Electronic Search Beam Stabilization

Compensating for ship's motion (roll and pitch) is a problem fundamental to shipboard radars. The more traditional aproach has been to mechanically stabilize the antenna structure. The alternative approach of stabilizing only the antenna beam is far from being new conceptually, but is more realizable with today's technology. The basic elements are a planar array with an elevation scan capability that rotates continuously in azimuth combined with a high speed digital processor. Electronic stabilization of such an antenna is inherently more challenging than that of a two-axis phase-scanned array. An algorithm is derived for surveillance beam positioning as the antenna rotates. The implementation of this algorithm provides hemispheric search beam stabilization.     

Bistatic Interference between Neighboring Radars

Radar transmitters characteristically generate broadband noise sidebands [1] over the entire tunable frequency band of the system for the duration of the transmitted pulse. The noise will be backscattered over a substantial range interval. In certain circumstaces, this bistatic reflection of ground clutter emerges as the predominant mode of interference between adjacent radars operating in common bands. Closed form mathematical expressions are derived which relate this mutual interference to the system noise temperature. These results in turn are applied to a typical S-band radar.