Patent ID: 7417597

Claim:
A GPS antenna system, comprising: a vertically extending structure; an array of primary radiator units supported by said structure at vertically spaced positions and each configured to provide an omnidirectional azimuth pattern; an array of auxiliary radiator units supported by said structure each at a position adjacent to at least one of said primary radiator units and each configured to provide an omnidirectional azimuth pattern; an excitation configuration coupled to each of said primary radiator units and to each of said auxiliary radiator units and arranged to provide at a first port a first signal formed by combining at predetermined relative signal levels signals received via said primary radiator units and at a second port a second signal formed by combining at predetermined relative signal levels signals received via said auxiliary radiator units; and an adjustable signal combiner coupled to said first and second ports and arranged to subtractively combine said first and second signals with relative signal levels, at least one of which is adjustable, to provide at an output port an output signal representative of an antenna pattern having a vertically-steerable null.