Raytheon Company

Other

Raytheon Corporation

Leon Green

Joseph A Preiss

Thomas V Sikina

Yueh-Chi Chang

Eli Brookner

Yuchoi Francis Lok

Peter R Drake

Jacqueline M Bourgeois

Kai-Chiang Chang

Daniel F Rypysc

Francis Hartwich

A radar system uses a rotating antenna array having rows that display dispersive properties while feeding multiple radiating elements. In some embodiments, the radiating elements are dual polarized. In at least one embodiment, beam spoiling may be used to generate an unfocused transmit beam that covers an entire elevation range of interest. Digital beam forming may be used during a receive mode to achieve a stack of narrow-width receive beams in elevation. Frequency scanning may also be used to achieve stacked beams in azimuth.

Phased array antenna using stacked beams in elevation and azimuth

An active array radar system is controlled by photonic signals. The array of N antenna elements is divided into M subarrays, each having N/M antenna elements. Tunable lasers provide M optical wavelengths within non-overlapping bands. For transmission, a microwave transmit pulse is amplitude modulated onto the M optical signals. Time delays are introduced for an offset between elements in a subarray and for an offset between subarrays. By using wavelength division multiplexing each antenna element on the array has a true time delay.

Photonically controlled active array radar system

An active array radar system is controlled by photonic signals. The array of N antenna elements is divided into M subarrays, each having N/M antenna elements. Tunable lasers provide M optical wavelengths within non-overlapping bands. For reception, the microwave signals are optically modulated onto a single fiber for each subarray. Time delays are introduced for an offset between elements in a subarray and for an offset between subarrays. By using wavelength division multiplexing, a true time delay is attributed to each antenna element on the array. A non-coherent optical combiner having an array of N photodetectors demodulates the receive signals and recovers the coherent sum of the RF signals.

Reactive combiner for active array radar system

A radar system includes a null processor coupled to transmit receive modules. The null processor inserts nulls in the sum pattern at locations for suppressing a jamming source. The null processor determines the difference pattern based upon the product: sum*sin(x), where sum is the sum pattern and x is the azimuth angle.

Simultaneous nulling in low sidelobe sum and difference antenna beam patterns

A multi-faced radar system illuminates a common area of space by radiating a first signal at a first frequency from a first antenna face and a second signal at a second frequency from a second antenna face and cooperatively processes the first and second signal returns on the first and second antenna faces. A processor combines first signal energy from the first and second faces and combines second signal energy from the first and second faces. The processor then combines the aggregate first and second signal returns. The cooperative processing of the first and second signals on the first and second antenna faces increases signal sensitivity and dramatically reduces the time on target required for relatively high scan angles,

Cooperative radar system

A switching unit for a photonic phased array for use in the microwave frequency bands uses lasers and other photonic devices to perform various functions in the phased array such that signals can be carried to the antenna elements on a single optical fiber. In one embodiment of the invention, a set of fixed phase shifters generates signals each having different phases. In the switching unit, each resulting signal, which is of a particular phase, modulates a laser of a different color. Each different laser color is thus associated with a given phase. Alternatively, time-delay units produce signals of different time-delay states which signals are then associated with lasers of different colors. The lasers are then used for selection of the signals to be applied to each element in the array. The laser signals are combined and carried on a single optical fiber to an optical network of tunable optical filters which can be located at the element level. The single optical filter allows the phase shifters and lasers to be located remotely from the antenna elements. Using an associated beam steering controller, the optical filters are tuned such that each element in the array has a predetermined signal to thereby adjust the time gradient across the array to steer the beam.

Growing community of inventors

Newton, MA, United States of America

Leon Green