Apparatus, method, and software systems for smartphone-based fine-grained indoor localization

• US 9,894,531 B2
• Filed: 12/03/2013
• Issued: 02/13/2018
• Est. Priority Date: 12/03/2012
• Status: Active Grant

• Current Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Original Assignee: University of Florida Research Foundation, Incorporated (State University System of Florida)
• Inventors: Li, Xiaolin, Liu, Kaikai
• Primary Examiner(s): HEIBER, SHANTELL LAKETA
• Application Number:
  US14/129,213
• Publication Number:
  US 20150156637A1
• Time in Patent Office: 1,533 Days
• Field of Search: None
• CPC Class Codes: G01S 1/725 Marker, boundary, call-sign or like beacons transmitting signals not carrying directional information
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 56/002 Mutual synchronization
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

Techniques for accurate, low-complexity, scalable indoor localization. Low-complexity anchor nodes generate acoustic beacon signals, which are passively detectable by a mobile device, which may be unmodified smartphones operating in an acoustic frequency range. The acoustic beacon signals are modulated via codes in a boundary band of audio and ultrasound frequencies, imperceptible to humans yet detectable via a voice microphone of an unmodified smartphone. An application on the mobile device passively captures the acoustic beacon signals and determines relative distances to the anchor nodes. Localization and distance update techniques, implemented on the mobile device and/or a remote server, determines and updates in real-time the location of the mobile device. The system may be scalable to support any number of mobile devices. Based on the tracked location, the indoor localization system may provide indoor location-based-services (LBS) to the mobile devices, and transmit to the mobile device information relevant to its location.

Claims

1. A method of determining location of a portable electronic device within a region, the method comprising:

emitting acoustic signals with a frequency bandwidth of about 17 to 20 KHZ from each of a plurality of source devices, the plurality of source devices being controlled to emit acoustic signals with an identifier of the respective source device at synchronized times, wherein each identifier of the respective source device is orthogonal to each of the other identifiers of the plurality of source devices;

receiving at a microphone on the portable electronic device acoustic signals from at least a portion of the plurality of source devices, wherein at least two acoustic signals of the acoustic signals comprise the same identifier and have different times of receipt at the microphone;

selecting from the at least two acoustic signals the acoustic signal with an earlier time of receipt;

performing code matching to identify a plurality of identifiers from the acoustic signals;

computing from the received acoustic signals a position of the portable electronic device with a resolution of less than 10 cm based at least in part on known location information of the source devices associated with the plurality of identifiers; and

automatically rendering information to a user of the portable electronic device selected based on the computed position.

2. The method of claim 1, wherein computing from the received acoustic signals a position of the portable electronic device comprises:

transmitting information derived from the received acoustic signals to a remote server;

calculating, at the remote server, a position of the portable electronic device based on the transmitted portion of the received acoustic signals;

receiving, from the remote server, the calculated position of the portable electronic device.

3. A portable electronic device comprising:

a user output component;

a voice microphone configured to receive voice input; and

a processor,

wherein the processor is configured to process acoustic signals received through the voice microphone to

select acoustic signals with amplitude exceeding a threshold, wherein each acoustic signal of the selected acoustic signals comprises a symbol associated with a source device,

compute relative times of arrival of selected acoustic signals by synchronizing a pattern of transmission times of the selected acoustic signals with a list of symbols to obtain times of arrival of the selected acoustic signals with symbols associated with respective source devices,

determine, based at least in part on the computed relative times of arrival of acoustic signals, a location of the portable electronic device with a resolution of less than 30 cm and

render information through the user output component selected based on the determined location.

4. The portable electronic device of claim 3, wherein:

the portable electronic device comprises a commercially available smartphone configured with an app.

5. The portable electronic device of claim 4, wherein:

the app controls the smartphone to acquire the information rendered through the user output component over a wide area network.

6. The portable electronic device of claim 3, wherein the processor is configured to process acoustic signals received through the voice microphone to determine a location of the portable electronic device by:

identifying non-line-of-sight (NLOS) signals from the received acoustic signals;

computing the location of the portable electronic device based at least in part on the received acoustic signals that are not NLOS signals.

7. The portable electronic device of claim 3, wherein the acoustic signals are emitted from each of a plurality of source devices and have a frequency bandwidth of about 17 to 20 KHz.

8. The portable electronic device of claim 3, wherein the processor is further configured to perform distance updating, wherein the distance updating comprises determining an updated time-of-arrival based on incremental information received from the acoustic signals.

9. The portable electronic device of claim 8, wherein the distance updating comprises computing an average of at least one past time-of-arrival estimate and a current time-of-arrival estimate.

10. The portable electronic device of claim 3, wherein the processor is configured to dynamically select the threshold based at least in part on a false alarm rate and an average amplitude of the received acoustic signals.

11. At least one non-transitory computer-readable storage medium comprising computer-executable instructions that, when executed by at least one processor of a device having a user output component and a voice microphone configured to receive voice input, perform of a method of:

receiving a plurality of acoustic signals through the voice microphone at each of a plurality of times, wherein each acoustic signal of the plurality of acoustic signals comprises a unique symbol associated with a source device and wherein at least two acoustic signals of the plurality of acoustic signals comprise the same symbol and have different times of receipt at the voice microphone;

selecting from the at least two acoustic signals of the plurality of acoustic signals the acoustic signal with an earlier time of receipt;

synchronizing a pattern of transmission times of the plurality of acoustic signals with a list of symbols to obtain times of receipt of the selected acoustic signals with symbols associated with respective source devices;

based on the times of receipt of the selected acoustic signals, determining a relative position between the device and respective sources of the plurality of acoustic signals with a resolution of less than 30 cm;

based on locations of the sources of the acoustic signals, determining a position of the device;

selecting information based on the determined position; and

rendering the selected information on the user output component.

12. The at least one non-transitory computer-readable storage medium of claim 11, wherein:

the computer-executable instructions comprise a smartphone app.

13. The at least one non-transitory computer-readable storage medium of claim 11, wherein:

selecting information comprises interacting with at least one server to obtain information associated with locations within a region.

14. The at least one non-transitory computer-readable storage medium of claim 11, wherein:

determining the position of the device comprises tracking the position of the device in real-time.