Abstract: A DF or HF chemical laser gain generator fabricated by a platelet technique in which internal passages are more easily formed because the generator is made as a stack of thin platelets that are separately etched and then stacked together. The gain generator is water cooled through passages formed in it during the platelet fabrication process. Water cooling results in lower and more uniform operating temperatures and gas pressures, allowing the use of stronger metals which facilitate the elimination of supporting structures that can degrade laser beam quality. The fabrication method allows for the elimination of gas dynamic and thermally induced density gradients which further degrade laser beam quality.

Abstract: A generator of energy-depleted radiation and various methods and applications using the energy-depleted radiation. Various embodiments are disclosed of the energy-depleted radiation generator and an energy-restored radiation generator, which permits detection of wave properties of the radiation without regard to the depletion of its energy. The energy-depleted radiation generator functions in one embodiment by selective transmission of destructively interfering radiation. Other embodiments use two-beam coupling or directional coupling to achieve energy depletion. Restoring energy to an energy-depleted radiation beam is accomplished by transferring energy to it from a reference beam, in a beam-to-beam transfer or in an optical amplifier. The invention has important applications in fields such as communications, specimen analysis, photorefractive recording, holography, and other fields in which the reduction of energy content in the associated radiation is advantageous.

Abstract: A laser weapon system using a high energy deuterium fluoride (DF) or hydrogen fluoride (HF) laser, for which all necessary reactants and other materials are carried on an easily movable vehicle. Reactant gases are stored mixed with a diluent gas, such as helium, for ease of handling and to provide nearly ideal gas behavior. Cooling water for the laser is also employed in a high pressure steam generator that uses diesel fuel and oxygen to produce heat. Apart from a fluorine generator, the system uses only four storage tanks for reactant gases.

Abstract: A method and apparatus for implementing multicast in a space-based communication system is disclosed. The present invention allows for the use of a buffer in which to store data packets prior to replication in a multicast application. The present apparatus includes a buffer (102), a header memory (103), and an ASIC (101) to store and extract received data packets and replicate them as required. The ASIC (101) includes a switch interface (201), a queue manager (203), a header processor (205), a holding buffer (207), and a arbitration interface (209). The switch interface (201) is connected to the queue manager (203). The queue manager (203) is connected to the buffer (102), the header processor 205, the holding buffer (207), and the arbitration and switch interface (204). The header processor (205) is connected to the header memory (103).

Abstract: A spacecraft electronics module in which electronics components (16) are housed in a box (12) that is mounted directly on a radiator panel structure, which includes a radiator panel (40′) and a thermally conductive backing panel (42). The radiator panel structure is secured in such a way that the conductive backing panel (42) serves as a baseplate for the box (12) and heat from the electronics components is, therefore, conducted as directly as possible to the radiator panel (40′). Maintenance or replacement of the electronics components is effected without removal of the box from its installed location, by instead removing the radiator panel structure to permit direct access to components in the box.

Abstract: A method for use in a communication network having multiple users and limited bandwidth, wherein up to N users are allocated to the same frequency band at the same time, and the method provides for processing signals received at an M-element antenna array, using a cumulant-based signal recovery system to separate and recover the signals transmitted by the respective users.

Abstract: A method of routing a frequency hopping signal to one of two transmitting antennas in a multiple carrier communication system is disclosed. The method comprises storing known a-priori information regarding frequency hopping signal assignments, scanning a transmitter frequency and antenna path assignment table to determine the closest existing transmitting frequency and its antenna to the frequency hopping signal to be assigned, assigning the frequency hopping signal to an available path on the other antenna, and updating the transmitter frequency and antenna path assignment table. In addition the method includes determining whether the assigned path on the other antenna conflicts with existing frequency assignments, and preempting the antenna assignment when a conflict exists.

Abstract: Method and apparatus for providing a standardized measure of accuracy of each biometric device in a biometric identity authentication system having multiple users. A statistical database includes continually updated values of false acceptance rate and false rejection rate for each combination of user, biometric device and biometric device comparison score. False acceptance rate data are accumulated each time a user successfully accesses the system, by comparing the user's currently obtained biometric data with stored templates of all other users of the same device. Each user is treated as an “impostor” with respect to the other users, and the probability of an impostor's obtaining each possible comparison score is computed with accumulated data each time a successful access is made to the system. The statistical database also contains a false rejection rate, accumulated during a test phase, for each combination of user, biometric device and biometric device comparison score.

Abstract: A three-array pole antenna highly suited for use in a communication system, and mounted in a cylindrical cover that may be supported atop a conventional pole of similar diameter. The antenna includes a ground plane structure (26) with three outwardly facing facets (28) that are joined together to form a rigid structure. Three antenna feed printed circuit boards (14) each provide two antenna feeds to an array of antenna patches (16) that are electromagnetically coupled to the circuit boards. Metal-to-metal connections are limited to radio-frequency (RF) feed connectors to the circuit boards (24), to minimize intermodulation effects. The entire antenna structure is of low cost and is easy to assemble and install.

Abstract: A GLONASS receiver and a corresponding method for its calibration for more precise carrier phase measurements. The receiver includes a conventional receiver channel (36), having a bandpass filter (40) for establishing the sampling bandwidth prior to digitizing a plurality of received satellite signals, each having a different frequency. The receiver also includes a calibration channel (50) in which multiple satellite signals are bandbass filtered (in filter 58) at a single intermediate frequency, to avoid errors resulting from group delay variation introduced by passing multiple satellite signals through a common bandpass filter. The calibration channel (50) downconverts (56) to the intermediate frequency, bandpass filters (58), and then upconverts (60) again. Each satellite signal in turn is processed in this manner by selecting appropriate difference frequencies for downconversion and upconversion.

Abstract: A magnetic torquer (10) for spacecraft attitude control, providing a torque that is controllable over an extended range greater than a normally used linear range, and thereby providing a higher ratio of maximum torque to device weight. In one form of the torquer, a feedback loop including a sensor (20), a signal subtraction circuit (24), a controller (28) and an adjustable power supply (16), continuously determines a corrected command signal that results in the generation of a desired magnetic moment and a corresponding torque, over the extended range, regardless of non-linearity across the extended range. In an alternate form of the torquer, the corrected command signal is generated from a mathematical model (56) of the magnetic torquer (10). Use of the invention also minimizes the effect of any residual magnetic moment that might by present when the actuating current is reduced to zero.

Abstract: A standardized interface between a spacecraft backbone structure (48) and multiple spacecraft modules (26) that are coupled to the backbone structure mechanically, electrically and optically. The interface structure includes power connection pins (42 or 50) that connect to a power bus in the backbone structure, data signal pins (44) that connect to a conventional data bus in the backbone structure, and an optical connection (46 or 56) that connects to an optical data bus (60) in the backbone structure. Optionally, the interface also includes a wireless data bus (54) using infrared propagation along the backbone structure, and a radio-frequency (RF) microstrip connector (52) for transmission of data at radio frequencies. The optical data connection employs an optical interface unit (62) in each spacecraft module (26) to convert optical signals from the optical data bus (60) to corresponding electrical signals, and a cross-point switch (74) to distribute the signals to appropriate destinations on the module.

Abstract: A singly or doubly encapsulated actuator/sensor package in which a ceramic actuator/sensor (10) may be first encapsulated in a primary encapsulating material (12) and is encapsulated in a fiber-reinforced composite material (20, 22). A combination of the material and ply angles (&thgr;) of the fiber-reinforced composite material (20, 22) are used to control selection of a composite coefficient of thermal expansion (CTE) and the stiffness or compliance of the package with respect to a selected axis. By optimal selection of the material and the ply angle, based upon a suitable actuation strength figure of merit, a CTE of zero or a CTE matching that of an underlying structural member (24) is obtained, while simultaneously maximizing the actuation strength in a selected actuation direction.

Abstract: Apparatus for transmitting and receiving signals over a fiber-optic waveguide using different frequency bands of light, i.e. by wavelength division multiplexing. A plurality of signal couplers interfaces modulated signals onto the waveguide in separate optical frequency bands, and a plurality of signal probes forming a probe array at one or more places in the waveguide, receives the signals, which are subject to scrambling and distortion as a result of physical irregularities in the waveguide. A recovery system coupled to the signal probes effects recovery and separation of the received signals using cumulant computations based on cumulants of the fourth or higher even order.

Abstract: A precision mirror mount that is adjustable and able to be securely locked in angular orientation about two perpendicular axes (20, 30), to a high degree of angular resolution. A mirror (10) is bonded to a mirror cell (12), to which is rigidly connected a rod (18). The rod (18) engages a hole in a block 22 and is rotatable to adjust the angular orientation of the mirror about a first rotation axis. The block 22 is part of a mount stage (14) that also includes a second rod (26) designed to engage a hole in another block (28) that is part of a mirror mount stand (16). Rotation of the mount stage (14) about the axis (30) of the second rod (26) provide for mirror adjustment about a second rotation axis. Each of the blocks (22, 28) has a slot (34, 42) and a locking screw (36, 44) that together form locking mechanisms that clamp the respective rods (18, 26) to prevent unwanted angular movement.

Abstract: An improved method and apparatus for effecting code synchronization in a global positioning system receiver is disclosed herein. Within the receiver, digital in-phase (I) and quadrature (Q) samples of a plurality of received pseudorandom noise (PRN) encoded signals are provided to a code synchronization circuit. The code synchronization circuit is designed for coherent-mode operation when the receiver has achieved phase-lock with one of the PRN encoded signals, and operates in a non-coherent mode otherwise.The code synchronization circuit includes an I-channel correlator for producing a coherent-mode discrimination signal by correlating in-phase (I) samples of a first of said PRN encoded signals with a discrimination pattern, wherein the first PRN encoded signal is encoded with a first PRN code.

Abstract: A technique for minimizing or eliminating the effect of multipath signals in a receiver processing pseudorandom (PRN) code signals, such as in a global positioning system (GPS) receiver. The presence of multipath signals adversely affects both code measurements and carrier phase measurements of received PRN signals. One aspect of the invention provides for improved code tracking in the presence of multipath signals, by sampling the received code with a multipath mitigation window (MMW) (FIG. 25D) that results in a code error function (FIG. 25F) that reduces or eliminates the multipath effects. The MMW, which may be any of a number of preferred waveforms (FIGS. 35B-35E), provides a code error function that varies in opposite directions from zero at a desired tracking point (402), but assumes a nearly zero value when the MMW is advanced from the tracking or synchronization point by more than a small fraction of a code chip.

Abstract: An electron beam exposure method is described which provides a means of curing spin-on-glass formed on a semiconductor wafer which insulates the conductive metal layer and planarizes the topography in the process of manufacturing multilayered integrated circuits. The method utilizes a large area, uniform electron beam exposure system in a soft vacuum environment. A wafer coated with uncured siloxane spin-on-glass is irradiated with electrons of sufficient energy to penetrate the entire thickness of the spin-on-glass and is simultaneously heated by infrared heaters. The wafer is exposed to a predetermined dose of electrons while simultaneously raised to a peak temperature in a soft vacuum environment. The electron beam and infrared heaters are then extinguished and the substrate cooled before removing from vacuum.

Abstract: A method for increasing the payload that can be delivered by a given launch vehicle to a selected target in an interplanetary space mission, without increasing the transfer time to reach the target. In accordance with the disclosed method, a conventional multi-stage launch vehicle is used to accelerate a payload spacecraft to near earth's escape velocity. Then the spacecraft is separated from the upper stage of the launch vehicle and is further accelerated by applying a velocity impulse with an onboard propulsion system into a transfer trajectory that takes the spacecraft to the target planet. Because the upper stage of the launch vehicle is not accelerated into the same transfer trajectory, a larger payload mass can be delivered to the target planet without increasing the transfer time. Alternatively, the transfer time can be reduced without decreasing the payload mass or changing the launch vehicle configuration.

Abstract: Three folded Maksutov/Bouwers telescopes formed in a single housing to provide focused images from three angularly spaced fields of view. The fields of view are positioned 30.degree. from a central axis and are spaced 120.degree. apart in azimuth. Light enters the telescopes through a common upper aperture, in which a concentric corrector is installed, is reflected from a common lower plane mirror and from one of three inclined mirrors into one of three spherical primary mirrors. The spherical mirrors focus the respective beams onto three focal planes located outside the housing, through openings in the respective inclined mirrors. The concentric corrector compensates for spherical aberration in the spherical primary mirrors, without the need for holographic optical elements, resulting in a simple, compact, lightweight and low-cost device.