Position determination system having a deconvolution decoder

Patent metadata

Field	Value
Publication number	US-11977176-B2
Application number	US-202217991064-A
Country	US
Kind code	B2
Filing date	Nov 21, 2022
Priority date	Dec 29, 2017
Publication date	May 7, 2024
Grant date	May 7, 2024

Abstract

The present disclosure relates to an acoustic position determination system that includes a mobile communication device and at least one base transmitter unit. The mobile communication device is configured to transmit and receive acoustic signals. Due to relative movements between the mobile communication device and the base transmitter unit, frequencies of the received signals shift due to Doppler effect. The mobile communication device is configured to compensate Doppler frequency shifts in the received acoustic signals prior to performing a deconvolution decoding process. The mobile communication device is further configured to compensate Doppler frequency shifts and perform deconvolution decoding process on acoustic signals received from multiple signal transmission paths.

First claim

What is claimed is:

1. A method performed by a mobile communication device, comprising:
receiving one or more acoustic signals from a transmitting device, the one or more acoustic signals including a signal code associated with the transmitting device;
storing a plurality of signature templates;
sampling the one or more acoustic signals to generate sampled acoustic signals, the sampling being performed at or higher than a chip rate;
performing a Fast Fourier Transform (FFT) on the sampled acoustic signals to generate frequency-domain sampled acoustic signals;
cross-correlating the frequency-domain sampled acoustic signals with at least one of the plurality of signature templates to determine a Doppler shift frequency of the sampled acoustic signals;
shifting the frequency-domain sampled acoustic signals by the Doppler shift frequency resulting in compensated acoustic signals;
de-convolving the compensated acoustic signals by the signal code to generate a response function;
performing a peak analysis on the response function to identify valid peaks and identifying one or more signature templates transmitted from the plurality of signature templates using the identified valid peaks; and
determining a location of the mobile communication device based on the identified valid peaks and the signal code.

2. The method of claim 1 , wherein each signature template of the plurality of signature templates comprises a plurality of phase shift keyed signals.

3. The method of claim 1 , wherein the cross-correlating further comprises determining the Doppler shift frequency with sub-sample resolution frequency using a peak fit algorithm.

4. The method of claim 1 , further comprising determining the identity of the transmitting device using the identified valid peaks.

5. The method of claim 1 , wherein the frequency-domain sampled acoustic signals are shifted in frequency by a value of the Doppler shift frequency.

6. The method of claim 1 , further comprising calculating the response function using an Inverse Fast Fourier Transform (IFFT) prior to performing the peak analysis.

7. The method of claim 1 , wherein the Doppler shift frequency is determined by using a maximum magnitude correlation between the at least one of the plurality of signature templates and the frequency-domain sampled acoustic signals.

8. The method of claim 1 , wherein the performing the peak analysis comprises:
scaling the response function with a power law function;
performing a statistical distribution analysis;
removing outlier peaks; and
performing peak approximations using an envelope reconstruction function.

9. The method of claim 1 , wherein the cross-correlating further comprises determining the Doppler shift frequency with sub-sample resolution frequency using a peak fit algorithm.

10. The method of claim 1 , further comprising determining the valid peaks using respective signal-to-noise ratios.

11. A mobile communication device, comprising:
a receiver configured to receive one or more acoustic signals from a transmitting device, the one or more acoustic signals including a signal code associated with the transmitting device;
a memory unit configured to store a plurality of signature templates; and
one or more processors configured to:
sample the one or more acoustic signals to generate sampled acoustic signals, the sampling being performed at or higher than a chip rate;
perform a Fast Fourier Transform (FFT) on the sampled acoustic signals to generate frequency-domain sampled acoustic signals;
cross-correlate the frequency-domain sampled acoustic signals with at least one of the plurality of signature templates to determine a Doppler shift frequency of the sampled acoustic signals;
shift the frequency-domain sampled acoustic signals by the Doppler shift frequency resulting in compensated acoustic signals;
de-convolve the compensated acoustic signals by the signal code to generate a response function;
perform a peak analysis on the response function to identify valid peaks and identify one or more signature templates transmitted from the plurality of signature templates using the identified valid peaks; and
determine a location of the mobile communication device based on the identified valid peaks and the signal code.

12. The mobile communication device of claim 11 , wherein each signature template of the plurality of signature templates comprises a plurality of phase shift keyed signals.

13. The mobile communication device of claim 11 , wherein the one or more processors are further configured to cross-correlate by determining the Doppler shift frequency with sub-sample resolution frequency using a peak fit algorithm.

14. The mobile communication device of claim 11 , wherein the one or more processors are further configured to determine an identity of the transmitting device using the identified valid peaks.

15. The mobile communication device of claim 11 , wherein the one or more processors are further configured to shift the frequency-domain sampled acoustic signals in frequency by a value of the Doppler shift frequency.

16. The mobile communication device of claim 11 , wherein the one or more processors are further configured to calculate the response function using an Inverse Fast Fourier Transform (IFFT) prior to performing the peak analysis.

17. The mobile communication device of claim 11 , wherein the one or more processors are further configured to determine the Doppler shift frequency by using a maximum magnitude correlation between the at least one of the plurality of signature templates and the frequency-domain sampled acoustic signals.

18. The mobile communication device of claim 11 , wherein the one or more processors are further configured to:
scale the response function with a power law function;
perform a statistical distribution analysis;
remove outlier peaks; and
perform peak approximations using an envelope reconstruction function.

19. The mobile communication device of claim 11 , wherein the one or more processors are further configured to determine the Doppler shift frequency with sub-sample resolution using a peak fit algorithm.

20. The mobile communication device of claim 11 , wherein the one or more processors are further configured to determine the valid peaks using respective signal-to-noise ratios.

Assignees

• Sonitor Technologies As

Inventors

• Booij Wilfred Edwin

Classifications

• G01S5/18 Primary

  using ultrasonic, sonic or infrasonic waves · CPC title

• G01S3/8022

  using the Doppler shift introduced by the relative motion between source and receiver · CPC title

• G01S5/30

  Determining absolute distances from a plurality of spaced points of known location · CPC title

• G01S11/14

  using ultrasonic, sonic or infrasonic waves · CPC title

• H04B11/00

  Transmission systems employing ultrasonic, sonic or infrasonic waves · CPC title