US 10,310,081 B2Granted

System and method for ultrasound distance detection

AssigneeSz Dji Technology Co., Ltd.

InventorsJiebin Xie, Litian Zhang, Wei Ren

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Abstract

A system for using ultrasound to detect distance on mobile platform and methods for making and using same. The system includes an ultrasound transceiver that can transmit and/or receive ultrasound waves and determine distance from an object of interest using a time-of-flight of the ultrasound wave. The system is adapted to reduce noise by using a dynamic model of the mobile platform to set constraints on the possible location of a received ultrasound echo. A linear, constant-speed dynamic model can be used to set constraints. The system can further reduce noise by packetizing a received ultrasound waveform and filtering out noise according to height and width of the packets. The system likewise can remove dead zones in the ultrasound transceiver by subtracting an aftershock waveform from the received waveform. The systems and methods are suitable for ultrasound distance detection on any type of mobile platform, including unmanned aerial vehicles.

Claims19

Dependent claims

A method of ultrasound distance detection for a mobile platform, the method comprising:

emitting an ultrasound wave from the mobile platform;
estimating, based on a dynamic model and using a state of the mobile platform at a time when the ultrasound wave is emitted, a state of the mobile platform at a time when an ultrasound echo of the ultrasound wave, which is reflected by an object, is expected to be received by the mobile platform, the state of the mobile platform including a position of the mobile platform and a change of the position of the mobile platform over time, and the dynamic model including a relationship between the state of the mobile platform, a change of the state of the mobile platform over time, and an assumed noise;
predicting a location of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform based on an average value and a variance of the state of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform;
determining a set of timing constraints on a timing of the ultrasound echo being received by the mobile platform using the predicted location of the mobile platform, including determining a width and a position of the timing constraints according to the average value and the variance, respectively, of the state of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform;
identifying the ultrasound echo from a received sonic waveform within the timing constraints, including distinguishing the ultrasound echo from noise on the received sonic waveform by:
dividing the sonic waveform into packets;
and
filtering the packets using a threshold packet bandwidth or amplitude to identify one of the packets that corresponds to the ultrasound echo, the threshold packet bandwidth being multiple of an average width of previously known echoes, and the threshold packet amplitude being a fraction of an average amplitude of the previously known echoes;
and
determining a distance between the mobile platform and the object based upon the ultrasound echo.

7 more elements

An apparatus for ultrasound distance detection comprising:

an ultrasound transmitter for emitting an ultrasound wave;
an ultrasound receiver for receiving an ultrasound echo of the ultrasound wave, which is reflected by an object;
and
a processor configured to:
estimate, based on a dynamic model and using a state of a mobile platform at a time when the ultrasound wave is emitted, a state of the mobile platform at a time when the ultrasound echo is expected to be received by the mobile platform, the state of the mobile platform including a position of the mobile platform and a change of the position of the mobile platform over time, and the dynamic model including a relationship between the state of the mobile platform, a change of the state of the mobile platform over time, and an assumed noise;
predict a location of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform based on an average value and a variance of the state of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform;
determine a set of timing constraints on a timing of the ultrasound echo being received by the mobile platform using the predicted location of the mobile platform, including determining a width and a position of the timing constraints according to the average value and the variance, respectively, of the state of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform;
identify the ultrasound echo from a received sonic waveform within the timing constraints, including distinguishing the ultrasound echo from noise on the received sonic waveform by:
dividing the sonic waveform into packets;
and
filtering the packets using a threshold packet bandwidth or amplitude to identify one of the packets that corresponds to the ultrasound echo, the threshold packet bandwidth being multiple of an average width of previously known echoes, and the threshold packet amplitude being a fraction of an average amplitude of the previously known echoes;
and
determine a distance between the mobile platform and the object according to the ultrasound echo.

10 more elements

A mobile platform comprising:

an ultrasound transmitter for emitting an ultrasound wave;
an ultrasound receiver for receiving an ultrasound echo of the ultrasound wave, which is reflected by an object;
and
a processor configured to:
estimate, based on a dynamic model and using a state of the mobile platform at a time when the ultrasound wave is emitted, a state of the mobile platform at a time when the ultrasound echo is expected to be received by the mobile platform, the state of the mobile platform including a position of the mobile platform and a change of the position of the mobile platform over time, and the dynamic model including a relationship between the state of the mobile platform, a change of the state of the mobile platform over time, and an assumed noise;
predict a location of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform based on an average value and a variance of the state of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform;
determine a set of timing constraints on a timing of the ultrasound echo being received by the mobile platform using the predicted location of the mobile platform, including determining a width and a position of the timing constraints according to the average value and the variance, respectively, of the state of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform;
identify the ultrasound echo from a received sonic waveform within the timing constraints, including distinguishing the ultrasound echo from noise on the received sonic waveform by:
dividing the sonic waveform into packets;
and
filtering the packets using a threshold packet bandwidth or amplitude to identify one of the packets that corresponds to the ultrasound echo, the threshold packet bandwidth being multiple of an average width of previously known echoes, and the threshold packet amplitude being a fraction of an average amplitude of the previously known echoes;
and
determine a distance between the mobile platform and the object according to the ultrasound echo.

10 more elements

A non-transitory computer-readable medium with instructions stored thereon that, when executed by a processor, perform a method comprising:

instructing an ultrasound transmitter to emit an ultrasound wave;
estimating, based on a dynamic model and using a state of a mobile platform at a time when the ultrasound wave is emitted, a state of the mobile platform at a time when an ultrasound echo of the ultrasound wave, which is reflected by an object, is expected to be received by the mobile platform, the state of the mobile platform including a position of the mobile platform and a change of the position of the mobile platform over time, and the dynamic model including a relationship between the state of the mobile platform, a change of the state of the mobile platform over time, and an assumed noise;
predicting a location of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform based on an average value and a variance of the state of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform;
determining a set of timing constraints on a timing of the ultrasound echo being received by the mobile platform using the predicted location of the mobile platform, including determining a width and a position of the timing constraints according to the average value and the variance, respectively, of the state of the mobile platform at the time when the ultrasound echo of the ultrasound wave is expected to be received by the mobile platform;
identifying the ultrasound echo from a received sonic waveform within the timing constraints, including distinguishing the ultrasound echo from noise on the received sonic waveform by:
dividing the sonic waveform into packets;
and
filtering the packets using a threshold packet bandwidth or amplitude to identify one of the packets that corresponds to the ultrasound echo, the threshold packet bandwidth being multiple of an average width of previously known echoes, and the threshold packet amplitude being a fraction of an average amplitude of the previously known echoes;
and
determining a distance between the mobile platform and the object based upon the ultrasound echo.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 15/169,449Filed 31 May 2016 · continuation
Priority: 9 Jul 2015
Published: US 2017/0059704 A12 Mar 2017
Granted: 4 Jun 2019
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

G01S 15/08
Systems determining the position data of a target: systems for measuring distance only
G01S 15/10
Systems for measuring distance only: using transmission of interrupted, pulse-modulated waves
G01S 15/93
Sonar systems specially adapted for specific applications: for anti-collision purposes
B64U 10/00
Type of uav

Family

PCT/CN2015/083638Parent of this continuation · filed 9 Jul 2015
US 2017/0059704 A1Pre-grant publication · published 2 Mar 2017
US 10,310,081 B2This patent

From the US filing history. Foreign family members aren’t listed.

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