Errors in directional measurements using the relative amplitudes of signals received by two aerials

An analysis is made of the statistical properties of the estimated direction of arrival of radio waves. The estimate is considered to be obtained from the relative amplitudes of the signals received by two narrow-beam aerials whose directions differ by approximately one aerial beamwidth, and the errors in the estimated direction are produced by narrowband noise in the two aerial channels. The results of numerical calculations are presented in the form of curves relating the root-mean-square error in a single measurement, expressed as a percentage of the beam spacing, to the actual direction of the signal and the signal/noise power ratio.