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

A method for estimating a polarization ellipticity angle τ of a response signal of a crossed-loop antenna or an Adcock antenna array in response to an incident electromagnetic wave received on said antenna, the method comprising:

• measuring a phase offset Δφ between signals acquired on the cosine and sine path of the antenna;
• measuring a ratio R between amplitudes of the signals acquired on the cosine and sine path of the antenna;
• and
• determining the polarization ellipticity angle τ by the following relation:
• sin
• ⁡
• (
• 2
• ·
• τ
• )
• =
• 2
• R
• +
• 1
• R
• ·
• sin
• ⁡
• (
• Δ
• ⁢
• ⁢
• φ
• )
• wherein
• R
• =
• 
• a
• _
• c
• 
• 
• a
• _
• s
• 
• ,
• ∥āc∥ is the amplitude of the signal acquired on the cosine loop, and
• ∥ās∥ is the amplitude of the signal acquired on the sine loop.

A method for discriminating ionospheric waves from sea or ground waves, the method comprising:

• detecting an electromagnetic wave on a crossed-loop antenna or Adcock antenna array;
• measuring a phase offset Δφ between signals acquired on the cosine and sine path of the antenna;
• measuring a ratio R between amplitudes of the signals acquired on the cosine and sine path of the antenna;
• determining a polarization ellipticity angle τ of an antenna response signal to the detected wave based on the phase offset Δφ and on the ratio R;
• comparing the polarization ellipticity angle value τ to a predetermined threshold value;
• and
• classifying said wave as an ionospheric wave if the polarization ellipticity angle value τ is greater than the predetermined threshold value.

A device placed on the ground or in the sea, the device comprising a crossed-loop receive antenna or an Adcock antenna array and a processing module, the processing module configured to determine a polarization ellipticity angle τ of a response signal of the antenna to an electromagnetic wave received by the antenna by:

• measuring a phase offset Δφ between signals acquired on the cosine and sine path of the antenna;
• measuring a ratio R between amplitudes of the signals acquired on the cosine and sine path of the antenna;
• and
• determining the polarization ellipticity angle τ based on the phase offset Δφ and on the ratio R.