Robust Filtering for TDR Traces

Time-domain reflectometry (TDR) is a valuable technique for the measurement of dielectric properties of soils. The filtering of noisy TDR traces is treated in this paper. The problem of biased estimation occurs when the permittivity of the soil varies with the depth. In practical issues, only the apparent permittivity of the soil along the TDR line is available. Hence, robust optimal filtering has to be developed to provide a robust and reliable estimation. This filtering step is essential for the estimation of the permittivity with the depth.