Localization using modulated ambient sounds
View Patent ↗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.
1. A mobile device, comprising:
a sensor configured to receive an audio signal comprising at least one from among a pseudorandom sequence seed representing a periodic pseudorandom white noise and modulated music;
an arrival time calculating unit configured to compare the received audio signal to a plurality of pre-stored audio tracks and estimate an arrival time of the received audio signal comprising the at least one from among the pseudorandom sequence seed representing the periodic pseudorandom white noise and the modulated music; and
a location determination unit configured to determine a location of the mobile device based on the estimated arrival time the received audio signal comprising the at least one from among the pseudorandom sequence seed representing the periodic pseudorandom white noise and the modulated music and a location associated with each of the pre-stored plurality of audio tracks,
wherein the arrival time calculating unit is configured to compare the received audio signal to the plurality of audio tracks by cross correlating the received audio signal with the plurality of pre-stored audio tracks.
2. The mobile device of claim 1 , wherein the arrival time calculating unit is further configured to correct for a clock drift of the received audio signal based on the comparing.
3. The mobile device of claim 1 , wherein the arrival time calculating unit receives the plurality of audio tracks from a server.
4. 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.
5. 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 comprising at least one from among a pseudorandom sequence seed representing a periodic pseudorandom white noise, an inaudible noise and modulated music;
comparing the received audio signal to a plurality of pre-stored audio tracks;
estimating an arrival time of the received audio signal comprising the at least one from among the pseudorandom sequence seed representing the periodic pseudorandom white noise, the inaudible noise, and the modulated music; and
determining a location of a mobile device based on the estimated arrival time of the received audio signal comprising the at least one from among the pseudorandom sequence seed representing the periodic pseudorandom white noise, the inaudible noise and the modulated music and a location associated with each of the pre-stored plurality of audio tracks,
wherein the comparing compares the received audio signal to the plurality of pre-stored audio tracks by cross correlating the received audio signal with the pre-stored plurality of audio tracks.
6. The computer program product of claim 5 , further comprising code for correcting for a clock drift of the received broadcast based on the comparing.
7. The computer program product of claim 5 , further comprising code for receiving a selection of the plurality of audio tracks for the comparing.
8. The computer program product of claim 5 , 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.
9. A method, comprising:
receiving a broadcast comprising at least one from among a pseudorandom sequence seed representing a periodic pseudorandom white noise and modulated music;
comparing the received broadcast to a plurality of pre-stored audio tracks;
estimating an arrival time of the received broadcast comprising the at least one from among the pseudorandom sequence seed representing the periodic pseudorandom white noise and the modulated music; and
determining a location of a mobile device based on the estimated arrival time of the received broadcast comprising the at least one from among the pseudorandom sequence seed representing the periodic pseudorandom white noise and the modulated music and a location associated with each of the pre-stored plurality of audio tracks,
wherein the comparing compares the received broadcast to the plurality of pre-stored audio tracks by cross correlating the received audio signal with the pre-stored plurality of audio tracks.
10. The method of claim 9 , further comprising correcting for a clock drift of the received audio based on the comparing.
11. The method of claim 9 , further comprising receiving a selection of the plurality of audio tracks for the comparing.
12. The method of claim 9 , 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.
13. The method of claim 12 , wherein the calculating the estimated arrival time further comprises setting a value for a height of the mobile device.
14. The method of claim 13 , wherein the calculating the estimated arrival time further comprises retaining the first time and the value to determine the location of the mobile device in a subsequent determination.