| ABSTRACT:
A signalling system in time-frequency space for detecting targets
in the presence of clutter and for penetrating media, includes a transmitter
antenna system, receiver and processor system. The transmitter antenna
system generates and launches into a medium containing the targets an energy
pulse (wave packet) having a predetermined duration and frequency characteristic,
and which energy pulse matches at least one of the following: 1) the time-frequency
reflection characteristics of the target(s) but not the clutter, or 2)
the penetration time-frequency dielectric window of the medium, or 3) the
time-frequency characteristics of the window of the receiver. Preferably,
the time-frequency wave packet is the complex conjugate of the impulse
response of the combined medium and target. Theprocessor solves the wave
equation for transmissions through the medium, reflectance from the target(s)
and transmission back through the medium and causes a match of the generated
wave packet signals to both the medium and target for maximum propagation
through the medium and reflectance from the target, the wave packet match
to the medium and the target being with respect to both time and frequency
response characteristics. |