# US 2017/0285133 A1 · Determining location using time difference of arrival > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0285133 A1 - Document ID: US20170285133A1 - Status: Published application - Kind: A1 - Application number: 15/513,758 - Filed: 2014-09-23 - Published: 2017-10-05 - Earliest claimed: 2014-09-23 - Assignees: Hewlett-Packard Development Company, L.P. - Applicants: Hewlett-Packard Development Company, L.P. - Inventors: Bowon Lee; Souvik Sen - Web page: https://patentgrep.com/patent/US20170285133A1 ## CPC - G01S 5/26: Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements (G01S5/28 takes precedence) - G01S 5/28: by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial - G06F 3/02: Input arrangements using manually operated switches, e.g. using keyboards or dials - G06F 3/0433: {in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member} - G06F 3/04886: by partitioning the display area of the touch-screen or the surface of the digitising tablet into independently controllable areas, e.g. virtual keyboards or menus - 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 - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract Example implementations relate to determining a location using time difference of arrival (TDOA). For example, a computing device may include a first sensor to receive a signal at a first time, where the signal is generated by a user contact at a particular location on a keyboard associated with the computing device. The computing device also includes a second sensor to receive the signal at a second time and a third sensor to receive the signal at a third time. The computing device may also include a processor. The processor may calculate a set of TDOAs associated with the first time, the second time, and the third time. The processor may determine the particular location of the user contact using a triangulation based on the set of TDOAs and may identify a character on the keyboard, where the character is associated with the particular location. ## Claims ### Claim 1 A computing device comprising: a first sensor to receive a signal at a first time, the signal generated by a user contact at a particular location on a keyboard associated with the computing device; a second sensor to receive the signal at a second time; a third sensor to receive the signal at a third time; and a processor to: calculate a set of time differences of arrival (TDOAs) associated with the first time, the second time, and the third time; determine the particular location of the user contact using a triangulation based on the set of TDOAs; and identify a character on the keyboard, the character being associated with the particular location. ### Claim 2 (depends on 1) The computing device of claim 1, wherein the first sensor, the second sensor, and the third sensor are each a microphone or an accelerometer. ### Claim 3 (depends on 1) The computing device of claim 1, wherein the processor is further to access additional information relating to at least one of a keyboard layout of the keyboard and machine-learned information, the particular location being determined using the triangulation and the additional information. ### Claim 4 (depends on 1) The computing device of claim 1, wherein the keyboard is a physical keyboard or a virtual keyboard. ### Claim 5 (depends on 1) The computing device of claim 1, wherein the processor is further to perform a calibration of the keyboard with respect to the computing device. ### Claim 6 (depends on 5) The computing device of claim 5, wherein power to the keyboard is turned on only during the calibration. ### Claim 7 A method comprising: detecting a signal by a first sensor of a computing device at a first time, a second sensor of the computing device at a second time, and a third sensor of the computing device at a third time, the signal generated by a user contact at a particular location on a keyboard associated with the computing device; generating, by the computing device, a set of time differences of arrival (TDOAs) associated with the first time, the second time, and the third time; triangulating, by the computing device, the particular location of the user contact using the set of TDOAs; and determining a character on the keyboard, the character being associated with the particular location. ### Claim 8 (depends on 7) The method of claim 7, wherein the first sensor, the second sensor, and the third sensor are each a microphone or an accelerometer. ### Claim 9 (depends on 7) The method of claim 7, further comprising: accessing additional information relating to at least one of a keyboard layout of the keyboard and machine-learned information, the particular location being determined using the additional information. ### Claim 10 (depends on 7) The method of claim 7, wherein the keyboard is a physical keyboard or a virtual keyboard. ### Claim 11 (depends on 7) The method of claim 7, further comprising: calibrating the keyboard with respect to the computing device. ### Claim 12 A computing device comprising: a first sensor to receive a signal at a first time, the signal generated by a user contact at a particular location on a keyboard associated with the computing device; a second sensor to receive the signal at a second time; and a processor to: calculate a time difference of arrival (TDOA) associated with the first time and the second time; access additional information relating to the keyboard with respect to the computing device; determine the particular location of the user contact using the TDOA and the additional information; and identify a character on the keyboard, the character being associated with the particular location. ### Claim 13 (depends on 12) The computing device of claim 12, wherein the first sensor and the second sensor are each a microphone or an accelerometer. ### Claim 14 (depends on 12) The computing device of claim 12, wherein the additional information includes at least one of a keyboard layout of the keyboard, information associated with signal signatures of the signal received at the first sensor and the second sensor, and machine-learned information. ### Claim 15 (depends on 12) The computing device of claim 12, wherein the keyboard is a physical keyboard or a virtual keyboard.