Correlation-Based UWB Radar for Thin Layer Resolution

Liquid level measurement and material identification with ultrawideband (UWB) free-space radar is considered in this letter. Traditional level measurement methods cannot distinguish between overlapping pulses, and their accuracy in identifying thin layers of material is limited by the width of the pulse used. A thin layer resolution algorithm is introduced to estimate the amplitudes of overlapping pulses, which in turn increases the accuracy in thin layer identification. The proposed thin layer resolution algorithm is shown to outperform spectral estimation methods such as multiple signal classification (MUSIC). A complete test setup was developed in laboratory, and the proposed signal processing method was tested on measurement data. The thin layer resolution method can recognize a 1-cm top layer of oil that corresponds to an overlapping of 66% between the first two reflected pulses.