System and method for detecting aerial vehicle position and velocity via sound

• US 10,473,752 B2
• Filed: 04/19/2017
• Issued: 11/12/2019
• Est. Priority Date: 02/03/2015
• Status: Active Grant

• Current Assignee: SZ DJI Technology Co., Ltd. (d/b/a DJI) (iFlight Technology Company Limited)
• Original Assignee: SZ DJI Technology Co., Ltd. (d/b/a DJI) (iFlight Technology Company Limited)
• Inventors: Xie, Jiebin, Zhao, Cong
• Primary Examiner(s): Nguyen, Duc
• Assistant Examiner(s): Mohammed, Assad
• Application Number:
  US15/490,939
• Publication Number:
  US 20170219686A1
• Time in Patent Office: 937 Days
• CPC Class Codes: G01S 11/14 using ultrasonic, sonic, or infrasonic waves
• CPC Class Codes: G01S 2205/03 Airborne
• CPC Class Codes: G01S 5/28 by co-ordinating position lines of different shape, e.g. hyperbolic, circular, elliptical or radial
• CPC Class Codes: H04R 1/04 Structural association of microphone with electric circuitry therefor in deaf-aid sets H04R25/00
• CPC Class Codes: H04R 1/406 microphones
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407
• CPC Class Codes: H04R 3/04 for correcting frequency response

Abstract

A system for determining a signal source position and velocity, and methods for manufacturing and using same are provided. An exemplary method includes determining a signal source position and velocity by performing a direction analysis on a plurality of audio signals and performing an intensity analysis on the audio signals. Another exemplary method includes determining that a signal source is on a collision course with a moving platform and providing an instruction for altering the course of the moving platform to avoid a collision with the signal source. An exemplary system includes an acoustic sensing system, having a primary microphone array, a secondary microphone, and a processing device for determining a signal source position and velocity by performing a direction analysis on a plurality of audio signals and performing an intensity analysis on the audio signals.

Claims

1. A method of determining a position and a velocity of a signal source, comprising:

obtaining a plurality of audio signals from a primary microphone array arranged at a first location of a moving platform;

obtaining a noise audio signal from a secondary microphone arranged at a second location of the moving platform, the first location and the second location being at opposing sides of the moving platform;

generating a plurality of processed audio signals by subtracting the noise audio signal from each of the plurality of audio signals;

identifying, from the plurality of processed audio signals, a set of processed audio signals that match an audio signature of the signal source according to characteristics associated with the audio signature, the characteristics associated with the audio signature including a number of signature peaks in the audio signature, intensities of the signature peaks in the audio signature, and shift distances of detected peaks in the set of processed audio signals respectively from corresponding ones of the signature peaks in the audio signature;

performing a direction analysis on the set of processed audio signals;

performing a frequency analysis on the set of processed audio signals;

estimating the position and the velocity of the signal source according to a result of the direction analysis and a result of the frequency analysis; and

determining whether the signal source is on a collision course with the moving platform according to the position and the velocity of the signal source.

2. The method of claim 1, further comprising:

conducting a frequency estimation on the set of processed audio signals; and

determining a signal direction of the signal source based on the set of processed audio signals.

3. The method of claim 2,

wherein the set of processed audio signals are a first set of processed audio signals, the method further comprising:

identifying, from the plurality of processed audio signals, a second set of processed audio signals that match the audio signature of the signal source according to the characteristics associated with the audio signature; and

conducting a frequency estimation on the second set of processed audio signals.

4. The method of claim 3,

wherein the signal direction is a first signal direction,

the method further comprising:

determining a second signal direction of the signal source based on the second set of processed audio signals.

5. The method of claim 4, further comprising:

determining whether the signal source is approaching or moving away from a detection position by performing a Doppler analysis of the first and second sets of processed audio signals.

14. The method of claim 1, wherein the audio signature includes a pattern of one or more frequency peaks.

15. The method of claim 1, further comprising:

comparing one or more intensities of the set of processed audio signals with one or more baseline intensities associated with a type of the signal source to determine a relative distance between the signal source and the moving platform; and

estimating the position and the velocity of the signal source based on the relative distance.

16. The method of claim 1, further comprising:

comparing one or more intensities of the set of processed audio signals with one or more baseline intensity associated with a type of the signal source at one or more known distance values to the signal source to determine a relative distance value between the signal source and the moving platform; and

estimating the position and the velocity of the signal source based on the relative distance value.

17. The method of claim 1, further comprising determining a type of the signal source.

18. The method of claim 1, wherein types of microphones of the primary microphone array are different from a type of the secondary microphone.

19. The method of claim 1, wherein:

a frequency range of the plurality of audio signals obtained by the primary microphone array include one or more of subsonic frequency, sonic frequency, and ultrasonic; and

a frequency range of the noise audio signal obtained by the secondary microphone includes one or more of subsonic frequency, sonic frequency, and ultrasonic.

20. The method of claim 1, wherein the audio signature uniquely identifies the signal source.

6. A method of determining a position and a velocity of a signal source, comprising:

obtaining a plurality of audio signals from a primary microphone array arranged at a first location of a moving platform;

obtaining a noise audio signal from a secondary microphone arranged at a second location of the moving platform, the first location and the second location being at opposing sides of the moving platform;

generating a plurality of processed audio signals by subtracting the noise audio signal from each of the plurality of audio signals;

identifying, from the plurality of processed audio signals, a first set of processed audio signals and a second set of processed audio signals that match an audio signature of the signal source according to characteristics associated with the audio signature, the characteristics associated with the audio signature including a number of signature peaks in the audio signature, intensities of the signature peaks in the audio signature, and shift distances of detected peaks in the set of processed audio signals respectively from corresponding ones of the signature peaks in the audio signature;

conducting a frequency estimation on the first set of audio signals;

determining a first signal direction of the signal source based on the first set of audio signals;

conducting a frequency estimation on the second set of audio signals;

determining a second signal direction of the signal source based on the second set of audio signals;

determining whether the signal source is approaching or moving away from a detection position by performing a Doppler analysis of the first and second sets of audio signals;

determining the position and the velocity of the signal source based on the Doppler analysis, a direction analysis, and an intensity analysis; and

determining whether the signal source is on a collision course with the moving platform according to the position and the velocity of the signal source.

7. An acoustic sensing system, comprising:

a housing of a moving platform;

a primary microphone array positioned at a first location of the housing and comprising a plurality of microphones;

a secondary microphone positioned at a second location of the housing and being operably connected to the primary microphone array, the first location and the second location being at opposing sides of the housing; and

a processing device configured to;

obtain a plurality of audio signals from the primary microphone array;

obtain a noise audio signals from the secondary microphone;

generate a plurality of processed audio signals by subtracting the noise audio signal from each of the plurality of the audio signals;

identify, from the plurality of processed audio signals, a set of processed audio signals that match an audio signature of the signal source according to characteristics associated with the audio signature, the characteristics associated with the audio signature including a number of signature peaks in the audio signature, intensities of the signature peaks in the audio signature, and shift distances of detected peaks in the set of processed audio signals respectively from corresponding ones of the signature peaks in the audio signature;

determine a position and a velocity of the signal source based on a direction analysis and an intensity analysis of the set of processed audio signals associated with the signal source, and

determine whether the signal source is on a collision course with the moving platform according to the position and the velocity of the signal source.

8. The acoustic sensing system of claim 7, wherein the primary microphone array points in a first direction and the secondary microphone points in a second direction that is different from the first direction.

9. The acoustic sensing system of claim 8, wherein the first direction is opposite to the second direction.

10. The acoustic sensing system of claim 8, wherein the first direction is substantially perpendicular to the second direction.

11. The acoustic sensing system of claim 7, wherein microphones of the primary microphone array are positioned on a substrate in a matrix configuration having rows and columns.

12. The acoustic sensing system of any claim 7, wherein the processing device is further configured to:

conduct a frequency estimation on the set of processed audio signals; and

determine a signal direction of the signal source based on the set of processed audio signals.

13. The acoustic sensing system of claim 7, wherein the processing device is further configured to predict a future position and a future velocity of the based on a Doppler analysis, the direction analysis and the intensity analysis of the set of processed audio signals.