Abstract: Thermal apparatus that reduces passive intermodulation products generated on a satellite or other spaceborne vehicle. Exemplary passive intermodulation free thermal blankets comprise a reflector stack including multiple polyimide layers with metallized film on one side thereof, a binding layer that secures the reflector stack together, and an outer cover layer that wraps around the binding layer and reflector stack to cover an outer surface of the thermal blanket and form a hem on an inner surface of the thermal blanket. Multiple small thermal blankets or patches may be bound together using grounding inserts and polyimide tape to form a quilt-like assembly. The quilt-like assembly is enclosed by an outer cover layer that wraps around the multiple patches to cover one surface thereof and form a hem on an opposite surface thereof.

Abstract: A passband transversal equalizer that uses a novel partitioning of circuits to improve the dynamic range and minimize unwanted signal interactions. The passband transversal equalizer uses a novel interconnection matrix and may be implemented using GaAs monolithic microwave integrated circuit (MMIC) devices for improved performance. The passband transversal equalizer comprises a divider that splits an input signal along a predetermined number of signal paths. Coaxial delay lines delay the signals propagating along the respective signal paths by a first set of nominal relative delays. A plurality of active divider having push-pull outputs are respectively coupled to the coaxial delay lines. An interconnection matrix respectively couples outputs of the active divider to one of a plurality of complex weighting and combiner circuits. A second plurality of coaxial delay lines delay the signals output by the complex weighting and combiner circuits by a second set of nominal relative delays.

Abstract: Multi-directional (reversible and parallel) loop heat pipe thermal systems for use on a spacecraft. The multi-directional loop heat pipe thermal systems may comprise reversible or parallel loop heat pipes that provide efficient thermal pathways that are directionally independent between any combination of equipment mounting panels and radiator panels. Loop heat pipes of the reversible loop heat pipe thermal system are coupled between opposite ends of respective evaporator/condenser flanges. The evaporator/condenser flanges each comprise a condenser and an evaporator. The parallel loop heat pipe thermal system comprises pairs or sets of parallel heat pipes that are respectively coupled between a condenser flange and an evaporator flange. The reversible or parallel loop heat pipes may be routed to a multiple number of radiator panels in order to optimize the use of a radiator panel by always transporting heat to the coolest radiator panel.

Abstract: An autocalibrating modulating array transmitter 10 and autocalibration method 30. The autocalibrating modulating array transmitter is used to gain-balance and phase-balance parallel amplifier stages 11 for coherent combining. The novelty of the autocalibration technique involves periodic substitution of calibration symbols into a valid data stream, the use of only the error magnitude (as opposed to magnitude and phase), and a random selection of either gain or phase adjustments to avoid limit cycles.

Abstract: Systems and methods that increase the data transmission rate through a given length of optical fiber, or increase the distortion-limited distance for an optical fiber link at a given data rate using band efficient modulation. This is achieved by modulating data for transmission onto a carrier signal. The modulated signal is predistorted and an optical carrier is amplitude modulated using the predistorted signal. The amplitude modulated optical carrier is transmitted over the optical fiber link. The original modulated microwave signal is reproduced at a receiver. The original signal is demodulated to generate the originally transmitted data. In addition, to reduce the bandwidth required by the modulated carrier, it may be single-sideband modulated. By increasing the number of bits per symbol and keeping the symbol rate constant, the data rate for a given length of optical fiber may be increased using the present invention without introducing additional distortion in the fiber.

Abstract: A filter that produces a multiple passband response as a single device. The multiple passband filter has a plurality of poles concentrated in a desired passband of the filter. A plurality of zeroes are located outside of the desired passband to form passband edges. One or more zeroes are located in a central portion of the passband to form multiple passbands within the passband edges.

Abstract: Methods that extend capabilities of wireless data transport services. The methods provide for communication with many wireless remote data transport devices. In one embodiment, the identity of each wireless remote data transport device is subdefined by placing additional identification information into data fields of packets transmitted by the wireless remote data transport devices. In another embodiment, identification numbers assigned to wireless remote data transport devices are time division multiplexed across a large number of remote devices. In another embodiment, multiple wireless remote data transport devices share the same primary identification number and are communicated with by transmitting a page of the shared identification number, followed by a page containing a secondary identification number, followed by a page containing a command to transmit data.

Abstract: An improved constellation pruning and partial Gray coding method for generating constellations that are transmitted by a transmitter. The approximate symbol error rate (SER) for each possible subconstellation is first determined. Then, each of the subconstellations are scaled in terms of power so that each subconstellation has the same symbol error rate. Then, the subconstellation that requires the least amount of power to generate is selected as the pruned constellation for use by the transmitter. After the pruned constellation is determined, it is then coded a single time, and this coded pruned constellation is used by the transmitter.

Abstract: Communications network architectures integrate communications using a geosynchronous satellite communications system including a geosynchronous communications satellite operating in the fixed satellite service (FSS) band and a low earth orbit satellite communications system including a plurality of low earth orbit communications satellites. A low earth orbit gateway having a terminal is used to communicate with the low earth orbit communications satellites using multiple access communication channels, and is used to communicate with a public switch telephone network. A geosynchronous gateway having a terminal is used to communicate with the geosynchronous communications satellite by overlaying multiple access communication channels onto fixed channel assignments and transmitting the overlayed channel assignments. The terminal in the geosynchronous gateway is also used to communicate with the public switch telephone network.

Abstract: Portable compact disk storage systems that are designed to hold one or more circular compacts disks. The storage systems may be made as a single molded plastic embodiment or a two-part molded plastic embodiment. An exemplary compact disk storage system comprises a lower housing having a plurality of slots formed along one side thereof that are sized to receive individual compact disks therein, and a frictional pad disposed on the plurality of slots. The frictional pad provides a frictional surface that assists removal of the compact disks from the storage system. An upper housing is coupled to the lower housing by way of a living hinge. A locking mechanism is provided for locking the lower and upper housings together when the storage system is closed.

Abstract: A compact disk labeling, cleaning and repairing system for use in applying an adhesive label to a surface of a compact disk, and for cleaning and repairing a readable surface of a compact disk. In an exemplary system, a top portion is used for labeling the compact disk and has a side wall with a shape that matches the shape of the compact disk and a flat shelf that forms an upper cavity. A plurality of tabs are formed around the periphery of the side wall that hold the compact disk above the label prior to attachment and which register the compact disk. The flat shelf has a plurality of slots therein that form a plurality of tabs, and a plurality of vertical projections extend away from the tabs to form a hub. The hub is sized to allow a central hole in the adhesive label to register thereto. The slots allow the tabs or hub to flex during application of the label. A bottom portion of the system may be used to clean and repair the compact disk.

Abstract: Systems and methods for launching a satellite into orbit that optimize the mass of the satellite delivered into orbit. A satellite carrying one or more chemical propulsion devices and one or more electric propulsion devices is launched into a transfer orbit using a launch vehicle. In one embodiment, a selected chemical propulsion device is fired to raise the orbit of the satellite from the transfer orbit to an intermediate orbit. One or more electric propulsion device is fired to raise the orbit of the satellite from the intermediate orbit to final geosynchronous orbit and the one or more electric propulsion device is throttled to produce variable thrust levels so as to operate at all optimum specific impulse level to optimize the mass of the satellite delivered into orbit. In another embodiment, the electric propulsion device may deliver the satellite into a near-geosynchronous orbit instead of final geosynchronous orbit.

Abstract: A quadrifilar helix antenna system that is wound with a helical structure that changes pitch towards top of the antenna. An exemplary antenna system has first and second bifilar helical loops that each comprise a pair of orthogonal windings disposed around a common central axis. Each loop has a winding pitch that varies along the axis to achieve backlobe radiation suppression from the antenna system. First and second terminals are coupled to respective top ends of the bifilar helical loops. The terminals may be fed in phase quadrature by a quadrature hybrid. The antenna system may also include short circuit coupled to respective bottom ends the first and second bifilar helical loops. The antenna system is preferably used in vehicle-to-satellite mobile communication applications.

Abstract: Systems and methods that increase the maximum data rate capacity per optical carrier on an optical link. The present invention intensity modulates an optical carrier with one or more (microwave) carriers that have been higher order modulated (M-ary ASK, PSK, QAM, and the like) using bandwidth efficient modulation. Consequently, as the number of bits/symbol is increased, the bit rate increases without an increase in occupied bandwidth. Thus, 2 bit/Hz or more of optical channel bandwidth may be transmitted.

Abstract: A system and method that computes the degree of translational offset between corresponding blocks extracted from images acquired by two sensors, such as electro-optic, infrared sensors, and radar for example, so that the images can be spatially registered. The present invention uses fast Fourier transform (FFT) correlation to provide for speed, and also uses gradient magnitude and phase (direction) information to provide for reliability and robustness.

Abstract: Active switch matrix apparatus that is used in a satellite communications system that provides for reconfigurability of the communication channels of the communications system. The active switch matrix apparatus has redundan channels and components that provides for a high probability of success during the lifetime of the satellite. The active switch matrix apparatus is comprised of two switch matrices, one for each polarization (horizontal and vertical). Each of the switch matrices contains redundancy, including redundant paths through power dividers, power combiners and amplifiers to outputs of the apparatus. This is accomplished using a plurality of controllable switches 16 in the power dividers and a plurality of controllable output switches coupled to outputs of the amplifiers. Each of the switch matrices are coupled to redundant DC/DC converters and switch matrix controllers.

Abstract: Feed horn apparatus for use in a multiple-feed antenna system. The present invention comprises a corrugated feed horn and an antenna array or cluster of feed horns arranged in a hexagonal lattice pattern. The feed horn comprises a hexagonal aperture formed by a circular-to-hexagonal transition section a corrugated section disposed adjacent to the circular-to-hexagonal transition section, a tapered section disposed adjacent to the corrugated section, and an input section having an input/output port disposed adjacent to the tapered section. The corrugated feed horn has good beam pattern symmetry, low cross-polarization, and sidelobe levels, along with an increased horn aperture area. As a result, the efficiency of the corrugated feed horn is improved by transitioning from a circular to the hexagonal aperture.