METHOD AND DEVICE FOR DETERMINING THE POSITION OF A PISTON OF A PISTON CYLINDER USING MICROWAVES

摘要

The invention relates to a method for determining the position of a piston of a piston cylinder, wherein a microwave transmission signal is emitted in the direction of the piston, and microwaves reflected by the piston are detected, allowing a high level of measurement precision at high measurement speed and minimally invasive engagement in the piston cylinder, wherein the transmitted signal comprises a modulated signal having a sinusoidal base frequency modulated at a modulation frequency, wherein an analysis of the phase between the transmitted signals and received signals is performed, wherein a phase determination is performed at the base band and a simultaneous phase determination is performed at at least one side band, wherein the phase determination at the base band is used for finely determining the piston position, and the phase determination at the at least one side band is used for coarsely determining the piston position, and wherein a bandpass filtering is performed on the received signals and transmitted analysis signals with respect to the base frequency or an intermediate frequency, and a bandpass filtering takes place with respect to the modulation frequency.