12) relative to the Earth (30), where the satellite (12) is in an orbit substantially greater than 20,000 kilometers. The inventive system (10) includes plural transmitters (14, 16, 18, 20, 22, and 24) located within 20,000 kilometers of the Earth for transmitting information relating to the ephemeris of each transmitter relative to the Earth and time. This information is received and processed onboard the satellite (12) to provide ephemeris data. In a specific implementation, the transmitters (14, 16, 18, 20, 22, and 24) are GPS transmitters. One or more of the transmitters may be a ground or air based pseudolite. The transmitters have a geometric dilution of precision of six or less. Each pseuodlite transmitter includes a power supply sufficient to ensure that the signal received by the medium to high orbit satellite is of sufficient signal strength (e.g., -170 dBw to -160 dBw).

Abstract: A four-port transmission line device that processes two incoming RF signals of arbitrary phase and amplitude to output two corresponding RF signals of equal phase and amplitude. Two sets each of two quarter-wave transmission line segments are connected in series between corresponding input and output ports. A short circuit interconnect shorts together the junctions of the two series connected line segments. A resistive element is connected across the two input ports, and another resistive element is connected across the two output ports. The short circuit interconnection forces the combination of the two input signals into one resultant signal at the short circuited junction. Out-of-phase components of the resultant signal are absorbed in the resistor across the input ports. The remaining in-phase components are divided into two outputs signals of equal phase and amplitude.

Abstract: A monolithically integrated solar cell microarray includes an isolation layer or multiple isolation layers between a substrate and a solar cell layer, and a trench in the solar cell layer that exposes the isolation layer. Together the isolation layer and trench define solar cells that are spaced apart and electrically isolated on the monolithic substrate. The solar cells are scaled to provide a desired current. Base contacts and integral emitter contact/interconnects connect a number of the scaled solar cells in series to sum their voltages to supply a desired output voltage and current. The trench and integral emitter contact/interconnects are formed using photolithographic etching and liftoff processes, respectively, which are much quicker and less expensive than the conventional dicing and soldering processes.

Abstract: A boundary scan test circuit that includes Y scan flip-flops serially connected in a sequence from a first scan flip-flop to a Y.sup.th scan flip-flop and clocked with a system clock signal, and circuitry for providing scan input data to the first scan flip-flop synchronously with a test clock signal and for receiving scan output data from the Y.sup.th scan flip-flop synchronously with the test clock signal, wherein the test clock signal and the system clock signal have a test clock period to system clock period ratio that is equal to any fixed integer ratio M.