Scanning antenna having phase center diversity

摘要

The object of this invention is to reduce the adverse effects of reflected electromagnetic radiation on the measurement threshold of a scanning beam. It has particular application to the time reference scanning beam of the international microwave landing system (MLS). In the present MLS configuration, the reflection induced errors during the "TO" scan are additive to those of the "FRO" scan. This invention describes a method and apparatus for compensating errors by reversing the phase of the reflections during the "FRO" scan, by displacing the phase center of the transmitantenna during that scan. System performance is enhanced by the errors compensation.