# US 2018/0324507 A1 · Sensor system for measuring acceleration and pressure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2018/0324507 A1 - Document ID: US20180324507A1 - Status: Published application - Kind: A1 - Application number: 15/961,679 - Filed: 2018-04-24 - Published: 2018-11-08 - Earliest claimed: 2017-05-03 - Assignees: PGS Geophysical AS - Applicants: PGS Geophysical AS - Inventors: Stig Rune Lennart Tenghamn; Frederick James Barr - Web page: https://patentgrep.com/patent/US20180324507A1 ## CPC - G01V 13/00: Manufacturing, calibrating, cleaning, or repairing instruments or devices covered by groups G01V1/00 – G01V11/00 - G01L 23/10: by pressure-sensitive members of the piezoelectric type - G01L 27/005: {Apparatus for calibrating pressure sensors} - G01P 15/09: by piezoelectric pick-up - G01P 21/00: Testing or calibrating of apparatus or devices covered by the preceding groups - H04R 1/02: Casings; Cabinets {; Supports therefor;} Mountings therein (H04R1/28 takes precedence {; attachments for microphones H04R1/08; mounting of transducers in earpieces H04R1/1075}) - H04R 1/42: Combinations of transducers with fluid-pressure or other non-electrical amplifying means - H04R 1/44: Special adaptations for subaqueous use, e.g. for hydrophone - H10N 30/302: {Sensors} - G01V 1/164: {Circuits therefore} - G01V 1/187: {Direction-sensitive hydrophones} - G01V 1/38: specially adapted for water-covered areas (G01V1/28 takes precedence) - G01V: GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS (means for indicating the location of accidentally buried, e.g. snow-buried, persons A63B29/02) - G01L: MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE (weighing G01G) - 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}) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract Techniques are disclosed relating to sensors configured to measure acceleration and pressure. In various embodiments, an apparatus includes a first hydrophone sensor having a first piezoelectric material and a first housing structure and a second hydrophone sensor having a second piezoelectric material and a second housing structure. In some embodiments, the apparatus includes a first pair of wires configured to provide a first differential voltage and a second pair of wires configured to provide a second differential voltage. The first pair of wires may be coupled to the first hydrophone sensor and the second pair of wires may be coupled to the second hydrophone sensor. In various embodiments, the apparatus is configured to determine, based on the first and second differential voltages, a pressure and an acceleration experienced by the first and second hydrophone sensors. ## Claims ### Claim 1 An apparatus, comprising: a first hydrophone sensor having a first piezoelectric material and a first housing structure; a second hydrophone sensor having a second piezoelectric material and a second housing structure; a first pair of wires configured to provide a first differential voltage, wherein a first one of the first pair of wires is coupled to the first housing structure and a second one of the first pair of wires is coupled to the first piezoelectric material; and a second pair of wires configured to provide a second differential voltage, wherein a first one of the second pair of wires is coupled to the second housing structure and a second one of the second pair of wires is coupled to the second piezoelectric material; and wherein the apparatus is configured to determine, based on the first and second differential voltages, a pressure and an acceleration experienced by the first and second hydrophone sensors. ### Claim 2 (depends on 1) The apparatus of claim 1, further comprising: a first voltage divider configured to adjust the first differential voltage provided by the first pair of wires, wherein the first voltage divider includes a first variable resistor configured to facilitate adjustment of the first differential voltage; and a second voltage divider configured to adjust a second differential voltage provided by the second pair of wires, wherein the second voltage divider includes a second variable resistor configured to facilitate adjustment of the second differential voltage. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the first and second variable resistors are configurable to remove an imbalance between voltages generated by the first and second piezoelectric materials. ### Claim 4 (depends on 2) The apparatus of claim 2, further comprising: a first differential amplifier coupled to the first voltage divider and configured to amplify the first differential voltage; and a second differential amplifier coupled to the second voltage divider and configured to amplify the second differential voltage. ### Claim 5 (depends on 1) The apparatus of claim 1, wherein the apparatus is configured to determine the acceleration by determining a difference between the first differential voltage and the second differential voltage. ### Claim 6 (depends on 1) The apparatus of claim 1, wherein the apparatus is configured to determine the pressure by adding the first differential voltage and the second differential voltage. ### Claim 7 (depends on 1) The apparatus of claim 1, wherein the apparatus is a streamer having a plurality of sets of hydrophone sensor pairs, and wherein a first set of the plurality of sets includes the first and second hydrophone sensors. ### Claim 8 (depends on 7) The apparatus of claim 7, wherein the plurality of sets of hydrophone sensor pairs are arranged such that the first set is configured to measure an acceleration in a first direction and a second set of the plurality of sets of hydrophone sensor pairs is configured to measure an acceleration in a second direction orthogonal to the first direction. ### Claim 9 (depends on 7) The apparatus of claim 7, wherein a respective first hydrophone sensor of two or more of the first set of hydrophone sensor pairs is coupled to a first differential amplifier and a respective second hydrophone sensor of the two or more hydrophone sensor pairs is coupled to a second differential amplifier. ### Claim 10 An apparatus, comprising: a first hydrophone sensor having a first piezoelectric material; a second hydrophone sensor having a second piezoelectric material, wherein the first and second piezoelectric materials are configured to provided voltages in response to being stressed; and a calibration circuit coupled to the first piezoelectric material and configured to adjust a voltage produced by the first piezoelectric material to match a voltage produced by the second piezoelectric material when the first and second piezoelectric materials are subjected to an acceleration; and wherein the voltages provided in response to being stressed are indicative of an acceleration and a pressure experienced by the first and second piezoelectric materials. ### Claim 11 (depends on 10) The apparatus of claim 10, further comprising: an amplifier circuit coupled to the calibration circuit and configured to adjust a voltage from the calibration circuit to match a voltage associated with the second piezoelectric material when the first and second piezoelectric materials are subjected to a pressure. ### Claim 12 (depends on 11) The apparatus of claim 11, further comprising: an array of hydrophone sensor pairs, wherein one of the hydrophone sensor pairs includes the first and second hydrophone sensors, and wherein one or more of the hydrophone sensor pairs are coupled to a respective calibration circuit that is coupled to the amplifier circuit. ### Claim 13 (depends on 10) The apparatus of claim 10, wherein the calibration circuit is a voltage divider network that includes a variable resistor that is adjustable to affect an adjustment of the voltage produced by the first piezoelectric material. ### Claim 14 (depends on 10) The apparatus of claim 10, wherein the first and second piezoelectric materials are piezoelectric ceramics, wherein the apparatus is a streamer, and wherein the first and second hydrophone sensors are one of a plurality of hydrophone sensor pairs included in the streamer. ### Claim 15 An apparatus, comprising: a set of hydrophone sensor pairs configured to facilitate a measuring of acceleration and pressure, wherein the set of hydrophone sensor pairs includes respective first and second piezoelectric sensors; a first amplifier coupled to the respective first piezoelectric sensors, wherein the first amplifier is configured to produce a first voltage; a second amplifier coupled to the respective second piezoelectric sensors, wherein the second amplifier is configured to produce a second voltage; and wherein the apparatus is operable to derive an acceleration and a pressure based on the first and second voltages. ### Claim 16 (depends on 15) The apparatus of claim 15, further comprising: a voltage divider coupled to one of the hydrophone sensor pairs and configured to adjust voltages produced by the hydrophone sensor pair, wherein the first amplifier is coupled to the hydrophone sensor pair via the voltage divider. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein the voltage divider includes a resistance adjustable to match a voltage produced by the respective first piezoelectric sensor included in the hydrophone sensor pair to a voltage produced by the respective second piezoelectric sensor included in the hydrophone sensor pair. ### Claim 18 (depends on 15) The apparatus of claim 15, wherein the first amplifier is configured to produce the first voltage such that the first voltage is a differential between a voltage produced by a first piezoelectric material included in the respective first piezoelectric sensor and a voltage produced by a second piezoelectric material included in the respective first piezoelectric sensor. ### Claim 19 (depends on 15) The apparatus of claim 15, wherein a first hydrophone sensor pair of the set of hydrophone sensor pairs is oriented such that the first hydrophone sensor pair is configured to measure acceleration in a first direction, and a second hydrophone sensor pair of the set of hydrophone sensor pairs is oriented such that the second hydrophone sensor pair is configured to measure acceleration in a second direction that is perpendicular to the first direction. ### Claim 20 (depends on 15) The apparatus of claim 15, wherein the apparatus comprises a streamer configured to measure acceleration and pressure while being towed behind a survey vessel, and wherein the apparatus includes a plurality of hydrophone sensor pairs.