Multi-layer Level Measurement Using Adaptive Filtering

In several applications the measurement of the levels of multi-layer liquids cannot be carried out using sensors in direct contact with the substances. In these cases, one alternative is to use contactless ultrasonic transducers and measure the time-of-flight of the echoes produced by the reflection of a known signal by the different layers. We propose a measurement system for using with ultrasonic transducers that is composed by an adaptive filter for noise cancellation and cross-correlation measurement to identify the time instants of the received echoes. Simulations results are presented for the measurement of the level of two-layer liquids and show the efficiency of the proposed structure.