Raytheon Company

Kaichiang Chang

Jack J Schuss

Jeffrey C Upton

Yuchoi Francis Lok

Fernando Beltran

Landon L Rowland

Michael G Sarcione

William Kennedy

Thomas V Sikina

Jerome Howard Pozgay

Yueh-Chi Chang

Fritz Steudel

Richard L O'Shea

Gregory M Fagerlund

Sharon Ann Elsworth

Kenneth S Komisarek

Stephen M Sparagna

Jerome D Hanfling

Marvin Fredberg

Edward A Geyh

Yong Liu

Richard Warnock

Daniel F Rypysc

Benjamin L Caplan

Dean Pichon

Jeffrey R Holley

David R Schmidt

Frederic C Stevens, Iv

Drew S Ganter

Garret E Murdza

Michael Anderson

Robert D Foltz

Iv Frederic C Stevens

A radar system uses multiple-beam maximum likelihood estimation (MLE) during both search and tracking operations. During search, a four beam sequential beam cluster may be used to search for targets in a region-of-interest. During tracking, a three beam triad may be used to track one or more detected targets. In some embodiments, a beam selector switch may be used to allow two offset receive beams to time share a beamformer output port to generate the four beam sequential cluster.

Sequential multi-beam radar for maximum likelihood tracking and fence search

A ship-based over-the-horizon (OTH) radar system provides mobile, persistent, wide-area air and ship surveillance across large ocean expanses and in anti-access/area denial (A2AD) environments. A transmit ship may include a log-periodic antenna (LPA) array adapted for use on a ship and a receive ship may include a plurality of monopole or dipole whip antennas. The transmit/receive antenna is fronted by a ground screen, which can be sized taking into account the sea as a naturally reflective surface. The transmit/receive ship can include advanced software to compensate for ship movement and synthetic aperture radar (SAR) techniques can be employed to includes the effective size of the radar receiver aperture. A modular design, using standard commercial container ships and shipping containers, allows for rapid deployment/stowage of radar equipment. Related methods are also described.

Ship-based over-the-horizon radar

Methods and apparatus for a phased array radar system including an array comprising columns of super-elements containing radiator elements located along a length of the super-element, wherein the super-elements form the columns such that super-elements are arranged end-to-end, wherein the super-elements are arranged in the column at randomized locations to reduce sidelobes. In a further embodiment, super element lengths can be randomized.

Method and apparatus for reducing sidelobes in large phased array radar with super-elements

Methods and apparatus for a super-element assembly for a phased array radar aperture, the super-element assembly having a first port and a second port to receive a first signal at the first port to generate a main beam, and receive a second signal at the second port to generate an image beam for generating scan volume coverage using the main and image beams.

Methods and apparatus for volumetric coverage with image beam super-elements

Embodiments of the present invention are directed to techniques and systems for modifying the transmit beam of a phased array antenna in order to effect a shape change in the beam that pre-compensates for platform motion and clutter considerations in the local environment. The techniques and systems herein disclosed take advantage of the phase controlling capability of phased array antennas to adjust the performance of each element in a way that de-focuses or spoils the transmit beam. This spoiling, in turn, enables the transmission of a broader, tailored beam that provides illumination over an area that would otherwise require multiple scans from narrow transmit beams. The techniques described provide a closed-form solution that sacrifices some antenna pattern efficiency in exchange for greatly reduced computational complexity over prior art, optimal search techniques.

Broad beam antenna design for a tilted phased array with platform motion

An array antenna is provided that operates at high-band and low-band, comprising a first array of high-band radiators and a second array of low-band radiators, each respective low-band radiator disposed so as to be interleaved between the high-band radiators so as to share an aperture with the high-band radiators. Each low-band radiator comprises a coaxial section, a dielectric section, a waveguide, and a planar section. The dielectric section is formed of a continuous piece of dielectric material and includes a hollow opening formed perpendicular to the coaxial section, and a plurality of step transitions, wherein at least one of the step transitions is disposed within and partially fills the waveguide operably coupled to the planar section. The planar section is oriented to the portion of high-band radiators such that the output of the respective low-band radiator is disposed between and within the spacing between adjacent high-band-radiators.

Compact loaded-waveguide element for dual-band phased arrays

A motion compensation method and system is included in a radar antenna system mounted on a moving platform which is subject to pitch, yaw and roll. The radar antenna system includes a main array antenna, and an auxiliary antenna. The auxiliary channel associated with the auxiliary antenna utilizes roll, pitch and yaw angle motion compensations as its auxiliary antenna always steers a horizontal fan shape beam at the horizon to blank any surface (land or sea) based EM interferences. Such motion compensations are provided by a ship motion compensator component and process included within the antenna system. The ship motion compensator component in response to platform motion signals indicative of changes in platform motion angles generates new sets of values using an initial set of weighting coefficient values as a function of such angle motion changes. This produces changes in both amplitude and phase weighting coefficient values which results in both the quadrant phase rotation and the element weighting rotation. The process steers and spreads out the received auxiliary antenna pattern making sidelobe coverage broad enough to compensate for such changes in platform motion.

Adaptive sidelobe blanking for motion compensation

An air-supported sandwich radome with a hemispherical top region and a prolate region has a high strength, RF transmissive, low dielectric flexible wall. There is a defined region where damaging RF radiation is reflected. At least in the defined region, a flexible high strength, RF transmissive low dielectric layer is added and there is a low dielectric gap between the wall and the layer providing a 180&#xb0; phase delay between RF energy reflected off the wall and RF energy reflected off the layer to cancel the effect of said reflected RF energy on radar equipment housed by the radome.

Air-supported sandwich radome

A radar system comprises a first transmit/receive module for a first frequency band and a first polarization, a second transmit/receive module for the first frequency band and a second polarization orthogonal to the first polarization, a third transmit/receive module for a second frequency band and the first polarization, a fourth transmit/receive module for the second frequency band and the second polarization orthogonal to the first polarization, a first plurality of splitter/combiners to receive outputs from the first and second transmit/receive modules, a second plurality of splitter/combiners to receive outputs from the third and fourth transmit/receive modules, a plurality of lens phase shifter pairs to receive outputs from the first plurality of splitter/combiners, a plurality of diplexers to receive signals from the plurality of lens phase shifter pairs and from the second plurality of splitter/combiners, and, a radiator assembly including a series of radiator elements coupled to the plurality of diplexers.

Radar system having dual band polarization versatile active electronically scanned lens array

An adaptive processing method of and system for clutter rejection in a phased array beam pattern. The amplitude distribution of the transmit elements of a two-dimensional phased array is determined. A desired pattern with low side lobes for a linear array is synthesized. The amplitude distribution of the transmit elements of the two-dimensional phased array is compared with the synthesized pattern. Select elements of the two-dimensional array are disabled to best fit the determined amplitude distribution of the transmit elements of the two-dimensional phased array to the synthesized beam pattern. Phase only pattern synthesis is performed to produce a desired two-dimensional beam pattern with low side lobes to minimize any best fit errors.

Adaptive processing method of clutter rejection in a phased array beam pattern

According to a particular embodiment, a method for evaluating different antenna designs includes receiving different sets of antenna patterns representative of the different antenna designs from a corresponding number of data sources. The different sets of antenna patterns are applied to a characterizer component for generating a sidelobe banking (SLB) characteristic map for each set of antenna patterns received. A SLB effectiveness chart is generated from the SLB characteristic map. A best antenna weighting set is selected based on which auxiliary antenna pattern exhibits the best performance. The best of antenna weighting factors are used for designating the antenna design having superior SLB performance characteristics.

Sidelobe blanking characterizer system and method

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 phased array antenna having two stages of time steering control that achieve system performance requirements at minimum cost. The first-stage which is traditionally located at the subarray level, is a multi-bit time delay unit that has a sufficient number of bits to meet the system's range resolution requirements. The second-stage located at the radiating element level, is a single-bit time delay unit that meets the system's two-way instantaneous bandwidth requirements. This combination of first-stage and second-stage time steering control minimizes the number of subarrays required to achieve the system performance requirements.

Phased array radar antenna with two-stage time delay units

A low array antenna having transmit/receive (T/R) modules, which contain a digitally-controlled variable attenuator, for each of the two polarizations (horizontal and vertical). The array has a cylindrically curved surface which closely conforms to the shape of the fuselage of an airborne vehicle or another structure. Each polarization feeds into an elevation beamformer apparatus which provides both a uniform taper and a Bayliss/Taylor taper. As the beam is scanned in elevation, the amplitude taper is adjusted via the variable attenuator to control the taper of a sum pattern and thereby achieve low sidelobe far field sum patterns. The same attenuators that are used for the sum pattern also feed a difference network. The T/R module attenuators are set to yield the desired low sidelobe sum illumination for a desired elevation scan angle. As the array is steered in elevation, the Bayliss difference taper is distorted since the fixed elevation beamformer cannot adjust the difference pattern for the new scan angle. A T/R module is provided at each column of the array to combine the distorted Bayliss difference pattern with the compensated Taylor sum pattern output. This combining permits the distorted Bayliss array illumination to be resymmetrized thereby producing a high quality, low sidelobe, compensated Bayliss far field pattern. This apparatus provides for complete compensation of both sum and difference patterns with only a single attenuator at each element of the array and a simple monopulse feed network.

Scan compensation for array antenna on a curved surface

A radar type center fed antenna comprising a small radiating horn supported at the focal point of a parabolic reflector by three struts which are oriented to minimize the parallel polarization scattering and which have a low scattering ogive cross-section. The horn is mounted at the vertex of the parabolic surface and the intersection of the three struts using a bracket that provides minimal blockage. The struts are attached to the perimeter of the reflector. One strut having a feed waveguide is attached to the top-center of the reflector and the other two are attached at points on either side of the bottom-center at thirty degree angles to the vertical plane. The strut shape and feed-horn supporting and attaching arrangement and the integration of the feed waveguide into one of the struts results in a very low sidelobe antenna that produces a far-field pattern that has very low forward scattering due to feed and strut blockage.

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Northborough, MA, United States of America

Kaichiang Chang