WO2021104986A1 - Procede de surveillance d'une zone maritime - Google Patents
Procede de surveillance d'une zone maritime Download PDFInfo
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- WO2021104986A1 WO2021104986A1 PCT/EP2020/082670 EP2020082670W WO2021104986A1 WO 2021104986 A1 WO2021104986 A1 WO 2021104986A1 EP 2020082670 W EP2020082670 W EP 2020082670W WO 2021104986 A1 WO2021104986 A1 WO 2021104986A1
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Classifications
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- 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
- G01S7/521—Constructional features
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B22/00—Buoys
- B63B2022/006—Buoys specially adapted for measuring or watch purposes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B63—SHIPS OR OTHER WATERBORNE VESSELS; RELATED EQUIPMENT
- B63B—SHIPS OR OTHER WATERBORNE VESSELS; EQUIPMENT FOR SHIPPING
- B63B22/00—Buoys
- B63B22/18—Buoys having means to control attitude or position, e.g. reaction surfaces or tether
Definitions
- TITLE PROCESS FOR SURVEILLANCE OF A MARITIME ZONE
- the invention lies in the field of sonar and more particularly of the surveillance of maritime areas. It relates more particularly to systems for monitoring underwater areas. These surveillance systems include submerged acoustic receiving antennas.
- These systems conventionally comprise a set of sonar devices, for example buoys drifting at sea, each comprising one of the acoustic reception antennas making it possible to acquire acoustic measurements and processing means configured to process the acoustic measurements in order to to detect and classify noise makers in the maritime area.
- the term "noise generator” is understood to mean any underwater or surface sound source.
- An aim of the invention is to improve the detection and / or location and / or classification performance of this type of system.
- the invention relates to a method for monitoring a maritime area from a set of acoustic reception antennas, the acoustic reception antennas of the set each comprising several acoustic transducers, the reception antennas being reconfigurable so as to be able to be in several reception configurations in which they are immersed, the method comprising a cycle of the following successive steps:
- each noisemaker of interest being characterized by a set of at least one primary characteristic comprising a positioning zone of the noisemaker defined in a common global frame of reference to all the noisemakers of interest, and, when the set of noisemakers of interest includes at least one noisemaker of interest:
- an optimal configuration set comprising a reception configuration optimal for each antenna of a subset of the receiving antennas of the receiving antenna set, so that each receiving antenna of the subset is able to detect, in the next cycle, acoustic signals originating from a noisemaker of interest from the set of noisemaker of interest,
- each acoustic reception antenna of the sub-assembly according to the optimal reception configuration defined for this reception antenna, the cycle of processing steps being repeated at least once.
- the determination step comprises the following steps:
- each local noise generator of the set of local noise makers being characterized by a set of at least one local noise generator characteristic comprising a local noise generator positioning zone in a reference point linked to the receiving antenna,
- each noise generator of interest being characterized by a set of characteristics of the noise generator of interest comprising a positioning zone in a global frame of reference common to all local noise makers.
- the cycle of steps includes a step of determining the kinetic characteristics of the set of at least noisemaker of interest.
- the cycle of steps comprises a step of classifying the set of at least one noisemaker of interest from the kinetic characteristics of the set of at least one noisemaker of interest and from the set of at least one primary characteristic.
- the cycle of steps comprises a step of estimating an evolution of the set of at least one noisemaker of interest at a following cycle from the set of at least one primary characteristic. , kinetic characteristics and from the classification of the set of at least one noisemaker of interest.
- the step of determining the optimum configuration set comprises, when the set of at least one noisemaker of interest comprises several noisemakers of interest, a step of determining an order of priority of the noise makers of interest, from the characteristics of the noise makers of interest, and a step of determining the optimal configuration set from characteristics of the noise makers of interest and from the order of priority.
- a first antenna of the sub-assembly is linear and comprises an elongated body from a first end to a second end, the determination of the optimal configuration of the reception antenna of the first sonar device comprising the determination of '' an elevation angle of the second end and / or the determination of an azimuth of the second end in a frame linked to a negative buoyancy support connected to the first end of the first receiving antenna, the reconfiguration of the first antenna reception including adjustment of the elevation angle and / or azimuth.
- the determination of the optimum configuration set comprises the determination of a relative positioning of the acoustic transducers of at least one second receiving antenna of the sub-assembly, the reconfiguration comprising the adjustment of the relative positioning of the acoustic transducers of the second receiving antenna.
- the determination of the optimal configuration comprises the determination of an immersion of a third antenna of the sub-assembly, the adjustment of the configuration of the third sonar device comprising the adjustment of the immersion of the antenna.
- the reception antennas can be reconfigured independently.
- the invention also relates to a sonar system comprising:
- the reception antennas each comprising several acoustic transducers, the reception antennas of the set being reconfigurable so as to be able to be in several reception configurations, the set of antennas being able to acquire acoustic measurements,
- the sonar system being configured to implement the method according to the invention.
- the sonar system comprises a set of sonar devices comprising a first sonar device comprising a negative buoyancy support and a first acoustic receiving antenna of the set of antennas, the first receiving antenna being linear and comprising a elongated body from a first end to a second end, the elongated body being connected by the first end at a fixed connection point relative to the support, the sonar device being adapted to be in a plurality of receiving configurations in which the antenna body and support are fully submerged, the antenna body extending substantially vertically from the first end to the second end towards the seabed in at least one receiving configuration, the first sonar device comprising orientation adjustment means for adjusting, when the first sonar device is in the operative configuration ational and the support is fixed with respect to the terrestrial frame of reference, an elevation angle and an azimuth of the second end in the frame of reference linked to the support centered on the connection point.
- the first acoustic receiving antenna is one of the antennas in the set.
- the system comprises means for adjusting the relative positioning of acoustic transducers of a second receiving antenna of the set of antennas.
- the system comprises a device for adjusting the immersion of a third receiving antenna of the set of antennas.
- the reception antennas can be reconfigured independently.
- Figure 1 shows schematically a sonar system according to the invention
- FIG.2 shows schematically the main steps of the monitoring method according to the invention
- Figure 3 shows schematically in more detail, the steps of the monitoring method according to the invention
- Figure 4 schematically shows a conical surface obtained from track formations from signals measured by a linear acoustic reception antenna
- FIG.5 Figure 5 schematically shows a sonar device according to a first embodiment in two reception configurations
- FIG.6 Figure 6 schematically shows part of the sonar device according to a second embodiment in a low vertical orientation, and two other reception configurations,
- FIG.7 Figure 7 schematically shows an example of a buoyancy modification device.
- the invention relates to a method for monitoring a maritime area.
- the SYS sonar system according to the invention comprising a plurality of sonar devices.
- Each of the sonar devices includes a reconfigurable acoustic receiving antenna.
- the monitoring method according to the invention uses the possibility of reconfiguring the acoustic reception antennas to improve the monitoring performance of noise makers located in the maritime area. It increases the spatial coverage area of the sonar system.
- the invention applies in particular to the underwater surveillance of private or military installations, to the surveillance of maritime surface and underwater traffic, and to the study of the flow of underwater animals.
- the antennas each comprise 3 transducers in the non-limiting example of FIG. 1.
- acoustic transducer TA j is meant a transducer capable of transforming an acoustic wave into an acoustic measurement, that is to say of acquiring an acoustic measurement.
- acoustic measurement is meant a signal representative of an acoustic intensity and an acoustic frequency as a function of time over an acquisition period.
- An acoustic transducer TA j is, for example, an electro-acoustic transducer, for example a hydrophone, transforming an acoustic wave into an electrical signal representative of an intensity and a frequency of the acoustic wave detected by the transducer , as a function of time over an acquisition period or else an opto-acoustic transducer, transforming an acoustic wave into an optical signal representative of an intensity and a frequency of the acoustic wave detected by the transducer, as a function of the time over an acquisition period /
- Each sonar device comprises, for example, an acoustic reception antenna A k , a main floating support F k, a diving line LP k and a support S k of negative buoyancy.
- the antenna A k is connected to the main floating support F k (that is to say with positive buoyancy) via the diving line LP k connecting the support S k to the main support F k .
- each sonar device comprises one or more acoustic reception antennas.
- Each Ak acoustic reception antenna is suitable for being in different acoustic signal reception configurations in which it is intended to acquire acoustic measurements.
- the acoustic reception antenna is reconfigurable. In these reception configurations, the acoustic reception antenna is completely submerged.
- Each reception configuration of the antenna Ak is characterized by a set of at least one configuration parameter representative of a position of the antenna and / or at least one configuration parameter representative of an orientation. of the antenna and / or at least one configuration parameter representative of a reception characteristic of the antenna.
- the set of at least one reception parameter comprises, for example, a parameter representative of an acoustic reception frequency of the antenna, such as, for example, a relative arrangement of the acoustic transducers of the antenna, such as for example a distance Dl k between the acoustic transducers TA kj and TA kj + 1 adjacent to the antenna A k and / or a minimum frequency from which the acoustic reception antenna is sensitive and / or a maximum frequency to from which the acoustic reception antenna is insensitive and / or a reception threshold comprising, for example, a minimum sound intensity from which the acoustic reception antenna is sensitive and / or a processing characteristic linked to the chain processing of the antenna, such as for example a characteristic of a filter.
- a parameter representative of an acoustic reception frequency of the antenna such as, for example, a relative arrangement of the acoustic transducers of the antenna, such as for example a distance Dl k between the a
- the set of at least one configuration parameter representative of a position of the antenna comprises, for example, an immersion corresponding to the depth of the receiving antenna and / or a horizontal position of the antenna. reception in a frame of reference common to all the reception antennas, such as the terrestrial frame of reference.
- the set of at least one configuration parameter representative of an orientation of the receiving antenna in a predetermined frame of reference comprises, for example an angle of elevation aa k of a part of the antenna and / or an azimuth pa k of the part of the antenna, these angles being defined in a predetermined frame of reference, for example a frame of reference linked to a support belonging to the sonar device DS k .
- configuration parameter adjustment means comprising elementary adjustment means REG k .
- the adjustment means comprise elementary adjustment means REG k distributed over the various sonar devices DS k .
- the sonar system according to the invention also comprises processing and control means TRC configured for:
- acquisition orders OA k so that the acoustic reception antennas A k of the sonar devices DS k acquire acoustic measurements.
- the processing and control means TRC are, for example, remote, that is to say not included in the sonar devices. They are, for example, installed in a TER processing plant, placed on land or on a seagoing vessel ("seagoing vessel” in Anglo-Saxon terminology) which can be a surface vessel ("surface ship” in Anglo-Saxon terminology). or a submarine, and are connected in communication, for example by satellite, with the sonar devices DS k in order to be able to receive the acoustic measurements J k and send the adjustment orders OR k and, optionally, acquisition orders OA k DS k sonar devices.
- the processing means are, for example, distributed over sonar devices, that is to say mechanically linked to the acoustic reception antennas of the sonar system.
- the antennas can be reconfigured independently of each other. This allows for the best performance in terms of detection and location.
- the invention relates to a method for monitoring a maritime area from a sonar system according to the invention.
- the method according to the invention is implemented while the acoustic reception antennas are completely immersed and each, in a reception configuration of the reception antenna, defined by a set of reception characteristics.
- Sonar devices are, for example, free in the water so as to drift under the effect of sea currents. This solution is light and presents a certain discretion in relation to a threat due to the unpredictable nature of the positions of the sonar devices.
- the receiving antennas are connected to a fixed support, for example to the seabed or to a marine vessel or to a monitoring device. Adjust making it possible to adjust the relative positions of the receiving antennas in a horizontal plane substantially parallel to the surface of the water in calm sea conditions.
- This solution is heavier and more expensive, but it does allow some control over the positions of the antennas and is suitable for monitoring port areas in which maritime traffic must not be disturbed.
- Each reception antenna is intended to cover a spatial coverage area. Acoustic noises generated by noise makers in this spatial coverage area are likely to be measured by the acoustic antenna.
- the receiving antennas are arranged so as to cover respective spatial coverage areas, at least some of which are able to partially overlap.
- the acoustic reception antennas of the assembly are able to acquire acoustic measurements originating from the same noise makers in the overlapping area of the spatial coverage areas, which makes it possible to obtain measurements. additional acoustics from the same noise makers.
- acoustic reception antennas A k k 1 to K, the antennas each being in a predetermined reception configuration
- each B b is characterized by a set of characteristics of the noise generator of interest comprising, in particular, a positioning zone PO b of the noise generator of interest B b defined in a global frame of reference common to all the noise makers of interest B b , the noise makers of interest B b being detected, in particular, by forming sonar channels from the acoustic measurements J k ,
- the cycle of steps is repeated at least once.
- the repetition of the cycle of steps is stopped when a stop criterion is verified.
- the stop criterion is, for example, a time criterion or a reception, by the processing and control means TRC of a stop order.
- the stopping criterion is, for example, met when the monitoring period has reached a predetermined duration threshold.
- the method according to the invention uses the possibility of reconfiguring the reception antennas to optimize the reception configurations of a subset of reception antennas, so that each of the reconfigured antennas can obtain measurements. acoustics from one of the detected noise makers. This makes it possible to obtain, in the next cycle, from the measurements acquired during the following cycle, new characteristics of this noisemaker and / or to improve the precision of characteristics of this noisemaker.
- the method according to the invention thus makes it possible to obtain better surveillance performance such as, for example, performance of detection and / or localization and / or classification and / or monitoring of noise makers than by using configuration reception antennas. of fixed reception or of which the variation is not controlled.
- the acquisition step 100 consists in generating, by each antenna A k of the set of acoustic reception antennas, a set of acoustic measurements J k , the acoustic reception antenna A k being in a configuration predetermined reception.
- Each set of acoustic measurements J k comprises a number Nk greater than 1 of elementary acoustic measurements.
- Each elementary acoustic measurement is delivered by one of the acoustic transducers TA kj of the reception antenna A k .
- Each acoustic transducer TA kj of the antenna A k implements, at each acquisition step, an elementary acquisition step during which it measures a acoustic signal during a non-zero acquisition period, the antenna A k being in a predetermined reception configuration throughout the acquisition period.
- the acquisition times are the same for all the acoustic transducers.
- the elementary acquisition steps of the different transducers of the same antenna are implemented substantially simultaneously or simultaneously. In other words, they begin substantially at the same initial instant and end substantially at the same final instant.
- the elementary acquisition steps of the acoustic transducers of the different reception antennas of a same acquisition step are also implemented simultaneously.
- This simultaneity is, for example, managed by the processing and control means TRC generating acquisition orders sent to the various reception antennas A k .
- this simultaneity is, for example, obtained by internal clocks of the various reception antennas so that, for example, each acoustic transducer implements an elementary acquisition step at identical regular time intervals for all the transducers, during an identical acquisition period for all transducers.
- Each acoustic transducer TA kj delivers, during each elementary acquisition step, an acoustic measurement M kj representative of an acoustic intensity and an acoustic frequency as a function of time over the acquisition period.
- the acoustic measurement M kj delivered by an acoustic transducer comprises, for example, several series of elementary intensity measurements carried out during different elementary durations of the acquisition duration. Each series of elementary measurements is carried out at a predetermined acoustic frequency or in a predetermined acoustic frequency band distinct from the other frequencies / frequency bands of the other elementary series.
- the acoustic measurement delivered by a transducer is, for example, in the form of a series of intensity-time matrices carried out at different frequencies. Each matrix or elementary measurement comprises intensity values measured during different elementary durations at a determined frequency or in a frequency band determined. The different elementary measurements are obtained at different frequencies or in different frequency bands.
- the preprocessing steps can, for example, include filtering, coherent processing to correlate a received signal with a transmitted signal in the case of an active sonar system or a standardization for the detection of noise makers.
- the location means are, for example, satellite location means comprising LOC k receivers of satellite signals installed on the floating supports. This example is absolutely not limiting, other locating means can be used.
- Inertial units linked to the main supports F k can for example be provided.
- the processing and control means TRC are configured to generate, at each cycle, acquisition orders OA k sent to the reception antennas A k so that the transducers of the acoustic reception antennas A k put implementing, at each acquisition step, the acoustic measurement step for an acquisition period.
- the antennas are configured to implement the measurement steps at regular time intervals as specified previously.
- NB is a number of noise makers detected during step 200. This number NB can be zero.
- sonar channels are formed from acoustic measurements acquired during step 100.
- At least one sonar channel v is formed from the set of acoustic measurements J k acquired by antenna A k .
- a sonar channel is formed by applying a set of electronic delays to the different sets of acoustic measurements J k delivered by the different acoustic transducers A k .
- the applied delay sets are different for the different sonar channels. This makes it possible to obtain, for each channel v, an acoustic signal S kv
- the acoustic signal S kv formed by a channel v is representative of an acoustic intensity as a function of the acoustic frequency according to the listening direction representative of the channel corresponding.
- This set is, for example, in the form of a frequency - channel directivity matrix comprising different values of intensity of acoustic signals S k obtained for different frequency - channel directivity pairs.
- several sonar channels are formed from the set of acoustic measurements J k acquired for each antenna A k ..
- tracks are formed in azimuth and / or in elevation (site).
- the antenna extends substantially linearly and substantially along a vertical axis z, channels are formed only in elevation and if the antenna extends substantially linearly and substantially along a horizontal axis, only channels are formed in elevation. azimuth. If the antenna is in an intermediate orientation, it is advantageous to form tracks in azimuth and in elevation.
- no local noise generator is detected during step 202.
- Each local noise generator Bw detected during step 202 is characterized by a set of CBw characteristics comprising:
- the positioning zone is defined (positioned and oriented) in a local frame of reference linked to the antenna A k ,
- a linear antenna makes it possible to obtain different listening directions by forming several channel formations by applying different sets of delays to the same set of acoustic measurements acquired simultaneously by the different acoustic transducers of the antenna. It is possible to form different channels according to different respective channel directions (or channel directivities) forming different angles with the longitudinal axis l k of the antenna A k . On the other hand, in the absence of directivity of the acoustic transducers, it is not possible to form channels in directions forming different angles around the longitudinal axis of the antenna.
- the positioning zone defined for a local noise generator B ki detected from a channel having a direction (or channel directivity) forming an angle yw with the longitudinal axis l k of the antenna A k corresponds to a globally conical local volume with axis l k and apex SO, comprising the first local conical surface C ki and having an angular opening around the local angle gki-
- the angular opening decreases with the angle y ⁇ from 0 to p / 2 because the angular positioning accuracy, due to the smoothness of the track, increases in this direction.
- the detection 202 of the local noise makers B w is carried out on the basis of the channels formed as a function of a detection criterion.
- the detection criterion can be predetermined or depend on at least one reception configuration parameter of the antenna in the current cycle and / or in a previous cycle and / or on channels formed in a previous cycle for the same.
- the detection criterion may include an intensity threshold beyond which a noisemaker is detected which may be fixed or depend on at least one of the aforementioned parameters and / or an acoustic frequency.
- the selection criterion may include a frequency criterion, which may include an acoustic frequency band within which the acoustic frequency must lie. This frequency criterion can be fixed or depend on at least one of the aforementioned parameters.
- each local noise generator is characterized by a set of characteristics CB ki comprising the positioning zone Z ki in which the local noise generator is detected.
- the positioning zone Z ki is defined in a local coordinate system linked to the corresponding reception antenna A k. The spatial coverage areas of the antennas partially overlap, some local noise makers detected by different antennas corresponding to the same noise maker.
- Step 203 is a merging step comprising a step 203a for changing the reference mark of the positioning zones Z w of the local noise makers B ki defined in the respective local reference systems to define them in the global reference system and a merging step 203b of local noise makers Bw respecting a predetermined fusion criterion.
- a step 203a for changing the reference mark of the positioning zones Z w of the local noise makers B ki defined in the respective local reference systems to define them in the global reference system and a merging step 203b of local noise makers Bw respecting a predetermined fusion criterion.
- the set of noise makers of interest Bb comprises a set of at least one noise maker of interest resulting from the fusion of local noise makers when the latter satisfy the fusion criterion and / or a set of at least one local noise generator (when the latter is detected by a single antenna).
- a positioning zone ZGw of each local noisemaker B ki in the global frame of reference is determined from its positioning zone P ki in the local frame of reference of the antenna A k . This step is carried out from the values of the parameters of the reception configurations of the reception antennas and from the positions of the reception antennas in the global frame of reference, during the acquisition step, and more particularly during the steps elementary measurements implemented by the various acoustic transducers.
- This step is advantageously carried out on the basis of a probability of detection of the antenna or POD, with reference to the English expression "Performance of the Day".
- the POD defines a probability of detection of a noise generator by means of measurements obtained by the antenna in the spatial coverage area of the receiving antenna.
- the probability of detecting a noise generator located outside the spatial coverage area, using acoustic measurements acquired by the antenna, is zero.
- the shapes of the spatial coverage areas obtained are relatively complex and non-uniform due to the non-linearity of sound propagation in water. They are defined (position, orientation) in a reference linked to the antenna.
- the method can then include a step of determining the POD of the antenna.
- the POD is, for example, determined, by a method known to those skilled in the art, from:
- At least one environmental characteristic taken from a temperature or a temperature curve around the sensor, a depth of the seabed, a type of seabed, sea noise linked to traffic and / or the state of the sea , a direction of the waves.
- the POD is predetermined for the values of the configuration parameters of the receiving antenna.
- the system includes, for example, a database storing POD values for different antenna reception configurations.
- the merging step 203b consists in merging local noise makers B w , when the number of local noise makers detected during step 203a is greater than 1.
- This step consists in merging the local noise makers B ki respecting a predetermined fusion criterion, from the positioning zones ZGw of the local noise makers B w in the global frame of reference and from the other characteristics of the local noise makers, such as the acoustic signals (intensity / frequency) Slki associated with the respective local noise makers.
- the criterion of fusion between local noise makers B w is a criterion of spatial and frequency concordance.
- Two local noise generators are merged to form a noise generator of interest if there is sufficient spatial agreement of their respective positioning zones and possibly sufficient frequency agreement of the signals associated with these local noise generators in an area of overlap of the spatial coverage areas of the antennas.
- step 203b comprises, for each pair of local noise makers detected from different reception antennas, the respective spatial coverage areas of which overlap at least partially:
- the step of verifying the spatial concordance criterion consists, for example, in verifying whether the absolute value of the difference between the acoustic frequencies of the signals of the two local noise makers is less than or equal to a predetermined frequency difference threshold. Only the local noise makers respecting the spatial concordance and the possible frequency concordance are merged.
- a CBIb characterization of the noisemaker of interest is also constructed on the basis of the characteristics of local noisemakers from which the noisemaker of interest Bb originates.
- of interest Bb is characterized by a set of primary characteristics CBb, when it is obtained from the fusion of several local noise makers, by: - a set ESb of at least one acoustic signal comprising the acoustic signal of each local noise generator Bw from which the noise generator of interest B b originates,
- the positioning zone Zb of a noise generator of interest Bb resulting from the merger of several local noise makers is obtained by determining an overlap zone of the positioning zones of the local noise makers from which it comes.
- the primary characteristics of the noise makers of interest corresponding to local noise makers remain the characteristics of the local noise makers.
- the following steps are implemented when at least one noisemaker of interest is detected.
- no noise generator of interest we return, for example, directly to the acquisition step without going through the following steps.
- the method advantageously, but not necessarily, comprises at least one of the following steps: determining 204 of the kinetic characteristics of the noise makers of interest, classifying 205 the noise makers of interest, estimating 206 an evolution of the noise makers of interest, a step construction 207 of a synthesis relating to the noise makers of interest.
- step 204 of determining the kinetic characteristics CCb of the noise makers of interest Bb for example, a direction of movement and / or a speed of each noise generator of interest Bb and / or an acceleration of the noise is calculated. noisemaker of interest.
- This step is carried out, for each noisemaker of interest Bb, from the set of primary characteristics CBb of noisemaker of interest Bb. This step can be carried out by a Doppler method or by comparison with the previous one. cycle.
- the Doppler method can be used for noise makers of interest obtained by merging local noise makers detected by at least two acoustic reception antennas, that is to say, detected from channels formed for at least two antennas of acoustic reception. This method is based on the offset in frequency of the acoustic signals of the local noise makers merged with respect to a reference frequency.
- the "Doppler" effect tells us that an acoustic reception antenna having acquired, for the local noisemaker at the origin of the noisemaker of interest, a signal exhibiting a positive frequency shift with respect to a reference frequency predetermined, sees the noisemaker approaching it and that an acoustic receiving antenna having acquired, for the local noisemaker at the origin of the noisemaker of interest, a signal exhibiting a negative frequency shift with respect to the reference frequency sees the noisemaker moving away from her.
- the reference frequency is normally the emission frequency of the buzzer of interest stationary relative to the antenna. However, as this frequency is not known, a reference frequency is chosen arbitrarily. This is, for example, a frequency of an acoustic signal from a local noisemaker at the origin of the noisemaker of interest. This frequency is measured by one of the acoustic reception antennas. This antenna is identified in the characteristics of the noise generator of interest.
- Step 204 therefore comprises:
- the method "by comparison with the previous cycle” consists, from positioning zones of a noise generator calculated at two cycles (current cycle and previous cycle) in the global frame of reference, in calculating the speed from the distance traveled between these cycles and the time elapsed between the acquisition steps of these two cycles.
- This step can be performed before the classification step or after the classification step using the result of the classification step. classification of the noise generator of interest and possibly from a synthesis obtained from a cycle prior to the current cycle.
- the step 205 of classifying each noisemaker of interest Bb is carried out on the basis of the primary characteristics CBb of the noisemaker of interest Bb concerned and possibly the kinetic characteristics CCb of the noisemaker of interest.
- the classification step 205 consists in associating the noisemaker of interest Bb with a type of noisemaker Tb or in identifying the noisemaker, the noisemaker then for example being associated with an identity Ib.
- the step 205 of classifying the noise generator of interest Bb is advantageously implemented on the basis of known characteristics of noise makers of different known types stored in a so-called CLAS classification database belonging to the SYS system.
- Each type of noise generator is associated with different characteristics with which the characteristics of the noise generator and possibly its kinetic characteristics are compared.
- the type of noisemaker associated with a noisemaker of interest is determined by a conventional comparison method, for example, by correlation or by a pairing method.
- a noise generator of interest Bb can be associated with a type of marine or carrier vessel according to its acoustic frequency (obtained from the frequency of the acoustic signal of at least one local noise generator originally noisemaker of interest) and its speed and frequency and speed characteristics of known carriers, such as a freighter and an outboard.
- an outboard will have a frequency signature and a speed different from those of a freighter.
- the acoustic intensity of the acoustic signal of an antenna at the origin of the noise generator of interest can be used for classification in combination with the positions of the antenna and of the acoustic noise generator and, optionally, of a characteristic. reception of the antenna.
- This step consists in estimating a change in the behavior of a noise generator of interest Bb at one or more following cycles. It uses primary characteristics CBb and kinetic characteristics CCb of the noise generator of interest Bb, and possibly the classification (type Tb or identity Ib) of the noise generator of interest and / or possibly at least one primary characteristic CBb and / or one kinetic characteristic CCb of a noisemaker of the same type or of the noisemaker of interest obtained during at least one preceding cycle, to estimate at least one primary characteristic of the noisemaker of interest and / or at least one kinetic characteristic of the noisemaker with one or more subsequent cycles.
- an estimate is obtained of a set of characteristics of the noise generator ECIb at at least one following cycle.
- the step cycle includes a synthesis step 207. This step makes it possible to build, for each noisemaker of interest Bb, a synthesis Sb of its characteristics from the following inputs:
- the synthesis Sb can, for example, be constructed to be viewable by a user. It can represent positions (positioning zones) of different noisemakers of interest on a three-dimensional map by associating, with each noisemaker of interest, a speed vector and / or a possible estimate of a position of the noisemaker of interest in the next cycle and / or a type.
- the syntheses determined at the different cycles are advantageously stored in a database of the syntheses.
- This step comprises a step 301 determining an order of priority of noise makers of interest Bb from characteristics of the noise makers of interest or from the synthesis when a synthesis is constructed. This order of priority is determined for a specific mission.
- This step consists in establishing a so-called order of priority of interest OP, of the noise makers of interest, on the basis of a predetermined order of priority and on the basis of at least one characteristic of the set of calculated characteristics CBIb. for each noise maker.
- This predetermined order of priority is, for example, stored in a so-called PRIO priority database.
- This characteristic has, for example, an order of priority according to the type of noise generator.
- the step therefore consists in establishing an order of priority of interest of the noise makers of interest according to the types of noise makers (obtained during the classification step) and of the predetermined order of priority.
- a priority buzzer is, for example, an outboard moving towards a predetermined zone, for example a hill, and / or having a speed included in a predetermined speed interval.
- Step 300 then comprises a step 302 of determining optimal reception configurations of a subset of reception antennas at from the characteristics of the noise makers of interest or from the synthesis, when a synthesis is constructed, and from the order of priority of interest of the noise makers of interest. It is also carried out, from the adjustable configuration parameters, of the various reception antennas of the sub-assembly. More precisely, this step is carried out on the basis of sets of possible reception configurations for each reception antenna of the subset. Each receive configuration is defined by a set of adjustable configuration parameter values. The set of possible reception configurations of an antenna corresponds to a set of sets of possible values of the possible adjustable configuration parameters.
- the subset of antennas can include all or part of the antennas of the set.
- the method may include a step 302a of determining the subset of antennas of the set of antennas to be reconfigured.
- This subset can be empty or include one or more antennas.
- the subset of antennas to be reconfigured is determined on the basis of at least one characteristic of at least one noisemaker of interest, for example the noisemaker of interest having the highest priority, or of several noisemakers of interest. , and possibly at least one other characteristic of the noisemaker of interest.
- the sub-assembly is also determined from at least one technical characteristic of the reception antennas of the assembly, taken from the technical characteristics of the antenna listed above, from the current configurations of the reception antennas, from the positions of the different reception antennas at the time of the measurement.
- This step 302a can consist in determining, among the antennas of the set, the antennas capable of measuring acoustic signals coming from the noise generator of priority interest or from at least one of the noise makers of interest of the set at current cycle or the next cycle.
- This step 302a of determining the subset can comprise:
- reception antennas capable of measuring acoustic signals having frequency and / or intensity characteristics representative of the noise generator of interest. Indeed, it is not useful to reconfigure antennas incapable of detecting a frequency emitted by the noise generator of interest. In in other words, only the antennas of the set capable of detecting at least part of the signal emitted by the noise generator of interest are selected,
- the reception antennas of the set of which at least one of the possible PODs includes an estimated position of the noise generator of interest in a following cycle is not useful to reconfigure reception antennas that are unable to detect the noise generator of interest in the next cycle.
- An antenna is selected if it satisfies one and / or the other of these selection criteria.
- This method can therefore comprise a step of determining a set of possible PODs for each receiving antenna from a set of possible configurations of the antenna, that is to say for different sets of values. antenna configuration parameters.
- the method does not include the step of selecting the subset of antennas to be reconfigured.
- the subset of antennas to be reconfigured is then the set of receiving antennas.
- this solution is more costly in terms of calculations.
- the method then comprises a step 302b of determining, for each receiving antenna of the subset, an optimal set of values of the adjustable configuration parameters described above.
- This optimal set of parameters defines the optimal configuration of the receiving antenna considered in order to follow the noise generator of interest in the next cycle and / or improve the accuracy of at least one characteristic of the noise generator of interest (for example, its positioning area).
- This step comprises, for example, for each receiving antenna of the sub-assembly, a series of following steps:
- Step 302b uses the POD of a reception antenna of the sub-assembly to determine the optimal configuration of this reception antenna.
- the step of determining the optimal configuration consists, for example, in determining the configuration of the antenna in which the antenna has a maximum probability of detecting the noise generator of interest at one or more following cycles, among the subset of configurations.
- This step uses antenna PODs determined for a set of antenna reception configuration, a position of the antenna in the current cycle, an estimate of the position of the antenna, a position of the antenna in the current cycle or at several cycles, for example in the horizontal plane, and a position of the noise generator of interest in the current cycle and / or an estimate of a position of the noise generator at this or these following cycles.
- a BPOD database advantageously stores PODs of the antennas defined for different possible configurations of the antenna.
- the optimal configuration is, for example, that in which the probability of detection of the noisemaker of interest, at a following cycle or during several following cycles, is maximum.
- the optimum configuration is that in which the probability of detection of the noise generator is non-zero for a maximum of subsequent cycles.
- the optimal configuration is, for example, determined by simulation.
- the noise generator of interest becomes the noise generator of the next priority and the sub-set of configurations contains only those configurations with the same maximum probability of detection.
- the subset of configurations of a reception antenna comprises for example a set of configurations verifying a criterion of proximity with the current configuration.
- the subset of configurations includes all possible configurations of the receiving antenna. The latter solution is more expensive in terms of computation time.
- it can take a long time to modify the antenna configuration if the current configuration and the following configuration are far from each other which can limit the performance of the system in terms of monitoring by extending latency times. between acquisitions of two consecutive cycles.
- a major change in the antenna configuration can be costly in energy.
- Step 302 consisting in determining, for each reception antenna, an optimal configuration, advantageously uses at least one environmental characteristic taken from among the environmental parameters listed above.
- the synthesis determined at one cycle is for example compared to a previous cycle in order to allow learning with respect to the technical (capacity, failure) and strategic (mission) device of the system and thus improve the cycles following the syntheses. and assumptions made during the process (for example during the estimation of the evolution).
- the comparison can be a difference calculation, for example between the position that was expected for a noise generator against the refined position obtained in the following cycle. If there is too much difference it may be due to:
- each of the reception antennas of the sub-assembly is in its optimal reception configuration during the acquisition step of the following cycle.
- the syntheses determined during the different cycles are, for example transmitted to an operator, to help him in the decision, or used by the processing and control means TRC to build a global synthesis of the behavior of the noise generator of interest. over several cycles and possibly trigger an alarm in case of detection of suspicious behavior of a buzzer of interest.
- the system according to the invention constitutes an autonomous permanent or semi-permanent sonar surveillance system that can be reconfigured to improve its detection capabilities, location of possible classification and / or monitoring in a given maritime area where the assembly is located. independent reception antennas.
- FIG. 5 An example of a sonar device comprising one of the reconfigurable acoustic reception antennas is shown in FIG. 5.
- the sonar device D comprises a float F and a dive line LP connecting the float F to a support S.
- the support S has negative buoyancy.
- the support S connects the diving line LP to an acoustic reception antenna A.
- the antenna A comprises an antenna body C integrating the acoustic transducers TAj of the antenna A k .
- the antenna body C is an elongated body, extending longitudinally, from a first end E1 to a second end E2.
- the antenna body C is connected to the support S.
- the antenna A is linear. It comprises a plurality of acoustic transducers distributed along a line of transducers likely to be straight, that is to say rectilinear.
- the antenna body C is elongated along the line of transducers.
- the acoustic transducers TA j are arranged at different curvilinear abscissas along the line of transducers d.
- the antenna of the embodiment of FIG. 1 comprises a single acoustic transducer at each curvilinear abscissa.
- the antenna comprises several acoustic transducers at each curvilinear abscissa.
- Acoustic transducers are, for example around a line of transducers.
- this line of transducers is a straight line d.
- the elongated body C is connected by the first end E1 to the support S and, more particularly, to a fixed connection point relative to the support PL.
- the antenna is in a ball joint connection with the support S.
- the first longitudinal end E1 is fixed in translation with respect to the support S along three axes of a linked orthogonal frame. to the support S.
- the point of connection PL is the center of the ball joint in this embodiment.
- the second end E2 of the antenna body C is free.
- the sonar device D is configured to operate, that is to say perform acoustic measurements and locate noise makers, when it is in a reception configuration.
- the sonar device D according to the invention is suitable for being in several reception configurations.
- each reception configuration as shown in Figure 5, the body of the antenna C and the support S are completely submerged and the antenna is in a reception configuration.
- the float F floats on the surface of the water and the diving line LP extends substantially vertically under the effect of the positive buoyancy of the float F and of the negative buoyancy of the support S.
- a vertical direction or a vertical axis is substantially perpendicular to the sea surface in calm sea conditions.
- the acoustic reception antenna is connected to the support S and configured so as to be capable of occupying several orientations in a reference linked to the support centered on the connection point PL.
- the antenna is likely to be in a low vertical orientation OVB visible in Figure 5, in which the antenna body C is suspended from the support S and extends substantially vertically from the first end E1 to the second end E2 towards the seabed.
- the antenna body C is configured and connected to the connection point PL so that the second end E2 is movable relative to the support S and relative to the first end E1 and more particularly so that an angle of site and an azimuth of the second end E2 in an orthogonal coordinate system (r; x1; z) linked to the support S and centered on the link point PL are variable.
- Each antenna reception configuration is characterized by an elevation angle and an azimuth (when it exists).
- the sonar device D also comprises means for adjusting the orientation of the antenna A, making it possible to adjust an elevation angle and an azimuth of the second end E2 with respect to the support, ie. that is to say in a reference linked to the support S centered on the connection point PL.
- These orientation adjustment means make it possible to adjust the orientation of the antenna when the sonar device D is in a reception configuration or the antenna is in a reception configuration and the support S is fixed with respect to the terrestrial reference frame.
- the orientation adjustment means make it possible to adjust a position of the second end E2 of the antenna body C relative to the support S according to the three directions of a three-dimensional mark linked to the support S when the support S occupies a fixed position in the terrestrial frame of reference.
- the orientation adjustment means making it possible to ensure this adjustment when the sonar device D is in a reception configuration and the support S is fixed with respect to the terrestrial reference frame.
- the elevation angle of the second end E2 is the angle formed between a horizontal plane (r; x1) passing through the connection point PL and the line connecting the connection point PL to the end E2 and l 'azimuth of the second end E2 is the angle formed around a vertical axis z of the reference (r; x1; z) linked to the support S between a horizontal reference axis r of this reference and the line connecting the point of connection PL at the E2 end.
- the elevation angle is positive when the second end is above the horizontal plane (r; x1) and negative when it is below.
- the orientation adjustment means belonging to the elementary adjustment means REG k , comprise drive means ENT allowing, when the support S is fixed, to move the second end E2 of the antenna body C relative to to the support S in the three directions of the mark linked to the support.
- These drive means ENT make it possible to move the second end E2 relative to the support S so as to vary its elevation angle and its azimuth in the reference frame linked to the support. This displacement of the second end E2 relative to the support causes a displacement of the second end E2 relative to the first end E1.
- the drive means ENT make it possible to move the end E2, even when the support S is fixed in the terrestrial frame of reference, relative to the support S, from the position it occupies when the antenna body C is in the low vertical orientation OVB to an inclined orientation Ol, as shown in dotted lines in Figure 5.
- the second end In the low vertical orientation OVB, the second end has an elevation angle a1 of -p / 2, the azimuth not being defined, that is to say does not exist, for this angle of elevation.
- the azimuth exists and is adjustable when the elevation angle is different from -p / 2 or p / 2.
- the second end has a negative elevation angle a2 greater than -p / 2 and an azimuth b2.
- the drive means ENT make it possible to continuously vary the angle of elevation of the second end E2 between -p / 2 and a maximum angle of elevation.
- the maximum elevation angle is greater than -p / 2. It can be negative, zero or positive. It can, for example, be equal to p / 2.
- the drive means ENT make it possible to continuously vary the azimuth of the second end E2 between 0 and 2p excluded when the elevation angle is different from -p / 2 and p / 2.
- the orientation adjustment means also comprise control means making it possible to control the drive means so that the drive means ENT adjust the elevation angle of the second end E2 to a target elevation angle and the azimuth of the second end E2 on a target azimuth, when the support S is fixed in the terrestrial frame of reference, that is to say with respect to the earth.
- the antenna A of the sonar device D according to the invention is thus dynamically orientable in space, even if the support S is fixed.
- the possible adjustment of the elevation angle and of the elevation angle of the second end E2 allows reconfiguration of the antenna A according to the characteristics of the noise makers of interest, which makes it possible to improve the detection, location and classification capabilities of the sonar system according to the invention. It is, for example, possible to improve the positioning accuracy of the noise generator of interest by modifying the orientation of the antenna for the next cycle and therefore the conical surface C1, during the following cycle, which makes it possible to improve the precision of the positioning zone of a noise generator of interest detected in a previous cycle by the same antenna or by another antenna. This reorientation capability also allows the orientation of the antenna to be changed for the next cycle, depending on the movement of the noisemaker of interest to follow it in the next cycle.
- the system according to the invention makes it possible to obtain good performance in terms of detection, localization, classification and monitoring of noise makers of interest from sonar devices having a linear antenna of simple geometry and economical in terms of acoustic transducers. . It is not necessary to provide directional acoustic transducers allowing the resolution of ambiguity.
- the sonar device according to the invention is able to be implemented from a static support. It does not require the towing of the antenna by a marine vessel which makes it economical and capable of being used in an area of limited size. It is also discreet. [0177] Furthermore, this sonar device is easily deployable from a single attachment point (buoy).
- the transducer line d is a straight line.
- the antenna is configured so that the line of transducers has this linear shape in the receive configuration, regardless of the position of the end E2.
- the drive means ENT make it possible, as shown in FIG. 5, to vary an inclination of the antenna A, in particular of the straight line of transducers with respect to a horizontal plane linked to the support S and with respect to a vertical plane linked to the support S and containing the axis r.
- the antenna AA differs from the antenna of Figure 5 in that it is flexible.
- the transducers are distributed along a line of transducers capable of being straight or rectilinear and capable of bending under the effect of a displacement of the end E2 relative to the support S. This is permitted by the flexibility of the DC antenna body.
- the acoustic transducers are arranged at different curvilinear abscissas according to the line of transducers.
- the antenna of the embodiment of FIG. 6 comprises a single acoustic transducer at each curvilinear abscissa.
- the antenna includes several acoustic transducers at each curvilinear abscissa, the acoustic transducers being distributed around a line of transducers.
- the antenna AA is, for example, configured to extend in a substantially vertical straight line in the low vertical orientation OVB shown in FIG. 6 on the left and to be curved in inclined configurations such as shown in FIGS. 6 on the left. middle and right.
- the antenna undergoes bending when the drive means ENT moves the second end E2 away from its position of equilibrium shown in Figure 6 on the left.
- the end E2 is, for example, able to occupy the points of a SURF surface which is generally semi-spherical or spherical or generally ellipsoid or semi-ellipsoid as shown in Figure 6.
- the antenna A can be connected to the support S by a ball joint as shown in FIG. 5. More generally, the antenna can be connected to the support S by a connection with three degrees of freedom in rotation. A certain clearance may, for example, be authorized along one or more axes of translation.
- the first end E1 of the flexible AA or straight linear antenna A is, for example, connected to the support S by a connecting body capable of deforming under the effect of the displacement of the second end. E2 by the drive means ENT relative to its equilibrium position.
- the antenna body CC is flexible and fixed directly to the support S, in other words, the first end E1 and the connection point PL occupy the same position.
- the drive means ENT comprise, for example, as shown in FIG. 5, a propellant PROP making it possible to move the second end E2 relative to the support S (when the support is fixed in the terrestrial frame of reference) at least according to two orthogonal directions in a horizontal plane, and preferably, but not necessarily, along a vertical z axis.
- the PROP thruster comprises turboprop engines configured and arranged around the second end E2 so as to allow the second end to be moved relative to the support S in three orthogonal directions, when the support is fixed in the terrestrial frame of reference.
- the ENT drive means comprise a device for modifying the buoyancy MF mounted on the second end E2. This limits the energy consumed by the PROP thruster to change its elevation angle, then maintains it at a predetermined elevation angle without using the thruster and therefore limits the energy consumed. Moreover, the fact of not having to use the ENT drive means to maintain the fixed elevation angle makes it possible to avoid pollution of the measurements acquired by the antenna by acoustic, electrical or magnetic noise, liable to be generated by the ENT drive means.
- the ENT drive means are configured to make it possible to maintain the site angle constant over the entire site angle range extending from the minimum site angle to the angle. maximum site.
- the buoyancy modification device makes it possible to accelerate the reconfiguration of the antenna and therefore to limit the latency time between two successive acquisitions.
- the low vertical orientation OVB is a rest or equilibrium orientation of the antenna body C. This is, for example, the rest orientation of the antenna when MF buoyancy variation means have minimal buoyancy while a PROP thruster, linked to the antenna, is stationary.
- the antenna body C can have neutral buoyancy.
- the antenna body exhibits negative or positive buoyancy.
- the device for modifying the buoyancy MF comprises, for example, a BAL ballast with variable density, that is to say with fixed volume and variable mass or with fixed mass and with volume.
- variable and controllable means making it possible to vary this mass or this volume.
- the ballast BAL has a fixed volume and a variable mass. It comprises a BOIT box containing a gas and a liquid and a piston PS sealingly separating a first sealed compartment CE1 from the BOIT box containing the gas G and a second compartment CE2 from the BOIT box containing the liquid L and communicating fluidly with the marine environment outside by an OR orifice.
- the buoyancy modification device MF comprises an actuator ACT making it possible to move the piston PS in translation so as to modify the volumes of the compartments CE1 and CE2, the volume of the compartment CE1 increasing when the volume of the compartment CE2 decreases.
- the displacement of the piston PS in translation thus modifies the quantity of liquid in the second compartment CE2 which modifies the buoyancy of the ballast BAL also causes the modification of the volume occupied by the gas G in the first compartment CE1.
- the drive means ENT are arranged at the level of the second end of the antenna A. This position is advantageous from the point of view of the length of the lever arm. In the case of a flexible antenna, it is also advantageous from the point of view of controlling the shape of the antenna during its movement and makes it possible to obtain a continuous evolution of the radius of curvature of the antenna over its entire length. length.
- the drive means ENT are arranged between the ends E1 and E2 or else distributed along the antenna.
- the ENT drive means are mounted on the antenna.
- the ENT drive means comprise, for example, a cable of adjustable length connected to the antenna, for example at the second end, and a winch making it possible to adjust the length of the cable so as to allow adjusting the elevation angle of the second end E2 and a rotary actuator for adjusting the azimuth of the second end E2.
- the sonar device comprises ENT drive means comprising an independent thruster capable of co-operating transiently with the antenna to move the second end of the antenna.
- the thruster is for example of the underwater drone type.
- the sonar device comprises immersion adjustment means or an immersion adjustment device making it possible to adjust the depth or immersion IM of the antenna A.
- the immersion adjustment means make it possible, when the antenna is at a certain depth, to obtain acoustic measurements from a zone which is a shadow zone for the antenna when the latter is located at another. depth.
- a shadow zone is created by the underwater acoustic propagation defined by the bathy-celerimetry profile of the acoustic waves as a function of depth.
- Lowering the second antenna therefore makes it possible to move a shadow area and to confirm or specify the detection and / or the position of a noisemaker.
- Varying the antenna immersion can also improve the signal-to-noise level of a noise generator detected by the antenna.
- the sonar device comprises relative positioning adjustment means making it possible to adjust a relative positioning of the acoustic transducers TA j of the antenna A, when the antenna body C is fixed relative to the support S.
- the variation in the relative positioning of the transducers conditions the performance linked to the detected frequency ranges and to the range of the antenna.
- the positioning adjustment means comprise, for example, linear actuators capable of linearly moving the different transducers on the same straight line and position sensors making it possible to detect the positions of the different sensors on the straight line, the sensors sending the detected positions to transducer control means.
- the transducers are kept spaced in pairs by compression springs, end stops make it possible to keep the springs in compression. Linear actuators are provided to vary the distance between the end stops so as to vary the spacing between the transducers. Other solutions are of course possible.
- the immersion adjustment means are then included in the elementary adjustment means.
- each reception configuration of the reception antenna is characterized by a set of configuration parameters comprising an elevation angle, an azimuth (when it exists), a immersion of the receiving antenna and a relative position between the sensors.
- These configuration parameters can be adjusted independently by the elementary adjustment means.
- the elementary adjustment means associated with the antenna Ak of a sonar device as described above therefore comprise the means for adjusting the orientation of the antenna, the positioning adjustment device and the means for adjusting the position. the immersion.
- the sonar system according to the invention can comprise a plurality of sonar devices with reconfigurable reception antenna, such as represented in FIG. 5.
- the sonar system comprises a plurality of sonar devices with reconfigurable acoustic reception antenna each comprising at least one adjustment configuration parameter taken from: an immersion (depth) of the reception antenna and / or an elevation angle of the second end adjustable, and / or an azimuth of the second end adjustable, and / or a relative positioning between the transducers adjustable when the orientation and the immersion of the antenna are fixed, and the associated adjustment means.
- the antenna is linear.
- the antenna is a two-dimensional antenna, the transducers being distributed in a plane, or three-dimensional, the transducers being distributed over three dimensions.
- the sonar system comprises sonar devices comprising at least one linear acoustic detection antenna and / or at least one two-dimensional acoustic detection antenna and / or at least one three-dimensional acoustic detection antenna.
- the float F or main support is located above the support S along a vertical axis.
- the main support is located above the surface of the water, like a platform of a helicopter, or any partially submerged or totally submerged support located above the support S along a vertical axis. in operational configuration.
- the buoy to be substantially fixed with respect to the terrestrial frame of reference or to be free at sea.
- the sonar system according to the invention comprises a plurality of sonar devices each comprising an antenna connected to a main support.
- the main supports are, for example, free buoys at sea or buoys that are substantially fixed with respect to the land or of the helicopter type (the sonar devices are then wet sonar).
- the system can include sonar devices of the different types listed above.
- the sonar system according to the invention is for example passive, which gives it a certain discretion and a certain autonomy in energy which makes it possible to carry out long-term monitoring, or active, it then has a greater range but is then more expensive and more energy consuming.
- the sonar system comprises means for determining an orientation and / or a position of the support in the terrestrial frame of reference.
- These means include, for example, an inertial unit or MEMS, making it possible to integrate the movements of the support (acceleration and angular speed) to estimate its position and / or its orientation (roll, pitch and heading angles) and / or its speed.
- the medium may include a GPS receiver making it possible to geolocate the medium by satellite.
- the measurements of orientation and / or position of the support are advantageously used when detecting noise makers of interest (change of frame of reference and / or merging) and / or when determining the optimal configurations.
- the means for adjusting the orientation of the antenna comprise means for monitoring the position of the second end.
- These means can, for example, include MEMS making it possible to integrate the movements of the second end of the antenna. They can also use the measurements from the means for determining an orientation and / or a position of the support in the terrestrial frame of reference to monitor the position of the second end E2.
- the antenna can include sensors for determining a curvature of the receiving antenna. This curvature is advantageously used during the formation of tracks. This allows you to digitally compensate for the distortion of the antenna.
- the receiving antennas are configured so as to allow detection of acoustic waves having a frequency between 1 kHz to 10 kHz.
- the processing and control means TRC and the control means may comprise one or more dedicated electronic circuits or a circuit for general use.
- Each electronic circuit can include a reprogrammable computing machine (a processor or a microcontroller for example) and / or a computer executing a program comprising a sequence of instructions and / or a dedicated computing machine (for example a set of logic gates such as an FPGA, DSP or ASIC, or any other hardware module).
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US4493064A (en) * | 1981-07-17 | 1985-01-08 | Sintra-Alcatel | Sonar System |
US20020071345A1 (en) * | 2000-04-06 | 2002-06-13 | Teratech Corporation | Sonar beamforming system |
US20030081503A1 (en) * | 2001-10-23 | 2003-05-01 | Barnard Thomas J. | System and method for localizing targets using multiple arrays |
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2019
- 2019-11-27 FR FR1913281A patent/FR3103572B1/fr active Active
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2020
- 2020-11-19 WO PCT/EP2020/082670 patent/WO2021104986A1/fr active Application Filing
- 2020-11-19 AU AU2020393299A patent/AU2020393299A1/en active Pending
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US4493064A (en) * | 1981-07-17 | 1985-01-08 | Sintra-Alcatel | Sonar System |
US20020071345A1 (en) * | 2000-04-06 | 2002-06-13 | Teratech Corporation | Sonar beamforming system |
US20030081503A1 (en) * | 2001-10-23 | 2003-05-01 | Barnard Thomas J. | System and method for localizing targets using multiple arrays |
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AU2020393299A1 (en) | 2022-06-09 |
FR3103572A1 (fr) | 2021-05-28 |
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