FMCW-based distance measurement device

Abstract

The invention relates to a distance measuring device (1) based on an FMCW radar, which is particularly advantageous for measuring the filling level, and to a method for operating the distance measuring device (1). The distance measuring device (1) is characterized in that, in addition to analog high-pass filtering and analog low-pass filtering, the evaluation signal (IF), which is typical for the FMCW, is subjected to subsequent digital filtering. In this case, the analog / digital conversion takes place by means of oversampling. As a result, according to the present invention, all of those frequencies (fIF) in the evaluation signal (IF) that are not less than or equal to the frequency corresponding to the distance (d) of the object (2) are effectively suppressed. Meanwhile, analog filters (131, 132, 133) can be constructed with a very low level of complexity. As a result, the space requirements and costs of the simulation components (131, 132, 133) are reduced. In addition, the dependency of the distance measuring device (1) on temperature is thus reduced. And the potential high range resolution is also maintained.

Description

technical field [0001] The present invention relates to a distance measuring device based on FMCW. Background technique [0002] In automation technology, especially for process automation, field devices are often used, which are used to detect various measured variables. The measured variable to be determined can be, for example, the fill level, flow, pressure, temperature, pH, redox potential, conductivity or dielectric value of the medium in the process plant. In order to detect the corresponding measured values, the field devices each include suitable sensors or are based on suitable measuring principles. Several different field device types are manufactured and sold by the Endress+Hauser group of companies. [0003] For measuring the fill level of the filling material in a container, radar-based measurement methods have been established because they are robust and require minimal maintenance. Within the scope of the present invention, the term "vessel" is also unders...

AI Technical Summary

Problems solved by technology

Therefore, however, the implementation of an analog filter is very costly

In addition, when the number of capacitive or inductive components increases, the robustness of the filter decreases, e.g. with respect to component tolerances and temperature effects

This in turn reduces the potential accuracy of the distance measurement

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