Electronic Device for Determining the Distance of a Drone From an Obstacle With Filtering Adapted to the Speed of the Drone, Drone, Determination Method and Computer Program

Patent metadata

Field	Value
Publication number	US-2018348350-A1
Application number	US-201815994902-A
Country	US
Kind code	A1
Filing date	May 31, 2018
Priority date	May 31, 2017
Publication date	Dec 6, 2018
Grant date	—

Abstract

An electronic device for determining a distance of a drone from an obstacle, the electronic device comprising:
an emission module to command the emission of an ultrasound signal toward the obstacle; a reception module to receive a signal representative of an ultrasound signal reflected by the obstacle; a calculation module to calculate the distance of the drone from the obstacle, from the received signal; and a filtering module comprising at least one filter matched to a respective Doppler offset, each matched filter generating a respective filtered signal as a function of a convolution product of the emitted ultrasound signal, to which the respective Doppler offset is applied, with the received ultrasound signal;

the calculation module then calculating the distance of the drone from the obstacle, from the filtered signal(s) from the filtering module.

First claim

1 . An electronic device for determining a distance of a drone from an obstacle, the electronic determination device comprising:
an emission module configured to command the emission of an ultrasound signal toward the obstacle; a reception module configured to receive a signal representative of an ultrasound signal reflected by the obstacle; a calculation module configured to calculate the distance of the drone from the obstacle, from the received signal; wherein it further comprises: a filtering module comprising at least one filter matched to a respective Doppler offset, each matched filter being configured to generate a respective filtered signal as a function of a convolution product of the emitted ultrasound signal, to which the respective Doppler offset is applied, with the received ultrasound signal; the calculation module then being configured to calculate the distance of the drone from the obstacle, from the filtered signal(s) from the filtering module.

2 . The electronic device according to claim 1 , wherein the filtering module comprises a plurality of filters each matched to a respective Doppler offset, arranged in parallel, the calculation module then being configured to calculate the distance of the drone from the obstacle, from filtered signals from the filtering module.

3 . The electronic device according to claim 2 , wherein the device further comprises a selection module configured to select, based on a speed of the drone toward the obstacle, a matched filter from among the plurality of matched filters, the calculation module then being configured to calculate the distance of the drone from the obstacle, from the filtered signal from the selected matched filter.

4 . The electronic device according to claim 1 , wherein the emission module is configured to command the emission of the ultrasound signal in the form of at least one frequency-modulated pulse.

5 . The electronic device according to claim 4 , wherein the emission module is further configured to command the emission of the ultrasound signal in the form of at least one non-frequency-modulated pulse, and
wherein the device further comprises a switching module configured to switch the emission module between a first emission mode of the ultrasound signal in the form of at least one frequency-modulated pulse and a second emission mode of the ultrasound signal in the form of at least one non-frequency-modulated pulse.

6 . The electronic device according to claim 5 , wherein the switching module is configured to switch the emission module between the first emission mode and the second emission mode, based on at least one property from among a distance between the drone and an obstacle and a signal-to-noise ratio associated with the last ultrasound signal reception (s).

7 . The electronic device according to claim 1 , wherein the reception module comprises several reception channels arranged in parallel, each reception channel being configured to record the received signal with a respective gain value.

8 . A drone comprising an electronic determination device configured to determine the distance of the drone relative to an obstacle,
wherein the electronic determination device is according to claim 1 .

9 . A method for determining a distance of a drone from an obstacle, the method being carried out by an electronic device and comprising:
commanding the emission of an ultrasound signal toward the obstacle; receiving a signal representative of an ultrasound signal reflected by the obstacle; calculating the distance of the drone from the obstacle, from the received signal; wherein it further comprises: filtering the received signal with at least one filter matched to a respective Doppler offset, each matched filter generating a respective filtered signal as a function of a convolution product of the emitted ultrasound signal, to which the respective Doppler offset is applied; calculating the distance of the drone relative to the obstacle, from the filtered signal(s).

10 . A non-transitory computer-readable medium including a computer program comprising software instructions which, when executed by a computer, carry out a method according to claim 9 .

11 . The electronic device according to claim 4 , wherein each frequency-modulated pulse has a time duration greater than or equal to 2 ms.

12 . The electronic device according to claim 11 , wherein each frequency-modulated pulse has a time duration greater than or equal to 4 ms.

13 . The electronic device according to claim 12 , wherein each frequency-modulated pulse has a time duration greater than or equal to 6 ms.

14 . The electronic device according to claim 5 , wherein each non-frequency-modulated pulse has a time duration less than or equal to

2
×
R

c

,

where R is a resolution with a predefined distance and c represents the speed of the sound in the air.

15 . The electronic device according to claim 14 , wherein each non-frequency-modulated pulse has a time duration less than or equal to 1 ms.

16 . The electronic device according to claim 6 , wherein the number of emissions in a given emission mode from among the first emission mode and the second emission mode is greater than or equal to a predetermined minimum number.

17 . The electronic device according to claim 16 , wherein the predetermined minimum number is greater than or equal to 3.

18 . The electronic device according to claim 17 , wherein the predetermined minimum number is equal to 4.

19 . The electronic device according to claim 7 , wherein each gain value is distinct from one reception channel to another.

Assignees

• Parrot Drones

Inventors

• Remond Fabien
• Hourioux Jerome

Classifications

• G01S15/93 Primary

  for anti-collision purposes · CPC title

• G01S15/52

  Discriminating between fixed and moving objects or between objects moving at different speeds · CPC title

• G01S15/101

  Particularities of the measurement of distance (G01S15/12, G01S15/14, and G01S15/18 take precedence) · CPC title

• G01S15/104

  wherein the transmitted pulses use a frequency- or phase-modulated carrier wave · CPC title

• G01S7/5273 Primary

  using digital techniques · CPC title