Raytheon Company

Harry A Schmitt

Delmar L Barker

Dennis C Braunreiter

Hai-Wen Chen

Alphonso A Samuel

Stephen M Schultz

Nitesh N Shah

Donald E Waagen

David James Knapp

Thomas K Lo

Wesley Howard Dwelly

Vinh N Adams

Michael R Beylor

George Thomas David

Andrew Greentree

David A Zaugg

Dennis J Garrood

Hai-Wai Chen

Steven Schultz

Jack G Riddle

Andrew D Greentree

The present invention describes a system and method of OAM diverse signal processing using classical beams for applications in which OAM signal character is controlled such as optical tagging and applications in which OAM signal character is not controlled such as clutter mitigation and interference cancellation for target detection, identification etc. This is accomplished by transmitting a source beam having a prescribed state with one or more non-zero OAM components, reflecting the beam off a 'tagged' or 'untagged' target and receiving the return beam in the direct return path to measure the one or more OAM components to identify the target. OAM processing provides additional degrees of processing freedom to greatly enhance the processing capabilities to detect and identify both &#x2018;tagged&#x2019; and &#x2018;untagged&#x2019; targets.

System and method of orbital angular momentum (OAM) diverse signal processing using classical beams

On-chip multispectral imaging and data management is provided in the form of an Adaptive Focal Plane Array (AFPA) that is capable of spectral tunability at the pixel level. Layers of photonic crystals are registered with pixels of a broadband focal plane array. Spectral tuning is accomplished by switching the photonic crystal layers on/off and/or by changing their material structure to tune their photonic band gaps and provide a passband for incident photons. The photonic crystal layers are preferably segmented to independently address different regions or 'cells' of pixels down to a pixel-by-pixel resolution. The AFPA may simultaneously sense different regions of a scene at different spectral wavelengths, spatial resolutions and sensitivities.

Multispectral imaging chip using photonic crystals

An identification system for identifying objects of interest is disclosed. The system includes an enhancement mechanism for enhancing Raman scattering from a plurality of Raman active molecules (RAMs). An interrogator transmits a signal toward an object of interest and receives a return signal therefrom. The return signal includes a Raman signature, and the interrogator classifies the object based on the Raman signature.

Electric field resonance assisted Raman scattering for ladar IFF

Systems and methods of tracking a beam-aspect target are provided. In embodiments, a target is tracked with a Kalman filter while detections are received. After a detection is missed, the Kalman filter may be concurrently propagated with a blind-zone particle filter until a probability that the target is in a blind zone exceeds a threshold. When the probability exceeds the threshold, the Kalman filter may refrain from further propagating. After a gated detection is received, the blind-zone particle filter and an unrestricted-zone particle filter may be concurrently propagated while a probability that the target is in an unrestricted zone exceeds a threshold. The system may return to tracking with the Kalman filter when a covariance of the unrestricted-zone particle filter falls below a predetermined covariance.

System and method for tracking beam-aspect targets with combined Kalman and particle filters

A non-traditional, non-uniformity compensation processor. In the illustrative embodiment, the feedforward adaptive non-uniformity compensation processor includes a multiplier which receives a video image and generates a compensated video image by multiplying the video signal by one of a noise reducing constant or one. The inventive processor further includes a shunting multiplication processor which supplies a selected one of the noise reducing constant or one to the multiplier in response to the presence of one of fixed pattern noise (FPN) and temporal noise (TN) in adjacent frames of the video image. In an illustrative embodiment, the inventive system cones the output of an FPA to generate a coned output signal. The system isolates the FPN in the coned output signal and feedforward processes the coned output signal on a pixel-by-pixel basis to generate a FPN-reduced output signal. In an exemplary embodiment, the feedforward processing step includes the step of multiplying the coned output signal by a predetermined value which is substantially smaller, i.e., approximately zero, than the coned output signal.

Non-traditional adaptive non-uniformity compensation (ADNUC) system employing adaptive feedforward shunting and operating methods therefor

An oscillator to generate a low phase-noise reference signal at an oscillation frequency includes a frequency generator to generate the reference signal responsive to a control signal, and a delay element made of a high-temperature superconductor material. The delay element time-delays the reference signal and provides a low phase-noise time-delayed reference signal when cooled to a cryogenic temperature. The oscillator includes a phase detector to generate the control signal from a phase difference between the time-delayed reference signal and a phase-shifted reference signal. The delay element may comprise a coplanar waveguide having a length between 500 and 1000 meters arranged randomly on a substrate having a diameter of between five and thirteen centimeters. The delay element may provide a delay ranging from five to fifteen microseconds. The coplanar waveguide may be comprised of Yttrium-Barium-Copper Oxide disposed on either a Lanthanum-Aluminum Oxide or a Magnesium Oxide substrate.

Low phase-noise local oscillator and method

A device is provided that can capture and store electrically neutral excited species of antimatter or exotic matter (a mixture of antimatter and ordinary matter), in particular, excited positronium (Ps*). The antimatter trap comprises a three-dimensional or two-dimensional photonic bandgap (PBG) structure containing at least one cavity therein. The species are stored in the cavity or in an array of cavities. The PBG structure blocks premature annihilation of the excited species by preventing decays to the ground state and by blocking the pickoff process. A Bose-Einstein Condensate form of Ps* can be used to increase the storage density. The long lifetime and high storage density achievable in this device offer utility in several fields, including medicine, materials testing, rocket motors, high power/high energy density storage, gamma-ray lasers, and as an ignition device for initiating nuclear fusion reactions in power plant reactors or hybrid rocket propulsion systems.

High density storage of excited positronium using photonic bandgap traps

A compensated radome is provided, comprising an inner layer of a negative index of refraction material, often referred to as a &ldquo;metamaterial&rdquo;, and an outer layer of a positive index of refraction material. The thickness of the two materials and their respective refractive indices are adjusted so that a beam of light passing through the radome is effectively not refracted. The metamaterial-compensated radomes solve the bore sight angle problem with a minimum of complexity.

Radome compensation using matched negative index or refraction materials

A method of absorbing microwave radiation is provided. The method comprises placing a structure in the path of the microwave radiation, the structure comprising an array of metal plates supported over a metal substrate by vertical conducting vias. The structure finds specific use in missiles having a dome portion that operates in a stealth mode. At least the inside of the dome portion is provided with the above-described structure for absorbing microwave radiation. The structure also finds use in anechoic chambers for use in testing microwave-emitting devices. Such anechoic chambers have walls, a floor, and a ceiling, which are provided with the above-described structure for absorbing microwave radiation. Surface patterning is thus used to enhance the micro-wave absorption. In addition, the frequency over which the material is highly absorptive can be shifted by changing the height of the structure, thus allowing active control (&ldquo;tunable in real time&rdquo;).

Microwave absorbing material

A system and method for detecting a target. The inventive method includes the steps of receiving a complex return signal of an electromagnetic pulse having a real and an imaginary component; extracting from the imaginary component information representative of the phase component of the return signal; and utilizing the phase component to detect the target. Specifically, the phase components are those found from the complex range-Doppler map. More specific embodiments further include the steps of determining a power spectral density of the phase component of the return signal; performing a cross-correlation of power spectral density of the phase component of the return signal between different antenna-subarray (quadrant channels); and averaging the cross-correlated power spectral density of the low frequency components. In an alternative embodiment, the cross-correlation is performed on the phase component of the range-Doppler map directly. This signal can then be averaged to potentially provide improved detection of targets. The cross-correlations of the power spectral densities derived from the complex valued range-Doppler map are then used to detect the target in the presence of monostatic clutter. An additional teaching relates to a utilization of the phase component to ascertain a direction of the target and thereby effect target tracking as well as target detection.

System and method for detecting and estimating the direction of near-stationary targets in monostatic clutter using phase information

A method for measuring acceleration uses an accelerometer apparatus having an optically transparent, stress-birefringent material, a source of polarized light positioned to direct a polarized beam of light into the optically transparent, stress-birefringent material, and a detector system positioned to detect an output beam from the optically transparent, stress-birefringent material. The accelerometer apparatus is accelerated, and the acceleration of the accelerometer apparatus is simultaneously determined from a measurement of stress-induced optical birefringence in the optically transparent, stress-birefringent material.

Optical accelerometer and its use to measure acceleration

A radar antenna for a guided missile is calibrated in flight using a point source of microwave radiation and a lens to emulate a far field source. The microwave source and lens fit behind a metal cap at the leading end of the radome and so do not adversely affect the radar. A variety of techniques to power the point source are disclosed, and a variety of lens arrangements are disclosed. The invention allows a radar antenna to be calibrated in flight, and so insures against mis-calibration due to aging components as well as the heat and mechanical forces associated with storage and/or launch of the missile.

Far field emulator for antenna calibration

A multi-resolution feature extraction method and apparatus. In the illustrative embodiment, the feature extractor includes circuitry for receiving and transforming a time variant data signal into a multi-resolution data signal. The multi-resolution data signal is compared to each of a plurality of object templates. The system then generates a feature vector based on a correlation of the multi-resolution data signal to one of the object templates. The multi-resolution feature extraction method employs object templates formed by transforming time variant image data for each of a plurality of objects into a respective multi-resolution template and averaging all templates for each respective object. The method includes steps for transforming an incoming time variant data signal into a multi-resolution data signal, comparing the multi-resolution data signal to each of the object templates, and generating a feature vector when the multi-resolution data signal correlates to one of the object templates. In a more specific implementation, the method further includes the steps of calculating a confusion matrix (CM), classifying the feature vectors as one of the objects to thereby produce classified objects responsive to the CM, and selecting a target from the classified objects. A multi-resolution feature extractor according to the present invention employs object templates formed by transforming time variant image data for each of a plurality of objects into a respective multi-resolution template and averaging all templates for each respective object to thereby generate object templates.

Multi-resolution object classification method employing kinematic features and system therefor

A system and method adapted for use with a focal plane array of electromagnetic energy detectors to receive first and second frames of image data from electromagnetic energy received from at least a portion of a scene. The first frame is a focused frame and the second frame is a blurred frame. In a feed-forward path the system compares the first frame to the second frame and provides an error signal in response thereto. In a main path, the system multiplies at least a portion of the second frame of image data with the error signal to provide an noise error corrected output signal. In the preferred embodiment, the error signal is scaled prior to being multiplied by the second frame. A min-mean filter is provided to remove dome shading effects from the frames of image data. In the best mode, the min-mean filter is disposed in the main path and blurred and focused outputs therefrom are weighted, averaged and stored. The weighted, averaged and stored focused frames are compared to the weighted, averaged and stored blurred frames to provide a fixed pattern noise error signal. A temporal noise error signal is identified from the weighted, averaged and stored focused frames. The fixed pattern and temporal noise error signals are fed forward and shunted from a current frame using multiplication or division. Thereafter, a constant mean value may be added to provide the output signal. Pixel replacement is consolidated into a single circuit and positioned prior to the min-mean filter.

Adaptive non-uniformity compensation using feedforward shunting and min-mean filter

An image processing system and method. In accordance with the inventive method, adapted for use in an illustrative image processing application, a first composite input signal is provided based on plurality of data values output from a sensor in response to a scene including a target and clutter. The composite signal is processed to provide a plurality of tap weights. The tap weights are generated by the matrix of data values which is first filtered by a wavelet transform to provide a set of coefficients. The coefficients are sparsened to provide a sparse matrix. The sparse matrix is then inverse wavelet transformed to provide the tap weights. Finally, the tap weights are applied to the composite signal to yield a clutter reduced output signal. In the illustrative implementation, the matrix is a covariance matrix. However, a method for implementing the teachings of the invention in the data domain is also disclosed. In the illustrative implementation, the sparsed matrix is inverted and a set of steering vectors is applied to create the tap weights. The invention affords an enhanced Signal-to-Interference&plus;Noise Ratio (SINR) because (i) wavelets provide better bases for nonstationary processes and therefore offer improved sample support performance and (ii) coefficient thresholding in wavelet domain removes noisy data that is difficult to estimate.

Growing community of inventors

Tucson, AZ, United States of America

Harry A Schmitt