Raytheon Company

United States of America As Represented by the Secretary of the Air Force

Fritz Steudel

David V Manoogian

Kaichiang Chang

Eli Brookner

Fernando Beltran

Kai-Chiang Chang

George D Thome

Thomas P Sifferlen

Robert P Enzmann

Systems and techniques for coherent combining radars include generating a phase and range calibration and initialization values for adjusting a time delay and a phase of a transmitted pulse from one of the radars, resulting in received composite target echoes at each of the radars having contributions from monostatic and bistatic echoes. The method further includes predicting phase and range correction values for further adjusting the time delay and the phase of subsequent radar pulses transmitted by one of the radars to continue to result in received composite target echoes at each of the radars. The method further includes coherently summing the composite target echoes.

System and method for coherently combining a plurality of radars

A method and apparatus for determining range of a radar target is provided. Signal samples based on returns of a target during tracking are processed to produce a wideband envelope range estimate for components of target motion. The components of target motion include precession and spin motion. Ambiguous phase values are measured. An unambiguous phase value indicative of range is produced from the wideband envelope range estimate and measured ambiguous phase values.

Process for phase-derived range measurements

A mechanism for combining signals of multiple radars to achieve increased range, radar sensitivity and angle accuracy is provided. A first signal beam is radiated from an antenna of a first radar in the direction of a target. A second signal beam is radiated from an antenna of a second radar in the direction of the same target. The echo signals from the first signal beam and the second signal beam are received at both radars. The echo signals received at the first radar are processed to produce first radar processed echo signals and the echoes signals received at the second radar are processed to produce second radar processed echo signals. The first and second radar processed echo signals are combined to form an aggregate value.

Multiple radar combining for increased range, radar sensitivity and angle accuracy

A radar system including a blanker and a sidelobe canceler is described including an open loop nulling circuit for introducing one or more nulls in the main beam and a blanker beam. With this arrangement, the blanker can be operated even in the presence of strong sidelobe jamming without the conventional problems attributable to noise amplification. Also described is an antenna configuration for implementing the open loop nulling, including a pair of orthogonal linear arrays. One of the arrays is omnidirectional in azimuth and directional in elevation and the other array is omnidirectional in elevation and directional in azimuth in order to point the main and blanker beams in the direction of jammers. In one embodiment, the radar system further includes a spoofer and the crossed linear arrays process the spoofer signals on transmit and process blanker signals on receive.

Radar system having spoofer, blanker and canceler

An array antenna includes two different types of super elements each having transmit/receive (TR) modules coupled thereto. The TR modules are widely spaced and the super elements are arranged such that by selectively activating certain ones of the super elements the antenna provides a dual field of view in elevation. A Narrow Field of View (NFOV) is achieved by activating all super elements in the antenna aperture. A Wide Field of View (WFOV) utilizes only super elements which are arranged in a center portion of the antenna aperture.

Array antenna having a dual field of view

A phased array radar antenna uses time-steering subarray notch weightings to produce a wideband notch in the direction of interference for Electronic-Counter-Measure (ECM) interference suppression. A predetermined set of subarray notch weightings, each set being identical for each subarray, is stored in controllers each of which is coupled to a plurality of phase shifters and attenuators for feeding radiating elements of the antenna. Interference suppressors operate from a plurality of controllers to produce a subarray pattern having a notch in the direction of interference. Beamformers then combine outputs of all time-steering subarrays in the antenna so as to produce an antenna pattern having a wideband notch in the direction of interference.

Wideband interference suppressor in a phased array radar

A non-linear digital waveform generator apparatus utilizing a variable clock to produce a predistorted transmission signal which is opposite to the distortion that is produced by the target's velocity.

Doppler compensated digital non-linear waveform generator apparatus

In a radar system employing an array antenna and microwave circuitry coupled thereto for developing sum and difference signals, a correction circuit utilizes the sum and difference signals for providing increased accuracy to elevation and azimuthal angle measurements of wide bandwidth radar signals. A correction is applied to the difference signal by subtracting therefrom a weighted time derivative of the sum channel, the weighting being proportional to the boresight error slope and the sines of the elevation and azimuth angles.

Correction circuit for wide bandwidth antenna

A system for a phased array antenna including a set of power amplifiers for amplifying the power of a signal to be transmitted by radiating elements of the antenna. A set of hybrid couplers are connected between the power amplifiers and the radiating elements with individual ones of the hybrid couplers being cross-connected for sharing the power of each amplifier among a set of radiating elements. The coupling of power is selectively varied between the amplifiers and the radiating elements by shifting the phase of the signal applied to each power amplifier.

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Sudbury, MA, United States of America

Fritz Steudel