Method of determining the direction of arrival of a high-frequency electromagnetic wave

A method of measuring a bearing angle of arrival θ of HF band radio signals received by a crossed loop antenna or an Adcock antenna array, the method comprising:

• in a preparatory calibration phase, acquiring and recording measurements, made by an antenna, of a calibration signal which has a variable bearing angle of arrival θ and has a fixed or variable frequency;
• and
• in a detected signals measurement phase:
• acquiring detected signals in at least one frequency channel;
• and
• for each frequency channel fi, correlating the acquired detected signals with the recorded calibration signals resulting from a frequency calibration of approximately fi, and determining, using a processor, the direction of arrival of the detected signals by finding the bearing angle of arrival θ having the maximum correlation value,
• wherein each acquisition in the preparatory calibration phase is recorded in a table in the form of an intercorrelation vector, the intercorrelation vectors in the table being correlated with another intercorrelation vector obtained from the detected signals acquired in the detected signals measurement phase,
• the method further comprising calculating each of the intercorrelation vectors by:
• acquiring, on a sine loop and a cosine loop of the antenna, N signal measurements, where N≧1, over a time interval Δt;
• calculating, for p measurements out of the N measurements, an elementary intercorrelation vector Xk;
• and
• calculating a mean intercorrelation vector X by determining a mean of the p elementary intercorrelation vectors Xk.

A method of measuring a bearing angle of arrival θ of HF band radio signals received by a crossed loop antenna or an Adcock antenna array, the method comprising:

• in a preparatory calibration phase, acquiring and recording measurements, made by an antenna, of a calibration signal which has a variable bearing angle of arrival θ and has a fixed or variable frequency;
• in a detected signals measurement phase:
• acquiring detected signals in at least one frequency channel, and
• for each frequency channel fi,correlating the acquired detected signals with the recorded calibration signals resulting from a frequency calibration of approximately fi, and determining, using a processor, the direction of arrival of the detected signals by finding the bearing angle of arrival θ having the maximum correlation value;
• and
• estimating the quality of a bearing angle of arrival θ measurement, a quality score Q being assigned to the bearing angle of arrival θ measurement as a function of a level of the maximum correlation value, the quality score Q being an increasing monotonic function of the maximum correlation value.