A choke ring antenna is a directional antenna designed for reception of GNSS signals from satellites. It consists of a number of concentric conductive cylinders around a central antenna. The first choke ring antennas were invented at JPL; since 1989 they have been improved and extended by many companies. Due to its intricate construction, it is often enclosed in a protective cover or radome when placed outside and exposed to the elements.
Benefits Choke ring antennas have excellent phase center stability, polarization purity, suppression of radiation below the horizon and multipath rejection. This makes them highly suited for satellite navigation. In a GNSS ground-based receiver, a choke ring antenna can provide millimeter precision measurements for use in surveying and geological measurements.
See also Patch antenna - a directional type of antenna. Magellan Navigation - one manufacturer of this product. Trimble Inc. - another manufacturer of this product.
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