Abstract: A circuit comprises a receive processing window formation subsystem, a matched filter subsystem, a keystone interpolation subsystem, a phase modulation subsystem, and an image forming subsystem. The receive processing window formation subsystem forms, for each radar return from a scene, a receive processing window containing the radar return as an unbroken radar return. The matched filter subsystem creates a motion model for a reference point target disposed at a predetermined location within the scene, based on a set of motion compensation parameters for range and range rate, to compensate for at least some effects of fast time Doppler on the reference point target. The keystone interpolation subsystem rescales slow time information from the matched filter subsystem. A phase modulation subsystem applies phase modulations to a keystone-interpolated 2-D output array of information associated with the scene, to ensure proper registration in a range-Doppler map output of the scene.

Abstract: A signal identification system includes an analog adaptive channelizer having a plurality of channels. Each channel has a channel size defined by a bandwidth and a gain. The system further includes an electronic signal identification (ID) controller in signal communication with the analog adaptive channelizer. The ID controller is configured to determine a dynamic range event that modifies an energy level of an affected channel among the plurality of channels, and output a feedback signal including channel parameters based on the dynamic range event. The analog adaptive channelizer actively adjusts at least one of the bandwidth and the gain of the affected channel based on the feedback to change the channel size of the affected channel.

Abstract: A system and method for forming synthetic aperture radar images. Radar return pulses are grouped into sub-dwells, and their frequency content is separated into frequency sub-bands. A coarse image is formed for each sub-band/sub-dwell combination. The coarse images are iteratively interpolated to higher resolution and combined, to form a single high-resolution synthetic aperture radar image.

Abstract: A signal identification system includes an analog adaptive channelizer having a plurality of channels. Each channel has a channel size defined by a bandwidth and a gain. The system further includes an electronic signal identification (ID) controller in signal communication with the analog adaptive channelizer. The ID controller is configured to determine a dynamic range event that modifies an energy level of an affected channel among the plurality of channels, and output a feedback signal including channel parameters based on the dynamic range event. The analog adaptive channelizer actively adjusts at least one of the bandwidth and the gain of the affected channel based on the feedback to change the channel size of the affected channel.

Abstract: A signal identification system includes an analog adaptive channelizer having a plurality of channels. Each channel has a channel size defined by a bandwidth and a gain. The system further includes an electronic signal identification (ID) controller in signal communication with the analog adaptive channelizer. The ID controller is configured to determine a dynamic range event that modifies an energy level of an affected channel among the plurality of channels, and output a feedback signal including channel parameters based on the dynamic range event. The analog adaptive channelizer actively adjusts at least one of the bandwidth and the gain of the affected channel based on the feedback to change the channel size of the affected channel.

Abstract: A system and method for forming synthetic aperture radar images. Radar return pulses are grouped into sub-dwells, and their frequency content is separated into frequency sub-bands. A coarse image is formed for each sub-band/sub-dwell combination. The coarse images are iteratively interpolated to higher resolution and combined, to form a single high-resolution synthetic aperture radar image.

Abstract: A signal identification system includes an analog adaptive channelizer having a plurality of channels. Each channel has a channel size defined by a bandwidth and a gain. The system further includes an electronic signal identification (ID) controller in signal communication with the analog adaptive channelizer. The ID controller is configured to determine a dynamic range event that modifies an energy level of an affected channel among the plurality of channels, and output a feedback signal including channel parameters based on the dynamic range event. The analog adaptive channelizer actively adjusts at least one of the bandwidth and the gain of the affected channel based on the feedback to change the channel size of the affected channel.

Abstract: A method for estimating a target direction of a wideband signal received on an electronically steered array includes: applying convolutional or stretch processing to spatial frequency data of the wideband signal; initializing a stabilization direction to a beam pointing direction; stabilizing the spatial frequency data to the stabilization direction; compressing the spatial frequency data to a plurality of frequency range or time bins; selecting range or time bins and forming a covariance matrix; calculating an estimated target direction using the covariance matrix; determining if a stabilization direction accuracy condition is met; recalculating the stabilization direction based on the estimated target direction if the stabilization direction accuracy condition is not met; and iteratively repeating until the stabilization direction accuracy condition is met.

Abstract: Methods and systems are provided for efficiently packing nodes within an electromagnetic state space.

Abstract: Methods and systems are provided for efficiently packing nodes within an electromagnetic state space.

Abstract: A method for estimating a target direction of a wideband signal received on an electronically steered array includes: applying convolutional or stretch processing to spatial frequency data of the wideband signal; initializing a stabilization direction to a beam pointing direction; stabilizing the spatial frequency data to the stabilization direction; compressing the spatial frequency data to a plurality of frequency range or time bins; selecting range or time bins and forming a covariance matrix; calculating an estimated target direction using the covariance matrix; determining if a stabilization direction accuracy condition is met; recalculating the stabilization direction based on the estimated target direction if the stabilization direction accuracy condition is not met; and iteratively repeating until the stabilization direction accuracy condition is met.

Abstract: A method for estimating a target angle of a wideband signal received on an electronically steered antenna array includes: generating spatial frequency data from the received wideband signal; stabilizing the spatial frequency data to a beam steering direction; compressing the stabilized spatial frequency data to a plurality of frequency range bins; calculating a monopulse discriminant from the stabilized spatial frequency data; and calculating the target angle using the monopulse discriminant.

Abstract: A method for estimating a target direction of a wideband signal received on an electronically steered array includes: applying convolutional or stretch processing to spatial frequency data of the wideband signal; initializing a stabilization direction to a beam pointing direction; stabilizing the spatial frequency data to the stabilization direction; compressing the spatial frequency data to a plurality of frequency range or time bins; selecting range or time bins and forming a covariance matrix; calculating an estimated target direction using the covariance matrix; determining if a stabilization direction accuracy condition is met; recalculating the stabilization direction based on the estimated target direction if the stabilization direction accuracy condition is not met; and iteratively repeating until the stabilization direction accuracy condition is met.

Abstract: A method for estimating a target angle of a wideband signal received on an electronically steered antenna array includes: generating spatial frequency data from the received wideband signal; stabilizing the spatial frequency data to a beam steering direction; compressing the stabilized spatial frequency data to a plurality of frequency range bins; calculating a monopulse discriminant from the stabilized spatial frequency data; and calculating the target angle using the monopulse discriminant.

Abstract: A radar system is mounted on a moving platform moving along a great circle. The radar comprises a radar receiver for digitizing radar returns having a phase from a scatterer (target) in a scene. A computer focuses the phase of the radar returns from the scatterer in the scene, using cylindrical coordinates to arrive at an image. An initial position estimate of the scatterer (target) within the image is made. This initial position is converted from cylindrical coordinates to geodesic coordinates of initial latitude, initial longitude and initial elevation. The geodesic coordinates are used to compare with a database descriptive of earth's surface. The initial elevation is replaced with that contained in the database. A second scatterer (target) location is computed using the database elevation. The second target location is compared with the first target location to obtain a difference. If the difference is above a threshold, the second scatterer location is substituted for the initial position estimate.

Abstract: A synthetic aperture image of a scene is acquired using a radar system. The scene has one or more radar scatterers located on a horizontal flat {circumflex over (x)},? plane. The radar system is mounted on a moving platform moving at an angle ?tilt with respect to the {circumflex over (x)},? plane, with a component of motion in a perpendicular {circumflex over (z)} direction. The synthetic aperture image acquisition requires digitizing radar returns having a phase returned from scatterers in the scene, adjusting the phase of the radar returns in response to ?tilt to generate phase adjusted returns, then computing the synthetic aperture image from said phase adjusted returns. The phase adjustment takes into account ?tilt platform motion with respect to the scene.

Abstract: Motion compensation for coherent combination of pulses facilitates a SAR image of a scene on earth's surface. A great circle (406) is centered with respect to the earth's center, The great circle (406) has an axis (412) perpendicular to a first plane. Axis (412) passes through the earth's center. The first plane contains great circle (406) and includes the earth's center. Great circle (406) has a first center defined by an intersection of the first plane and axis (412). The scene has one or more radar scatterers and is located on a surface (402). The radar system is mounted on a moving platform (400) moving with a component of motion in a direction along great circle (406). The radar comprises a radar receiver for digitizing the radar returns having a phase from scatterers on surface (402), and a computer for focusing the phase of said radar returns from the scatterers on surface (402).