Audio localization using multilateration

• US 9,618,604 B1
• Filed: 12/18/2013
• Issued: 04/11/2017
• Est. Priority Date: 09/13/2012
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Holt, Jason, Lyon, Richard Francis
• Primary Examiner(s): Hulka, James
• Application Number:
  US14/133,423
• Time in Patent Office: 1,210 Days
• Field of Search: 367117, 367124, 367127
• CPC Class Codes: G01S 3/8083 determining direction of source
• CPC Class Codes: G01S 5/10 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements , e.g. omega or decca systemsG01S5/12 takes precedence ; beacons and receivers cooperating therewith G01S1/306, G01S1/308
• CPC Class Codes: G01S 5/26 Position of receiver fixed by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/28 takes precedence

Abstract

Systems and methods for providing audio localization are provided. In some aspects, a method includes receiving phase offsets of a plurality of fixed transmitters from a source other than the plurality of fixed transmitters, detecting an audio localization signal from each of the plurality of fixed transmitters, determining a received phase of the audio localization signal from each of the plurality of fixed transmitters, determining time differences of flight from the mobile receiver to the plurality of fixed transmitters using the received phases, determining distance differences from the mobile receiver to the plurality of fixed transmitters using the time differences of flight, and determining the location of the mobile receiver by performing multilateration using the distance differences.

Claims

1. A wireless positioning system, comprising:

a plurality of fixed transmitters each of which transmits a unique audio localization signal, each fixed transmitter configured to transmit the audio localization signal via a first communication channel using one or more speaker devices associated with the fixed transmitter; and

a fixed receiver for receiving the audio localization signals from the fixed transmitters, receiving locations of the fixed transmitters, determining phase offsets of the fixed transmitters, and transmitting phase offset and location data of the fixed transmitters to a mobile receiver as metadata via a second communication channel;

wherein the mobile receiver is configured to receive the audio localization signals from the plurality of fixed transmitters, and to determine a location of the mobile receiver based at least in part on the received audio location signals and the phase offset and location data of the fixed transmitters provided by the fixed receiver.

2. The system of claim 1, wherein each fixed transmitter comprises a pseudorandom sequence generator for receiving a seed number and generating a pseudorandom sequence and a speaker for transmitting the audio localization signal.

3. The system of claim 1, wherein the fixed receiver further comprises a phase detector for determining a relative time of flight from the fixed receiver to each of the plurality of fixed transmitters using the audio localization signal of the respective fixed transmitter.

4. The system of claim 3, wherein the phase detector further comprises a convolution unit for determining the relative time of flight to each of the plurality of fixed transmitters by performing convolution on a pseudorandom sequence, wherein the convolution unit determines the relative time of flight to each of the plurality of fixed transmitters by performing fast Fourier transform or Delay Locked Loops on the pseudorandom sequence.

5. The system of claim 3, wherein the fixed receiver further comprises a time of flight calculator for determining a time of flight from the fixed receiver to each of the plurality of fixed transmitters using a distance between the fixed receiver and the respective fixed transmitter.

6. The system of claim 5, wherein the fixed receiver further comprises a subtractor for determining the phase offset of a fixed transmitter by subtracting the relative time of flight from the fixed receiver to the respective fixed transmitter from the time of flight from the fixed receiver to the respective fixed transmitter.