Abstract: A security system for detecting contraband such as explosives. The system has a source of radiation and a detector array. A detector array is made of many small detectors, each with a fast response time. The fast response time allows individual radiation photon interactions with each detector to be counted. By counting the number of interactions in an interval of time, the amount of radiation reaching the detector can be measured. The magnitude of the response from the detector to each radiation interaction allows measurement of the energy level of the photons interacting with the detector. Such a system provides significant flexibility in analyzing data collected from items under inspection. For example, objects such as contraband can be identified within the item under inspection by processing the data to accurately determine both the density and type of material.

Abstract: A method is presented for estimating a phase error for first (rI) and second (rQ) orthogonal signal components spread respectively by different first cI and second cQ spreading codes. A cross-despread value IdQ and/or QdI is determined by despreading one signal component with the spreading codes associated with the other signal component (rI with cQ or rQ with cI). In parallel, the same signal component is also despread with its associated spreading code to determine an estimated data symbol for that component. An interference of Q into I or I into Q is calculated and multiplied by the estimated data symbol, and subtracted from the cross-despread value to achieve an estimate of phase error. Preferably, both cross-despread values are obtained, normalized to a common data rate, scaled to maximize signal to noise ratio, and combined into one phase error estimate. A phase error detector includes despreaders, multipliers, and adders to determine the cross-despread value and subtract the interference from it.

Abstract: A method and system for compressing an asynchronous transfer mode (ATM) header suitable for wireless ATM systems is provided. The ATM Virtual Path Identifier (VPI) and Virtual Channel Identifier (VCI) are replaced with four and eight bit pointers, respectively. In addition, Generic Flow Control (GFC) and Header Error Control (HEC) fields are removed.

Abstract: A power supply for an ion engine comprises a multiphase alternator and a power converter comprising a voltage multiplier coupled to each phase of the alternator. Each voltage multiplier comprises one or more staged voltage doublers. The alternator phases may be coupled to each other in a Y configuration such that no common return line is required, and each phase of the alternator provides equal amounts of constant power in a balanced, sequential flow. The converter corrects for the alternator's inherent internal reactance, thereby minimizing the required output of the alternator and reducing the overall power required of the system. A controllable impedance can be inserted into a low voltage portion of the multiplier for selectably varying the output voltage and power of the supply.

Abstract: A free space laser communication system uses subcarrier multiplexing to prepare multiple data communication channels for impressing onto a laser carrier. Sending and receiving terminals mutually track to insure acquisition of the transmitted data signals.

Abstract: Methods and systems for detection of. One method includes receiving light of a predetermined wavelength range from a source, and splitting the received light into multiple components having differing wavelengths. The method further includes directing the components toward individual locations spaced from one another. In addition, this illustrative method includes detecting at least some of the components at the locations. One illustrative system includes a plurality of detectors provided along an image facing plane of an array, wherein each detector has a width less than or equal to that of its conesponding pixel location, wherein at least two detectors are located within a single pixel location, wherein the size of each pixel location is approximately equal to the blur spot or smallest visible spot for the focal plane array, and a plurality of light pipe regions, wherein at least two light pipe regions are located within a single pixel location.

Abstract: An embodiment disclosed herein is directed to an electromagnetic shielding defect monitoring system that includes a transmit system adapted to transmit a first electromagnetic field toward a first surface of an electromagnetically shielded enclosure, thereby generating a first current on the first surface, a stationary receive system adapted to detect a second electromagnetic field transmitted from a second surface of the electromagnetically shielded enclosure by a second current induced on the second surface by the first current and to generate a corresponding detected signal; control circuitry adapted to control operations of the transmit and receive systems; and analysis circuitry adapted to identify a location of a defect in the electromagnetically shielded enclosure based upon operations of the transmit and receive systems and based upon the detected signal.

Abstract: Various novel apparatuses and methods for generating X-rays are disclosed. In some embodiments, for example, an apparatus may be configured and arranged so that, for at least one interception point on a particular portion of a scan path on a surface of a target along which a steering element steers an accelerated electron beam (e-beam), both an angle and its complement between a line corresponding to a direction in which the accelerated e-beam is traveling at the interception point and a line oriented normal to the surface of the target at such interception point are greater than forty five degrees.

Abstract: Sensing moving entities includes transmitting a stepped-frequency radar signal including multiple frequencies through a wall from a first side of the wall to a second side of the wall. Portions of the radar signal that are reflected by entities located beyond the second side of the wall are detected. The reflected portions are processed to generate processed data including information associated with frequency shifts between the transmitted signal and the detected signal. The processed data is analyzed to determine if reflected portions are associated with moving entities.

Abstract: A carrier frequency in a filtered received M-ary phase-shift keyed (MPSK) modulated signal having in-phase and quadrature components is detected by processing the filtered received signal to remove modulation components and thereby generate a test signal at the carrier frequency; processing the test signal to provide an amplitude spectrum of samples at different test frequencies; and processing the amplitude spectrum to detect the carrier frequency in accordance with the test frequency at which there is a test statistic of the highest magnitude. The magnitude of the test statistic is determined by processing a signal statistic in relation to a noise statistic. The signal statistic is the amplitude of the largest-amplitude sample. The filtered received signal is processed to provide approximate values of the modulus of the received signal and the phase of the received signal; and the approximate modulus and phase values are processed to generate the test signal.

Abstract: A system may comprise a cathode, a target, one or more switches, and a conductive element. The cathode may be configured and arranged to generate an electron beam, and the target may be configured and arranged to emit radiation when electrons in the electron beam impact the target after being accelerated by an energy source. The one or more switches may be configured and arranged to apply either a first voltage or a second voltage from a power supply between the cathode and the target. The conductive element may be disposed between the cathode and the target so as to inhibit the electron beam generated by the cathode from reaching the target when a signal is applied to the conductive element.

Abstract: A method and apparatus provides for accurately synchronizing a plurality of sensors, as well as for providing accurate timing information (e.g. timing metadata) associated with the synchronized data capture. According to one aspect of the invention, an apparatus includes a synchronization circuit that stores a counter having a value corresponding to the delay characteristics of an associated sensor. The counter is used to provide a synchronization pulse to the associated sensor which is offset from a desired synchronization time by an amount that will compensate for the delay characteristics. In one example, one counter is provided for each associated sensor, allowing a high degree of accuracy in synchronization among a plurality of sensors. According to another aspect of the invention, the synchronization pulses are locked onto and derived from a pulse received from a GPS receiver.

Abstract: A firearm laser training system of the present invention includes a target assembly, a laser transmitter assembly that attaches to a firearm, a detection device and a processor in communication with the detection device. The system simulates targets at extended ranges and accounts for various environmental and other conditions. The target may be in the form of a target image or a display screen. The detection device captures images of the target for processing by the processor to determine beam impact locations. The processor applies various offsets to the beam impact locations to account for the various conditions and determine the impact locations relative to the target. The processor displays an image of the target including the determined impact locations and scoring and/or other information that is based on those impact locations. An electronic laser filter may be employed by the system to minimize false impact detections.

Abstract: An aircraft component including a first section adapted to be attached at an exterior surface of an aircraft to close an access opening through the exterior surface; and a second section extending outward from the first section and forming heat transfer surfaces to transfer heat from the first section to air passing by the exterior surface and second section during flight of the aircraft. The first and second sections are integrally formed as a one-piece member.

Abstract: An apparatus may comprise a frame supporting at least first and second skewed radiation sources and at least first and second radiation detectors. The first and second radiation detectors may be substantially non-contiguous such that a substantial gap exists between the first and second radiation detectors that is free of any radiation detectors. Each of the first and second radiation detectors may also configured and arranged to detect radiation emitted by each of the first and second skewed radiation sources.

Abstract: A system for efficiently filtering interfering signals in a front end of a GPS receiver is disclosed. Such interfering signals can emanate from friendly, as well as unfriendly, sources. One embodiment includes a GPS receiver with a space-time adaptive processing (STAP) filter. At least a portion of the interfering signals are removed by applying weights to the inputs. One embodiment adaptively calculates and applies the weights by Fourier Transform convolution and Fourier Transform correlation. The Fourier Transform can be computed via a Fast Fourier Transform (FFT). This approach advantageously reduces computational complexity to practical levels. Another embodiment utilizes redundancy in the covariance matrix to further reduce computational complexity. In another embodiment, an improved FFT and an improved Inverse FFT further reduce computational complexity and improve speed.

Abstract: A method for operating an inspection system is disclosed in which an item under inspection may be moved in a first direction relative to and at least partially between at least one radiation source and at least some radiation detectors illuminated by the at least one radiation source. The radiation source and detectors may be operated such that ray paths extending linearly between the at least one radiation source and at least some of the radiation detectors form acute angles with respect to a plane having a normal direction coinciding with the first direction that are substantially in excess of three degrees. Data accumulated by the radiation detectors may be processed to form a three-dimensional tomographic data image of at least a portion of the item under inspection.

Abstract: A contraband detection system using a cone beam computed tomography scanner. The cone beam scanner allows for rapid acquisition of data for computing three dimensional density maps of objects within items under inspection. Where greater resolution is desired, the image information obtained with the cone beam computed tomography scanner may be combined with higher resolution images formed with a single view scanner. A multi-energy single view scanner may be used to additionally provide information on the effective atomic number of objects contained within items under inspection. Additionally, information obtained with the cone beam computed tomography scanner may be used to increase the accuracy of the computation of the effective atomic number of objects within the item under inspection.