Abstract: An apparatus and method for controlling the temperature of a battery used in a spacecraft or an electric vehicle are disclosed. The apparatus includes a thermal conductor, such as a thermally-conductive heat pipe or forced-fluid cooling loop, that is in thermal contact with thermally-conductive cell terminals of the battery, and a heat sink, such as a radiator. The inventive method includes operating the battery to generate and conduct heat to the thermally-conductive battery cell terminals. The generated heat is passed via conduction from the terminals to the thermal conductor. The heat is conducted through the thermal conductor to a heat sink which may be remotely located with respect to the battery. Preferably, the thermal conductor remains electrically insulated from the battery cell terminals and the heat sink.

Abstract: A satellite communications system includes hub satellite which are equipped to communicate with at least three other satellites. The hub satellites include crosslink interfaces for each of the other satellites with which it may communicate and a switching system for routing those communications between interfaces. A system of a given number of satellites may include several hubs and may be configured in a way which permits any satellite within the system to communicate with a hub either directly or after transiting one or more intervening satellites. Systems which include fewer hubs may require communication with more than one intervening satellite before a hub is reached.

Abstract: A system and method for slewing a spacecraft with a reaction wheel system including determining initial total momentum, determining maximum forward and reverse rates that can be realized within the reaction wheel system maximum storage capacity, determining a slew rate and slew direction from the maximum forward and reverse rates so as to minimize slew time for known slew angles or maximize slew rate for arbitrary slew angles, and slewing the spacecraft.

Abstract: An apparatus for statistically multiplexing a plurality of video signals is provided with a complexity detector, coupled to receive a pre-compressed video signal, for generating a complexity signal which relates to the complexity of the pre-compressed video signal, an encoder for compressing a non-compressed video signal at a variable compression rate to generate a compressed video signal, a controller for controlling the variable compression rate of the encoder based on the complexity signal, and a multiplexer coupled to receive the pre-compressed video signal and the compressed video signal. The apparatus may be provided in a broadcasting system, such as a satellite broadcasting system. The broadcast system may include a transmitter coupled to receive the video signals from the multiplexer, a satellite coupled to receive the video signals from the transmitter, a receiver for receiving video signals from the satellite, and one or more decoders connected to receive video signals from the receiver.

Abstract: A printed wiring board has an aluminum backing, a dielectric layer overlying the aluminum backing, and a copper layer overlying the dielectric layer. Holes are drilled through the copper and the dielectric layers, and either partially or fully through the aluminum backing, and plated to provide a conductive path between the copper layer and the aluminum backing. Tin-lead traces are applied to the upper surface of the copper layer and the copper layer is etched to define conductive paths. The copper exposed and aluminum exposed surfaces are protected so as to permit processing of the printed wiring board in otherwise-incompatible etchants and other solutions.

Abstract: An electromagnetic resonator comprises a waveguide body having a generally tubular side wall and a pair of end wall assemblies. The end wall assembly includes a bowed aluminum plate and an INVAR disk, attached to one another at the periphery thereof. The INVAR disk includes a relatively thick outer annular portion and a relatively thin inner circular portion. The bowed aluminum plate bows in response to increased temperature, thereby counteracting expansion of the waveguide body.

Abstract: A method and apparatus for storing memory modeling data (20) in computer memory (76). The memory modeling data (20) is converted into an X-data value (36) according to a first mapping scheme (32). The first mapping scheme (32) associates the value of each digit of the memory modeling data (20) with a predetermined digit which has one of three values. The X-data value (36) is partitioned into subgroups (52). A character is mapped to each of the subgroups (52) according to a second mapping scheme (64). The mapped characters (60) are stored in computer memory (76).

Abstract: An integrated antenna system for satellite and VHF/UHF reception is provided. The elements of a VHF/UHF antenna are embedded in a satellite antenna. The satellite and VHF/UHF signals are combined and transmitted on a single cable to the receiver. The receiver splits the signals. A switch within the receiver unit for displaying either the VHF/UHF or satellite transmissions is provided. The receiver also powers amplifiers at the antenna using the single cable.

Abstract: An automatic and iterative simulation method for adjusting linearizer parameters to achieve desired AM/AM and AM/PM characteristics is disclosed. The disclosed method includes the steps of choosing a set of linearizer parameters, modeling the performance of the linearizer circuit and the power amplifier to calculate a performance index. The performance index is compared to a threshold. The method continues to iterate until the performance index is acceptable in comparison to the threshold. When the process is completed, the linearizer parameters are output for use by the designer. The disclosed method eliminates the need to engage in trial and error methods in a laboratory when combining a linearizer and a power amplifier to produce linear output characteristics.

Abstract: A frequency generation device for a satellite communication system composed of a central hub station and a number of remote units. The remote units contain a single synthesizer located in an indoor unit. In this invention, the indoor-located synthesizer is a direct digital synthesizer which modulates the baseband signal and conveys the modulated signal to an outdoor unit for communication between the remote unit and the central hub. In the outdoor unit, the signal is converted directly by a fixed number to a Ku band frequency and transmitted to the central hub.

Abstract: A method for compressing the bit data of an alpha mask image frame composed of an array of pixels having bit data indicative of a level of brightness includes selecting a modifying function identifier which represents a mathematical transformation, applying a threshold function to the alpha mask image frame to generate a binary image frame, and encoding the binary image frame and the modifying function identifier for transmission. The method may include receiving an encoded signal containing the binary image frame and the modifying function identifier, decoding the encoded signal to extract the binary image frame and the modifying function identifier, selecting the mathematical transformation represented by the modifying function identifier, and then transforming the bit data of at least one pixel in accordance with the mathematical transformation.

Abstract: A system in which a personal computer sends messages into a TCP/IP network using a conventional dial-up link and downloads data from the TCP/IP network using a high-speed one-way satellite link. A preferred embodiment uses a conventional SLIP provider to connect to the TCP/IP network and uses a commercial software TCP/IP package that has a standard driver interface. A spoofing protocol compensates for the long propagation delays inherent to satellite communication.

Abstract: A system and method for communication of information using channels of different latency combine a high latency communication channel with a low latency communication channel to reduce the communication delay perceived by a user. The system and method includes separating information into first and second components based on a parameter correlated to the perceived delay, communicating the first component via a first channel, communicating the second component via a second channel having a communication delay greater than the first channel, and generating a representation of the information based on the first component. The second component of the information may be used to augment or modify the information represented by the first component.

Abstract: A method is provided for reducing the number of data bits required for storage or transmission of the data representing the alpha masks of objects in a single image or frame of a video sequence by jointly encoding overlapping boundaries between two adjacent objects within the image and by avoiding redundant encoding and transmission of an alpha mask which can be reconstructed from other encoded alpha mask data.

Abstract: A system in which a personal computer sends messages into a network such as a TCP/IP network using a conventional dial-up link and downloads data from the TCI/IP network using a high-speed one-way satellite link. A preferred embodiment uses a conventional SLIP provider to connect to the TCP/IP network and uses a commercial software TCP/IP package that has a standard driver interface. A spoofing protocol compensates for the long propagation delays inherent to satellite communication.

Abstract: A method of simultaneously controlling East/West and North/South positioning and unloading momentum of a spacecraft while orbiting an object. The spacecraft has a thruster array and a momentum accumulator. The method entails moving said spacecraft towards a node of the orbit. At a predetermined position on the orbit, separate from the node, a thruster of the thruster array is fired so as to control the orbital position of the spacecraft. While the thruster is being fired, momentum is dumped from the momentum accumulator at the predetermined position so that any loss in control in the attitude of the spacecraft is reduced.

Abstract: Multiple diversity used in a fading or shadowed error prone, framed, random access channel enhances the probability of successful transmission and reduces delays. This is important, for example, in mobile telephone service, in which traffic channels are only assigned on a speech spurt basis. Selected control messages (such as reverse allocation requests and deallocation requests) are transmitted with multiple diversity. More particularly, an identical control message is transmitted at multiple instants in time (such as three), each transmission occurring on a different carrier frequency, and each transmission occurring at a randomly selected power level.

Abstract: An adaptive constant false alarm rate system provides a method and apparatus for reliably detecting burst information by minimizing the effects of noise levels and signal quality on the detection decision. In particular, the adaptive constant false alarm rate system of the present invention acquires an accurate estimate of the noise floor during a time when no signals information is present on the channel. Accordingly, any activity on the channel during this idle time is a relatively accurate indication of the channel's noise activity. This noise floor estimate is incorporated into a constant false alarm detection scheme to thereby minimize the effects of both the noise level and signal quality on the detection scheme.

Abstract: In a base transceiver station in a cellular network, a digital signal processor generates a baseband input signal, which is converted to analog and transmitted by a transmitter at radio frequency. In accordance with the present invention, the baseband input signal is scaled by a selected factor from a predetermined table of scaling factors. The scaling factors are determined based on measured output power characteristics of the transmitter and provide frequency compensation caused by filtering ripple and/or attenuation compensation caused by uncertainties in internal attenuators.