Radio direction finder

Abstract

A radio direction finder for obtaining the bearing of a transmitter with respect to a receiver comprises a multi-element receiving antenna, two separate scanning means coupled to said antenna for simultaneously generating a rightward and a leftward rotating antenna pattern of the same rotating frequency, and two separate receivers having approximately the same group delay. Also included are demodulating means for generating two separate bearing signals of AM or FM-type modulation for the rightward and leftward rotating antenna pattern, respectively, and evaluator and indicator means for obtaining the bearing of a signal received by the antenna from the phases of the two bearing signals and a reference signal. As a result, the radio direction finder provided, being of the most simple structure, permits quick evaluation of the bearing, for instance, during one revolution only of the antenna characteristic, and yet includes no bearing errors caused by delay.

Dependencies are inferred from the claim text.