Height finding radar

Claim 1

In a range/azimuth radar system having transmitting, receiving, and duplexing means connected to a beam-forming planar array arranged with M vertically stacked horizontal rows of N radiating elements each, said array being rotatable in the azimuth plane for azimuth scanning, apparatus for contemporaneous elevation angle determination comprising: first means comprising M first power divider/combiners each having N ports, one connected to each of said N radiating elements of a corresponding one of said M horizontal rows of radiating elements, each of said first power divider/combiners having a main input/output terminal therefor, thereby providing M main input/output terminals; second means comprising a second power divider/combiner having M individual ports and a main input/output port, and M vertical feeds, one from each individual port of said second power divider/combiner to a main input/output port of a corresponding one of said first power divider/combiners; third means comprising a secondary vertical power combiner having M input ports, and means for coupling a predetermined portion of the signal energy in each of said M vertical feeds discretely to a corresponding input of said secondary vertical power combiner; fourth means within said third means for providing first and second outputs, said first output comprising the combination of said M vertical feed signals weighted in a predetermined order beginning from a first end input port of said secondary vertical power combiner, said second output comprising the combination of said M vertical feed signals weighted in said predetermined order having the same progression throughout said M vertical feed signals as applied to said first output, except that said weighting is applied beginning from the second input port of said secondary vertical power combiner; and fifth means for determining said vertical angle as a function of the phase difference between said first and second outputs of said fourth means.