Abstract: The present invention relates to an apparatus and method for the encryption and decryption of optically transmitted data, and more particularly to the encryption and decryption of optical data transmitted and received using only optical components. Because only optical components are used, the encryption and decryption is independent of the data rate of the optical signal. The apparatus may include an encryption device that operates by receiving and combining both an unencrypted optical signal as well as a delayed optical signal that is based on the unencrypted optical signal. An optical delay may be configured in a number of different ways and may be used for delaying the unencrypted optical signal. The apparatus may further include a decryption device that receives and combines an encrypted optical signal as well as a delayed optical signal that is based on the encrypted optical signal.

Abstract: An apparatus and method for controlling the communication frequencies of a software controlled radio by using GPS to calibrate one or more local oscillators and compensating within the digital radio processing for the local oscillator inaccuracies.

Abstract: An embodiment of the invention generally relates to an apparatus for deploying a segmented reflector antenna. The apparatus includes a plurality of segments that can be rigid or flexible where each segment is hinged to an adjacent segment on either longitudinal side. The apparatus also includes a base, a plurality of inner deployment beams, and a plurality of outer deployment beams. Each inner deployment beam connects an inner side of a respective segment to the base and having a folded position and an extended position. Each outer deployment beam connects an outside side of a respective segment to the base and has a folded position and an extended position. The plurality of segments in a hinged folded position in response to the plurality of inner deployment beams being in the folded position and the outer deployment beams being in the folded position.

Abstract: An apparatus and method for controlling the communication frequencies of a software controlled radio by using GPS to calibrate one or more local oscillators and compensating within the digital radio processing for the local oscillator inaccuracies.

Abstract: A method and device are provided for controlling access to data. Portions of the data are protected and rules concerning access rights to the data are determined. Access to the protected portions of the data is prevented, other than in a non-useable form; and users are provided access to the data only in accordance with the rules as enforced by a mechanism protected by tamper detection. A method is also provided for distributing data for subsequent controlled use of those data. The method includes protecting portions of the data; preventing access to the protected portions of the data other than in a non-useable form; determining rules concerning access rights to the data; protecting the rules; and providing a package including: the protected portions of the data and the protected rules. A user is provided controlled access to the distributed data only in accordance with the rules as enforced by a mechanism protected by tamper protection.

Abstract: An exemplary embodiment of the present invention includes an optical circulator. The circulator may have, for example, a first port, a second port, and a third port. The first port may be configured to introduce light into the optical circulator. The system may also include a tunable fiber filter Bragg grating connected to the second port of the circulator and a tunable dispersion-compensating fiber Bragg grating connected to the third port of the optical circulator. The tunable dispersion compensating fiber Bragg grating and the tunable fiber filter Bragg grating may be configured to be tuned by a single actuator. This tuning may be either compression or strain tuning.

Abstract: A deployable cellular structure providing impact energy absorption capability is disclosed. The structure may be packed when not in use and deployed automatically or manually to provide impact protection. The structure is useful in a variety of situations including vehicular protection of occupants, deployable highway safety barriers, and aviation emergency safety devices.

Abstract: Control system for electromechanical arrangements having open-loop instability. The system includes a control unit that processes sensing signals and provides control signals to maintain a movable member, such as a rotor or shaft, in the desired position. The control unit according to the invention includes a unifying plant compensation filter, which isolates the open-loop instability characteristics so that the shaft is treated as a mass having substantially no open-loop structural properties. In magnetic bearings, the open-loop instability is manifested as negative stiffness. The invention isolates the negative stiffness thus providing for better positive stiffness and improved bandwidth. Various filters, summers, and other operators required to carry out the invention are preferably implemented on a programmed processing platform such as a digital signal processor (DSP) or an arrangement of multiple digital signal processors.

Abstract: A method according to a first aspect may include performing a first analog-to-digital (A/D) conversion using an A/D converter. Data associated with this first A/D conversion may be read using a processor. A command may then be issued from a processor when the reading of the data has started. This command may instruct the A/D converter to perform a second A/D conversion. This data may then be stored in a data structure located within a memory device while the A/D converter is performing the second A/D conversion. In addition to performing such pipelined A/D conversions, the present invention may include a system, method and software for filtering out noise in a voltage measurement after the voltage measurement has been converted to a digital signal by omitting the highest and lowest voltage values and averaging the remainder of the voltage values, thereby reducing noise in the voltage measurements.

Abstract: A fast, accurate and reliable sensor applicable to chemical and biological analytes resides in an optical grating-based sensor, sensing system, and method of use. The sensor, configured for use with an illumination source and a signal detector in the system embodiment, includes first and second periodic diffraction gratings superimposed and shifted laterally relative to each other by a distance of less than one period, such that the illumination from the source is affected by both gratings before reaching the detector. An analyte recognition material disposed on a surface of the second diffraction grating. In operation, the output of the detector is first used to establish a baseline optical phase signal. The analyte recognition material is exposed to a sample, and the output of the detector is used to to determine a second optical phase signal. The baseline optical phase signal is compared to the second optical phase signal to detect the presence of the analyte, if any, in the sample.

Abstract: A fiber transition segment for transitioning an optical fiber from a hydrophone module to the central axis of the module. The segment comprises a conical, elongated element and a cylindrical portion of reduced diameter that protrudes longitudinally from the wide end of the conical element. The cylindrical portion is reciprocally mounted within an interconnect spring at the end of the hydrophone assembly. The fiber transition segment has a helical internal groove for receiving the optical fiber from the interconnect spring. The groove is aligned with and approximately matches the pitch of the groove in the interconnect spring to provide a smooth transition to the fiber transition segment and then to the central axis of the module.

Abstract: An eddy current sensor that can be mounted on the outside of a casing for a turbine or other rotating machinery to measure characteristics of nearby, moving, electrically conductive objects through the casing. Monodirectional and omnidirectional sensors are provided. High-strength uniaxial permanent magnets generate static magnetic fields. A signal voltage is produced on a wound coil in response to a variable magnetic field caused by eddy currents in the conductive object as the conductive object passes through the stationary magnetic field. The present invention sensors are also directed to measuring characteristics of turbine blades through jet engine casings.

Abstract: The invention according to a first aspect may include an optical system. The optical system may have an axial axis. This optical system may have a number of primary mirror segments. A number of reflectors may be arranged about the axial axis. The primary mirror segments may be configured to reflect a number of principal rays along a first set of chords to corresponding reflectors. These reflectors may be configured to reflect the corresponding principal rays along a second set of chords. Both the first set of chords and the second set of chords may have an angle in excess of 45 degrees with respect to the direction of the axial axis. The invention according to a first aspect may also include a second set of reflectors. The second set of reflectors may be configured to direct the light to an image plane. Other aspects of the invention may include a method of receiving light using an optical system configured to spiral light though the system and a method of making such a system.

Abstract: The invention according to a first aspect may include an optical system. The optical system may have an axial axis. This optical system may have a number of primary mirror segments. A number of reflectors may be arranged about the axial axis. The primary mirror segments may be configured to reflect a number of principal rays along a first set of chords to corresponding reflectors. These reflectors may be configured to reflect the corresponding principal rays along a second set of chords. Both the first set of chords and the second set of chords may have an angle in excess of 45 degrees with respect to the direction of the axial axis. The invention according to a first aspect may also include a second set of reflectors. The second set of reflectors may be configured to direct the light to an image plane. Other aspects of the invention may include a method of receiving light using an optical system configured to spiral light though the system and a method of making such a system.

Abstract: A neutron detector may include a neutron counter and a plurality of optical fibers peripherally arrayed around the counter. The optical fibers have thereon a layer of scintillator material, whereby an incident fast neutron can transfer kinetic energy to nuclei in one or more of the optical fibers to produce recoil protons. The recoil protons interact with the coating to produce scintillation light that is channeled along the optical fiber or fibers with which the neutron interacted. The slowed neutron passes into the neutron counter where the neutron effects generation of a signal coincident with the light produced in the optical fibers in which the neutron deposited energy.

Abstract: A system and method are presented for determining the detection and location of persons and objects using ultrasonic acoustic sensors. The system allows detection of stationary and moving persons and other objects, through atmospheric conditions, to a distance of at least 300 feet. The invention further provides for enhanced signal processing through the use of arrays of transmitters and receivers, where one or more transmitter arrays may be oriented substantially perpendicularly to one or more receiver arrays, allowing high directionality and good rejection of reverberations, background noise, clutter and objects not of interest.

Abstract: A system and method are provided for detecting local interference in GPS signals. A GPS receiver is capable of determining its GPS coordinates. A memory is capable of storing an initial location of the GPS receiver and a user-defined range of error. A processor is programmed to determine whether GPS coordinates from the GPS receiver differ from the initial location by more than a range of error, and for issuing a warning in response thereto.

Abstract: An improved structure and method for building large-aperture lightweight deformable mirrors uses a hinged substrate. In addition to reduced weight, the approach provides rigidity to the mirror, which is necessary for the accurate response to actuator commands and tolerance to disturbances. No stresses are induced in the substrate due to the commanded deformation of the substrate, regardless of the magnitude of the deformation. Any stresses in the substrate structure are those induced due to forces in the face sheet, which are likely to be small using advanced nano-laminate and membrane face sheet technologies. The magnitude of the deformation (dynamic range) is limited only by the actuator stroke, and not by the stresses induced in the substrate. The design therefore accommodates small-force, large-stroke actuators, as opposed to the current designs that use large-force, small-stroke actuators.

Abstract: A bi-static continuous wave radar system and related methods for detecting incoming threats from ballistic projectiles includes a remote source of RF illumination, and a local receiver installed in one or more target aircraft. A first receiving channel acquires direct path illumination from the source and provides a reference signal, and a second receiving channel acquires a scatter signal reflected by a projectile. A processor coupled to each receiver corrects scatter signal Doppler offset induced by relative source motion, isolates narrowband Doppler signals to derive signatures characteristic of the projectile, and by executing appropriate algorithms, compares the derived signatures to modeled signatures stored in memory. If the comparison yields a substantial similarity, the processor outputs a warning signal sufficient to initiate defensive countermeasures.

Abstract: A first optical fiber is coupled to a second optical fiber by ablating a portion of the cladding from the first and second optical fibers, thus exposing or nearly exposing the fibers' cores, bringing the ablated regions close together in the presence of an optical couplant, adjusting the alignment of the fibers so as to achieve a desired optical coupling ratio, and securing the fibers relative to each other. The ablation can be accomplished using a laser. The fibers can be secured mechanically or using adhesives. The finished coupler can be sleeved or otherwise encapsulated for physical protection. The technique can be applied to pairs of fiber ribbons, each having multiple optical fibers.