Abstract: Systems and methods for transferring very large data files to a remote location. The systems and methods fragment the very large data file into smaller ordered blocks using file conversion software loaded onto a computer processor. The ordered fragmented files or blocks transmitted to the remote location using a data distribution system. For example, the data distribution system may include a transmitter, a satellite transmission link, and a receiver at each remote location. At each remote location, received ordered fragmented files or blocks are reassembled in accordance with the original ordering scheme using file conversion software loaded on a computer. This produces the original very large data file. Once the very large data file is reassembled, it may be processed or archived.

Abstract: A dual polarized horn antenna that increases the efficiency of a square or rectangular aperture which may be used in situations where a high efficiency aperture is needed in a constrained space. The antenna has a body that is tapered from a first end to a second end, wherein the first end is smaller in cross section than the second end. A flange is formed around the periphery of the body adjacent to the first end. An opening is formed in the first end of the body. A tuning iris is preferably disposed in the opening that provides for impedance matching. An insert is disposed in the central tapered opening 16 adjacent to the second end that has a central cross-shaped tapered member. The central cross-shaped tapered member extends into the central tapered opening and forms a plurality waveguide passages that form a corresponding plurality of quadrants. A plurality of cross-shaped members are respectively disposed in the quadrants and extend a short distance into the central tapered opening.

Abstract: An injection molded phased array antenna system such as may advantageously employed on satellites. The antenna system comprises a plurality of metal plated, injection molded plastic horn radiating elements respectively coupled to a plurality of metal plated, injection molded plastic orthomode junctions that produce a corresponding plurality of vertically and horizontally polarized outputs. A metal plated, injection molded plastic vertical and horizontal beamforming networks is coupled to outputs of the plurality of orthomode junctions that establish unique phases and amplitudes that produce two separate outputs associated with two independent beams.

Abstract: Variable beamwidth antenna systems for use on spacecraft that is capable of changing their beamwidths while the spacecraft in on orbit. The variable beamwidth antenna systems include a main reflector, a subreflector, a feed horn, a main reflector displacement mechanism and a feed horn (or subreflector) displacement mechanism. For broaden the beamwidth, the RF feed horn and the subreflector are moved close together by proper distance. The main reflector is moved away from the subreflector along a line through centers of their respective surface by a distance given by a predetermined equation.

Abstract: A support system employing a load equalizing floating platform. The support system comprises four jacks 30 including opposed pairs of jacks for coupling to four respective supports. Each jack has a support rod with upper and lower pressure plates attached thereto that are disposed in a cavity to form first, second, third and fourth pressure chambers. Each of the first pressure chambers of all jacks are coupled together. Also, the respective second pressure chambers of jacks are coupled to the opposite jack third pressure chambers. Each of the fourth pressure chambers of all jacks are coupled together. The load equalizing floating platforms equalizes support forces and prevents rotation of the support system due to overturning moments at all support points. The system eliminates stresses and deformations in structures due to unequal support movement.

Abstract: A high resolution, high speed digital camera that produces a high resolution image representative of an image scene viewed by the camera. The digital camera comprises an input lens system and an iris that couple light from the image scene into the camera. A first imager generates a sequence of high resolution, low speed digital frames of the image scene. A second imager generates a sequence of low resolution, high speed digital frames of the image scene.

Abstract: A delay element and method for delaying an RF/microwave signal. The delay element uses a laser and an RF modulator to modulate a laser beam using an applied RF/microwave input signal. Collimating optics collimate the modulated laser beam and couple the beam to a delay element that controllably delays the modulated laser beam and hence the RF/microwave signal. The delay element has fixed retroreflectors, moveable retroreflectors disposed on a moveable armature or permanent magnet, and a coil disposed on a spring and coupled to the moveable armature. The beam is reflected multiple times between the fixed and multiple moveable retroreflectors. A dash pot may be used to suppress mechanical oscillation of the permanent magnet and moveable retroreflectors. A delay control current source supplies current to the coil to control movement of the moveable retroreflectors and thus the path length and delay experienced by the modulated laser beam.

Abstract: A broadband linearizer for use with a power amplifier. The broadband linearizer includes a preamplifier, a postamplifier and a broadband linearizer bridge coupled between the preamplifier and postamplifier. The linearizer bridge comprises a power divider for coupling power to linear and nonlinear arms, and a power combiner for combining outputs of the linear and nonlinear arms. The linear arm includes a first equalizer and a delay line, and the nonlinear arm includes a distortion generator and an attenuator. A second equalizer is coupled between the power combiner and the postamplifier. A control circuit controls settings of the preamplifier, the broadband linearizer bridge, and the postamplifier. The control circuit outputs voltage bias and constant current signals to control operation of the broadband linearizer.

Abstract: A method of simulating the appearance of smoke in an electronically generated video image that uses one or more intersecting opaque spheres. Each sphere has a nonuniform smoke density that produces feathered edges. The smoke sphere is an object modeled as a center point (the coordinates of the center of the sphere in three dimensions), a radius (in database coordinates), and a set of parameters that include density and color. The center point is transformed into display screen coordinates, and the radius is transformed into a screen coordinate length. The sphere is projected into a circle in screen coordinates, and a bounding square is generated in screen coordinates that is centered at the sphere center point. The bounding square is then converted into a transparency having color and density attributes added to its data structure. Thus the bounding square has the same data structure as transparent or opaque objects and is processed in the same manner.

Abstract: A mobile space lift range system using a ground control station and an unmanned airborne vehicle that relayed data to and from a space lift vehicle to control it. The unmanned airborne vehicle may selectively include one or more sensor systems, a radar system, a command and telemetry system, and a user test system. The unmanned airborne vehicle is a high attitude, long endurance vehicle that provides a flexible, mobile range to support launch-anywhere space lift scenarios.

Abstract: Apparatus and methods for compressing an audio signal. An analog to digital converter is used to digitize the audio signal. A linear predictor processes the digitized audio signal to attenuate coherent noise and produce a residual output signal that is representative of the audio signal. An improved synchronized overlap add processor employs a one bit correlator and a smoothly-shaped window compresses the digitized audio signal. The synchronized-overlap-add processing may be used with voice or audio processing systems to change the time scale of the voice (audio) signal without changing the pitch of the processed signal. The synchronized-overlap-add processing may also be used to reduce noise in the processed signal. The present synchronized-overlap-add processing technique makes the computations required very quick, improving the utility of the processing.

Abstract: Zero voltage switching isolated boost converters that provide high efficiency power conversion between input and output DC voltages. The boost converters includes a voltage amplifying stage including first and second switching transistors, an input coupled inductor, and an output transformer. The voltage amplifying stage amplifies the DC input voltage which is transformed by the output transformer to produce the DC output voltage. A zero voltage control input circuit is coupled to gates of the switching transistors and to the output of the voltage amplifying stage. The input circuit generates synchronization signals that synchronize rising edges of gate drive signals applied to the switching transistors with a resonant circuit. This is achieved by observing the state of gate and drain voltages of the switching transistors and detecting the moment when both drains are low, and both gates are not high.

Abstract: Methods that provide stationkeeping maneuvering of a yaw steered spacecraft that orbits around a central body, such as the Earth, and experiences solar radiation pressure produced by the sun. The methods comprise the following steps. A spacecraft having a solar array is launched into orbit at a desired orbital location. Once the spacecraft is in orbit at the desired orbital location, a reflected component of the solar radiation pressure is caused to selectively apply a force to the spacecraft that moves the spacecraft to perform stationkeeping maneuvers. The reflected component of the solar radiation pressure may be caused to selectively apply a force to the spacecraft in two exemplary ways. In one embodiment, the spacecraft is yaw steered to follow a yaw steering profile so that the axis of the solar array is substantially normal to a plane containing the sun vector and nadir vector.

Abstract: Systems and methods for integrating a telephone internal access return link with an upstream data carrier using a fiber optic network and downstream data transfer using a cable TV system. The systems and methods provide for a cost effective implementation of a data over cable TV system using the cable system for downstream data transfer and a telephone modem for upstream data transfer. The telephone return path is terminated at a neighborhood node or optical network interface of the cable TV system. The optical network interface combines, modulates, and multiplexes the upstream data onto an upstream fiber carrier. At the cable headend, the carrier is demultiplexed, demodulated, and the data is forwarded to a remote access server of an Internet service provider.

Abstract: A battery charging system that may advantageously be used to directly charge a battery of a spacecraft, for example. The battery charging system permits charging of the battery without the use of power conditioners or dedicated charging arrays. Primary and secondary solar array strings are coupled by way of a shunt regulator circuit to a power bus, such as a power bus of the spacecraft. A shunt regulator circuit is coupled to the secondary solar array string and to the power bus. Charge control relays are coupled between the secondary solar array string and the battery. A computer is coupled to the shunt regulator circuit and to the charge control relays. Current from the secondary solar array string is used to charge the battery when the charge control relays are closed. If the computer determines that the battery is fully charged, the charge control relays are commanded open and current flows to the power bus unless shunted by the shunt regulator circuit.

Abstract: A combining technique for coherently combining signals transmitted from a moving satellite that are received by separate antennas. The combining technique corrects for differential delays that are large enough to cause misalignments in the symbols of the communication signal as well as the phase of the signal. Further the combining technique tracks changes in the differential delay, keeping the phase and the symbols properly aligned for combining.

Abstract: Improved active multiple beam antennas that comprise an amplifier array or grid amplifier having substantially identical amplifiers. A feed array having a plurality of antenna elements provides RF energy. A microwave lens is disposed adjacent to the feed array that weakly focuses the RF energy from the feed array. The amplifier array or grid amplifier is disposed opposite the microwave lens from the feed array. The feed array illuminates the amplifier array or grid amplifier via the microwave lens. The weakly focused RF signals are amplified without changing their respective directions of propagation, which forms powerful multiple beams in the far field.

Abstract: Delay systems that employ switched discrete delay elements and continuously variable controlled delay elements to achieve a continuous (glitchless) delay range. The delay systems incorporate several technologies and subsystems to realize very high bandwidth-time product delay elements to provide for precise and continuous delay control.

Abstract: An automatic apparatus and method that is used to switch actuators, such as momentum wheels, used on a spacecraft without impacting the pointing performance of the spacecraft. The apparatus and method allows an actuator to be automatically deactivated without affecting spacecraft performance such as is caused by a failed actuator. A plurality of local actuator controllers are respectively coupled to a plurality of actuators. A system controller is coupled to the plurality of local controllers and implements a control algorithm corresponding to the present method that determines forces/torques for each of the actuators and outputs force/torque commands to each of the actuators to control the pointing direction of the spacecraft. This is achieved by estimating the drag exerted by or integral control signal produced by each actuator to determine if it is approaching failure.

Abstract: A transversal filter equalizer comprising a programmable transmitter baseband equalizer for use in high rate digital transmitters. The programmable transmitter baseband equalizer processes digital data using a 1/2-symbol spaced transversal filter to produce I and Q baseband signals. The 1/2-symbol spaced transversal filter comprises I and Q n-bit wide shift register stages having alternate pairs of I and Q shift register stages driven by opposite phases of an input data clock, multiplying digital-to-analog converters driven by two direct tap weights and two cross tap weights, and I and Q combiners for generating I and Q baseband signals. The I and Q baseband signals are fed to a quadrature modulator that produces the desired constellation.