Westinghouse Electric Corporation

Norman F Powell

Henry E Lee

Carl E Nothnick

Francisco J Guillen

A segmented stretch waveform for wide band high duty cycle tracking application. The waveform is divided into multiples of two spaced segments as the tracking range closes. Target returns received during spaced segments are combined to correspond to the complete waveform; and range is determined in accordance with the combined waveform. Tracking range can be varied without changing bandwidth, FM slope, duty cycle or processing time.

Radar system and method having variable tracking range

The invention comprises a jam resistant radar system. The system comprises a primary radar transmitter which is coupled to a primary antenna having a predominant main beam and sidelobes. A second wide beam antenna is coupled to a second radar transmitter which transmits a signal having a frequency spectrum encompassing the main beam with the power density being substantially equal to the power density of the sidelobes of the primary antenna. The second transmitter is frequency modulated over a spectrum in discrete steps while the primary transmitter is pulse-to-pulse or look-to-look randomly modulated over the spectrum. This prevents a listening jammer positioned in the sidelobes from determining the pulse-to-pulse or look-to-look frequency being used by the primary radar transmitter.

System for obscuring antenna sidelobe signals

A system for adjusting the sidelobe response of a main antenna is disclosed. This iterative process results permits the sidelobe canceling in sequential step reduction in interference thereby greatly reducing the time required to respond to changes in the characteristics of the interference. The response of the phased array is adjusted by combining the composite signal from the main antenna with signals from auxiliary channels which have an adjustable phase and amplitude. The desired amplitude and phase of the auxiliary channels is determined using an iterative mathematical process which emphasizes the most recent data. Emphasizing the most recent data permits the system to be used in the scanning mode or to reduce interference from moving sources.

Hybrid adaptive sidelobe canceling system

A synthetic aperture radar in which radial motion compensation is provided by a monopulse null tracking loop which tracks the null position of a stabilized monopulse antenna, and in which tangential motion compensation is provided by a tangential velocity measurement loop which tracks the cross-over angle of the monopulse antenna pattern. Since the motion compensation for the synthetic aperture radar is made in relation to a stabilized monopulse antenna, the imaging process for the synthetic aperture radar may be controlled in response to the angular scan rate of the antenna.

Monopulse motion compensation for a synthetic aperture radar

A target seeker circuit contained in a projectile having a trajectory guidance mechanism cross-correlates returns of a cross-polarized antenna pattern to distinguish between target returns reflected by man-made targets and clutter returns reflected by naturally occurring articles to cause the trajectory guidance mechanism to direct the projectile towards the target. One coordinate of diversity in the cross-polarized returns is achieved by changing the RF frequency of the antenna pattern while a second coordinate of diversity is achieved by changing the aspect range of the clutter. The target returns are distinguished from the clutter returns either by comparison to a threshold value which is set in relation to the worst case clutter level or, alternatively, by comparison to an adaptive threshold which is responsive to the dynamic clutter level.

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Ilchester, MD, United States of America

Norman F Powell