Description: High-frequency (HF) sky-wave radar
signals propagate to and from the target by means
of the ionosphere. The difficulty in obtaining very
narrow beamwidths at HF, and the long ranges
involved, mean that the signal backscattered from
the ground is often several orders of magnitude
greater than the target echo. To resolve the target,
coherent signal processing techniques are necessary,
detecting the target echo by virtue of the
Doppler shift caused by the target’s radial velocity.
Unfortunately, movement of the ionospheric
layer by which the radar signal has propagated
often causes the clutter spectrum and target to
spread in the frequency domain, rendering
extended coherent integration pointless. The
movement of the ionosphere can be regarded as
producing frequency modulation of the radar
signal, and thus if this modulation can be estimated
the radar signal may be corrected for the ionospheric
contamination. A technique using the
complex argument of the first-order mo
File list (Check if you may need any files):
Use of theWigner-Ville distribution to compensate for ionospheric layer move.pdf