New developments in direction-of-arrival measurement based on Adcock antenna clusters

The author shows how to extend the utility of Adcock-type clusters to the determination of the radial (combining azimuth and elevation) angle of arrival and enhance performance instrumental resolution and accuracy by increasing the cluster aperture to values exceeding a wavelength and by structuring the receiver for robust processing of the group of Adcock-pair difference signals. The basic theory is reformulated in order to: (1) show how both azimuth and elevation angle of arrival can be derived from the amplitudes of the Adcock-pair difference signals; and (2) bring out the bases for, and the conditions under which, an Adcock-type antenna cluster can be effectively configured with apertures well in excess of one wavelength. The discussion is then directed to structuring the receiver to ensure instrumental stability and low associated systematic errors. The additional receiver functional-structure requirements are specified for application to signals of wideband modulation characteristics, such as wide band-spreading FM, and direct-sequence and frequency-hopping spread spectrum