Abstract : A study with the goal of contributing to the development of adaptive phased array radar techniques is presented. Adaptive phased array radar is concerned with modification by closed loop control of the radar in response to a change of radar environment such that performance is improved with respect to performance before modification. This study has been concerned with selection of a quantitative measure of radar system performance and relating this measure of performance to control of phased array radar parameters. Modeling of the general radar problem has established a framework of language and functional representation. An adaptive illumination function synthesizer for a tracking radar operating in a point target environment was completed and significant progress was made on completion of an adaptive waveform synthesizer. (Author)


An unconstrained, adaptive, null-steering phased-array optical processor that utilizes a photorefractive crystal to time-integrate the adaptive weights, and null out correlated jammers is described. A passive processor is presented, where it is assumed that it is only known a priori that the signal is broad-band and the jammers are narrow-band. The passive processor computes the angle(s) of arrival of the jammers and extinguishes them. Also presented is an active processor in which the temporal waveform of the desired signal is known, but the look direction is not. The processor computes the angle(s) of arrival of the desired signal and steers the array to look in that direction while nulling any narrow-band jammers. These are two embodiments of a class of processors which use the angular selectivity of volume holograms to form the nulls and look directions in an adaptive phased array radar antenna pattern.


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