Src Corporation

Harvey K Schuman

Daniel D Thomas, Jr

Ping G Li

Michael Robinson

John G Wiley

Gregory J Kliss

Jason Michael Steeger

Dojana Y Salama

Anthony M Davis

Lun Z Chen

Donald M McPherson

David R Hagenmayer

An antenna array includes a first ground plane; a second ground plane disposed below the first ground plane; a folded monopole antenna disposed between the first ground plane and the second ground plane, the folded monopole antenna comprising a driven arm, a parasitic arm, and a short connecting the driven arm to the parasitic arm; an antenna disposed above the first ground plane; and a feedline in electrical communication with the antenna such that an electrical signal input to the feedline drives the antenna, wherein the feedline extends through a cavity formed within the parasitic arm of the folded monopole antenna.

Folded monopole antenna for use within an array

An airborne radar system and signal interpretation approach that detects slow moving ground targets using angle and Doppler of Keystone formatting process, and is referred to as Angle-Doppler Keystone Formatting (ADK). ADK collapses the clutter ridge to a constant Doppler or to a constant angle, thereby transforming a clutter ridge in angle-Doppler space into a horizontal line of constant Doppler or a vertical line of constant angle. Clutter may then be filtered more effectively, such as by using multiple beams as the source of STAP training data or by using multiple Doppler bins.

Angle-Doppler Keystone formatting for airborne look-down radar system

A radar system includes an antenna array including a plurality of antenna elements; and a transmitter portion coupled to the antenna array, the transmitter portion being configured to sequentially transmit a first transmit beam and a second transmit beam from a single pulse, the first transmit beam and second transmit beam being formed using the same aperture of the antenna array, wherein a skew angle of the first transmit beam is distinct from a skew angle of the second beam. Such radar system alternatively transmitting through subarrays and receiving each via the entire array and combining the signals such that the transmit and receive parts of one of two 2-way beams point in the same direction and the transmit and receive parts of the second 2-way beam point in the same direction and these directions are within a standard beamwidth of each other.

Angle diversity multiple input multiple output radar

A system and method for tuning a transistor-based circuit. The system includes a negative impedance converter circuit having a capacitor, a first transistor, and a second transistor. As a current travels through the capacitor, the first transistor and the second transistor each sample voltage at the capacitor and invert the voltage at an input of the negative impedance converter circuit. The negative impedance converter circuit also has a third transistor in series with the capacitor. The third transistor has a base voltage. Changing the base voltage of the third transistor changes the voltage sampled by the first transistor and the second transistor.

System and method for tuning transistor-based non-foster negative impedance circuits for low-frequency antennas

The present invention is directed to an antenna system and a method that is configured to compute calibration element voltage gain patterns as functions of a digital antenna model and a plurality of complex beamformer voltages, determine calibration through path transfer functions from the plurality of complex voltages, and remove the calibration element voltage gain patterns from the calibration through path transfer functions to determine a beamforming network transfer function. The beamforming network transfer function and the far-field element voltage gain patterns are combined to obtain a system transfer function used to revise a calibration table.

On-site calibration of array antenna systems

The present invention is directed to a method for processing radar signals in a distributed array radar that includes a first airborne platform and at least one second airborne platform. Doppler filtered radar return samples are obtained and a weight value is calculated as a function of first clutter signals and second clutter signals. The weight value is employed in a weight vector that is computed, as well, from a steering vector that need not be matched to the target vector. The weight vector is applied to a signal vector corresponding to the Doppler filtered radar return samples. An open loop feedback is implemented and configured to create beam pattern nulls at angles corresponding to the plurality of first interference signals within each of the Doppler bins without substantially tracking a position or velocity of the first airborne platform or the at least one second airborne platform.

Multiplatform GMTI radar with adaptive clutter suppression

The present invention is directed to a ground moving target (GMTI) radar that can detect targets, including dismounts, with very small minimum detectable velocities by combining signals from antennas on different spatially separated platforms in a main beam clutter-suppressing spatially adaptive process without requiring that the relative positions of the antenna phase centers be accurately tracked. The clutter nulling is in addition to that provided by the Doppler filters. The spatial displacement provides a narrow main beam clutter null reducing undesired target suppression. The clutter-suppressing spatially adaptive structure is used in both the sum and delta channels of the monopulse processor so that the beam distortion caused by the spatial nulling is compensated for, and the monopulse look-up process is preserved to maintain angle accuracy. Noncoherent integration is employed to recover signal to noise loss resulting from the uncertain relative locations of the platforms.

The present invention is directed to a ground moving target (GMTI) radar that can detect targets, including dismounts, with very small minimum detectable velocities by combining signals from antennas on different spatially separated platforms in a main beam clutter-suppressing spatially adaptive process without requiring that the relative positions of the antenna phase centers be accurately tracked. The clutter nulling is in addition to that provided by the Doppler filters. The spatial displacement provides a narrow mainbeam clutter null reducing undesired target suppression. The clutter-suppressing spatially adaptive structure is used in both the sum and delta channels of the monopulse processor so that the beam distortion caused by the spatial nulling is compensated for, and the monopulse look-up process is preserved to maintain angle accuracy. Noncoherent integration is employed to recover signal to noise loss resulting from the uncertain relative locations of the platforms.

Multiplatform GMTI radar with enhanced SNR, monopulse

A radar system includes a transmit antenna array having subarrays disposed at predetermined positions. An orthogonal waveform signal is directed to a corresponding one of the subarrays. On receive, an adaptive processor derives a plurality of adaptive weight factors from a plurality of receive signals and applies them to the receive signals to obtain a jammer cancelled signal. That signal is separated into its orthogonal waveform components by passing it through a bank of correlators. The correlator system provides a plurality of unique receive signals substantially corresponding one-to-one to the unique transmit subarrays. The receive beamformer derives an angular estimate of at least one target relative to boresight from the unique receive signals.

MIMO angle estimation with simultaneous mainlobe jammer cancellation

A method for determining beamformer scattering parameters for a plurality of phased array radar antenna subarrays that each include a radiating (e.g., dipole) component and a beamformer component provides for obtaining for the plurality of phased array radar antenna subarrays a plurality of electromagnetic measurements at a plurality of ports. Analogous electromagnetic measurements are obtained for a reference subarray including a radiating component but absent a beamformer component. The plurality of phased array radar antenna subarray electromagnetic measurements and the reference subarray electromagnetic measurements provide a plurality of beamformer scattering parameter values for the plurality of phased array radar antenna subarrays that may be used in modeling and calibrating a phased array radar apparatus that may be assembled from the plurality of phased array radar antenna subarrays.

Bench-top measurement method, apparatus and system for phased array radar apparatus calibration

The present invention is directed to a system that includes a sensor having a plurality of antenna elements arranged in a three-dimensional array. None of the plurality of antenna elements is configured as a loop antenna element. Each of the plurality of antenna elements are configured to provide a sensor output signal in response to an incident electromagnetic field having predetermined characteristics. A processing circuit is coupled to the sensor, the processing circuit being configured to obtain a directional vector to a source of the incident electromagnetic field from the plurality of sensor output signals. The sensor output signals correspond to a plurality of field components of the incident electromagnetic field at a point. The plurality of field components include differential values such that the plurality of field components providing at least nine (9) degrees of freedom (DOFs).

Growing community of inventors

Fayetteville, NY, United States of America

Harvey K Schuman