# US 2022/0034702 A1 · Method for measuring a filling level > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2022/0034702 A1 - Document ID: US20220034702A1 - Status: Published application - Kind: A1 - Application number: 17/297,491 - Filed: 2019-11-11 - Published: 2022-02-03 - Earliest claimed: 2018-11-28 - Assignees: Endress + Hauser GmbH + Co. KG - Applicants: Endress+Hauser SE+Co. KG - Inventors: Winfried Mayer; Manuel Sautermeister - Web page: https://patentgrep.com/patent/US20220034702A1 ## CPC - G01F 23/284: Electromagnetic waves - G01F 23/2845: {for discrete levels (G01F23/288, G01F23/292 take precedence)} - G01S 7/354: {Extracting wanted echo-signals (Doppler systems G01S13/50)} - G01S 13/34: using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal - G01S 13/88: Radar or analogous systems specially adapted for specific applications (electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00) - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES ## Abstract A method for radar-based measurement of a filling level of a filling material in a container includes, in successive measurement cycles, generating an evaluation curve, and the relevant current evaluation curve is stored; a first difference curve is formed based on the evaluation curve of the current measurement cycle and a stored evaluation curve of a preceding measurement cycle; and the filling level is determined based on a maximum in the current first difference curve. The filling level is thus established from the difference curve rather than from the evaluation curve, and the filling level can be determined with greater certainty—in particular in the case of filling material having rippled surfaces. ## Claims ### Claim at position 1 1-14. (canceled) ### Claim 15 A method for radar-based measurement of a filling level of a filling material in a container, the method comprising the following steps, which are repeated in successive measuring cycles: emitting a microwave signal in a direction of the filling material; receiving a receive signal generated after reflection of the microwave signal inside the container; generating an evaluation curve based on at least the receive signal; progressively storing the current evaluation curve in each measuring cycle; calculating a first difference curve based on the evaluation curve of a current measuring cycle and a stored evaluation curve of a preceding measuring cycle; and determining the filling level based on a maximum of the current, first difference curve. ### Claim 16 (depends on 15) The method of claim 15, wherein the evaluation curve is created with complex values. ### Claim 17 (depends on 16) The method of claim 16, wherein the first difference curve is created with complex values, and wherein the filling level is determined based on a maximum of the imaginary part or of the real part of the current, first difference curve. ### Claim 18 (depends on 15) The method of claim 15, wherein the measuring cycles in which the filling level is in each case re-determined are repeated at a defined measuring rate. ### Claim 19 (depends on 18) The method of claim 18, wherein a first distance of the current measuring cycle to the preceding measuring cycle, from which the stored evaluation curve is used to calculate the first difference curve, is set to be inversely proportionally as a function of the measuring rate. ### Claim 20 (depends on 15) The method of claim 15, wherein the first difference curve is calculated based on the current evaluation curve and of the evaluation curve created in the immediately preceding measuring cycle. ### Claim 21 (depends on 15) The method of claim 15, wherein, analogously to the first difference curve, a second difference curve is created, and wherein a second distance of the current measuring cycle to the preceding measuring cycle is selected, from which the stored evaluation curve is used to calculate the second difference curve, deviating from the first distance of the current measuring cycle to the preceding measuring cycle, from which the stored evaluation curve is used to calculate the first difference curve. ### Claim 22 (depends on 21) The method of claim 21, wherein, the filling level cannot be determined based on the first difference curve, the filling level is determined based on the second difference curve. ### Claim 23 (depends on 21) The method of claim 21, wherein the filling level is determined from the difference curve whose maximum has a greater amplitude. ### Claim 24 (depends on 15) The method of claim 15, wherein, when the filling level cannot be determined based on the first difference curve and/or based on the second difference curve, the filling level is determined based on the current evaluation curve. ### Claim 25 A radar-based filling-level measurement device for determining a filling level of a filling material in a container, the device comprising: a signal-generation unit configured to emit a microwave signal in a direction of the filling material in each case in successive measuring cycles; a receiving unit configured to receive a corresponding receive signal generated after reflection of the microwave signal inside the container; an evaluation unit configured to: generate an evaluation curve in each measuring cycle based on at least the receive signal; progressively store the respective current evaluation curve; calculate a first difference curve by subtracting the evaluation curve of the current measuring cycle and the evaluation curve of a preceding measuring cycle; and determine the filling level based on the first difference curve. ### Claim 26 (depends on 25) The device of claim 25, wherein the signal-generation unit and the evaluation unit are configured to generate the evaluation curve and calculate the difference curve with complex values. ### Claim 27 (depends on 25) The device of claim 25, wherein the signal-generation unit, the receiving unit, and the evaluation unit are configured to determine the filling level based on the FMCW principle. ### Claim 28 (depends on 25) The device of claim 25, wherein the signal-generation unit is configured to emit the microwave signal in a frequency band of at least 60 GHz, and wherein the receiving unit and the evaluation unit are configured to process the corresponding receive signal.