Abstract: An accelerometer has an acceleration transducer producing uncorrected analog acceleration signals representing vertical, lateral, and longitudinal components of acceleration. An error correction system is connected to the acceleration transducer for receiving the uncorrected analog acceleration signals. The error correction system includes a system controller for generating a plurality of correction coefficients, an analog to digital converter which converts the uncorrected analog acceleration signals to uncorrected digital acceleration signals, a filter for filtering the uncorrected digital acceleration signals, an error compensation circuit receiving the correction coefficients to compensate the uncorrected digital acceleration signals, and a digital to analog converter which converts the corrected digital acceleration signals to corrected analog acceleration signals. The error compensation circuit corrects for bias offset, cross-axis alignment errors, scaling errors, and thermal offset.

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 method of detecting energetic materials, such as explosives, includes energizing a sample area that contains particles of energetic materials. In the method, temperature characteristics from the sample area are monitored, and a temperature released from exothermic decomposition of the particles is detected. The method further includes analyzing the detected temperature to determine the presence of the exothermic compound which caused the decomposition.

Abstract: The preambles of narrow band signals and DSSS signals are prepared for compatible detection. The preamble is encoded by encoding a sequence of identical preamble blocks with sequentially corresponding code elements of a preamble encoding sequence. Each of the identical preamble blocks has the same predetermined pattern of code elements. When the signal is a DSSS signal, the preamble is a spread preamble in which each of the blocks has a number of code elements corresponding to a spread-factor multiple of the number of code elements in a block of an unspread preamble for a narrow band signal. The preambles of both types of received signals are detected by processing a metric representing detected coherent energy with a metric representing detected noncoherent energy, after first determining that the detected noncoherent energy is greater than the average energy of the received signal.

Abstract: A method and apparatus for detecting a spread spectrum signal is described. Signals can be detected using correlation techniques. When a signal is detected, declaring of signal presence is inhibited for offsets of signal parameters from the parameters of the detected signal, where the offset corresponds to a known sidelobe of the spreading code. This helps to reduce false detections caused by sidelobes of the spreading code.

Abstract: Fissionable materials are distinguished from other high-effective atomic number materials by producing dual-energy x-ray radiation sufficient to cause fission in fissionable materials and directing the dual-energy x-ray radiation sufficient to cause fission in fissionable materials towards a physical region. X-ray radiation and a product of fission from the physical region are sensed. An absorption of the dual-energy x-ray radiation by the physical region is determined based on the sensed x-ray radiation, and whether the physical region includes fissionable material is determined based on the presence of a product of fission.

Abstract: A surveillance system is disclosed. In some embodiments, the surveillance system may include at least one controller configured to receive information data from at least one upstream information source and to control operation of at least one controllable downstream information source based, at least in part, on the information data. A surveillance method also is disclosed. In some embodiments, the method may include analyzing screening data, obtaining information data, and reanalyzing the screening data based, at least in part, on the obtained information data.

Abstract: An electron beam amplification device provides trajectory modulation of an electron beam, and includes an electron gun, a modulator, an interceptor, an output circuit, and a collector. The electron gun produces an electron beam. The modulator receives an RF input signal and provides a corresponding electromagnetic field region that alters trajectory of the electron beam in correspondence with the RF input signal. The interceptor has at least one aperture oriented such that the electron beam transmits through the aperture when the electron beam altered by the modulator follows a particular transmission path and impacts upon the interceptor when the electron beam trajectory altered by the modulator follows a path other than the particular transmission path. The output circuit is arranged so that the electron beam transmitted through the interceptor aperture passes therethrough and produces an RF output signal. The collector recovers remaining energy of the electron beam after passing through the output circuit.

Abstract: A compact, reliable scanning electron-beam x-ray source achieves reduced complexity and cost. In particular, the x-ray source includes an electron beam that is propagated parallel to an x-ray target and is swept across the target in response to a moving magnetic cross field. Rather than scanning the beam by deflecting it about a single point, the point of deflection is translated along the target length, dramatically reducing the volume of the device. The magnetic cross field is translated along the target length using either mechanical systems to move permanent magnets, or electrical systems to energize an array of electromagnets.

Abstract: A method of detecting energetic materials, such as explosives, includes energizing a sample area that contains particles of energetic materials. In the method, temperature characteristics from the sample area are monitored, and a temperature released from exothermic decomposition of the particles is detected. The method further includes analyzing the detected temperature to determine the presence of the exothermic compound which caused the decomposition.

Abstract: A scalable architecture for providing real-time multi-camera distributed video processing and visualization. An exemplary system comprises at least one video capture and storage system for capturing and storing a plurality of input videos, at least one vision based alarm system for detecting and reporting alarm situations or events, and at least one video rendering system (e.g., a video flashlight system) for displaying an alarm situation in a context that speeds up comprehension and response. One advantage of the present architecture is that these systems are all scalable, such that additional sensors (e.g., cameras, motion sensors, infrared sensors, chemical sensors, biological sensors, temperature sensors and like) can be added in large numbers without overwhelming the ability of security forces to comprehend the alarm situation.

Abstract: A technique for receiving multiple spread spectrum bursts is disclosed. Each spread spectrum burst is encoded with a common spreading code and may include an individual message and unique signal parameters. The technique includes the detection of the spread spectrum encoded bursts and estimation of the reception signal parameters. A single one of a plurality of burst receivers is assigned to each detected burst to extract the individual message of the detected burst.

Abstract: A system and method for detecting a spread spectrum encoded message within a received signal is described. The spread spectrum encoded message has an unknown code phase, unknown code frequency offset, and unknown carrier frequency offset. A plurality of code phase hypotheses, code frequency offset hypotheses, and carrier frequency offset hypotheses are searched in parallel. The unknown code phase, unknown code frequency offset, and unknown carrier frequency offset may also be estimated.

Abstract: Systems and methods for detection and geolocation of multiple emitters that are emitting RF signal energy on a common frequency, and that may be implemented to separate, geolocate, and/or determine the number of emitters (e.g., radio users) emitting on a common RF frequency. Real-time signal qualification processing may be employed to continuously monitor and collect incoming receiver tuner data for signal activity and ignore irrelevant noise data. Each set of data blocks from an emitter transmission signal may be defined as an emission cluster, and a set of time difference of arrival (TDOA)/frequency difference of arrival (FDOA) pairs may be computed for each emission cluster with each TDOA/FDOA pair yielding a geolocation result. A statistical qualification method may be used to produce a final geolocation answer from each set of emission cluster geolocation results, and a geolocation error ellipse computed for the final geolocation answer of each emission cluster.

Abstract: A representation of an amount of energy incident on a radiation sensor formed from multiple sensing elements coupled together along a direction parallel to a direction of propagation of the incident radiation is received. The radiation sensor has an adjustable border positioned between any two of the multiple sensing elements. From the representation, an amount of energy incident on the radiation sensor is determined. A position of the border is selected based on the amount of energy incident on the radiation sensor. After selecting the position of the border, an absorption characteristic of a region imaged by the radiation sensor is determined.

Abstract: An object within a region is exposed to a first beam of penetrating radiation. The first beam of penetrating radiation is sensed on a side opposite the region from a source of the first beam. An attenuation of the first beam caused by passing the first beam through the object is determined, the attenuation is compared to a threshold attenuation. If the attenuation exceeds the threshold attenuation, a parameter of a second of beam of penetrating radiation is adjusted based on the determined attenuation.

Abstract: A distribution of heavy particle stopping power is be determined. A distribution of effective atomic number of a three-dimensional space is accessed, and a distribution of an x-ray stopping power of the three-dimensional space is accessed. A conversion is applied to the distribution of the effective atomic number and the distribution of x-ray stopping power. A distribution of the heavy particle stopping power of the three-dimensional space is generated based on the conversion, the heavy particle stopping power being an indication of a depth of penetration for a heavy particle incident on the three-dimensional space.

Abstract: A method is disclosed for transmitting low data rate symbols from a communications terminal to a burst radar transceiver. A plurality of bursts can be emitted from a burst radar transceiver, each burst having a burst interval and separated by an inter-burst interval. A symbol can be transmitted from the communications terminal to the burst radar transceiver. The symbol has a symbol period that is substantially longer than a radar transceiver burst period comprising the burst interval and the inter-burst interval. Symbol energy can be accumulated during inter-burst intervals at the burst radar transceiver over a plurality of burst periods for approximately the symbol period.

Abstract: The invention provides a system and method for generating a high rate pseudo-random noise (PN) code with a parallel PN generator. The method includes the operation of configuring L programmable PN generators to each output every Lth chip of a PN code. Select PN generators of the L PN generators can be configured to have their output delayed for a predetermined number of chips less than or equal to L when a fine slip is needed to allow the high rate PN code to be delayed for a set number of chips to synchronize the high rate PN code with another PN code. The outputs of each of the L programmable PN generators can be multiplexed to produce the high rate PN code.

Abstract: A method of detecting a presence or absence of subject matter of interest, for example, sheet explosives and/or other potential threat objects is provided by various local and/or global gradient analysis methods including determining characteristics of gradient information of regions in an X-ray image to determine if the regions are associated with subject matter of interest for which detection may be desired, for example, contraband, explosives and/or other prohibited or unauthorized material.