Range information from signal distortions

Abstract

Abstract An electromagnetic signal having originally the time variation of a rectangular pulse is radiated into a lossy medium with conductivity σ. It is distorted by the medium to the distorted electromagnetic pulse f(σ,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 variation f(σ,y,t) of the distorted pulse can be calculated for any conductivity σ and distance y using the conductivity σ known from previous measurements to determine the range to the target distorted pulse f(σ,y,t). Consequently, distorted pulses f(σ,y n ,t) can be computed and compared to the received distorted pulse f(σ,y,t). The computed pulse f(σ,y n , t) that is most similar to the received pulse f(σ,y,t) determines the distance y n /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.

Inventors

• 👤 Henning F. Harmuth

Bibliographic Details