# US 2019/0170785 A1 · System for fusing acoustic and inertial position determination > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170785 A1 - Document ID: US20190170785A1 - Status: Published application - Kind: A1 - Application number: 16/212,075 - Filed: 2018-12-06 - Published: 2019-06-06 - Earliest claimed: 2017-12-06 - Assignees: InvenSense, Inc. - Applicants: InvenSense, Inc. - Inventors: Sebastian Riccardi; Karthik Katingari; Joe Youssef - Web page: https://patentgrep.com/patent/US20190170785A1 ## CPC - G01P 13/00: Indicating or recording presence, absence, or direction, of movement (electric switches H01H; counting moving objects G06M7/00) - G01C 21/165: {combined with non-inertial navigation instruments} - G01D 18/00: Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00 - G01S 5/18: using ultrasonic, sonic or infrasonic waves - G01S 11/12: using electromagnetic waves other than radio waves - G01S 11/14: using ultrasonic, sonic or infrasonic waves - G01S 11/16: using difference in transit time between electrical and acoustic signals - G06F 3/017: {Gesture based interaction, e.g. based on a set of recognized hand gestures (interaction based on gestures traced on a digitiser G06F3/04883)} - G06F 3/033: Pointing devices displaced or positioned by the user {, e.g. mice, trackballs, pens or joysticks}; Accessories therefor (digitisers characterised by the transducing means G06F3/041) - G06F 3/0346: with detection of the device orientation or free movement in a three-dimensional [3D] space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors - G06F 3/038: Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry - 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}) - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - 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 A synchronization system for an acoustic signal-based and inertial signal-based positioning system is provided that generates a magnetic field as a synchronization signal. The modulated magnetic synchronization signal is transmitted by a transmitter of the positioning system and received by the receiver of the positioning system. The receiver may make an acoustic position determination for the transmitter based on a received modulated synchronization signal and may make an inertial position determination for the transmitter based on the received inertial signal, such that the acoustic position determination and the inertial position determination are fused. ## Claims ### Claim 1 A positioning system, comprising: a transmitter, the transmitter comprising: an acoustic signal transmitter configured to transmit a modulated acoustic signal; a magnetic synchronization signal transmitter configured to transmit a modulated magnetic synchronization signal; and at least one inertial sensor assembly, having at least one sensor, configured to receive the modulated magnetic synchronization signal as an input, and configured to transmit a inertial signal; and a receiver, the receiver comprising: an acoustic signal receiver configured to receive the transmitted modulated acoustic signal; a magnetic synchronization signal receiver configured to receive the transmitted modulated magnetic synchronization signal; an inertial signal receiver configured to receive the transmitted inertial signal; and at least one processor configured to receive the modulated acoustic signal from the acoustic signal receiver, the modulated magnetic synchronization signal from the magnetic synchronization signal receiver and the inertial signal from the inertial signal receiver on a same time domain, and configured to determine a position of the transmitter based on the received modulated synchronization signal, a determined time delay of the received modulated acoustic signal and the received inertial signal. ### Claim 2 (depends on 1) The positioning system of claim 1, wherein the at least one processor is configured to determine a position of the transmitter by: making an acoustic position determination for the transmitter based on the received modulated synchronization signal and a determined time delay of the received modulated acoustic signal; making an inertial position determination for the transmitter based on the received inertial signal, and; fusing the acoustic position determination and the inertial position determination. ### Claim 3 (depends on 2) The positioning system of claim 2, wherein the acoustic position determination and the inertial position determination are synchronized based on the modulated magnetic synchronization signal. ### Claim 4 (depends on 3) The positioning system of claim 3, wherein the inertial sensor assembly is configured to receive an indication of the start of the modulated magnetic synchronization signal as an input and determine timing data with respect to the inertial signal. ### Claim 5 (depends on 4) The positioning system of claim 4, wherein the timing data comprises a time delay between the received indication of the start of the modulated magnetic synchronization signal and acquired inertial sensor samples. ### Claim 6 (depends on 5) The positioning system of claim 5, wherein the inertial sensor assembly is further configured to determine a timestamp of the received indication of the start of modulated magnetic synchronization signal based on the time delay. ### Claim 7 (depends on 6) The positioning system of claim 6, wherein the inertial sensor assembly receives the modulated magnetic synchronization signal on a dedicated input. ### Claim 8 (depends on 1) The positioning system of claim 1, wherein the inertial sensor assembly comprises at least one of an accelerometer and a gyroscope. ### Claim 9 (depends on 8) The positioning system of claim 8, wherein the inertial sensor assembly further comprises a magnetometer. ### Claim 10 (depends on 1) The positioning system of claim 1, wherein the receiver comprises at least one of a virtual reality display and an augmented reality display. ### Claim 11 (depends on 10) The positioning system of claim 10, wherein the transmitter comprises a handheld controller for the receiver. ### Claim 12 (depends on 1) The positioning system of claim 1, further comprising: an additional acoustic signal transmitter capable of experiencing independent movement and configured to transmit a modulated acoustic signal; a magnetic synchronization signal transmitter configured to transmit a modulated magnetic synchronization signal; and at least one inertial sensor assembly, having at least one sensor synchronized with the modulated magnetic synchronization signal and configured to transmit a inertial signal. ### Claim 13 (depends on 2) The positioning system of claim 2, wherein the inertial signal is transmitted using radio frequency communication. ### Claim 14 A portable transmitter comprising: an acoustic signal transmitter configured to transmit a modulated acoustic signal; a magnetic synchronization signal transmitter configured to transmit a modulated magnetic synchronization signal; and at least one inertial sensor assembly, having at least one sensor, configured to receive the modulated magnetic synchronization signal as an input and configured to transmit an inertial signal. ### Claim 15 (depends on 14) The portable transmitter of claim 14, wherein the inertial sensor assembly is configured to receive an indication of the start of the modulated magnetic synchronization signal as an input and determine timing data with respect to the inertial signal. ### Claim 16 (depends on 15) The portable transmitter of claim 15, wherein the timing data comprises a time delay between the received indication of the start of the modulated magnetic synchronization signal and acquired inertial sensor samples. ### Claim 17 (depends on 16) The portable transmitter of claim 16, wherein the inertial sensor assembly is further configured to determine a timestamp of the received indication of the start of modulated magnetic synchronization signal based on the time delay.