| ABSTRACT:
An electromagnetic signal having originally the time variation of
a rectangular pulse is radiated into a lossy medium withconductivity .sigma..
It is distorted by the medium to the distorted electromagnetic pulse f(.sigma.,y,t)
when it travels the distance y/2, in time t/2, from a transmitter to a
scattering or reflecting target and the same distance y/2, in time t/2,
back to the receiver. The time ariation f(.sigma.,y,t) of the distorted
pulse can be calculated for any conductivity .sigma. and distance y using
the conductivity .sigma. known from previous measurements to determine
the range to the target distorted pulse f(.sigma.,y,t). Consequently, distorted
pulses f(.sigma.,yn,t) can be computed and compared to the received distorted
pulse (.sigma.,y,t). The computed pulse f(.sigma.,yn, t) that is most similar
to the received pulse f(.sigma.,y,t) determines the distance yn /2 to the
scattering or reflecting object, which is the range to the target. The
comparison between the computed, distorted signals and the actually received
signal can be done by cross-correlation. If cross-correlation is used,
the peak amplitude or the energy of the received signal becomes unimportant
which means the physical size or radar cross-section of the target has
no effect on the distance determination. |