Level finding using multiple search steps

Abstract

A method of level finding includes providing characteristics of a shape of a transmitted pulse in time domain launched onto a waveguide into a tank having at least one material therein, physical properties of the waveguide and real and imaginary dielectric characteristics of the material at a frequency of the pulse. A level finding algorithm having a coarse search and a fine search is implemented, where the coarse search minimizes a prediction error between an echo signal (echo curve y(k)) and a sampled pulse model echo p(k) to obtain an objective function J(k) in a vicinity of a minimum prediction error (k*). The fine search calculates at least one minimum or maximum using J(k) in the vicinity of k*. The minimum or the maximum corresponds to a level of the material or an interface involving the material.