Abstract: One embodiment describes an imaging system. The system includes a first imaging system configured to provide first signals to a target area and to receive first response signals. The system also includes a second imaging system configured to provide second signals to the target area and to receive second response signals. The first and second signals can have separate frequency bands. The system further includes a processor configured to correct the first response signals based on the second response signals, and to generate an image based on the corrected first response signals.

Abstract: A detection system includes a polarization analyzer that generates one or more null detection values if an object is sensed in a received millimeter wave (MMW) brightness temperature data set. The polarization analyzer analyzes a polarization parameter in the received MMW brightness temperature data set to generate the one or more null detection values. An object detector detects if the object is present based on a comparison of the one or more null detection values to a predetermined threshold. A singular value decomposition (SVD) unit is enabled by the object detector to decompose the MMW brightness temperature data set into a plurality of image layers. Each image layer includes at least one feature of a scene. An identification unit analyzes the plurality of image layers from the SVD unit to determine a shape or a location of the object from the scene.

Abstract: One embodiment describes an imaging system. The system includes a first imaging system configured to provide first signals to a target area and to receive first response signals. The system also includes a second imaging system configured to provide second signals to the target area and to receive second response signals. The first and second signals can have separate frequency bands. The system further includes a processor configured to correct the first response signals based on the second response signals, and to generate an image based on the corrected first response signals.

Abstract: One embodiment of the invention includes a material detection system. The system includes a sensor system configured to collect radiation from a region of interest. The collected radiation can include a plurality of frequency bands. The system also includes a processing unit configured to detect a material of interest. The material of interest can be a concealed dielectric material, and the processing unit can be configured to decompose the collected radiation into natural resonance signals to analyze the natural resonance signals to detect an anomaly corresponding to the concealed dielectric material based on wave characteristics of the natural resonance signals. The processing unit could also include processing layers associated with the plurality of frequency bands for detecting and identifying the material of interest based on wave characteristics associated with each of the plurality of frequency bands of the collected radiation.

Abstract: A detection system includes a polarization analyzer that generates one or more null detection values if an object is sensed in a received millimeter wave (MMW) brightness temperature data set. The polarization analyzer analyzes a polarization parameter in the received MMW brightness temperature data set to generate the one or more null detection values. An object detector detects if the object is present based on a comparison of the one or more null detection values to a predetermined threshold. A singular value decomposition (SVD) unit is enabled by the object detector to decompose the MMW brightness temperature data set into a plurality of image layers. Each image layer includes at least one feature of a scene. An identification unit analyzes the plurality of image layers from the SVD unit to determine a shape or a location of the object from the scene.

Abstract: One embodiment of the invention includes a material detection and/or identification system. The system includes an electromagnetic (EM) sensor system configured to collect EM radiation from a region of interest. The collected EM radiation could comprise orthogonally-polarized EM radiation. The system also includes a processing unit configured to detect and identify a material of interest in the region of interest. As an example, the processing unit could measure reflectivity data associated with a material of interest based on the collected EM radiation and calculate a refractive index of a material of interest based on the measured reflectivity data, such that the material of interest is identified based on the refractive index. The processing unit can also be configured to calculate a surface roughness associated with the material, such that the refractive index can be calculated based on the surface roughness associated with the material.

Abstract: A sensor system uses ground emitters to illuminate a projectile in flight with a polarized RF beam. By monitoring the polarization modulation of RF signals received from antenna elements mounted on the projectile, both angular orientation and angular rate signals can be derived and used in the inertial solution in place of the gyroscope. Depending on the spacing and positional accuracies of the RF ground emitters, position information of the projectile may also be derived, which eliminates the need for accelerometers. When RF signals of ground emitter/s are blocked from the guided projectile, the sensor deploys another plurality of RF antennas mounted on the projectile nose to determine position and velocity vectors and orientation of incoming targets.

Abstract: A sensor system uses ground emitters to illuminate a projectile in flight with a polarized RF beam. By monitoring the polarization modulation of RF signals received from antenna elements mounted on the projectile, both angular orientation and angular rate signals can be derived and used in the inertial solution in place of the gyroscope. Depending on the spacing and positional accuracies of the RF ground emitters, position information of the projectile may also be derived, which eliminates the need for accelerometers. When RF signals of ground emitter/s are blocked from the guided projectile, the sensor deploys another plurality of RF antennas mounted on the projectile nose to determine position and velocity vectors and orientation of incoming targets.

Abstract: One embodiment of the invention includes a material detection and/or identification system. The system includes an electromagnetic (EM) sensor system configured to collect EM radiation from a region of interest. The collected EM radiation could comprise orthogonally-polarized EM radiation. The system also includes a processing unit configured to detect and identify a material of interest in the region of interest. As an example, the processing unit could measure reflectivity data associated with a material of interest based on the collected EM radiation and calculate a refractive index of a material of interest based on the measured reflectivity data, such that the material of interest is identified based on the refractive index. The processing unit can also be configured to calculate a surface roughness associated with the material, such that the refractive index can be calculated based on the surface roughness associated with the material.

Abstract: One embodiment of the invention includes a material detection system. The system includes a sensor system configured to collect radiation from a region of interest. The collected radiation can include a plurality of frequency bands. The system also includes a processing unit configured to detect a material of interest. The material of interest can be a concealed dielectric material, and the processing unit can be configured to decompose the collected radiation into natural resonance signals to analyze the natural resonance signals to detect an anomaly corresponding to the concealed dielectric material based on wave characteristics of the natural resonance signals. The processing unit could also include processing layers associated with the plurality of frequency bands for detecting and identifying the material of interest based on wave characteristics associated with each of the plurality of frequency bands of the collected radiation.

Abstract: One embodiment of the invention includes a system for measuring at least one thermal property of a material. The system includes a thermal source configured to generate an incident thermal wave that propagates through a medium and is provided onto the material at an incident angle. The system also includes a thermal detector that is configured to receive a reflected thermal wave corresponding to the incident thermal wave reflected from the material at a reflection angle that is approximately equal to the incident angle. The system further includes a controller configured to control a magnitude of the incident angle to ascertain a thermal Brewster angle of the material and to calculate the at least one thermal property of the material based on the thermal Brewster angle.

Abstract: Systems and methods are provided for extracting relative signal parameters representing two closely spaced targets from monopulse scan data. A maximum quadrature angle value from the scan data is compared with a threshold quadrature value representing a noise level. A linear polynomial model is utilized if the maximum quadrature angle exceeds the threshold value. The linear polynomial model fits a function of the azimuth angle values and quadrature angle values to a linear function of an exponential parameter derived from the boresight angles to produce polynomial coefficients and determines the relative signal parameters from the polynomial coefficients. A cubic polynomial model is utilized if the maximum quadrature angle fails to exceed the threshold value. The cubic polynomial model fits azimuth angle values to a cubic function of corresponding boresight angles to produce a set of polynomial coefficients and determines the relative signal parameters from the set of polynomial coefficients.

Abstract: An algorithm for a non-redundant multi-error correcting binary differential demodulator simplifies error detection and reduces memory requirements in circuits embodying the same. The demodulator includes a differential detectors (DD) module, an error signal generator (ESG) module, and an error detection-and-correction (EDAC) module. The DD module receives modulated binary input at each of (k+1) differential detectors, each producing (k+1) outputs. The ESG module combines the (k+1)2 output signals with k corrected feedback signals to derive syndromes orthogonal to an erroneous bit to be corrected and generates 2k error signals from the syndromes. The EDAC module generates a correction factor from the 2k error signals and combines the factor with the output of the first order detector delayed by k bits to correct an erroneous bit. The k corrected feedback signals may be derived by successively delaying the corrected erroneous bit.

Abstract: Systems and methods are provided for extracting relative signal parameters representing two closely spaced targets from monopulse scan data. A maximum quadrature angle value from the scan data is compared with a threshold quadrature value representing a noise level. A linear polynomial model is utilized if the maximum quadrature angle exceeds the threshold value. The linear polynomial model fits a function of the azimuth angle values and quadrature angle values to a linear function of an exponential parameter derived from the boresight angles to produce polynomial coefficients and determines the relative signal parameters from the polynomial coefficients. A cubic polynomial model is utilized if the maximum quadrature angle fails to exceed the threshold value. The cubic polynomial model fits azimuth angle values to a cubic function of corresponding boresight angles to produce a set of polynomial coefficients and determines the relative signal parameters from the set of polynomial coefficients.

Abstract: One embodiment of the invention includes a system for measuring at least one thermal property of a material. The system includes a thermal source configured to generate an incident thermal wave that propagates through a medium and is provided onto the material at an incident angle. The system also includes a thermal detector that is configured to receive a reflected thermal wave corresponding to the incident thermal wave reflected from the material at a reflection angle that is approximately equal to the incident angle. The system further includes a controller configured to control a magnitude of the incident angle to ascertain a thermal Brewster angle of the material and to calculate the at least one thermal property of the material based on the thermal Brewster angle.

Abstract: A method for mitigating multipath impacts on azimuth accuracy in a monopulse interrogator is accomplished by calculating samples of monopulse ratio for samples of antenna boresight angles based on data received from an interrogation of a target. Samples of traditional target azimuth from the samples of monopulse ratio are calculated. A mean of the samples of traditional target azimuth is calculated. An alternative target azimuth from the samples of monopulse ratio is calculated. Whether a multipath signal exists is determined from observing a standard deviation of the samples of traditional target azimuth, and using the mean of the traditional target azimuth if a multipath signal does not exist and using the alternative target azimuth if a multipath signal does exist.

Abstract: Systems and methods are provided for determining first and second azimuth angle values representing two closely spaced targets. Monopulse radar scan data is produced and processed to provide quadrature angle data, merged azimuth angle data, and a maximum magnitude of the quadrature angle. A quadrature angle methodology that derives the first and second azimuth angle values from an integration of the quadrature angle data over an angular region within the monopulse scan is applied if the maximum quadrature angle magnitude exceeds the threshold value. A merged azimuth angle methodology that fits the merged azimuth angle data to a polynomial as a function of a boresight angle of the monopulse radar to derive the first and second azimuth angle values is applied if the maximum quadrature angle magnitude does not exceed the threshold value. The first and second azimuth angle values are then displayed to a user.

Abstract: A non-redundant differential MSK demodulator with double-error correction capability includes a differential detection stage, an error signal generator stage, and an error detection-and-correction stage. Differential detectors receive modulated MSK input. The error signal generator converts outputs from the differential detectors into orthogonal error signals. The error detection-and-correction stage compares an algebraic sum of the error signals to a threshold value and outputs a correction value based thereon. The correction value is added to output from the differential detection stage to produce demodulated MSK output.

Abstract: A method for mitigating multipath impacts on azimuth accuracy in a monopulse interrogator is accomplished by calculating samples of monopulse ratio for samples of antenna boresight angles based on data received from an interrogation of a target. Samples of traditional target azimuth from the samples of monopulse ratio are calculated. A mean of the samples of traditional target azimuth is calculated. An alternative target azimuth from the samples of monopulse ratio is calculated. Whether a multipath signal exists is determined from observing a standard deviation of the samples of traditional target azimuth, and using the mean of the traditional target azimuth if a multipath signal does not exist and using the alternative target azimuth if a multipath signal does exist.

Abstract: An algorithm for a non-redundant multi-error correcting binary differential demodulator simplifies error detection and reduces memory requirements in circuits embodying the same. The demodulator includes a differential detectors (DD) module, an error signal generator (ESG) module, and an error detection-and-correction (EDAC) module. The DD module receives modulated binary input at each of (k+1) differential detectors, each producing (k+1) outputs. The ESG module combines the (k+1)2 output signals with k corrected feedback signals to derive syndromes orthogonal to an erroneous bit to be corrected and generates 2k error signals from the syndromes. The EDAC module generates a correction factor from the 2k error signals and combines the factor with the output of the first order detector delayed by k bits to correct an erroneous bit. The k corrected feedback signals may be derived by successively delaying the corrected erroneous bit.