Thales

Merlet, Eric

Eric Merlet

Jean-Luc Rogier

Arnaud Lecca

Jean-Christophe Mesnage

A method is provided for estimating the polarization ellipticity of an antenna response signal to an incident electromagnetic wave received on a crossed-loop antenna or an Adcock antenna array. The method comprises at least the following steps: measuring the phase offset &#x394;&#x3c6; between the signals acquired respectively on the cosine and sine path of the antenna; measuring the ratio R between the amplitudes of the signals acquired respectively on the cosine and sine path of the antenna; determining the ellipticity angle &#x3c4; based on the phase offset &#x394;&#x3c6; and on the ratio R. The invention applies notably to the discrimination of ionospheric waves from ground and/or sea waves, in particular for a surveillance, eavesdropping, or goniometry system using HF band signals.

Method for estimating the polarization ellipticity of an antenna response signal to an incident electromagnetic wave

A method of measuring the direction of arrival &#x3b8; of radio signals in the HF band received by a crossed loop antenna includes, in a preparatory calibration phase, acquiring and recording the measurements made by the antenna of a calibration signal which varies in its frequency and bearing angle; and in a measurement phase in which the bearing angle or angles of arrival of signals detected by the antenna is or are determined, acquiring the signals detected in at least one frequency channel, and then, for each frequency channel f, correlating the acquired signals with the recordings having frequencies close to f, resulting from the calibration, and determining the direction of arrival of the signals by finding the bearing angle &#x3b8; for which the maximum correlation is reached.

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Colombes, France

Eric Merlet