# US 10,502,862 B2 · Combined chemical and velocity sensors for fluid contamination analysis > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,502,862 B2 - Document ID: US10502862B2 - Status: Granted - Kind: B2 - Application number: 15/597,648 - Filed: 2017-05-17 - Published: 2018-11-22 - Granted: 2019-12-10 - Earliest claimed: 2017-05-17 - Assignees: International Business Machines Corporation - Applicants: International Business Machines Corporation - Inventors: Bruce G. Elmegreen - Web page: https://patentgrep.com/patent/US10502862B2 ## CPC - G01V 9/00: Prospecting or detecting by methods not provided for in groups G01V1/00 - G01V8/00 - G01P 5/001: {Full-field flow measurement, e.g. determining flow velocity and direction in a whole region at the same time, flow visualisation} - G01V 9/007: {by detecting gases or particles representative of underground layers at or near the surface (analysing earth materials G01N33/24; analysing gases per se G01N)} - G06F 7/64: Digital differential analysers, i.e. computing devices for differentiation, integration or solving differential or integral equations, using pulses representing increments; Other incremental computing devices for solving difference equations (G06F7/70 takes precedence; differential analysers using hybrid computing techniques G06J1/02 {; DDA application in numerical control G05B19/18}) - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Methods and systems for locating a chemical source include measuring chemical concentration with sensors at a plurality of different positions. Measurements from pairs of positions are cross-correlated to determine an average velocity vector for a group of positions. A convergence region is determined based on a plurality of average velocity vectors to determine a chemical source location. ## Claims ### Claim 1 A computer-implemented method for locating a chemical source, comprising: measuring chemical concentration with sensors at a plurality of different positions; cross-correlating measurements from pairs of positions using a processor to determine an average velocity vector for a group of positions that averages away turbulence contributions; and determining a convergence region based on a plurality of average velocity vectors to determine a chemical source location. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the convergence region comprises reversing a direction of each of average velocity vector. ### Claim 3 (depends on 1) The method of claim 1, wherein cross-correlating measurements comprises integrating over a product of concentration values measured at a pair of positions at times separated by a time lag to produce a cross-correlation product C. ### Claim 4 (depends on 3) The method of claim 3, wherein cross-correlating measurements further comprises determining a time lag that produces a maximum cross-correlation product. ### Claim 5 (depends on 4) The method of claim 4, wherein the cross-correlation product is calculated as: Cta,tb(τ)=∫tatbS1(t)S2(t−τ)dt where ta and tb are time limits, S1(t) and S2(t) are measurements from a first sensor and a second sensor at a time t, and τ is a time lag. ### Claim 6 (depends on 4) The method of claim 4, further comprising determining the average velocity vector based on a normalized sum of distances between each pair of positions divided by a respective determined time lag for each pair of positions. ### Claim 7 (depends on 1) The method of claim 1, wherein each group of positions comprises at least four chemical concentration sensors at respective positions. ### Claim 8 (depends on 7) The method of claim 7, wherein cross-correlating measurements from pairs of positions comprises determining respective average velocity vectors for a plurality of groups of positions. ### Claim 9 A combined chemical and velocity sensor system, comprising: a plurality of chemical concentration sensors configured to measure a concentration of a predetermined chemical; and a sensor control module comprising a processor configured to cross-correlate measurements from pairs of chemical concentration sensors and to determine an average velocity vector that averages away turbulence contributions to determine a chemical source location. ### Claim 10 (depends on 9) The system of claim 9, wherein the sensor control module is further configured to integrate over a product of concentration values measured at a pair of positions at times separated by a time lag to produce a cross-correlation product C. ### Claim 11 (depends on 10) The system of claim 10, wherein the sensor control module is further configured to determine a time lag that produces a maximum cross-correlation product. ### Claim 12 (depends on 11) The system of claim 11, wherein the cross-correlation product is calculated as: Cta,tb(τ)=∫tatbS1(t)S2(t−τ)dt where ta and tb are time limits, S1(t) and S2(t) are measurements from a first sensor and a second sensor at a time t, and τ is a time lag. ### Claim 13 (depends on 11) The system of claim 11, wherein the sensor control module is further configured to determine the average velocity vector based on a normalized sum of distances between each pair of positions divided by a respective determined time lag for each pair of positions. ### Claim 14 (depends on 9) The system of claim 9, wherein the plurality of chemical concentration sensors comprises at least four chemical concentration sensors. ### Claim 15 (depends on 14) The system of claim 14, wherein the four chemical concentration sensors are non-coplanar. ### Claim 16 A chemical source location system, comprising: a plurality of chemical and velocity sensor (CCVS) systems, each CCVS system comprising: a plurality of chemical concentration sensors configured to measure a concentration of a predetermined chemical; and a sensor control module configured to cross-correlate measurements from pairs of chemical concentration sensors and to determine an average velocity vector that averages away turbulence contributions; and an analysis module comprising a processor configured to determine a convergence region based on the plurality of average velocity vectors to determine a chemical source location. ### Claim 17 (depends on 16) The system of claim 16, wherein the analysis module is further configured to reverse the direction of each average velocity vector to determine the convergence region. ### Claim 18 (depends on 16) The system of claim 16, wherein each CCVS system comprises at least four chemical concentration sensors. ### Claim 19 (depends on 18) The system of claim 18, wherein the four chemical concentration sensors of each CCVS system are non-coplanar. ### Claim 20 (depends on 16) The system of claim 16, comprising at least four non-coplanar CCVS systems.