# US 2014/0150549 A1 · Fill level measurement system and method for determining a fill level > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0150549 A1 - Document ID: US20140150549A1 - Status: Published application - Kind: A1 - Application number: 14/089,131 - Filed: 2013-11-25 - Published: 2014-06-05 - Earliest claimed: 2012-11-28 - Assignees: Airbus Operations GmbH - Applicants: Airbus Operations GmbH - Inventors: Ulrich RIEGER - Web page: https://patentgrep.com/patent/US20140150549A1 ## CPC - G01F 23/296: Acoustic waves - G01F 23/2962: Measuring transit time of reflected waves - G01F 23/64: of the free float type {without mechanical transmission elements} - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME ## Abstract A measurement system for determining a liquid fill level of a tank, including a floating sensor configured to float on the surface of a liquid contained in the tank, at least three reference sensors mounted at a hull of the tank in a spatially fixed arrangement, and a control device to control the floating sensor and the reference sensors, wherein at least one of the floating sensor and the reference sensors can emit an acoustic signal to the remaining sensors, wherein the remaining sensors can receive the emitted acoustic signal, the control device configured to determine signal travelling times of the acoustic signal from the emitting sensor to the receiving sensor, to compute a spatial position of the floating sensor with reference to the reference sensors from the signal travelling times and to determine the liquid fill level on the basis of the computed spatial position of the floating sensor. ## Claims ### Claim 1 A measurement system for determining a liquid fill level of a tank, comprising: a floating sensor configured to float on the surface of a liquid contained in the tank; at least three reference sensors mounted at a hull of the tank in a spatially fixed arrangement; and a control device configured to control the floating sensor and the reference sensors, wherein at least one of the floating sensor and the reference sensors is configured to emit an acoustic signal to the remaining sensors, wherein the remaining sensors are each configured to receive the emitted acoustic signal, and wherein the control device is configured to determine signal travelling times of the acoustic signal from the emitting sensor to the receiving sensor, to compute a spatial position of the floating sensor with reference to the reference sensors from the signal travelling times and to determine the liquid fill level on the basis of the computed spatial position of the floating sensor. ### Claim 2 (depends on 1) The measurement system of claim 1, wherein the acoustic signals comprise ultrasonic signals. ### Claim 3 (depends on 1) The measurement system of claim 1, wherein the control device is an integral component of the floating sensor. ### Claim 4 (depends on 1) The measurement system of claim 1, wherein the control device is an integral component of one of the reference sensors. ### Claim 5 (depends on 1) The measurement system of claim 1, wherein the control device is connected to the floating sensor by a cable. ### Claim 6 (depends on 1) The measurement system of claim 1, wherein the control device is connected to the floating sensor by a wireless communication channel. ### Claim 7 (depends on 6) The measurement system of claim 6, wherein the floating sensor is supplied with electrical energy by a battery. ### Claim 8 (depends on 1) The measurement system of claim 1, wherein the tank comprises a potable water tank, a waste water tank or a fuel tank of an aircraft or spacecraft. ### Claim 9 (depends on 8) The measurement system of claim 8, wherein the control device is configured to receive declination parameters of the aircraft or spacecraft and to determine the liquid fill level on the basis of the declination parameters. ### Claim 10 A method for determining a liquid fill level of a tank, comprising: emitting a first acoustic signal by a floating sensor floating on the surface of a liquid contained in the tank; receiving the first acoustic signal by at least three reference sensors mounted at a hull of the tank in a spatially fixed arrangement; determining the signal travelling times of the first acoustic signal between the floating sensor and each of the reference sensors; computing the spatial position of the floating sensor with reference to the reference sensors from the determined signal travelling times; and determining the liquid fill level on the basis of the computed spatial position of the floating sensor. ### Claim 11 (depends on 10) The method of claim 10, further comprising: emitting a second acoustic signal by a first one of the at least three reference sensors; receiving the second acoustic signal by a second one of the at least three reference sensors; determining the signal travelling time of the second acoustic signal determining the signal travelling time of the second acoustic signal between the first and the second one of the reference sensors; and computing the speed of sound in the tank on the basis of the determined signal travelling time. ### Claim 12 (depends on 11) The method of claim 11, wherein the first and second one of the reference sensors are mounted at the hull of the tank substantially above the surface of the liquid, and wherein the computed speed of sound is the speed of sound in the atmosphere above the liquid in the tank. ### Claim 13 (depends on 11) The method of claim 11, wherein the first and second one of the reference sensors are mounted at the hull of the tank substantially below the surface of the liquid, and wherein the computed speed of sound is the speed of sound in the liquid in the tank. ### Claim 14 (depends on 10) The method of claim 10, wherein the first and/or second acoustic signal comprises a series of pulsed acoustic signals. ### Claim 15 (depends on 10) The method of claim 10, wherein the first and/or second acoustic signal comprises a message signal comprising information about the time of emitting and the identity of the emitting sensor.