Westinghouse Electric Corporation

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

Jerry A Kane

Francis W Hopwood

Martin J Decker

Winthrop W Smith

Thomas R Turlington

George A Ioannidis

David S Oros

A dual mode active aperture phased array system for pulsed radar and continuous wave applications. The system may be switched between the two modes without appreciable loss of average effective radiated power. Both the voltage and current of the biasing power to the amplifying transistors is varied to accommodate the difference in peak amplitude power while maintaining the optimum average effective radiated power. The DC power supply is a chopper.

Dual mode active aperture

The present invention includes an apparatus that prebiases a transmitted radar signal. The prebiasing of the transmit signal automatically aligns the return signals in one dimension or dimensionally transforms the return signals thereby removing the need for one of the dimensional processing operations of a conventinal two dimensional return signal interpolator. A map function generator produces small frequency (phase) changes in the transmitted signal during each pulse over the entire integration or exposure period. The map function generator produces a parabolic frequency change control signal applied during the integration period. The control signal is divided into segments where each segment controls a single transmit pulse. The control signal modifies a linear frequency modulation control signal. conventionally produced by high resolution radar systems.

Coordinate system transformation apparatus for a high resolution radar

An electronically steerable phased array radar antenna system for transmitting and receiving broadband linear FM signals is detailed. The antenna comprises a plurality of subarrays, each of which are connected by circulator means to a transmit-receive module. The highly linearized FM waveform is fed to the transmit-receive module, and a CW waveform is fed to a phase shifter in the module. The phase shifter applies a frequency offset to the CW waveform which is then added to the linear FM wideband signal for each antenna subarray. This frequency offset serves a beam steering function and can be considered a synthetic time delay.

Phased array radar antenna system

Using an electronically scanned phased array antenna, a technique is developed for aligning a broad elevation beam along an isodop for use in synthetic aperture mapping. A beam steering controller algorithm for practical implementation of the technique is described. Implementation is realized by means of a beam steering controller and the radar computer. The controller first finds the space stabilized row and column for a given phase shifter. A look-up table furnished by the radar controller provides a slope correction as a function of row. The slope is multiplied by the element column to give the correct linear phase function. This term is then subtracted from the term used to point the beam peak.

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Crofton, MD, United States of America

Jerry A Kane