LOCALIZATION USING MODULATED AMBIENT SOUNDS

• US 20130188456A1
• Filed: 01/25/2012
• Published: 07/25/2013
• Est. Priority Date: 01/25/2012
• Status: Active Grant

• Current Assignee: Fujifilm Business Innovation Corp. (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: ADCOCK, John, KIMBER, Donald, RISHABH, Ish
• Granted Patent: US 9,146,301 B2
• Time in Patent Office: Days
• US Class Current: 367/127
• CPC Class Codes: G01S 5/18 using ultrasonic, sonic, or infrasonic waves
• 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
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location

Abstract

Systems and methods for determining the location of a microphone by using sounds played from loudspeakers at known locations. Systems and methods may thereby require a minimal level of infrastructure, using sounds that would naturally be played in the environment. Systems and methods may thereby allow devices such as smart-phones, tablets, laptops or portable microphones to determine their location in indoor settings, where Global Positioning Satellite (GPS) systems may not work reliably.

Claims

1. A mobile device, comprising:

a sensor that receives an audio signal;

an arrival time calculating unit comparing the received audio signal to a plurality of audio tracks and estimating an arrival time of each of the plurality of audio tracks; and

a location determination unit determining a location of the mobile device based on the estimated arrival time of each of the plurality of audio tracks and a location associated with each of the plurality of audio tracks.

2. The mobile device of claim 1, wherein the arrival time calculating unit corrects for a clock drift of the received audio signal based on the comparing.

3. The mobile device of claim 1, further comprising an audio track selection unit that receives a selection of the plurality of audio tracks for the arrival time calculating unit.

4. The mobile device of claim 3, wherein the selection comprises a pseudorandom sequence seed representing a periodic pseudorandom white noise.

5. The mobile device of claim 1, wherein the arrival time calculating unit calculates the estimated arrival time of the each of the plurality of audio tracks by estimating a first time that a first one of the plurality of audio tracks starts playing.

6. The mobile device of claim 1, wherein the plurality of audio tracks comprises modulated music.

7. A computer program product comprising a non-transitory computer readable medium having computer readable program code embodied therewith, the computer readable program code comprising code for:

receiving an audio signal;

comparing the received signal to a plurality of audio tracks;

estimating an arrival time of each of the plurality of audio tracks; and

determining a location of a mobile device based on the estimated arrival time of each of the plurality of audio tracks and a location associated with each of the plurality of audio tracks.

8. The computer program product of claim 7, further comprising code for correcting for a clock drift of the received broadcast based on the comparing.

9. The computer program product of claim 7, further comprising code for receiving a selection of the plurality of audio tracks for the comparing.

10. The computer program product of claim 9, wherein the selection comprises a pseudorandom sequence seed representing a periodic pseudorandom white noise.

11. The computer program product of claim 7, wherein the code for calculating the estimated arrival time of the each of the plurality of audio tracks further comprises estimating a first time that a first one of the plurality of audio tracks starts playing.

12. The computer program product of claim 7, wherein the plurality of audio tracks comprises barely audible noise.

13. A method, comprising:

receiving a broadcast;

comparing the received broadcast to a plurality of audio tracks;

estimating an arrival time of each of the plurality of audio tracks; and

determining a location of a mobile device based on the estimated arrival time of each of the plurality of audio tracks and a location associated with each of the plurality of audio tracks.

14. The method of claim 13, further comprising correcting for a clock drift of the received audio based on the comparing.

15. The method of claim 13, further comprising receiving a selection of the plurality of audio tracks for the comparing.

16. The method of claim 15, wherein the selection comprises a pseudorandom sequence seed representing a periodic pseudorandom white noise.

17. The method of claim 13, wherein the calculating the estimated arrival time of the each of the plurality of audio tracks further comprises estimating a first time that a first one of the plurality of audio tracks starts playing.

18. The method of claim 17, wherein the calculating the estimated arrival time further comprises setting a baseline value for the location of the mobile device along a z-axis.

19. The method of claim 18, wherein the calculating the estimated arrival time further comprises retaining the first time and the baseline value to determine the location of the mobile device in a subsequent determination.