Method for localizing a marine mammal in an underwater environment implemented by a PAM system, corresponding device, computer program product and non-transitory computer-readable carrier medium

Patent metadata

Field	Value
Publication number	US-9625592-B2
Application number	US-201414296009-A
Country	US
Kind code	B2
Filing date	Jun 4, 2014
Priority date	Mar 12, 2014
Publication date	Apr 18, 2017
Grant date	Apr 18, 2017

Abstract

A method for localizing a marine animal in an underwater environment implemented by a passive acoustic monitoring (PAM) system. The passive acoustic monitoring system includes network of acoustic sensors adapted to carry out measurements of acoustic signals. The method includes: obtaining, from the network of acoustic sensors, measured data of an acoustic signal emitted by a marine animal; defining a space of dimensional representation of the underwater environment discretized in a plurality of predefined cells, for each cell of a predefined set, obtaining an error defined as a value of a cost function for the cell, the cost function giving a deviation between: at least some of the measured data; and corresponding theoretical data obtained by assuming the marine animal is located in the cell, the errors obtained for the predefined set of cells enabling to obtain at least one piece of information about localization of the marine animal.

First claim

The invention claimed is:

1. A method for localizing a marine animal in an underwater environment implemented by a first passive acoustic monitoring system, the first passive acoustic monitoring system comprising a network of acoustic sensors adapted to carry out measurements of acoustic signals, wherein the method comprises:
obtaining, from the network of acoustic sensors, a first set of measured data of an acoustic signal emitted by a marine animal;
defining a space of dimensional representation of the underwater environment discretized in a plurality of predefined cells;
for each cell of a predefined set of cells among said plurality, obtaining an error defined as a value of a cost function for said cell, said cost function giving a deviation between:
at least some of said measured data of the first set; and
corresponding theoretical data obtained by assuming that the marine animal is located in said cell,
said errors obtained for the predefined set of cells enabling to obtain at least one piece of information about localization of the marine animal;
establishing an error map from said errors obtained for the predefined set of cells;
visually providing said error map to the operator;
computing, from said error map, a probability distribution function of presence of the marine animal;
determining a zone of uncertainty of localization of the marine animal as a function of the probability distribution function;
comparing the zone of uncertainty of localization with a predefined safety exclusion zone; and
providing a piece of information on probability of presence of the marine animal inside the predefined safety exclusion zone, as a function of the result of the comparing.

2. The method according to claim 1 , wherein the method comprises determining a value of localization of the marine animal as a function of the probability distribution function.

3. The method according to claim 1 , wherein the method comprises providing a piece of information on probability of presence of the marine animal outside the predefined safety exclusion zone, as a function of the result of the comparing step.

4. The method according to claim 1 , wherein the method comprises:
detecting an intersection zone of the zone of uncertainty of localization and the predefined safety exclusion zone, and
providing a piece of information on probability of presence of the marine animal inside said intersection zone.

5. The method according to claim 1 , wherein the measured data belong to the group consisting of:
time difference of arrival data;
angle of arrival data;
data relative to location of the acoustic sensors;
data relative to underwater acoustic sound celerity.

6. The method according to claim 1 , wherein the method further comprises obtaining at least one second set of measured data of said acoustic signal emitted by the marine animal, collected from a network of acoustic sensors of at least one second passive acoustic monitoring system cooperating with said first passive acoustic monitoring system,
and wherein said defining and obtaining steps are carried out as a function of said first and second sets of measured data.

7. A non-transitory computer-readable carrier medium storing a computer program product that comprises program code instructions for implementing a method for localizing a marine animal in an underwater environment implemented by a first passive acoustic monitoring system, the passive acoustic monitoring system comprising a network of acoustic sensors adapted to carry out measurements of acoustic signals, wherein the method comprises:
obtaining, from the network of acoustic sensors, a first set of measured data of an acoustic signal emitted by a marine animal;
defining a space of dimensional representation of the underwater environment discretized in a plurality of predefined cells;
for each cell of a predefined set of cells among said plurality, obtaining an error defined as a value of a cost function for said cell, said cost function giving a deviation between:
at least some of said measured data of the first set; and
corresponding theoretical data obtained by assuming that the marine animal is located in said cell,
said errors obtained for the predefined set of cells enabling to obtain at least one piece of information about localization of the marine animal;
establishing an error map from said errors obtained for the predefined set of cells,
visually providing said error map to the operator;
computing, from said error map, a probability distribution function of presence of the marine animal;
determining a zone of uncertainty of localization of the marine animal as a function of the probability distribution function;
comparing the zone of uncertainty of localization with a predefined safety exclusion zone; and
providing a piece of information on probability of presence of the marine animal inside the predefined safety exclusion zone, as a function of the result of the comparing.

8. A device for localizing a marine animal in an underwater environment, comprised in a passive acoustic monitoring system, the passive acoustic monitoring system comprising a network of acoustic sensors adapted to carry out measurements of acoustic signals, wherein the device comprises:
means for obtaining, from the network of acoustic sensors, measured data of an acoustic signal emitted by a marine animal;
means for defining a space of dimensional representation of the underwater environment discretized in a plurality of predefined cells;
means for obtaining an error defined as a value of a cost function for a cell, activated for each cell of a predefined set of cells among said plurality, said cost function giving a deviation between:
at least some of said measured data; and
corresponding theoretical data obtained by assuming that the marine animal is located in said cell,
means for obtaining at least one piece of information about localization of the marine animal taking into account said errors obtained for the predefined set of cells,
means for establishing an error map from said errors obtained for the predefined set of cells;
means for visually providing said error map to the operator;
means for computing, from said error map, a probability distribution function of presence of the marine animal;
means for determining a zone of uncertainty of localization of the marine animal as a function of the probability distribution function;
means for comparing the zone of uncertainty of localization with a predefined safety exclusion zone; and
means for providing a piece of information on probability of presence of the marine animal inside the predefined safety exclusion zone, as a function of the result of the comparing.

9. The device according to claim 8 , wherein the passive acoustic monitoring system is configured to cooperate either with a navigation software unit or with a positioning streamer software unit.

Assignees

• Sercel Rech Const Elect

Inventors

• L'Her Christophe
• Vallez Simon
• L'Her Marrec Veronique

Classifications

• G01V2210/1293

  Sea · CPC title

• G01V1/001 Primary

  Acoustic presence detection · CPC title

• G01V2210/1423

  Sea · CPC title

• G01S3/80 Primary

  using ultrasonic, sonic or infrasonic waves · CPC title