Abstract: A spaceborne synthetic aperture radar having pipeline multiple-look data processing makes use of excessive azimuth bandwidth in radar echo signals to produce multiple-look images. Time multiplexed single-look image lines from an azimuth correlator go through an energy analyzer which analyzes the mean energy in each separate look to determine the radar antenna electric boresight for use in generating the correct reference functions for the production of high quality SAR images. The multiplexed single look image lines also go through a registration delay to produce multiple-look images.

Abstract: A solar-powered fluidized bed gasification system for gasifying carbonaceous material. The system includes a solar gasifier (10) which is heated by fluidizing gas and steam. Energy to heat the gas and steam is supplied by a high heat capacity refractory honeycomb (16) which surrounds the fluid bed reactor zone (14). The high heat capacity refractory honeycomb (16) is heated by solar energy focused on the honeycomb (16) by solar concentrator (32) through solar window (20). The fluid bed reaction zone (14) is also heated directly and uniformly by thermal contact of the high heat capacity ceramic honeycomb (16) with the walls of the fluidized bed reactor (12).Provisions are also made for recovering and recycling catalysts used in the gasification process. Back-up furnace (50) is provided for start-up procedures and for supplying heat to the fluid bed reaction zone (14) when adequate supplies of solar energy are not available.

Abstract: A method and apparatus is disclosed for use of a linear frequency chirp in a transmitter/receiver (14/16) having a correlator to synthesize a narrow beamwidth pattern from otherwise broadbeam transducers when there is relative velocity between the transmitter/receiver (14/16) and the target. The chirp is so produced in a generator (20) in bandwidth, B, and time, T, as to produce a time-bandwidth product, TB, that is increased for a narrower angle. A replica of the chirp produced in a generator (26) is time delayed and Doppler shifted for use as a reference in receiver (16) for correlation of received chirps from targets. This reference is Doppler shifted to select targets preferentially, thereby to not only synthesize a narrow beam but also aim the beam in azimuth and elevation.

Abstract: A display device particularly suited for providing the pilot of an aircraft with combined inflight attitude, heading, altitude, and horizontal situation information previously available only by using two or three devices providing separate displays. The preferred embodiment of this invention combines a commonly used and commercially available flight director-type device for providing a display in combination with a miniature aircraft supported for angular displacement from a vertical orientation to indicate heading error, or heading offset, and an extended course deviation indicator bar which projects into juxtaposition with the miniature aircraft for providing a true picture of the aircraft's horizontal situation relative to a selected VOR, ILS, or MLS course.

Abstract: A microwave limb sounder (MLS) to measure trace gases in the upper atmosphere by comparing spectral noise content of limb soundings with the spectral noise content of cold space utilizes an offset Cassegrain antenna system and a tiltable input mirror to alternately look out at the limb and up at cold space at an elevation angle of about 22.degree.. The mirror can also be tilted to look at a black body calibration target. Reflection from the mirror is directed into a radiometer the head of which functions as a diplexer to combine the input radiation and a local oscillator (klystron) beam. The radiometer head is comprised of a Fabry-Perot resonator consisting of two Fabry-Perot cavities spaced a number of half wavelengths apart. Incoming radiation received on one side is reflected and rotated 90.degree. in polarization by the resonator so that it will be reflected by an input grid into a mixer, while the klystron beam received on the other side is also reflected and rotated 90.degree.

Abstract: An optical gyroscope is described of the type which passes light beams in opposite directions through a single mode fiber optic wave guide that extends in a circle or coil, and which enables measurement of rotation rate of the coil by measuring the relative phase shifts of the beams by interferometric techniques, wherein simplification and enhanced accuracy are obtained. Beam splitting and phase shifting of the light is facilitated by utilizing brief pulses of light and by using light-controlling devices which are operated for a brief time only when the light pulse passes in one direction through the device but not at a different time when the pulse is passing in the opposite direction through the device. High accuracy in rotation measurement is achieved at both very slow and very fast rotation rates, by alternately operating the system so that at zero rotation the interfering waves are alternately 90.degree. out of phase and in phase.

Abstract: In a delay-lock one-delta (.+-.1/2 chip) dithered PN code tracking loop, an indication of lock in the PN code tracking loop is provided by delaying the dithered local PN code by a half chip to produce a +0, -1 dithered PN code that is then multiplied with the received PN-spread IF signal to produce a signal proportional to the correlation of this dithered code offset from the received code. The correlation signal is bandpass filtered, amplified with AGC control, and square-law detected to obtain a DC signal proportional to the degree of correlation. The DC signal is multiplied by the dithering control signal to effectively subtract noise voltage from the lock correlation signal which is then compared with a PN lock status signal.

Abstract: A Schottky barrier solar cell consists of a thin substrate of low cost material with at least the top surface of the substrate being electrically conductive. A thin layer of heavily doped n-type polycrystalline germanium, with crystalline sizes in the submicron range, is deposited on the substrate. But first a passivation layer may be deposited on the substrate to prevent migration of impurities into the polycrystalline germanium on a substrate of low-cost conductive material. Then the polycrystalline germanium is recrystallized to increase the crystal sizes in the germanium layer to not less than 5 microns, and preferably considerably more. It serves as a base layer on which a thin layer of gallium arsenide is vapor-epitaxially grown to a selected thickness. Then, a thermally-grown oxide layer of a thickness of several tens of angstroms is formed on the gallium arsenide layer.

Abstract: A high resolution interferometer is provided which is insensitive to slight misalignment of its elements, avoids channeling in the spectrum, generates a maximum equal path fringe contrast, produces an even two-sided interferogram without critical matching of the wedge angles of the beamsplitter and compensator wedges, and is optically phase tunable. The interferometer includes a mirror along the path of each beam component produced by the beamsplitter, for reflecting the beam component from the beamsplitter to a corresponding retroreflector and for reflecting the beam returned by the retroreflector back to the beamsplitter. The fact that the mirror "covers" the retroreflector, so that the mirror reflects the beam component before and after it reaches the retroreflector, results in the system being insensitive to slight tilting of the mirror.

Abstract: A method and apparatus for combining baseband signals from a large aperture antenna array in which none of the individual baseband signals has a sufficiently high signal-to-noise ratio to be used as a correlation or reference signal for phase adjusting the remaining baseband signals. More specifically, the invention provides a means whereby the baseband output signals of all but one of the receivers associated with each of the antennas are summed and used as a correlation reference for the baseband signal not contained in the summed signal, thereby providing a plurality of correlation or alignment loops, each having an output signal related to the phase difference between its input baseband signal and the summed signal. The invention further provides a means for subtracting an output or error signal generated in one of the correlation loops whose baseband signal has a predetermined phase delay from all the other alignment loops, thereby avoiding interaction and reflection effects in the signal combiner.

Abstract: In a push-pull converter, switching transistors are protected from peak power stresses by a separate snubber circuit in parallel with each comprising a capacitor and an inductor in series, and a diode in parallel with the inductor. The diode is connected to conduct current of the same polarity as the base-emitter junction of the transistor so that energy stored in the capacitor while the transistor is switched off, to protect it against peak power stress, discharges through the inductor when the transistor is turned on, and after the capacitor is discharged the energy now stored in the inductor discharges through the diode. To return this energy to the power supply, or to utilize this energy in some external circuit, the inductor may be replaced by a transformer having its secondary winding connected to the power supply or to the external circuit.

Abstract: A saturable inductor switch for compressing the width and sharpening the rise time of high voltage pulses from a relatively slow rise time, high voltage generator to an electric discharge gas laser (EDGL). The switch also provides a capability for efficient energy transfer from a high impedance primary source to an intermediate low impedance laser discharge network. More specifically, a saturable inductor switch is positioned with respect to a capacitive storage device, such as a coaxial cable, so that when a charge build-up in the storage device reaches a predetermined level, saturation of the switch inductor releases or switches energy stored in the capacitive storage device to the EDGL. Also disclosed are cascaded saturable inductor switches for providing output pulses having rise times of less than ten nanoseconds as required for efficient excitation of EDGL's, the pulse rise time being determined by the thickness of a high permeability material forming the saturable inductor switch.

Abstract: An electronic filter comprised of three active filter sections (A, B, C) is provided to smooth the stepped signal from a digital-to-analog converter. The first section has a noninverting low-pass filter transfer function, and the second has an inverting transfer function designed to pass a narrow frequency band centered at the step frequency of the stepped output signal with sharp cutoff on either side of that narrow band. The third section adds the noninverted output of the first section to the inverted output of the second section. This third section has a lead-lag transfer function designed to reduce the phase angle between the signal at its output terminal and the stepped signal at the input of the first section.

Abstract: A bracket for an electrical servo actuator wherein said servo actuator (10) is mounted on a support arm (12) which is allowed to pivot on a bolt (14) through a fixed mounting bracket (16). The actuator is pivotally connected to the end of the support arm by a bolt (18) which has an extension (24) allowed to pass through a slot (26) in the fixed mounting bracket. An actuator rod (34) extends from the servo actuator to a crank arm (32) which turns a control shaft (36). A short linear thrust of the rod pivots the crank arm through about 90.degree. for full-on control with the rod contracted into the servo actuator, and full-off control when the rod is extended from the actuator. A spring (28) is connected at one end to the fixed mounting bracket and at the other end to the extension (24) of the bolt (18) connecting the actuator to the support arm.

Abstract: A high-speed multiplexing system of keyboard data inputs in which keyboard entered data is sequentially and automatically sampled by the multiplexing system for input to a computer. More specifically, a system is disclosed whereby a plurality of data inputs from a plurality of keyboards are applied to a multiplexer having a single output connected to a computer. A sequencer is provided which sequentially and automatically controls the multiplexer to sample each keyboard input in accordance with a predetermined sampling sequence. Whenever keyboard entered data appears on input lines to the multiplexer, the system inputs the keyboard data to the computer during a brief time interval in which the multiplexer remains at the particular keyboard address or port. Thus, a high-speed sampling circuit is provided whereby the only operator action required is data entry through a keyboard.

Abstract: An improved oven (10) for maintaining the junctions of a plurality of reference thermocouples at a common and contant temperature. The oven (10) is characterized by a cylindrical body (12) defining a heat sink having an axially extended cylindrical cavity (14), a singularized heating element comprising a unitary cylindrical heating element consisting of a resistence heating coil (20) wound about the surface of a metallic spool (18) having an axial bore (22) defined therein and seated in the cavity, an annular array of radially extended bores (30) defined in the cylindrical body (12) and a plurality of reference thermocouple junctions (32) seated in the bores in uniformly spaced relation with the heating element, and a temperature sensing device (28) seated in the axial bore for detecting temperature changes as they occur in the spool and circuit (46) for applying a voltage across the coil in response to detected drops in temperatures of the spool.

Abstract: A magnetic amplifier having two saturable reactor cores with a separate excitation winding on each connected in series opposition, a common control winding and a common output winding, is adapted for use as a low level signal transducer by exciting the separate excitation windings in push-pull mode through a center tapped transformer, and including at least one diode in series with a load resistor connected to the output winding. A resistor in series with the output winding and load resistor is connected between the center tap of the excitation transformer and the connection between the two excitation windings of the saturable cores. This series resistor provides a return current path for the output winding and allows the excitation windings of the saturable cores to operate as primary windings of transformers.

Abstract: A correlated quadruple sampling processor for improved signal-to-noise ratio in the output of a charge-coupled device (CCD) is comprised of: switching means for momentarily clamping a CCD signal line at a first reference level A before a CCD data pulse and then obtaining a first data sample B with respect to the reference A during a CCD data pulse, and storing the positive sample B-A; switching means for momentarily clamping the CCD signal line a second time at the level C during the presence of the CCD data pulse and then obtaining a second data sample D with respect to the reference level C after the CCD data pulse, and storing the negative sample D-C; and means for obtaining the difference between the stored samples +(B-A) and -(D-C), thus increasing the net signal amplitude by a factor of about 2 while the noise would be increased by only a factor of .sqroot.2 since there will be no correlation in the noise between the double samples +(B-A) and -(D-C) effectively added.

Abstract: A system is described for guiding a claw to the proper distance and into the proper orientation in yaw and pitch, to engage a grappling fixture. The system includes four proximity sensors on the claw, that are arranged at the corners of an imaginary square, which sense the distance to the top surface of the grappling fixture. If a pair of sensors at opposite corners of the square sense a different distance to the top surface of the grappling fixture, then it is known that the claw is rotated about a corresponding axis with respect to the plane of the grappling fixture.

Abstract: A multifrequency, broadband, dual-polarized corrugated conical horn antenna is simultaneously fed a multiplicity of signals, two for each of five frequencies, with each of a pair of signals fed in each of two orthogonal planes for excitation of a desired spherical hybrid mode (HE.sub.11). The lowest frequency is fed into the horn through orthogonal pairs of colinear slots, each pair being fed by coaxial tee power dividers. Other signals are fed through a circular waveguide connected to the vertex. Band reject cavities block the next higher frequency from passing through the low frequency feed slots. The highest frequency signals are fed through orthogonal ports near the far end of the circular waveguide. The intermediate frequency signals are fed through orthogonal ports spaced along the waveguide.