Raytheon Company

Hughes Aircraft Company

Raytheon Command and Control Solutions LLC

Thomas W Miller

Christopher W Reed

James W Rakeman

Peter J Kahrilas

David E Stephens

Samuel P Lazzara

C Weldon Chapman

Robert D Kerwin

A system for providing remote target identification is provided that includes a radar system and an electro-optical detector. The radar system is configured to locate a remote target. The electro-optical detector is configured to detect an optical signal transmitted from the target when the target is located. The optical signal includes identifying data for the target.

System and method for providing remote target identification using radiofrequency identification

A beamforming system and method. The inventive beamforming system is adapted for use with an array antenna having a plurality of antenna elements and includes a Fast Fourier Transform (EFT) for transforming a signal received by an antenna into a plurality of frequency subbands. A plurality of adaptive processors are included for performing adaptive array processing on each of the subbands and providing a plurality of adaptively processed subbands in response thereto. A normalizing processor is also included for normalizing the adaptively processed subbands. In the illustrative embodiment, the signal is a Global Positioning System (GPS) signal and a digital multiplier for applying a weight to a respective frequency subband for each of the elements of the array. The weights are chosen to steer a beam in a direction of a desired signal. Normalization involves adjusting the amplitude of one or more of the subbands to remove any bias distortion due to the adaptive processing thereof.

System and method for subband beamforming using adaptive weight normalization

In accordance with one aspect of the present invention, a preprocessor is provided for use in an adaptive antenna array. The purpose of the preprocessor is to modify the incoming signals received by each antenna of an antenna array in such a manner as to reduce the amount of computation necessary to compute the adaptive array weights. In an adaptive array, the weight computation process generally requires calculations using digital electronics, which tend to be computationally intensive when applied to wideband, high sample rate signals. The preprocessor of the present invention solves this problem by filtering the data in such a manner as to reduce the sample rate of the signal without losing the essential characteristics of the signal. The preprocessor includes an input terminal for receiving an electromagnetic signal from an antenna element of the adaptive antenna array, and a frequency smearer operatively coupled to the input terminal. The frequency smearer is provided in order to smear the electromagnetic signal by varying the frequency of the electromagnetic signal across a predetermined frequency band and outputting the smeared electromagnetic signal to an averaging circuit. The averaging circuit, which is operatively coupled to the output of the frequency smearer, repetitively computes and outputs an average with respect to time of the smeared electromagnetic signal.

Adaptive weight calculation preprocessor

A phase-stabilized adaptive array system with a moving antenna array and a plurality of signal channels coupled to the antenna array, each for producing a channel signal. Each channel has adaptive signal weighting apparatus for weighting the channel signal by a channel weight. The system includes combining apparatus for combining the weighted channel signals to form a beam signal, and phase compensation apparatus for applying phase compensation weights to the array signals or the beam signal which vary in dependence on the array position such that the response to a signal at a known direction is held substantially constant while the antenna is moved, or as the weights are updated. A method for operating an adaptive array includes rotating the antenna array with respect to a target, providing a plurality of signal channels coupled to the antenna array, each for producing a channel signal, adaptively weighting each channel signal by a channel weight, and combining the weighted channel signals to form a beam signal. The method further includes, for phase stabilizing the response to a target at a given angular position, applying phase compensation weights to the array signals or the beam signal which vary in dependence on the antenna position such that the response to a signal at a known direction is held substantially constant while the antenna rotates, or as the weights are updated.

Phase stabilization in adaptive arrays

Electronic antenna-rotation compensation apparatus is provided for correcting data errors introduced into radar return signals by the rotation of phased array antennas. The apparatus includes circuitry for sampling and A-to-D converting I (in phase) and Q (quadrature) radar return signal components provided by individual antenna elements comprising the array antenna and for providing and applying correction factors to each ith signal components sample from each nth element across the antenna. The correction factors may be precomputed and stored in a memory for use when required or may be computed as needed. The corrected, digital I and Q signal component samples are supplied to a conventional processor, for example, as adaptive array processor, for extracting useful target data from return signal interference and clutter. A corresponding method is provided for compensating for the effects of phased array antenna rotation.

Antenna-rotation compensation apparatus and method for phased array

A phased array antenna system is disclosed which employs digital beamforming of multiple independent transmit beams. A waveform generator provides successive digitized time samples of a desired waveform, and the respective beamforming coefficients which produce the desired amplitude and phase distribution for each beam are applied to the waveform samples. The resulting digital samples are then mixed up to IF, converted to digital form, frequency converted to the desired RF frequency, amplified and passed to the respective antenna subarrays. The transmit system permits fine granularity phase control, providing accurate beamforming and positioning and improved sidelobe control.

Digital beamforming for multiple independent transmit beams

An adaptive array processor is disclosed for processing the signals from a main antenna and one or more auxiliary antennas to provide suppression of wideband interference. The outputs from the respective antennas are transformed into the frequency domain by synchronized chirp transformers conducted over a transform block length. The transformed auxiliary antenna signal is weighted by time varying, frequency dependent weights which are adaptively determined. The transformed main antenna and weighted auxiliary antenna signals are then combined. The combined signal is then transformed back to the frequency domain by an inverse chirp transformation.

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Yorba Linda, CA, United States of America

Thomas W Miller