Abstract: A method is disclosed for PN correlation and symbol synchronization of a spread spectrum signal at a receiver when a symbol boundary of the spread spectrum signal is not on a PN epoch or is otherwise unknown. The method includes the operation of modulating the spread spectrum signal with a PN code to form a potentially despread signal. The potentially despread signal can be integrated for a plurality of symbol times at a rate of N integrations per symbol time to form N symbol energies per symbol for a plurality of symbols. Each of the N symbol energies can correspond to a different symbol time hypothesis. The N symbol energies from the plurality of symbols can be added respectively to form N summed symbol time hypotheses. The Nth summed symbol time hypothesis having maximum power can be found. The Nth summed symbol time hypothesis can relate to a location of the symbol boundary.

Abstract: A method and apparatus for providing immersive surveillance wherein a remote security guard may monitor a scene using a variety of imagery sources that are rendered upon a model to provide a three-dimensional conceptual view of the scene. Using a view selector, the security guard may dynamically select a camera view to be displayed on his conceptual model, perform a walk through of the scene, identify moving objects and select the best view of those moving objects and so on.

Abstract: A distributed simulation system is composed of simulator stations linked over a network that each renders real-time video imagery for its user from scene data stored in its data storage. The simulation stations are each connected with a physics farm that manages the virtual objects in the shared virtual environment based on their physical attribute data using physics engines, including an engine at each simulation station. The physics engines of the physics farm are assigned virtual objects so as to reduce the effects of latency, to ensure fair fight requirements of the system, and, where the simulation is of a vehicle, to accurately model the ownship of the user at the station. A synchronizer system is also provided that allows for action of simulated entities relying on localized closed loop controls to cause the entities to meet specific goal points at specified system time points.

Abstract: An angular analysis system that can be controlled to receive radiation at a defined angle from a defined focus region. The angular analysis system is used for level 2 inspection in an explosive detection system. Level 2 inspection is provided by a three-dimensional inspection system that identifies suspicious regions of items under inspection. The angular analysis system is focused to gather radiation scattered at defined angles from the suspicious regions. Focusing may be achieved in multiple dimensions by movement of source and detector assemblies in a plane parallel to a plane holding the item under inspection. Focusing is achieved by independent motion of the source and detector assemblies. This focusing arrangement provides a compact device, providing simple, low cost and accurate operation.

Abstract: An infrared image detector system mounted on a printed circuit board (PCB) is disclosed for use with an infrared imaging system such as an infrared camera. A semiconductor die having an infrared detector array and connection points on a first surface is mounted to a PCB and electrically coupled to electrical connection points on a PCB. In addition, a heat sink can be coupled to an opposing second surface of the semiconductor die. Still further, the PCB can have a window within which the infrared image detector array can be positioned so that the infrared image detector system can be mounted to one side of the PCB while infrared radiation incident on the second side of the PCB will reach the infrared image detector array through the window.

Abstract: Systems and methods that may be implemented to determine the location of an emitter of electromagnetic radiation, such as an RF signal emitter having an unknown location, using at least two electromagnetic radiation sensor antennas that are co-located on a single sensing platform in combination with at least one other electromagnetic radiation sensor antenna located on another sensing platform.

Abstract: A system and method for displaying a three-dimensional image of airspace includes a series of translucent, horizontal “pavers” that lie like stepping stones marking the selected flight path. In addition, the display includes a series of vertical rectangles—called “wickets”—which bracket the selected flight path. One or more of the wickets may include a graphical representation of the direction of the aircraft should be flying through the wicket. The system accommodates changes in course by generating a new flight path when instructed to do so. The new flight path is created in a way that assures continuous guidance for the pilot and sufficient time for the pilot to adjust to the new course. The display can include a compass rose which indicates the aircraft's present heading and direction of flight.

Abstract: An embodiment disclosed herein is directed to a method of monitoring an electromagnetic shield effectiveness comprising transmitting a first electromagnetic field toward a first surface of an electromagnetic shield, detecting a second electromagnetic field transmitted from a second surface of the electromagnetic shield, generating a first signal corresponding to the second electromagnetic field and determining whether a defect exists at the electromagnetic shield by comparing the first signal to a predetermined threshold.

Abstract: A swept bandpass filter for receiving frequency varying input signals is disclosed. More particularly, a swept bandpass filter frequency modulated continuous wave (FMCW) receiver and related method are disclosed that provide an efficient solution for FMCW signals. The swept bandpass architecture eliminates the need for front-end mixing circuitry and allows for sampling across one or more Nyquist zones within the swept frequency band.

Abstract: A method and system for managing Priority Messages in a hybrid TDMA-Spread Spectrum (TDMA-SS) communication system is provided. The method and system include a HUB for generating a HUB TDMA epoch, wherein the HUB TDMA epoch includes at least one Priority Message (PM) slot. The PM slot includes a plurality of assignable PM sub-slots. The method and system also include at least one SPOKE, wherein the at least one SPOKE is adapted to transmit a Priority Message during its assigned PM sub-slot within the HUB TDMA epoch.

Abstract: A position of an object moving through a region of interest is determined, and at least one source of an air stream is selectively activated based on the determined position. The air stream is capable of dislodging a particle from the object moving through the region of interest. The air stream is directed toward the region of interest. An air collector is selectively activated, based on the determined position, to draw air from the region of interest. The drawn air is deposited on a sample collector, and the sample collector is analyzed to determine whether the deposition of the air stream left particles of a material of interest on the sample collector.

Abstract: A particle-harvesting material includes a flexible, reusable, and thermally conductive material including a rough surface having dimples of a size within a first range of sizes, a microstructure including interstices of a second range of sizes, the second range of sizes including sizes smaller than the first range of sizes, and an etched portion on the rough surface configured to attract particles upon contact between the particles and the etched portion.

Abstract: Reconfigurable direct radio frequency (RF) bandpass sampling receivers are disclosed that provide direct RF sampling of an input signal spectrum passed through a bandpass filter that is tunable over a wide frequency range of interest and that is sampled based on the bandwidth of the filter rather than the bandwidth of the total frequency range of interest. The bandwidth of the filter may further be variable to provide for optimized search against a variety of signal bandwidths. The reconfigurable direct RF bandpass sampling receiver may be implemented with a single fixed clock for applications where the signals of interest lie in adjacent non-overlapping frequency channels. For applications requiring arbitrary tuning, the reconfigurable direct RF bandpass sampling receiver can also use a programmable or switched sampling clock to avoid the Nyquist sample boundaries that occur with bandpass sampling and thus provide sampling of arbitrary frequencies.

Abstract: A method and apparatus for detecting emitter movement. The method and apparatus generally include acquiring a measured signal characteristic corresponding to a signal emitted from an emitter, estimating a signal characteristic corresponding to the signal, and comparing the measured and estimated signal characteristics to determine if the emitter is moving. Such a configuration enables a rapid and accurate detection of emitter movement without requiring multiple measurements, complex systems, or time-consuming calculations.

Abstract: A first multi-dimensional digital image of a scan region is generated. The scan region is included in a materials-detection apparatus and is configured to receive and move containers through the materials-detection apparatus. A pre-defined background range of values is accessed, the background range of values representing a range of values associated with non-target materials and the background range of values being distinct from values associated with the target materials. A value of a voxel included in the multi-dimensional digital image is compared to the background range of values to determine whether the value of the voxel is within the background range of values. If the value of the voxel is within the background range of values, the voxel is identified as a voxel representing a low-density material. A second multi-dimensional digital image that disregards the identified voxel is generated to compress the first multi-dimensional digital image.

Abstract: A system for generating a high voltage energy pulse comprises a capacitive energy storage arrangement that is coupled to a direct current (DC) power supply. The capacitive energy storage arrangement stores energy from the power supply. The system also includes a pulse forming network for forming frequency contents of a high voltage energy pulse. A dielectric insulated mechanical switch is coupled to the capacitive energy storage arrangement and the pulse forming network. The dielectric insulated mechanical switch is immersed in a dielectric substance. A controller is coupled to the dielectric insulated mechanical switch. The controller is programmed to selectively open and close the dielectric insulated mechanical switch so as to supply energy stored in the capacitive energy storage device to the pulse forming network and thereby form the high voltage energy pulse.

Abstract: A receiver (20) for performing timing recovery over at least one complex channel at low or less than zero SNR (signal power to noise power, in dB) has at least one receive element such as an antenna, an analog-to-digital converter 21 (ADC), a fractional interpolation filter 23, a matched filter 24, and a timing correction loop 26. The timing correction loop 26 selects a minimum mean square error from the output of the matched filter 24 to determine a timing signal output to the interpolation filter 23, and provides one-bit weights to the matched filter 24. Preferably, the timing correction loop 26 includes a magnitude detector 26c, a moving average filter 26b, and a timing error detector 26a that outputs an integer m and fractional ? timing factor to the interpolation filter 23. Within a phase correction loop 27 is a maximum likelihood channel estimator 27b and a phase error detector 27a that controls a phase rotator 22 disposed between the ADC 21 and the interpolation filter 23.

Abstract: A radial power divider-combiner is disclosed. Such a radial divider-combiner may include a plurality of waveguides, each of which extends between a central monopole antenna and a respective peripheral monopole antenna. Such a waveguide may have a central portion with a height-to-width ratio of two, and a peripheral portion having an aspect ratio of one. To improve impedance-matching, a transformer portion may be disposed between the central portion and the peripheral portion. Such a transformer portion may have any number of sections, from one to infinity, with each section having a respective height between that of the central portion and that of the peripheral portion. In the extreme case, where the number of “sections” is infinite, the height of the transformer portion may vary linearly from that of the central portion and that of the peripheral portion.

Abstract: Embodiments of the present invention provide a method and apparatus for all-polarization direction finding. The method and apparatus generally include acquiring measurements at least partially corresponding to an emitted signal and generated utilizing a blind signal extraction algorithm, forming an all-polarization cost function utilizing the acquired measurements, and determining an angle of arrival for the emitted signal utilizing the formed all-polarization cost function. Such a configuration enables angles of arrivals to be easily determined for signals having any polarization without using a multiple signal classification (MUSIC) algorithm.