Abstract: A satellite-based telecommunication system is provided which communicates with earth-based users located within a predetermined communications area. The communications areas have an associated interference pattern. A satellite antenna is controlled to form an antenna gain pattern distributed across the communications area. The antenna gain pattern represents the gain at any given point within the communications area. The interference pattern corresponds to the amount of interference associated with each point within the communications area. A method and apparatus are provided for controlling the gain defined by a transmitter and/or receiver of a satellite. The transmitter/receiver produces a desired antenna gain pattern. The preferred embodiment includes determining an interference pattern associated with a communications area of interest. Once the interference pattern is identified, a desired antenna gain pattern is then identified.

Abstract: An RF beam pointing apparatus (500, 600) compensates for the effects of settling errors on antenna pointing. The beam pointing apparatus includes an attitude reference system (502, 528, 530, 534) generating an antenna attitude output from the satellite attitude. Also included is attitude comparison circuitry (528, 530), coupled to the attitude reference system, that includes an antenna pointing error output. Control circuitry (528, 530) is coupled to the attitude reference system (502, 528, 530, 534) and the attitude comparison circuitry (528, 530). The control circuitry (528,530) directs the attitude comparison circuitry (528, 530) to generate control error output signals in response to dynamic settling antenna pointing errors induced by a mechanical slew on the satellite.

Abstract: Apparatus, and a method for its use, for automatically verifying the identity of a person seeking access to a protected property that is remotely located with respect to the apparatus, such as a remotely located computer file or building alarm system. The apparatus, which is disclosed in the form of a handheld device (14) or other portable device (14′), includes a sensor (16) for reading biometric data, such as a fingerprint image, from the person, and a correlator (28) for comparing the sensed data with a previously stored reference image (32) and for determining whether there is a match. If there is a match, the device (14) initiates an exchange of signals over a communication network, with the “door” (10) that protects the property. Specifically, the device (14) generates a numerical value, such as a cyclic redundancy code, from the stored reference image (32), encrypts the numerical value, and transmits it to the door (10) as confirmation of the person's identity.

Abstract: A micromirror device (10) is provided with a rotatable optical component (22) for use in a digital image processing application. The micromirror device (10) includes a semiconductor wafer (12), having a recess (14) formed therein, and a platform (20) with the optical component (22) deposited thereon that is movably coupled to the side surface of the recess (14). A first magnetic field source (24) is disposed around the periphery of the optical component (22) on the platform (20) and a second magnetic field source (26) is disposed proximate to this first magnetic field source (24), such that these magnetic field sources are selectively activatable to generate an electromagnetic field for rotating the platform (20). More specifically, the second magnetic field source (26) is disposed on the angular side surfaces of the recess (14) or adjacent to the recess (14) on a top surface of the wafer (12).

Abstract: A synthesized divert propulsion system adapted to be utilized in various vehicles, including kill vehicles, interceptors, rockets, missiles and the like. The system is fabricated using microelectromechanical system (MEMS) technology which eliminates complex interconnections required for traditional divert propulsion systems by integrating all propulsion fluid functions and all controlled electronic functions onto a plurality of wafers. The wafers are integrated into a complete synthesized divert propulsion system by stacking and bonding the wafers together.

Abstract: An optical amplifier for use with a solid state laser which includes a pair of elongated slabs of a solid state lasing material, such as a rare earth doped yttrium-aluminum-garnet (YAG) crystal. Two embodiments of the invention are disclosed. In both embodiments of the invention, each of the elongated slabs is formed with a square or generally rectangular cross-section. The slabs are configured such that the longitudinal axes of the slabs are generally co-axial aligned and the slabs are orientated such that the major axis of the slabs are generally orthogonal. By configuring the two slabs to be orthogonal with respect to one another, the integrated thermal lens becomes azimuthally symmetric and can be compensated by a simple external lens. In addition, the negative lensing affect along the major axis of one slab is used to compensate for the positive lensing affect along the minor axis of the other slab and vice versa, thus minimizing the affects of the astigmatism.

Abstract: A photodiode for an input light signal comprising an absorption layer having an absorption coefficient which is less than the absorption coefficient of InGaAs when measured at a wavelength of 1.55 &mgr;m. First and a second cladding layer are disposed on opposite sides of the absorption layer leaving exposed a side of the absorption layer. Positively and negatively polarized contact layers are disposed on the first and second cladding layers respectively. The input light signal is directed into the exposed side of the absorption layer and the absorption layer absorbs the input light signal and photo-generates therefrom carriers. The contact layers collect the carriers and generate therefrom photocurrent.

Abstract: A drive module comprising an elbow formed of composite material and having two generally tubular legs having a large bore. On one leg, elbow supports an azimuth drive module also formed in a generally tubular configuration and have a large bore. On the other leg, elbow supports an elevation drive module also formed in a generally tubular configuration and having a large bore. The respective modules are operatively connected to an outside diameter of the respective legs. Azimuth drive module and elevation drive module include motors which when energized enable displacement of the respective legs in order to control the azimuth and elevation of elbow to enable pointing of a structure, such as an antenna as may be located on a second elbow.

Abstract: An error correction encoding system (20) is provided for use in an in-flight programmable spacecraft. The error correction encoding system (20) includes a first data routing switch (22) which receives an uncoded data stream and directs the uncoded data stream to either of a first encoding device (26) or a second encoding device (24). The first encoding device (26) receives the uncoded data stream from the first data routing switch (22) and applies a first encoding function. Alternatively, the second encoding device (24), having a plurality of programmable logic blocks, receives the uncoded data stream from the first data routing switch (22) and applies a second encoding function. A controller (30) is connected to the second encoding device (24) for configuring the plurality of programmable logic blocks to perform the second encoding function.

Abstract: An apparatus for stabilizing optical interferometers utilized in an all analog to digital converter using an additional optical signal that differs in wavelength by a factor of two from the wavelength used for the analog to digital conversion is disclosed. The optical interferometers have an optical path length that is tunable. They develop a first interference pattern from the additional optical signal when the optical path length is a prescribed value. The interferometers develop a second interference pattern from the additional optical signal when the optical path length is not the prescribed value. Optoelectronic detectors are responsive to the optical interference pattern generated by the additional optical signal and develop electronic feedback signals when the first interference patterns are not present.

Abstract: A sealing ring assembly for sealing a joint between two members (20, 22). An annular sealing ring 28 abuts an annular backup ring (38, 44) of substantially the same diameter. The annular backup ring is split to permit radial expansion and has a greater thickness on its outer periphery than on its inner periphery. When the joint being sealed (24) is under high pressure, the sealing ring urges the backup ring to expand radially to cover any gap (32) between the members being sealed, maintaining the seal, even under high temperature conditions, and preventing the sealing ring from extruding into the gap.

Abstract: A resonant absorption cell filled with a gas, selected in accordance with the wavelength of the laser radiation of interest, such as DF. The gas within the cell is maintained at substantially atmospheric pressure. The energy state of the gas within the cell is raised by either external resistance heating or optical pumping. In an increased energy state, gas molecules resonate with the incoming laser radiation causing the molecules to absorb incident photons before the gas molecules have a chance to re-radiate the captured photons, collisions with other gas molecules within the cell transfer the excitation energy into heat in order to filter out laser radiation but past all other wavelengths.

Abstract: An interconnected apparatus for producing a low loss, reproducible electrical interconnection between a semiconductor device and a substrate includes a rod and rod receptor. The rod, generally cylindrically shaped, is attached to the semiconductor device and includes an outer circumferential wall which comes into contact with the rod receptor during a bonding process. A lip portion is formed on one end of the rod receptor for interlocking engagement with the rod. The rod receptor is plated on the substrate and includes a generally circularly shaped body which forms a centrally disposed well for receiving the rod. A lip portion is formed on one end or mouth of the rod receptor for interlocking engagement with the rod. When the rod and corresponding receptor are aligned and brought together, the rod deforms and interlocks with its corresponding rod receptor. A thermo-compression bonding process is utilized to bond the rod to the rod receptor, thereby producing a strong interlocking bond.

Abstract: An alignment system for multiple objects, such as gain generator modules for a distributed laser resonator. The present invention allows for banks or rows of objects, such as gain generator modules, to be maintained in alignment with one another under closed loop control. In particular, one module of every bank or row is designated as the reference or master module, for example, at one end of the bank. Each of the remaining modules or objects are designated as slave modules and carried by a positioning module. The positioning modules are used to control the x and y movements of the slave modules relative to the master or reference module under closed loop. An iris or target with an aperture is mounted on each of the slave modules. A laser source mounted on the master or reference module is dithered relative to the targets in the x and y directions. An optical system, for example, simple telescope at the base of each target images the laser onto a detector.

Abstract: A gimbal drive module comprising an elbow (24) formed of composite material and having two legs. On one leg, elbow (24) includes an azimuth drive module (26). On the other leg, elbow (24) includes an elevation drive module (30). Azimuth drive module (26) and elevation drive module (30) include motors which when energized enable displacement of the respective legs in order to control the azimuth and elevation of elbow (24) to enable pointing of a structure, such as an antenna (18), as may be located on a second elbow outboard end (20).

Abstract: A multi-pattern antenna for providing a plurality of antenna patterns at different frequencies or polarizations from a single reflector body eliminates the need for multiple reflector antennas on a single spacecraft. The reflector antenna comprises a reflector body and an illumination source. The illumination source illuminates the reflector with a plurality of RF signals each of a preselected frequency or polarization. The reflector comprises a plurality of zones with each zone reflecting preselected RF signals. A plurality of antenna patterns are generated from the reflected RF signals. Each zone is sized to a preselected shape such that the antenna patterns have a desired shape or beamwidth characteristic.

Abstract: A rack (70) for a plurality of electronics modules (36) that does not include inlet and outlet air cooling plenums. The rack (70) includes a heat exchanger (72) including three separate sections (78, 80, 82), where each section (78, 80, 82) include spaced-apart parallel fins (84, 86, 88). First and second end sections (80, 82) of the heat exchanger (72) include cooling fins (86, 88) that extend parallel to each other in a front-to-back direction relative to the direction the modules (36) are slid into the rack (70). The first and second end sections (80, 82) are positioned at opposite ends of a center section (78), where the fins (84) of the center section (78) extend in a direction transverse to the direction the modules (36) are slid into the rack (70). The channels between the fins (86, 88) in the first and second end sections (80, 82) are aligned with inlet and outlet ports (94, 98) extending through a back panel (52) of the rack (70).

Abstract: A singlet-delta oxygen generator 10 comprises a chamber 14 in which a gas stream 22 of singlet-delta oxygen, O.sub.2 (.sup.1 .DELTA.), is generated; a water vapor trap 40 to remove water vapor from the gas stream, and a liquid separator 60 downstream of the water vapor trap to separate liquid from the gas stream subsequent to removal of the water vapor. The water vapor trap comprises a liquid droplet dispersing device 42 which forms a droplet field 44 of cold liquid droplets in the chamber. The cold liquid droplets interact with and condense water vapor in the gas stream. The cold liquid is preferably hydrogen peroxide. The liquid separator comprises a baffle 62 arrangement which forms a tortuous flow path for the gas stream. Liquid in the gas stream is unable to traverse the baffles and is separated from the liquid, to produce an essentially dry gas stream for introduction into a gain generator 34 downstream of the singlet-delta oxygen generator.

Abstract: An orthogonal pilot tone servo controller provides a servo control loop for each tap in a delay line processor where each servo acquires its independence from the other tap's servos utilizing an orthogonal code set modulated on top of the existing tap values. The orthogonal codes are attenuated in amplitude such that the code sets are transparent to the processed signals of interest, but the code's length enables each tap's servo controller to independently recover the tap's state from the aggregate of signals and codes through processing gain realized in each loop's recovery circuit. A plurality of taps can be thus be servo controlled simultaneously, providing for extremely wide bandwidth processes which can be performed accurately with digital controls.

Abstract: An optical waveguide device (30) that limits the peak optical intensity applied to an optical absorbing device (36), such as a photodetector or electro-absorption modulator. The optical waveguide device (30) includes a single mode input waveguide (34) coupled to a multi-mode, waveguide interference coupler (32). A single mode output waveguide (38) collects the light from the interference coupler (32). The absorbing device (36) is defined in the waveguide coupler (32) by a reverse-biased p-i-n diode structure. A voltage potential applied to the diode structure creates an electric field across the waveguide coupler (32) that causes the waveguide coupler (32) to absorb. Light entering the interference coupler (32) from the single mode waveguide (34) expands into other propagation modes that interact to constructively and destructively interfere. Because the light expands in the coupler (32), the amplitude of the light decreases even though the overall power remains substantially the same.