Raytheon Company

Johan E Gonzalez

Theagenis John Abatzoglou

Raymond Samaniego

Joel K McWilliams

Albert Ezekiel

Mark B Yeary

Enrique A Santiago

A bistatic synthetic aperture radar (SAR) imaging system and method include: combining each radar return pulse from airborne radar platforms with a sinusoid; deskewing each reduced radar return pulse; estimating motion parameters based on a maximum likelihood estimation (MLE); performing MLE motion correction to generate motion-corrected radar return pulses; acquiring position and velocity estimates of the airborne radar platforms and scattering locations; defining bistatic range and velocity vectors; defining new bistatic range and velocity vectors in a new set of orthogonal axes; projecting vector distance differences between the radar scattering locations along the new set of orthogonal axes to generate new range and velocity measurements along the new set of orthogonal axes; converting the new range and velocity measurements to map Doppler frequency into cross-range; and forming a bistatic SAR image in range and cross-range based on cross-range extent derived from the Doppler frequency mapping.

Bistatic inverse synthetic aperture radar imaging

A synthetic aperture radar imaging method that combines each radar return pulse with a sinusoid to reduce the radar return pulses to a baseband frequency and deskew each radar return pulse. It includes determining a maximum likelihood estimate (MLE) of residual motion parameters for a dominant scatterer on the ground relative to the airborne radar and correcting for errors in inertial navigation system measurements based on the MLE residual motion parameters. It includes convolving each radar return pulse with its corresponding radar transmission pulse to generate a range compressed image for each radar return pulse and generating a sub-band range profile image for each radar return pulse and its corresponding radar transmission pulse based on the corresponding range compressed image that has been corrected for residual motion. Performing bandwidth extrapolation on each sub-band and subsequently combining the three bands to produce an enhanced resolution image without grating lobes.

Enhanced radar range resolution

The classification and segmentation system of the current invention makes use of information from pixels of an image, namely the magnitude of the pixels, to run specific analytics to classify and segment the image pixels into different groups. This invention includes a system for processing an image, the system including an input device, a processor, a memory and a monitor. The input device is configured to receive image data, where the image data includes pixels and each pixel has a magnitude. The memory has instructions stored in it that, when executed by the processor, cause the processor to run calculations. The calculations include: calculating the log-magnitudes from the magnitudes of at least a plurality of the pixels, calculating standard deviations of the log-magnitudes for subsets of the plurality of pixels and compute an integral of the standard deviations over a desired range. The pixels are classified into different groups based on a value of the integral relative to one or more integral values. In one embodiment, a monitor is configured to display a threshold image, wherein the threshold image includes the different groups of pixels.

Reduction of CFAR false alarms via classification and segmentation of SAR image clutter

System and method for calculating three dimensional residual motion errors of a moving platform with respect to a point of interest by receiving a radar signal from the point of interest (); forming a radar image including a plurality of scatterers (); using an MLE method to obtain range, radial velocity and acceleration of the moving platform for a first peak scatterer in the radar image (); correcting a location of the first peak scatterer with respect to a scene center of the point of interest (); updating the obtained radial acceleration responsive to the corrected location (); and updating the obtained radial velocity of the moving platform responsive to the updated radial acceleration ().

On-board INS quadratic correction method using maximum likelihood motion estimation of ground scatterers from radar data

A system and method for implementing a maximum likelihood estimator for making a joint estimation of range, range rate, and acceleration of a target utilizing a pulse doppler radar. The MLE of target motion parameters are determined by keystone processing a baseband signal, and generating a first estimate of the motion parameters based on the processed signal. The first estimate is utilized to set up sampling intervals for the performance of a coarse search. Then a fine search is performed using Newton's method to determine the MLE.

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Carson, CA, United States of America

Johan E Gonzalez