EP0142416B1 - Wandleranordnung zur Herstellung von Sonarbildern - Google Patents

Wandleranordnung zur Herstellung von Sonarbildern Download PDF

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Publication number
EP0142416B1
EP0142416B1 EP84402088A EP84402088A EP0142416B1 EP 0142416 B1 EP0142416 B1 EP 0142416B1 EP 84402088 A EP84402088 A EP 84402088A EP 84402088 A EP84402088 A EP 84402088A EP 0142416 B1 EP0142416 B1 EP 0142416B1
Authority
EP
European Patent Office
Prior art keywords
networks
antennas
transducer system
transducer
linear
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP84402088A
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English (en)
French (fr)
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EP0142416A2 (de
EP0142416A3 (en
Inventor
Georges Grall
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thomson CSF SA
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Filing date
Publication date
Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0142416A2 publication Critical patent/EP0142416A2/de
Publication of EP0142416A3 publication Critical patent/EP0142416A3/fr
Application granted granted Critical
Publication of EP0142416B1 publication Critical patent/EP0142416B1/de
Expired legal-status Critical Current

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    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/18—Methods or devices for transmitting, conducting or directing sound
    • G10K11/26—Sound-focusing or directing, e.g. scanning
    • G10K11/35—Sound-focusing or directing, e.g. scanning using mechanical steering of transducers or their beams
    • G10K11/352—Sound-focusing or directing, e.g. scanning using mechanical steering of transducers or their beams by moving the transducer
    • G10K11/355—Arcuate movement

Definitions

  • the present invention relates to a sonar transducer system for imaging.
  • An imaging sonar is a sonar device operating at a frequency of a few megahertz and allowing visualization of objects placed on the seabed, as is the case with an optical image. It replaces a television camera when the turbidity of the water is high.
  • An important element of such a sonar is the transmitting and receiving transducer system. This transducer system must provide a wide observation area with high resolution.
  • transducer system comprising a single receiving antenna and a single transmitting antenna insonating the entire observation sector.
  • the reception channels are preformed electronically, and it is necessary to ensure for each channel a different delay on each transducer signal.
  • an observation sector of 45 ° in a deposit with a beam having a width of a deposit of 0.6 °, 75 channels would have to be formed, which would require a very expensive electronic processing circuit.
  • this sonar system has, compared to a directive antenna system, a reduced antenna gain, which leads to an increase in the electric power necessary for its implementation.
  • the subject of the present invention is a sonar transducer system for imaging which is simple and inexpensive to produce, which does not complicate the associated electronic circuits, and which makes it possible to obtain a sufficient frame rate while having a sector of relatively large observation with high resolution.
  • the transducer system according to the invention is defined according to claim 1.
  • the transducer system comprises an even number of antennas constituted by superimposed linear arrays operating in half alternately, at each change of direction of rotation, in transmission and in reception, these antennas being mutually offset angularly at angles equal to each other and equal to the rotary alternative scanning angle to which all the antennas are subjected.
  • FIG. 1 simpfié, a machine 1 unmanned exploration of seabed, generally called “fish”. This machine can be self-propelled, or else towed by a surface boat 2 as shown in FIG. 1.
  • the "fish” When the conventional hull sonar (not shown) of the boat has identified and classified an object resting on the seabed 3, the "fish” performs a more precise identification, and it is then necessary to locate the “fish” with precision relative to this object.
  • the "fish” comprises a television camera 4 and a high frequency sonar 5 essentially comprising a transducer system 6, and associated conventional electrical circuits for transmission, reception, and processing, these circuits being supplied with energy. by a battery 8.
  • a cable 9 connects the "fish” 1 to the boat 2. Via this cable pass the video signals coming from the camera 4 and the sonar signals coming from the sonar 5, as well as any control signals intended for the "fish".
  • the video and sonar signals transmitted by the cable 9 are displayed on board the boat 2 on a standard television monitor (not shown), the operator of which controls the switching to the video or sonar signals.
  • FIG. 2 a set of beams 10 emitted by a transducer 11 with several transmission and reception channels has been symbolized (there are five channels in each direction and therefore five transmission beams in the case of FIG. 2 ). These beams are emitted obliquely (relative to the vertical) and insonify the seabed (a portion 12 of which is assumed to be substantially horizontal and planar has been represented) according to an observation sector having, in bearing, an angle 13.
  • angle 13 (see FIG. 2): 450.
  • Resolution 10 meters from the transducer: square surface with a side of 10 cm.
  • Maximum distance between the transducer and the point of impact of the end of a beam on the sea bottom (distance referenced 14 in Figure 1): 10 meters, the beam being delimited, by convention, by a contour at 3dB attenuation of the main lobe of the directivity diagram.
  • Minimum distance between the vertical passing through the transmitting face of the transducer and the point of impact of the end of a beam, below which there is no need to locate objects 2 meters (distance referenced 15 in Figure 1). This minimum distance 15 corresponds to a minimum distance 16 between the transducer and the point of impact of the beam.
  • the resolution that we have set imposes, at the aforementioned maximum distance of 10 meters, a bearing width of each of the beams in set 10 (see Figure 2) of 1/100 rd, i.e. 0.6 ° . the width in bearing being the value of the opening angle 17 of the conventional beam (that is to say considered according to the aforementioned convention).
  • the maximum oblique distances 14 and minimum 16 define an elevation angle 18 of 30 °.
  • the invention proposes to geometrically preform a small number of channels, five in a preferred embodiment, on transmission and on reception, and to subject the transducer system to mechanical scanning.
  • FIG. 3 shows a simplified top view of the linear networks of the transducer 19 of the preferred embodiment of the invention.
  • This transducer 19 comprises ten antennas with identical linear arrays superimposed, their center being located on an axis, perpendicular to the plane of FIG. 3, the trace of which can be seen in this figure. Five of these antennas operate in transmission, and the other five in reception.
  • five antenna networks referenced 21 to 25 for example the five transmitting networks arranged above the five receiving networks, the latter being respectively oriented in bearing in the same way as the networks d 'emission, and therefore being obscured by them in the top view of Figure 3.
  • the five networks 21 to 25 are mutually offset by an angle of 9 °.
  • Each of the networks 21 to 25 emits a directional ultrasonic beam, the beams being respectively referenced 26 to 30.
  • the direction of each beam is perpendicular to the longitudinal axis of the corresponding linear network and to the axis 20, and these beams are mutually offset at an angle of 9 °.
  • the assembly 19 of the ten antennas rotates around the axis 20 in an alternating movement of amplitude 9 ° (9 ° in one direction and 9 ° in the other direction). Consequently, this reciprocating movement allows the required 45 ° angular field to be observed completely.
  • Each linear network is formed by several elementary transmitting or receiving transducers, as the case may be, whose electrical signals on transmission or reception are added by simple electrical connection between the elementary transducers of the same linear network.
  • each network has a length of 60 ⁇ and a height of 2 ⁇ .
  • Such a network produces, at the operating frequency of 2 MHz (the operating frequency is advantageously between 1 and 5 MHz), a radiation diagram whose angular width (at 3 dB attenuation) in bearing is of the order 0.95 °, and that on site of the order of 30 °.
  • the required angular resolution in bearing of 0.60 ° is obtained by the product of the emission and reception diagrams.
  • the receiving networks are angularly offset with respect to the corresponding transmitting networks by making them undergo a slight rotation of angle a around the axis 20, (which makes that in all rigor, in the top view of FIG. 3), the receiving networks are not completely masked by the transmitting networks, but slightly exceed them) in order to ensure on emission a phase advance equal in value absolute said delay.
  • Each network is alternately transmitter and receiver in the direction of rotation, to ensure phase advance on transmission. Means, obvious to those skilled in the art, are provided for alternately switching the sonar transmission and reception channels on the corresponding networks.
  • FIG. 4 shows an exploded view of a preferred embodiment of a linear array antenna 31 according to the invention.
  • the antenna 31 comprises a linear array 32 consisting of a piezoelectric ceramic bar 33 on the upper and lower side faces of which there is by metallization a longitudinal strip 34 of electrically conductive material. Thin notches 35 are formed in the bar 33. They are regularly spaced perpendicular to the longitudinal axis of the bar, these notches cutting the ribbons 34. This gives a network formed of elementary transducers 36. In Figure 4 there is shown nine transducers.
  • the lateral face of the bar 33 opposite its active face is fixed by bonding to a bar 37, made of reflective material, of the same length and thickness as it.
  • the bar 37 is for example made of porous synthetic material such as "Klégécel".
  • the set of bars 33 and 37 is fixed by bonding to the flat front face of an insulating wafer 38 semicircular epoxy of the same thickness as these two bars.
  • the wafer 38 has at its rear part a notch 39 allowing the introduction of the end of an electrical connection cable 40 to a pair of shielded wires and the passage of the axis of rotation.
  • the plate 41 formed by the wafer 38 extended by the bars 37 and 33 is sandwiched between two wafers 42 and 43 of the same shape as it, and with a thickness of 0.6 mm for example.
  • the two wafers 42 and 43 are coated on their large external faces with a metallic film of electromagnetic shielding 44, 45 respectively, for example made of copper.
  • the internal faces (that is to say those applied to the plate 41) of the wafers 42 and 43 include a metallization, 46, 47 respectively, in the shape of a T whose "horizontal” bar is applied to the corresponding metallization 34 by establishing an electrical contact, and the "vertical" bar of which extends up to the level of the notch 39 where it ends in an eyelet in the center of which a blind hole is made, 48.49 respectively, thus allowing fixing by welding of each of the two wires of the conductor 40, the shielding braid of which is connected to the shieldings 44 and 45.
  • All of the elements of the antenna 31, once mounted and bonded, are coated with a neoprene sheath (not shown) ensuring the sealing of the assembly.
  • the transducer of the invention is formed by stacking five pairs of antennas such as the antenna 31 described above, the pairs being mutually offset by 9 °, and the two antennas of a pair being offset between them 0.6 °.
  • two stacks can be made, each comprising five antennas offset between them by 9 °, the two stacks being offset between them by 0.6 °.
  • the five output signals from networks operating in reception mode are processed separately in a manner known per se, by amplification, filtering, detection and integration, then are multiplexed to be transmitted to the surface boat 2 via cable 9.
  • These multiplexed signals are then digitized and stored in a memory, the writing addresses of which take account of the fact that the samples to be stored represent information originating from channels spaced apart by an angle of 9 °.
  • This memory is filled in the time interval corresponding to the duration of scanning of the sector of 9 °, ie 200 ms since the speed of rotation chosen in the example described is 45 ° / s.
  • This memory is read back to the high speed television standard for viewing on said television monitor.
  • the antenna gain is approximately 32 dB, which makes it possible to supply the five transmission networks in parallel with an electrical power of approximately 30 W, each network receiving approximately 6 W.
  • the diagram in FIG. 5 shows the evolution as a function of time t of the angular position A of the transducer of the invention in operation, that is to say when it performs an alternating scan at the angular speed of 45 ° / s , being driven by an electrically controlled speed-controlled gearmotor.
  • the curve of FIG. 5 has the shape of a regular sawtooth and symmetrical with respect to a time axis Ot located at half of the angular movement, sawtooth whose slope has the absolute value 45 ° / s and whose the vertices are rounded off because of the time To necessary for the establishment of the speed of rotation when changing the direction of rotation.
  • the linear part of the curve is between the angular positions -4.5 ° and + 4.5 °, in a useful zone Z.U of duration 200 mS.
  • FIG. 6 shows an exemplary embodiment of the control circuit of the drive motor 50 of the transducer of the invention.
  • the motor 50 drives the transducer 52 by means of a reduction gear 51.
  • the reduction gear 51 has a reduction ratio of 1/25 for example.
  • the motor 50 also drives a generator 53, the output voltage of which is sent to a comparator 54 receiving on the other hand from a switch 55 a set voltage switched alternately (according to a period equal to ZU + To) between the values + Vo and -Vo corresponding to the voltages supplied by the generator 53 for an angular deflection of + 4.5 and -4.5 ° (relative to an angular position at mid-deflection) of the transducer 52.
  • the output voltage of 54 is amplified by an amplifier 50A and supplies the motor 50.
  • the switching of the switch 55 is controlled by two amplifiers 56, 57 each connected to an optical bearing stop with photosensitive elements 58, 59 respectively, determining said angular deflections of + 4.5 ° and -4, 5 0.
  • the motor 50 is fixed on a removable support 60 itself tightly fixed (seal 61) on the shell 62 of the "fish" in a suitable place.
  • the output shaft 63 of the motor 50 drives the reduction gear 51 supported at the end by a bearing 64 and guided laterally by a guide ring 65, the bearing 64 and the ring 65 being integral with the support 60.
  • the reduction gear 51 is housed in a cavity of the support 60, closed in a sealed manner by a bored plate 66 by the bore of which the reducer 51 protrudes slightly beyond the support 60.
  • the transducer 52 is fixed at the end of the reducer 51 and protected by a radome 68 fixed tightly on the projecting end of the reducer 51.
  • the electrical connection cable 65 of the transducer 52 passes in the hollow axis of the reducer 51, exits laterally and is connected to the electronic circuits 7 of the "fish" (see FIG. 7) by making a loop allowing the alternating rotation of the transducer.
  • a pallet 70 is fixed on the shaft 63 of the motor 50 and cooperates with two optical detectors, for example of the reflection type, only one of which, referenced 71, is visible in FIG. 7, these two detectors being fixed on the support 60 in appropriate places. These two detectors include the photosensitive elements 58 and 59 shown in FIG. 6.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Measurement Of Velocity Or Position Using Acoustic Or Ultrasonic Waves (AREA)

Claims (6)

1. Sonarsondensystem zur Herstellung von Bildern des Meeresbodens mittels Ultraschall, dadurch gekennzeichnet, daß es mehrere Sende-und Empfangsantennen (21 bis 25) in Form linearer Sondennetze aufweist, die von einer Motorvorrichtung bewegt werden, wobei die Motorvorrichtung ihnen eine drehende Hin- und Herbewegung um eine Achse verleiht, die senkrecht zur Längsachse der linearen Netze verläuft.
2. Sondensystem nach Anspruch 1, dadurch gekennzeichnet, daß es eine gerade Anzahl von Antennen aufweist, die aus linearen übereinanderliegenden Netzen gebildet werden und je zur Hälfte abwechselnd bei jedem Wechsel der Drehrichtung als Sendeantenne bzw. als Empfangsantenne betrieben werden, wobei diese Antennen gemäß gleichen Winkeln gegeneinander vesetzt sind und diese Winkel dem Winkel der drehenden Hin- und Herbewegung gleichen, dem die Gesamtheit der Antennen unterworfen ist.
3. Sondensystem nach einem der Ansprüche 1 oder 2, dadurch gekennzeichnet, daß die Sendeantennen bezüglich der entsprechenden Empfangsantennen phasenmäßig um einen Winkel a voreilend versetzt sind, derart, daß a=2D ω/C ist, wobei w die Winkelgeschwindigkeit des Systems in °/s, C die Schallgeschwindigkeit im Wasser und D die maximale Beobachtungsentfernung ist.
4. Sondensystem nach einem beliebigen der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß jede Antenne ein lineares Netz aufweist, das von einem rechteckigen Stab aus einem piezoelektrischen Keramikmaterial (33) gebildet wird, wobei auf den oberen und unteren Seitenflächen des Stabes ein Längsstreifen (34) aus elektrisch leitendem Material durch Metallbeschichtung aufgebracht wird, in dem feine senkrechte zur Längsachse des Stabs verlaufende Einkerbungen (35) in regelmäßigen Abständen angebracht sind, um Sonden (36) zu bilden, wobei der Stab auf einem Reflektor (37) gleicher Dicke befestigt ist, der seinerseits auf der Stirnseite einer isolierenden Palette (38) gleicher Dicke befestigt ist, wobei das Ganze zwischen zwei außen (44,45) abgeschirmten Paletten (42,43) eingelegt ist, die je auf ihrer Innenseite eine Metallbeschichtung (46,47) besitzen, die mit den Metallbeschichtungen (34) des Keramikstabs in elektrischem Kontakt steht und mit einem Leiterdraht (40) zum Anschluß der Antenne verbunden ist.
5. Sondensystem nach Anspruch 4 für ein Sonargerät mit einem Beobachtungssektor in Azimutrichtung von 45° und einer Auflösung von 10 cm x 10 cm bei einem größten Beobachtungsabstand von 10 m, dadurch gekennzeichnet, daß es zehn übereinanderliegende Antennen mit linearen Netzen aufweist, wobei die Sendenetze ebenso wie die Empfangsnetze gegeneinander um 9° verschoben sind und das Ganze eine Hin- und Herbewegung einer Amplitude von 9° ausführt, und daß die Empfangsnetze bezüglich der entsprechenden Sendenetze um einen Winkel von 0,6° verschoben sind.
6. Sondensystem nach einem der Ansprüche 4 oder 5, dadurch gekennzeichnet, daß jedes lineare Netz eine Länge von 60λ und eine Höhe von 2 λ besitzt, wobei λ die Wellenlänge der ins Wasser ausgesandten Ultraschallwellen ist.
EP84402088A 1983-10-25 1984-10-17 Wandleranordnung zur Herstellung von Sonarbildern Expired EP0142416B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR8316994 1983-10-25
FR8316994A FR2553895B1 (fr) 1983-10-25 1983-10-25 Systeme transducteur de sonar pour imagerie

Publications (3)

Publication Number Publication Date
EP0142416A2 EP0142416A2 (de) 1985-05-22
EP0142416A3 EP0142416A3 (en) 1985-06-26
EP0142416B1 true EP0142416B1 (de) 1988-01-13

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP84402088A Expired EP0142416B1 (de) 1983-10-25 1984-10-17 Wandleranordnung zur Herstellung von Sonarbildern

Country Status (5)

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US (1) US4779239A (de)
EP (1) EP0142416B1 (de)
CA (1) CA1241731A (de)
DE (1) DE3468764D1 (de)
FR (1) FR2553895B1 (de)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2652164A1 (fr) * 1989-09-15 1991-03-22 Thomson Csf Procede de formation de voies pour sonar, notamment pour sonar remorque.
FR2653564B1 (fr) * 1989-10-20 1992-01-24 Thomson Csf Procede de formation de voies pour sonar.
FR2729041B1 (fr) * 1994-12-28 1997-01-31 Thomson Csf Procede d'emission acoustique pour sonar
FR2765447B1 (fr) * 1997-06-30 2002-12-06 Thomson Marconi Sonar Sas Antenne d'emission acoustique pour prospection sismique sous-marine
FR2795527B1 (fr) 1999-06-22 2001-09-07 Thomson Marconi Sonar Sas Systeme de prospection sismique sous-marine, notamment pour grands fonds
WO2007093002A1 (en) * 2006-02-16 2007-08-23 Ecobuoy Pty Ltd Sonar accessory & method

Family Cites Families (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2865014A (en) * 1953-12-14 1958-12-16 Honeywell Regulator Co Cyclic gain controls for sonar devices
GB778673A (en) * 1954-11-02 1957-07-10 Marconi Sounding Device Co Improvements in or relating to echo sounding systems
US3121855A (en) * 1959-11-02 1964-02-18 Atlas Werke Ag Method and apparatus of measuring direction and distances of reflecting objects
US4109642A (en) * 1972-04-03 1978-08-29 Institute Of Applied Physiology & Medicine Apparatus for ultrasonic arteriography
US3979711A (en) * 1974-06-17 1976-09-07 The Board Of Trustees Of Leland Stanford Junior University Ultrasonic transducer array and imaging system
AT342186B (de) * 1976-07-19 1978-03-28 Kretztechnik Gmbh Gerat zum untersuchen von objekten nach dem ultraschall-schnittbildverfahren
JPS5343987A (en) * 1976-09-30 1978-04-20 Tokyo Shibaura Electric Co Ultrasonic diagnostic device
JPS5483856A (en) * 1977-12-16 1979-07-04 Furuno Electric Co Ultrasonic wave transmitterrreceiver
JPS56103327A (en) * 1980-01-21 1981-08-18 Hitachi Ltd Ultrasonic image pickup apparatus
US4300215A (en) * 1980-06-06 1981-11-10 Westinghouse Electric Corp. Wide angle acoustic camera
US4601024A (en) * 1981-03-10 1986-07-15 Amoco Corporation Borehole televiewer system using multiple transducer subsystems
US4479206A (en) * 1981-07-30 1984-10-23 Granberg Mauritz L Scanning sonar display system
AT384545B (de) * 1981-12-01 1987-11-25 Kretztechnik Gmbh Ultraschall-untersuchungsgeraet
DE3224453A1 (de) * 1982-06-30 1984-01-05 Siemens AG, 1000 Berlin und 8000 München Ultraschall-tomographiegeraet

Also Published As

Publication number Publication date
FR2553895B1 (fr) 1986-02-07
EP0142416A2 (de) 1985-05-22
EP0142416A3 (en) 1985-06-26
CA1241731A (en) 1988-09-06
US4779239A (en) 1988-10-18
FR2553895A1 (fr) 1985-04-26
DE3468764D1 (en) 1988-02-18

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