WO2019122743A1 - Drone marin de surface et procédé de caractérisation d'un milieu subaquatique mis en œuvre par un tel drone - Google Patents
Drone marin de surface et procédé de caractérisation d'un milieu subaquatique mis en œuvre par un tel drone Download PDFInfo
- Publication number
- WO2019122743A1 WO2019122743A1 PCT/FR2018/053448 FR2018053448W WO2019122743A1 WO 2019122743 A1 WO2019122743 A1 WO 2019122743A1 FR 2018053448 W FR2018053448 W FR 2018053448W WO 2019122743 A1 WO2019122743 A1 WO 2019122743A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- sonar
- transmissions
- fish
- drone
- school
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 39
- 230000004044 response Effects 0.000 claims abstract description 27
- 230000005540 biological transmission Effects 0.000 claims description 129
- 241000251468 Actinopterygii Species 0.000 claims description 82
- 239000011159 matrix material Substances 0.000 claims description 29
- 238000006073 displacement reaction Methods 0.000 claims description 22
- 230000008569 process Effects 0.000 claims description 17
- 238000012512 characterization method Methods 0.000 claims description 12
- 230000006870 function Effects 0.000 claims description 3
- 238000005259 measurement Methods 0.000 description 6
- 238000004891 communication Methods 0.000 description 5
- 238000003384 imaging method Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 238000005265 energy consumption Methods 0.000 description 4
- 241000894007 species Species 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 238000012545 processing Methods 0.000 description 3
- 230000001681 protective effect Effects 0.000 description 3
- 238000002604 ultrasonography Methods 0.000 description 3
- 230000006399 behavior Effects 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000002349 favourable effect Effects 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 230000003071 parasitic effect Effects 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 241001465754 Metazoa Species 0.000 description 1
- 230000004931 aggregating effect Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 238000012876 topography Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D1/00—Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots
- G05D1/02—Control of position or course in two dimensions
- G05D1/0206—Control of position or course in two dimensions specially adapted to water vehicles
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/88—Sonar systems specially adapted for specific applications
- G01S15/96—Sonar systems specially adapted for specific applications for locating fish
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/88—Sonar systems specially adapted for specific applications
- G01S15/89—Sonar systems specially adapted for specific applications for mapping or imaging
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
- G01S7/523—Details of pulse systems
- G01S7/524—Transmitters
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/52—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S15/00
- G01S7/523—Details of pulse systems
- G01S7/526—Receivers
- G01S7/527—Extracting wanted echo signals
- G01S7/5273—Extracting wanted echo signals using digital techniques
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D1/00—Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots
- G05D1/0094—Control of position, course, altitude or attitude of land, water, air or space vehicles, e.g. using automatic pilots involving pointing a payload, e.g. camera, weapon, sensor, towards a fixed or moving target
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/70—Determining position or orientation of objects or cameras
Definitions
- the present invention generally relates to unmanned boats adapted to move autonomously or via a remote control.
- It also relates to a method for exploring an underwater environment.
- Unmanned boats adapted to move autonomously or via remote control also called “surface marine drones”, or “drones boats” are currently experiencing a strong development.
- Such a multibeam sonar conventionally comprises a set of sonic or ultrasonic transmitters, distributed along the longitudinal axis of the boat. These emitters emit a set of sound waves (or ultrasound waves) according to respective coplanar emission directions, contained in an emission plane perpendicular to the longitudinal axis of the boat. Otherwise formulated, these sound waves are emitted in a directive manner, forming together a layer (the "swath") which extends under the boat, in line with it. These emission directions cover a given angular sector, generally having an opening of several tens of degrees. The sound waves emitted by the sonar reach different points of the seabed, located along the aforementioned line of measurement.
- Receivers adapted to detect sound waves reflected from the bottom, then make it possible to obtain depth data for different points of this measurement line. These receivers are arranged more precisely along a line perpendicular to the longitudinal axis of the boat, which makes it possible, by combining the signals they receive, to determine from which point of the measurement line a retro acoustic wave thoughtful given.
- Such a classic multibeam sonar allows, when the boat moves (in a straight line), to obtain, line by line, a two-dimensional image representative of the topography of the seabed considered.
- the present invention proposes a surface marine drone comprising an onboard sonar, the sonar, of the multibeam type, comprising a plurality of sound wave transmitters arranged along a first axis and a plurality of receivers. sound waves arranged along a second axis that is not parallel to the first axis.
- the marine drone further comprises:
- a sonar control system configured to control, for a given position of the marine drone, a plurality of successive transmissions of sound waves
- control system controlling the different transmitters, at each transmission, by a respective plurality of transmission signals, each signal transmission having an amplitude and a time offset with respect to a reference signal
- control system varying the respective amplitudes or time offsets of said transmission signals, during said plurality of transmissions, in accordance with a predetermined transmission variation sequence, all the sound waves emitted during said plurality of emissions covering a given observation volume, and
- an acquisition unit configured to:
- multibeam sonars for determining a three-dimensional image of an underwater environment from a fixed position are, because of their high level of development, bulky, heavy, energy consumers, and sometimes expensive. These characteristics make them suitable for large-scale exploration or fishing vessels.
- a surface marine drone is generally small, but, on the other hand, particularly mobile, therefore encourages it to be equipped with a single-beam sonar, or a conventional multibeam sonar adapted only to record data. depth along a measurement line, an image of the underwater environment considered being then obtained by displacement of the drone, as explained in the preamble.
- the applicant proposes to equip such a marine drone with the aforementioned multibeam sonar, configured to raise, from a fixed position of the drone, a three-dimensional image of its underwater environment.
- this marine drone is technically difficult, for the reasons mentioned above. But, in return, this drone turns out particularly useful for monitoring and characterizing an underwater environment. Indeed, it makes it possible to carry out such a characterization:
- the surface marine drone according to the invention makes it possible to detect, monitor and characterize a school of fish, without disturbing it, from an optimal position, located for example in the center of this school of fish. It is indeed generally at the center of such a bench that the type of fish encountered, their concentration and their behavior are the most representative of the entire bank.
- the invention thus finds a particularly interesting application in the context of an oceanographic study such as the determination of morphological and dynamic properties of the observed bench, or for a preliminary identification to a fishing operation.
- the sonar is configured so that an aspect ratio of the observation volume, equal to the smallest dimension of the observation volume divided by the largest dimension of the observation volume, is greater than 0.2 ;
- the largest external dimension of the marine drone is less than 2 meters
- the sonar transmitters and receivers are integrated into the hull of the surface marine drone;
- the sonar includes an electronic control unit for transmitters and receivers housed in the hold of the surface marine drone;
- control system is further adapted to, prior to said plurality of sound wave emissions, control a displacement of the surface marine drone to said given position;
- control system is also suitable for:
- the marine drone being situated at said other position, the acquisition unit acquiring, for each of said transmissions, the echo signals picked up by the sonar receivers, response to the transmission considered, and determining, from the echo signals acquired in response to said plurality of transmissions, another three-dimensional image representative of the content of the observation volume;
- the control system is further adapted to determine a representative data of said school of fish, other than a position of a center of the school of fish, according to said other three-dimensional image;
- control system is further adapted to locate, according to said three-dimensional image, a center of the school of fish;
- the sound power emitted is concentrated, by interference between the sound waves emitted, in a transmission plane,
- the transmission plane pivots around a scanning axis
- the transmission plane sweeps, as a result of said pivoting, the entire observation volume
- the sonar transmitters are N in number.
- This arrangement generally makes it possible to record a three-dimensional image of the contents of the observation volume with a higher rate (that is to say in a shorter time) than by scanning a plane. resignation.
- the base of emission ie the matrix of rank N considered, can correspond in particular to
- first axis and the second axis are separated by an angle of between 60 degrees and 90 degrees, that
- the transmitters are distributed, along the first axis, at least 20 centimeters long, or at least 50 centimeters long, and that
- the receivers are distributed along the second axis, at least 20 centimeters long, or even at least 50 centimeters long.
- the invention also provides a method for characterizing an underwater environment implemented by a surface marine drone comprising an onboard sonar, the multibeam type sonar, comprising a plurality of sound wave transmitters arranged along a first axis and a plurality of sound wave receivers disposed along a second axis that is not parallel to the first axis.
- a control sonar control system for a given position of the marine drone, a plurality of successive transmissions of sound waves
- control system controlling the different transmitters at each transmission by a respective plurality of transmission signals, each signal having an amplitude and a time offset with respect to a reference signal
- control system varying the respective amplitudes or time offsets of said transmission signals, during said plurality of transmissions, in accordance with a predetermined transmission variation sequence, all the sound waves emitted during said plurality of emissions covering a given observation volume,
- an acquisition unit acquires, for each of said transmissions, echo signals picked up by the sonar receivers in response to the emission in question, and
- the acquisition unit determines, based on the echo signals acquired in response to said plurality of transmissions, a representative three-dimensional image the content of the observation volume.
- an aspect ratio of the observation volume equal to the smallest dimension of the observation volume divided by the largest dimension of the observation volume, is greater than 0.2;
- control system also controls, prior to said plurality of sound wave transmissions, a displacement of the surface marine drone to said given position;
- control system Whenever during the process, the control system:
- the marine drone being located at said other position, the acquisition unit acquiring, for each of said transmissions, the echo signals picked up by the sonar receivers; response to the transmission considered, and determining, from the echo signals acquired in response to said plurality of transmissions, another three-dimensional image representative of the content of the observation volume;
- the method further comprises a step of determining a datum representative of said school of fish, other than a position of a center of the school of fish, according to said other three-dimensional image;
- control system locates, according to said three-dimensional image, the center of the school of fish;
- control unit determines, according to said three-dimensional image, the respective positions of a plurality of points situated on the perimeter of the school of fish, and determines a position of the center of the school of fish according to the positions of these points; ;
- the sound power emitted is concentrated, by interference between the sound waves emitted, in a transmission plane,
- the transmission plane pivots around a scanning axis
- the transmission plane sweeps, as a result of said pivoting, the entire observation volume.
- the sonar transmitters being N in number
- said plurality of sound wave emissions being associated, in a memory of the control system, with a respective plurality of rows of a matrix of rank N , for each of said sound wave emissions, the respective amplitudes of said transmission signals are proportional to the coefficients of the line of the rank matrix N associated with the emission in question.
- This transmission mode is used in particular to record a three-dimensional image of the content of the observation volume in a shorter time than scanning a transmission plan.
- the base of emission that is to say the matrix of rank N considered, can correspond in particular to a matrix of Hadamard of rank N. Alternatively, it could correspond to a diagonal matrix of rank N or to any other type matrix of N rank, rather than a rank N Hadamard matrix.
- FIG. 1 diagrammatically, seen from the side, a surface marine drone implementing the teachings of the invention
- FIG. 2 diagrammatically represents the surface marine drone of FIG. 1, viewed from below,
- FIG. 3 diagrammatically shows characteristics of a first mode of operation of a sonar of the marine drone of FIG. 1;
- FIGS. 4, 5 and 6 schematically represent a set of sound waves emitted, according to this first mode of operation, by the sonar of the marine drone of FIG. 1, seen respectively from the front (from the front), from the side, and from above,
- FIGS. 7 to 9 schematically represent three successive transmissions of sound waves made according to another mode of operation of a sonar of the marine drone of FIG. 1;
- FIG. 10 schematically represents the main steps of a method for characterizing an underwater environment, implemented by the marine drone of FIG. 1,
- FIG. 11 diagrammatically, seen from above, a school of fish detected by the marine drone during the process of FIG. 10,
- FIG. 12 schematically represents, viewed from above, positions successively occupied by the marine drone during the process of FIG. 10, and
- FIG. 13 shows schematically, seen from above, a school of fish located partially in the observation volume of the surface marine drone.
- FIG. 1 schematically represents the main elements of a surface marine drone 1 equipped with an improved multibeam sonar 10, which, in a remarkable manner, is capable of probing the underwater environment E of the drone in a three-dimensional manner, without the drone have to move for that.
- the marine drone 1 comprises a hull 2, here of elongate shape along a longitudinal axis x (directed from the stern to the bow of the marine drone 1).
- the marine drone When the marine drone moves in a straight line, its direction of travel coincides with this longitudinal axis x, drift effects aside. As the marine drone 1 is unmanned, it can be small. Its largest external dimension, which here corresponds to the total length L of its shell 2, is thus less than 2 meters. Here, it is more precisely included in 0.6 meters and 1.5 meters.
- the marine drone Due to its small size, the marine drone is particularly discreet. It therefore advantageously makes it possible to monitor and / or characterize an underwater environment without disturbing it. Its small size makes it also very manageable, able to follow the movements of underwater species.
- the sonar 10 of the marine drone whose operating characteristics will be described later, comprises a plurality of transducers 12, and an electronic control unit 11 of these transducers 12.
- the transducers 12 are adapted to emit sound waves in the underwater environment surrounding the marine drone 1 and to receive sound waves reflected from this medium. Each of these transducers (12) is therefore adapted here to function both as a transmitter and as a receiver.
- the term "sound waves” refers to acoustic waves of any frequency, whether in the audible range or in the ultrasound range.
- Their control unit 11 may comprise digital-to-analog converters (for transmitting transducers) and analog-digital converters (for transducers operating in reception), as well as amplifiers and electronic filters adapted to shape transmission signals. to emit, or echo signals picked up by these transducers.
- the transducers 12 are arranged in a cross (FIG. 2):
- certain transducers are arranged one after the other along a first branch 13 of the cross, while
- the other transducers are arranged one after the other along a second branch 14 of the cross perpendicular to its first branch 13 (known as a "Mills cross" arrangement).
- the first branch 13 of the cross is here parallel to the longitudinal axis x of the marine drone 1, while its second branch 14 is parallel to a transverse axis y to the drone.
- This transverse axis y perpendicular to the longitudinal axis x, is parallel to the deck of the marine drone.
- the first and second branches 13, 14 preferably extend over more than 20 centimeters, here over more than 50 centimeters, so that the sonar has a high angular resolution.
- the transducers of a multibeam sonar and their control unit are housed in a sonar protection shell, intended to be immersed, this protective shell being for example dragged behind a ship or housed against the hull of the ship.
- the transducers 12 are integrated in the hull 2 of the marine drone 1, while their control unit 11 is housed in the hold 3 of the drone, isolated from the marine environment (that is to say in the interior volume of the drone delimited by its hull 2).
- the hull 2 of the marine drone fulfills the role of protective housing of the sonar.
- the transducers 12 are held together by a support member 15 itself inserted into a shallow housing 21 formed in the shell 2.
- This support part 15 facilitates the manipulation of the transducers 12, and their integration with the hull 2 of the marine drone. It also makes it possible to conveniently test the operation of the sonar antenna, which is constituted by all of these transducers 12, prior to the integration of this antenna with the hull 2 of the marine drone 1.
- the transducers 12 are electrically connected to their control unit 11.
- the marine drone 1 also includes:
- propulsion means 5 such as a motor driving a submerged propeller
- an inertial sensor 6 comprising in particular a gyrometer
- a communication module 7 adapted to exchange data over a wireless link, such as a radio transmission and reception module, and
- an electronic navigation unit 4 adapted to control the sonar 10, the propulsion means 5, and the communication module 7.
- the electronic navigation unit 4 comprises in particular a system sonar control 41, and a data acquisition unit 42 from the sonar.
- the electronic navigation unit 4 is made by means of one or more processors and at least one memory. It is housed in the hold 3 of the marine drone.
- control system 41 of the sonar 10 is configured to control, for a given position P1, P2, P3 of the marine drone 1 (FIG. 12), a plurality of successive transmissions of sound waves,
- control system 41 controlling the different transmitters 12, at each transmission, by a respective plurality of transmission signals S1, S2, S3, S4, ... each transmission signal having an amplitude A1, A2, A3, A4 , ... and a time shift At1, At2, At3, At4, ... with respect to a reference signal Sref (FIGS. 3 and 7),
- control system 41 varying the amplitudes A1, A2, A3, A4, ... or the time offsets At1, At2, At3, At4, ... of said transmission signals S1, S2, S3, S4, respectively, during said plurality of transmissions, in accordance with a predetermined transmission variation sequence, all the sound waves emitted during said plurality of transmissions covering a given observation volume V.
- the acquisition unit 42 is configured for it to:
- the time offsets At1, D ⁇ 2, D ⁇ 3, D ⁇ 4, ... respective transmission signals S1, S2, S3, S4, ... driving the emitters 12 are such that for each of said sound wave emissions, the transmitted sound power is concentrated, by interference between the sound waves emitted, in a transmission plane P.
- the power emitted is therefore emitted in a directive manner, the sound waves emitted forming together a sheet of sound waves, or "mowed", not very thick (here not very thick along the transverse axis y, as illustrated by the figures 4 and 5).
- the respective time offsets D 1, D 2, D 3, D 4, ... of said transmission signals vary so that the plane of P emission swivels around a scan axis, from one of the sound wave emissions to the next.
- the emission plan P scans the entire observation volume V.
- This first operating mode is described first of all for one of said transmissions.
- the scanning of the emission plane P which makes it possible to raise the above-mentioned three-dimensional image, is described next.
- the emission of sound waves is carried out by the second branch 14 of transducers 12, which extends transversely with respect to the marine drone 1.
- the emission signals S1, S2, S3, S4,... are produced from the same reference signal Sref, to which time offsets D1, D2, D3, D4 are applied. , ... respective.
- time offsets D 1, D 2, D 3, D 4,... are proportional to the respective positions of the emitters 12, along the transverse axis y.
- the sound waves are emitted in phase and interfere constructively in the plane (x, z) which extends under the marine drone 1, in line with it. Otherwise formulated, the emission plane P then corresponds to the plane (x, z).
- the global sound wave formed by the set of sound waves emitted (that is to say by the sum of these waves), propagates in the emission plane P by covering an angular sector S of this plane of which the angular aperture a is greater than 60 degrees, and can for example reach 120 degrees (Figure 5).
- the transducers 12 of the second branch 13, parallel to the longitudinal axis x, operate in reception. They make it possible to capture echo-like reflected sound waves by elements of the underwater environment E affected by the aforementioned sound wave web.
- a moment of reception of this reflected sound wave indicates the distance between the reflecting element and the sonar.
- the acquisition unit 42 determines from which direction, within the angular sector S, comes such a reflected sound wave. This direction, combined with the distance separating the reflecting element and the sonar, makes it possible to completely determine the position of the reflecting element in the emission plane P.
- These echo signals are acquired, by the acquisition unit, during a time interval which extends between the emission of sound waves considered, and the emission of sound waves following.
- the sonar angular resolution is fixed, perpendicularly to the emission plane P, by the angular aperture Q1 of the emitted sound wave sheet.
- this sheet is not very thick (the emission is directive, because of the extension, along the transverse axis y, of the second branch 14 of transducers 12): its angular aperture is, in practice, between 0.5 and 5 degrees.
- the angular resolution of the sonar in the emission plane P.sub.2 O.sub.2 (sonar directivity in terms of reception) is also between 0.5 and 5 degrees.
- the sonar thus individually probes the content of different approximately conical elementary zones ZO (FIG. 6), also called “beams", each of angular apertures 01 and 02 (respectively perpendicularly and parallel to the emission plane), distributed in the angular sector S of sonar emission.
- ZO approximately conical elementary zones
- An element of the underwater environment E present in one of these elementary zones can thus be detected and located relative to the marine drone.
- Data related to an equivalent surface of backscattering of the detected element (generally called “scattering cross-section" in English) is also determined by the control unit 11 of the sonar, notably on the basis of the power of the wave sound retro-reflected by this element.
- This data may be representative of a volume backscattering strength associated with this element, and / or of a point-specific backscattering intensity of this element ("target strength" in English).
- the number of distinct beams whose content is thus probed is greater than 20. In the embodiment considered, it is more precisely equal to 64.
- the detected element may correspond in particular to one or more fish, or to a parcel of the seabed located under the drone.
- this scanning is obtained by a rotation of the emission plane P of the sonar with respect to the scan axis.
- This scanning axis is here parallel to the deck of the marine drone 1.
- the scanning axis is horizontal, at least in the absence of waves, when the drone is stationary.
- the scan axis coincides more precisely with the longitudinal axis x of the marine drone 1.
- the control system 41 varies the time offsets D1, D2, D3, D4, ... respective of the different transmission signals S1, S2, S3, S4,. .. with respect to the reference signal Sref.
- the control system 41 thus varies, the angle the inclination b of the emission plane P between two angles tilt limit + bit ⁇ qc and - bit ⁇ qc.
- the angular amplitude 2bit ⁇ 3c of this scan may be greater than 60 degrees. Here, it can reach 120 degrees.
- the three-dimensional image determined by the acquisition unit 42 on the basis of the echo signals acquired in response to this sound wave emission sequence is representative of the content of each of the elementary zones ZO of the observation volume V and swept.
- This image gathers in particular information relating to the positions (in a three-dimensional reference, such as the reference (x, y, z) for example) and equivalent areas of backscattering of the elements contained in this observation volume V.
- the marine drone 1 makes it possible to monitor and characterize an underwater environment in a discrete manner, without disturbing it, and this from an optimal observation position.
- this three-dimensional image can in practice be obtained for energy consumption lower than that required to acquire such an image by displacement (on the surface of the water) of a drone equipped with a classic multibeam sonar without scanning capability.
- the observation volume V has a generally pyramidal shape (each of the sides of the base of this pyramid being either rectilinear or formed by an arc of hyperbole), with, at its summit, the sonar 10.
- This volume is limited vertically by the seabed, or if the aquatic environment is very deep, by the range of the sonar (higher here at 500 meters).
- the aspect ratio of the observation volume V equal to its smallest dimension (for example, its height), divided by its largest dimension (for example its length), can here be greater than 0.2.
- the ratio between the width and the length of the observation volume may in turn be greater than 0.5 .
- the observation volume then has a comparable extension in all directions of the horizontal plane, without arbitrarily favoring a given direction of observation.
- the elementary zones ZO of the observation volume V mentioned above correspond to approximately conical zones, as defined above, angularly offset with respect to each other about the transverse axis y, and also, thanks to the above-mentioned scanning, around the longitudinal axis x.
- the imprint on the seabed of the ply formed by all the sound waves emitted may be slightly curved, of hyperbolic shape, instead of being rectilinear.
- Sonar's emission plane P then corresponds to the mean plane defined by this layer of sound waves (which propagates along a slightly curved surface instead of being flat, whose intersection with the seabed is hyperbolic fingerprint mentioned above).
- the scanning of the angle of inclination b can be done very finely: this angle can for example take successively up to 64 different values distributed between the angles of inclination limit ⁇ bit ⁇ 3c, 64 successive emissions of sound waves are then necessary to obtain a three-dimensional image of the observation volume V.
- the control system 41 can therefore be programmed to control a more basic scan of the observation volume V, in which the inclination angle b has successively at most 10 different values ( and at least 2) distributed between the angles of inclination limit ⁇ max.
- the image of the observation volume V thus obtained is less detailed (it is nevertheless sufficient for certain applications, for example for a first location of a school of fish). In return, this simplified operation reduces the power consumption of the sonar 10 and thus improve the autonomy of the marine drone 1.
- the control system 41 is furthermore configured, in the event of detecting an element located at shallow depths below the marine drone 1, to control a focusing on this element of sound waves emitted by the transducers.
- This focus makes it possible in particular to compensate for various parasitic effects (caused by Fresnel diffraction for example) which, in the so-called near-field zone immediately below the marine drone 1 (this zone here extends for about ten meters under the drone), could interfere with the operation of the sonar 10.
- This focus allows in particular to maintain a reliable and calibrated to the aforementioned measures of backscattering intensity, even at shallow depth, from 1 meter under the marine drone 1.
- the marine drone 1 which is adapted by its small size to approach species evolving at shallow depth, without disturbing them, then allows a precise observation and characterization of such species.
- the above-mentioned focusing can for example be achieved by means of a focusing module (not shown) of the control unit 11 introducing, between the signals respectively transmitted to the different transducers 12 and / or received from them, respective delays. (quadratically varying according to the position of the transducer considered), suitable for focusing the sound waves emitted on the detected element, or for compensating for phase differences between the different signals received due to the proximity of this element.
- the acquisition unit 42 (or, alternatively, the control unit 11) is configured, thanks to the inertial sensor 6, to detect parasitic movements of the marine drone 1, for example roll or roll movements. pitch, and process the acquired data to compensate for the influence of such movements on the three-dimensional image obtained.
- the sonar 10 is furthermore configured to operate according to other modes of operation than the first operating mode which has just been described. This flexibility of use is permitted in particular by the fact that its transducers 12 can operate both in transmission and reception.
- the transducers 12 of the first branch 13 of the Mills cross operate in transmission, while those of the second branch 14 operate in reception.
- This second mode of operation is comparable in every respect to the first mode of operation, except that:
- the layer of sound waves emitted extends transversely with respect to the marine drone (instead of extending longitudinally with respect thereto), and
- the scanning axis coincides with the transverse axis y of the marine drone 1.
- a better compromise between resolution and acquisition time can be found by controlling the transducers 12 according to more elaborate transmission and reception schemes, such as that of the third mode of operation described below, with reference to FIGS. 7 to 9.
- This third mode of operation can in particular be used when the number N of emitters is equal to 2 P , where p is an integer.
- the receivers are also N.
- the emission signals S1, S2, S3, S4,... are produced from the same reference signal Sref, multiplied by gains g1, g2, g3, g4,. .. ( Figure 7).
- the emission signals thus have amplitudes A1, A2, A3, A4,... Proportional to the gains g1, g2, g3, g4, respectively.
- these transmission signals have no time shift with respect to each other (otherwise formulated, the time offsets At1, At2, At3, At4, ... of these signals with respect to the reference signal Sref all exhibit the same value).
- Each sequence of sound wave transmissions which makes it possible to record a three-dimensional image, comprises an M number of transmissions.
- Each of these emissions is identified, in this sequence, by an integer index (sequence number) i, the index i varying from 1 to M.
- the values of the gains g1 (i), g2 (i), ..., gN (i), i varying from 1 to M, applied to produce the transmission signals S1, S2, S3, S4, ... which control the transmitters 12 during this sequence of transmissions, are stored in a memory of the control system 41.
- the transmission sequence is more specifically associated, in this memory, with a respective plurality of lines of a matrix of rank N.
- the i-th emission of this sequence is associated with the j-th line of this matrix.
- the values of the gains g1 (i), g2 (i), ..., gN (i), stored in the memory of the control system, are then proportional to the coefficients of the row number j of this matrix of rank N.
- the transmission variation sequence is thus defined by the data of the M lines of the matrix of rank N associated respectively with the M emissions of each sequence of transmissions.
- the emission base used is that called Hadamard, for which the rank matrix N mentioned above is the rank N Hadamard matrix.
- the zones Z H of the observation volume V where the sound power emitted is maximum are schematically represented by dashes (thick) in these figures.
- observation volume V in a time advantageously shorter than what would be obtained by rotation of an emission plan (or by a method of opening synthesis sometimes called canonical method, described briefly below).
- the number M of emissions per image is less than the number N of transmitters 12.
- the applicant has indeed found that this reduction in the number of transmissions (which reduces by the duration of obtaining an image) degrades only very slightly the resolution of the image with respect to a reconstructed image from a sequence of N emissions (and associated receptions).
- the multibeam sonar 10 of the marine drone 1 having been presented, the Overall operation of this drone can now be described in more detail.
- the electronic navigation unit 4 is programmed to control the drone:
- the navigation unit 4 transmits, thanks to its communication module 7, compressed data produced from the data from the sonar 10, in particular from the image three-dimensional, or three-dimensional images, of the marine environment of the drone surveyed by sonar.
- compressed data notably allow the operator to visualize, at least in part, the contents of the underwater environment E of the drone, and to adapt his piloting of the drone to this content.
- Compression of the data from the sonar 10 limits the amount of data to be transmitted, and again reduce the power consumption of the drone.
- the electronic navigation unit 4 is programmed to record the data from the sonar in its memory. This data can be compressed before storage, to limit the memory space they occupy.
- the compression ratios used are, however, lower than those used to produce the compressed data to be transmitted: the stored data, complementary to the transmitted data, allow, a posteriori, a finer analysis of the underwater environment E than the data transmitted in real time to allow the piloting of the drone.
- the electronic navigation unit 4 records the data from the sonar, as explained above. It can also, optionally, transmit the compressed data mentioned above via the communication module 7.
- FIGS. 10 to 13 schematically represents the main steps of a method of characterizing an underwater environment E, implemented by a surface marine drone such as that presented above.
- This method starts with an optional step E0 for moving the marine drone to a first observation position P1.
- This movement controlled by the electronic navigation unit 4, is achieved by the displacement means 5 mentioned above.
- This first position P1 corresponds to a target position in the vicinity of which it is likely that fish or marine animals are present.
- This first position is located for example near a floating device, generally called fish aggregating device (or "DCP"), which gathers around him a pelagic fauna evolving at shallow depths.
- DCP fish aggregating device
- This first step allows, for example, the marine drone 1 to move from an initial position PO where it was launched, in the vicinity of a vessel 200 of larger tonnage maneuvered by a crew, to this position P1 observation.
- the method continues with a step a) of acquiring a three-dimensional image of the underwater environment E, that is to say a step during which the control system 41 controls the plurality of transmissions successive acquisition of sound waves, the acquisition unit 42 acquiring, for each of said transmissions, the echo signals picked up by the receivers 12 of the sonar 10 in response to the transmission considered, and determining, from the signals of echo acquired in response to said plurality of transmissions, a three-dimensional image representative of the contents of the observation volume V.
- the next step T0 is a test step in which it is determined if fish are present in this observation volume V.
- step E0 (arrow F2 of FIG. 10), by a displacement of the marine drone towards another target position.
- Several distinct target positions can be tested successively until the presence of a marine population is detected by the sonar.
- it can be provided to test, in step T0, whether the detected school of fish satisfies a given criterion, relating for example to a density of fish in the school, and, if this criterion is not satisfied, to execute step E0 again.
- step a) of acquiring a three-dimensional image of the underwater environment E
- step a) the marine drone 1 is therefore situated at the right, that is to say at the vertical position of the school of fish 100, this position being particularly favorable for observing and characterizing this school of fish 100.
- the position of the school of fish 100 determined in step b) here corresponds to a center C of this school of fish 100. It is very interesting that the marine drone 1 thus acquires three-dimensional images of this bench, being located at the vertical of its center C, because it is indeed generally in the center of such a bench that the type of fish encountered, their concentration and their behavior are the most representative of the whole of the bank. It is also from this position that the dimensions of the bench can be determined with the greatest precision.
- the ability of the marine drone 1 to acquire three-dimensional images of the aquatic environment, without having to move for it, is extremely useful in this process.
- this three-dimensional imaging capability allows the marine drone 1 to observe the entire school of fish 100 detected while staying in line with it, which is the most favorable in terms of observation of the bench.
- Steps b) and c) are now described in more detail, in the case of autonomous navigation of the marine drone 1.
- step b) to locate the center C of the fish bank 100, the control system 41:
- step a determines, by treatment of the three-dimensional image acquired during the previous execution of step a), the respective positions of a plurality of points situated on the perimeter 101 of the school of fish 100, then
- a position of the center C of the school of fish determines a position of the center C of the school of fish according to the positions of these points, for example by calculating the position of a centroid of these points (that is to say by calculating an average position defined by these points) .
- the positions of the points of the perimeter 101 of the school of fish can be determined by means of a contour detection algorithm.
- the center C of the school of fish may be determined, in step b), by directly calculating the position of a barycentre of the different points of the observation volume V at which one or more fish have been detected, rather than by previously detecting the outline of the bench.
- step b If only a part 100 'of the school of fish 101 is situated in the observation volume V (situation shown schematically in FIG. 13), it is the position of the center C of this part 100' of the school of fish which, here , is determined in step b) by the control system 41.
- Step b) is followed by a test step T, during which the control system 41 determines whether the surface marine drone 1 is located above the center C of the school of fish 100. If this is true the case, the process resumes in step a) (arrow F6 of Figure 10).
- step T shows that the marine drone 1 is shifted, in the horizontal plane (x, y), relative to the center C of the school of fish
- step c) of displacement from the marine drone 1 to the right of the center C of the school of fish (arrow F4 of Figure 10).
- step a) (arrow F5 of FIG. 10).
- FIG. 12 schematically illustrates such tracking.
- the marine drone 1, launched at the initial position PO, is first moved to the first observation position P1. From this first position, he acquires a three-dimensional image of his aquatic environment. This shows that a school of fish 100 is present in the observation volume V (FIG. 11), and makes it possible to determine its center C.
- the marine drone then moves to a second position P2 located at the center of this center. Then, following a subsequent displacement of the school of fish, the marine drone adjusts its position by moving to a third position P3 (located at the base of a new position occupied by the center of the bench), and thus of after.
- a third position P3 located at the base of a new position occupied by the center of the bench
- the control system 41 of the marine drone 1 is furthermore programmed here, after step a), to perform a step d) of determining at least one datum representative of the school of fish 100, other than the position of its center, according to the data acquired by the acquisition unit 42 in step a).
- Said datum may for example relate to the size of the school of fish (width, length, height, volume, etc.), to its morphology, to a density or to a number of fish in the bank (such an estimate can be based in particular on the above-mentioned backscattering intensity measurements), or on the mobility of these fish.
- the cross which is arranged sonar transducers could be aligned differently to the marine drone.
- the branches of this cross could for example be arranged at 45 degrees between the longitudinal axis and the transverse axis of the marine drone, instead of being aligned with them.
- the transducers could also be arranged in a grid (matrix), rather than cross.
- control system the acquisition unit, and the control unit of the transducers could be distributed differently between these units.
- determination of the center position of the school of fish could of course be done by the acquisition unit rather than by the control system.
- control and acquisition units could also be realized by means of the same electronic module of the electronic unit of navigation of the marine drone.
- the transducer control unit could also be integrated into the electronic navigation unit.
Landscapes
- Engineering & Computer Science (AREA)
- Remote Sensing (AREA)
- Radar, Positioning & Navigation (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- Acoustics & Sound (AREA)
- Aviation & Aerospace Engineering (AREA)
- Automation & Control Theory (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Theoretical Computer Science (AREA)
- Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)
- Control Of Position, Course, Altitude, Or Attitude Of Moving Bodies (AREA)
Abstract
Description
Claims
Priority Applications (5)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP18842537.5A EP3729129A1 (fr) | 2017-12-22 | 2018-12-20 | Drone marin de surface et procede de caracterisation d'un milieu subaquatique mis en ceuvre par un tel drone |
CA3086865A CA3086865A1 (fr) | 2017-12-22 | 2018-12-20 | Drone marin de surface et procede de caracterisation d'un milieu subaquatique mis en oeuvre par un tel drone |
JP2020533672A JP2021506668A (ja) | 2017-12-22 | 2018-12-20 | 海洋面ドローン及びそのようなドローンによって実施される水中環境を特性化するための方法 |
AU2018389732A AU2018389732A1 (en) | 2017-12-22 | 2018-12-20 | Marine surface drone and method for characterising an underwater environment implemented by such a drone |
US16/956,839 US20200333787A1 (en) | 2017-12-22 | 2018-12-20 | Marine surface drone and method for characterising an underwater environment implemented by such a drone |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR1763137A FR3075974B1 (fr) | 2017-12-22 | 2017-12-22 | Drone marin de surface et procede de caracterisation d'un milieu subaquatique mis en œuvre par un tel drone |
FR1763137 | 2017-12-22 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2019122743A1 true WO2019122743A1 (fr) | 2019-06-27 |
Family
ID=62067634
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/FR2018/053448 WO2019122743A1 (fr) | 2017-12-22 | 2018-12-20 | Drone marin de surface et procédé de caractérisation d'un milieu subaquatique mis en œuvre par un tel drone |
Country Status (7)
Country | Link |
---|---|
US (1) | US20200333787A1 (fr) |
EP (1) | EP3729129A1 (fr) |
JP (1) | JP2021506668A (fr) |
AU (1) | AU2018389732A1 (fr) |
CA (1) | CA3086865A1 (fr) |
FR (1) | FR3075974B1 (fr) |
WO (1) | WO2019122743A1 (fr) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US11105922B2 (en) | 2018-02-28 | 2021-08-31 | Navico Holding As | Sonar transducer having geometric elements |
US11047964B2 (en) | 2018-02-28 | 2021-06-29 | Navico Holding As | Sonar transducer having geometric elements |
US20220380043A1 (en) * | 2021-05-25 | 2022-12-01 | Hydronalix, Inc. | Unmanned aerial vehicle with underwater sonar scanning capability |
FR3126505B1 (fr) | 2021-09-02 | 2024-02-02 | Eca Robotics | Dispositif et procédé de détection et localisation d’objets immergés |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6198692B1 (en) * | 1998-03-31 | 2001-03-06 | Japan Radio Co., Ltd. | Apparatus suitable for searching objects in water |
US20160049143A1 (en) * | 2014-07-15 | 2016-02-18 | Garmin Switzerland Gmbh | Marine multibeam sonar device |
US20170227639A1 (en) * | 2011-10-26 | 2017-08-10 | Flir Systems, Inc. | Pilot display systems and methods |
EP3214522A1 (fr) * | 2016-03-01 | 2017-09-06 | Brunswick Corporation | Dispositif et méthode pour le pilotage d'un bateau |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6280577A (ja) * | 1985-10-03 | 1987-04-14 | Hitachi Zosen Corp | 魚群探知方法 |
JP3129749U (ja) * | 2006-10-13 | 2007-03-08 | 古野電気株式会社 | 水中探知装置 |
FR3026493B1 (fr) * | 2014-09-26 | 2021-02-12 | Centre Nat Rech Scient | Procede et dispositif d'imagerie acoustique. |
-
2017
- 2017-12-22 FR FR1763137A patent/FR3075974B1/fr active Active
-
2018
- 2018-12-20 US US16/956,839 patent/US20200333787A1/en not_active Abandoned
- 2018-12-20 WO PCT/FR2018/053448 patent/WO2019122743A1/fr unknown
- 2018-12-20 AU AU2018389732A patent/AU2018389732A1/en not_active Abandoned
- 2018-12-20 JP JP2020533672A patent/JP2021506668A/ja active Pending
- 2018-12-20 CA CA3086865A patent/CA3086865A1/fr active Pending
- 2018-12-20 EP EP18842537.5A patent/EP3729129A1/fr not_active Withdrawn
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6198692B1 (en) * | 1998-03-31 | 2001-03-06 | Japan Radio Co., Ltd. | Apparatus suitable for searching objects in water |
US20170227639A1 (en) * | 2011-10-26 | 2017-08-10 | Flir Systems, Inc. | Pilot display systems and methods |
US20160049143A1 (en) * | 2014-07-15 | 2016-02-18 | Garmin Switzerland Gmbh | Marine multibeam sonar device |
EP3214522A1 (fr) * | 2016-03-01 | 2017-09-06 | Brunswick Corporation | Dispositif et méthode pour le pilotage d'un bateau |
Non-Patent Citations (3)
Title |
---|
CORBIERES CHRISTOPHE ET AL: "Real-time acoustic fishing selectivity for sustainable practices", OCEANS 2017 - ANCHORAGE, MARINE TECHNOLOGY SOCIETY, 18 September 2017 (2017-09-18), pages 1 - 8, XP033282106 * |
HAUGE RUNE ET AL: "Fish finding with autonomous surface vehicles for the pelagic fisheries", OCEANS 2016 MTS/IEEE MONTEREY, IEEE, 19 September 2016 (2016-09-19), pages 1 - 5, XP033014371, DOI: 10.1109/OCEANS.2016.7761206 * |
R. HAUGE ET AL.: "Oceans 2016 MTS", 2016, IEEE, article "Fish findings with autonomous surface vehicules for the pelagic fisheries", pages: 1 - 5 |
Also Published As
Publication number | Publication date |
---|---|
US20200333787A1 (en) | 2020-10-22 |
EP3729129A1 (fr) | 2020-10-28 |
FR3075974B1 (fr) | 2019-12-27 |
CA3086865A1 (fr) | 2019-06-27 |
AU2018389732A1 (en) | 2020-07-09 |
FR3075974A1 (fr) | 2019-06-28 |
JP2021506668A (ja) | 2021-02-22 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP3729129A1 (fr) | Drone marin de surface et procede de caracterisation d'un milieu subaquatique mis en ceuvre par un tel drone | |
Hansen et al. | Challenges in seafloor imaging and mapping with synthetic aperture sonar | |
EP3117237B1 (fr) | Sonar a antenne synthetique et procede de formation de voies d'antenne synthetique | |
EP0685387B1 (fr) | Engin nautique pour effectuer des missions de reconnaissance d'un site, notamment des levés bathymétriques | |
EP2018579B1 (fr) | Sonar frontal ameliore | |
EP3850394B1 (fr) | Procédé de détermination d'une profondeur, ou d'un profil bathymétrique, sur la base d'un profil de célérité moyenne du son, procédé de détermination d'un tel profil de célérité, et système sonar associé | |
FR3080194A1 (fr) | Procede de guidage d'un vehicule sous-marin autonome et systeme associe d'acquisition de donnees d'analyse sous-marine | |
WO2021104986A1 (fr) | Procede de surveillance d'une zone maritime | |
FR3060113B1 (fr) | Procede et systeme d'acquisition de donnees d'analyse dans une zone d'observation d'un environnement subaquatique. | |
EP0688437B1 (fr) | Sonar pour detecter les objets enfouis | |
FR3076278B1 (fr) | Vehicule sous-marin et procede de commande | |
EP4396608A1 (fr) | Dispositif et procédé de détection et localisation d'objets immergés | |
FR2751425A1 (fr) | Procede et dispositif de lutte heliportee contre les mines sous-marines | |
FR3106416A1 (fr) | Échosondeur paramétrique dépointable, et procédé de caractérisation d’une partie du sous-sol d’un milieu subaquatique | |
Hagen et al. | SAS and side scan sonar systems compared: Experimental results from HUGIN AUVs | |
EP0628172B1 (fr) | Procede de stabilisation et de formation de voies pour sonar et sonar pour sa mise en oeuvre | |
Hagen et al. | Development of High-Resolution Synthetic Aperture Sonar for Demanding AUV Applications |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 18842537 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2020533672 Country of ref document: JP Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 3086865 Country of ref document: CA |
|
ENP | Entry into the national phase |
Ref document number: 2018389732 Country of ref document: AU Date of ref document: 20181220 Kind code of ref document: A |
|
ENP | Entry into the national phase |
Ref document number: 2018842537 Country of ref document: EP Effective date: 20200722 |