CA1206583A - Underwater detection system - Google Patents
Underwater detection systemInfo
- Publication number
- CA1206583A CA1206583A CA000419663A CA419663A CA1206583A CA 1206583 A CA1206583 A CA 1206583A CA 000419663 A CA000419663 A CA 000419663A CA 419663 A CA419663 A CA 419663A CA 1206583 A CA1206583 A CA 1206583A
- Authority
- CA
- Canada
- Prior art keywords
- sector
- signals
- degrees
- transmitting
- memory unit
- 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
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S15/00—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems
- G01S15/02—Systems using the reflection or reradiation of acoustic waves, e.g. sonar systems using reflection of acoustic waves
- G01S15/06—Systems determining the position data of a target
- G01S15/42—Simultaneous measurement of distance and other co-ordinates
Abstract
ABSTRACT OF THE DISCLOSURE
An underwater detection system which has a trans-mitting and receiving unit for radiating an ultrasonic wave pulse into the water within a narrow sector and receiving echo signals by a plurality of reception beams, and turns the transmitting and receiving unit by a pre-determined angle to search another narrow sector each time the search within the narrow sector is completed, thereby searching the water within a wide angular range.
An underwater detection system which has a trans-mitting and receiving unit for radiating an ultrasonic wave pulse into the water within a narrow sector and receiving echo signals by a plurality of reception beams, and turns the transmitting and receiving unit by a pre-determined angle to search another narrow sector each time the search within the narrow sector is completed, thereby searching the water within a wide angular range.
Description
:~2Y~6583 Underwater Detection System BA~:RGROUND OF THE INVENTION
This invention relates to an underwater detection system for searching the wa~er within a wide angular range. Particularly it relates to a system which has a transmitting and receiving unit for transmitting an ultrasonic wave pulse into the water within a narrow sector of a predetermined angle and receiving echo signals by a plurality of r~ception beams, and turns ~he transmitting and receiving unit by a predetermined angle to search another narrow sector each time the search within the preceding narrow sector is completed, thereby searching the water within a wide angular range.
As one of prior art underwater detection systems, a PPI sonar has been widely used. A PPI sonar is disclosed in U.S. patent No. 2,759,783. The PPI sonar slowly rotates a transducer which radiates an ultrasonic wave pulse into the water in a direction and receives echo signals therefrom with a reception beam, thereby trans-mitting ultrasonic wave pulses in successive different directions and hence searching the water within a wide angular range. One of the drawbacks of the PPI sonar is its slow speed of searching. Assuming now that the beam width of a transmission beam and a reception beam is six degrees and the detection range of the sonar is 12~ iS~3 750 meters, it takes one second to search the water in a given direction and hence it takes sixty seconds to complete the search in all directions i.e., 360 degrees.
Since the saarch in each direction is made every sixty seconds and the ship which is equipped with ~he P~I
sonar advances, there will be areas where the search is not made.
Another prior art underwater detection system as disclosed in U.S. patent No. 4,045,766 has also been widely used. The prior art system has a plurality of transducers disposed on a circle and successively forms a series of directional reception beams along a circum-ferential direction a~ high speed, ~hereby searching the water in all directions very rapidly. A narxow reception beam is formed in a direction by appropriately phase-shifting the reception signals caught by each of selected gxoups of transducers. Reception beams will be succes-sively formed in a circumferential direction by selecting different groups of transducers. But the construction of such a system will be complicated and the system inevitably will be bulky and costly.
SUMMARY OF THE INVENTION
Accordingly, an object of this invention is to provide an underwater detection system which is capable of searching the water within a wide angular range at a relatively high speed.
~Z~'~S~3 Another object of this invention is to provide an underwater Aetection system which successively searches the water within each of a plurality of narrow sectors, thereby searching the water within a wide angular range.
Another object of this invention is to provide an underwater detection system which has a transmitting and receiving unit Eor radiating an ultrasonic wave pulse into the water in a narrow sector of a predetermind angle and receiving echo signals by a plurali~y of reception beams formed within the sector, and turns the transmitting and receiving unit by a prdetermined angle to search another narrow sector each time the search within the preceding narrow sector is completed, thereby searching the water within a wide angular range.
To this end there is provided an underwater detection system comprising: a. transmitting means for transmitting an ultrasonic wave pulse into the water at least in a sector of an angle smaller than 36 degrees, b. a plurality of transducers, c. receiving means for forming directional reception beams in different azimuthal directions within the sector and producing echo signals successively obtained by the directional reception beams, each of the directional reception beams being formed by utiliæing the echo signals received by said plurality of transducers, d. turning means for turning said transmitting and receiving means by a i ~2~6~83 predetermined angle after a search within said sector is completed, thereby searching another sector, e. an indi-cator for displaying the signals received by said receiving means in sector form at portions corresponding to said search sector, f. a memory unit for storing the signals supplied from said rèceiving means, g. coordinate con-verting means for producing output signals based on the dixection and range of the echo signals, h. writing means for writing output signals from said receiving means into said memory unit controlled by the output signals from said coordinate converting means, and i. reading means for reading out stored signals from said memory unit and supplying them to said indicatorO
~IEF DESCRIPTI N OF THE DRAWINGS
In the drawings:
Fig. 1 shows a schematic block diagram of an under-water detection system according to an embodiment of the invention, Fig. 2 shows a schematic block diagram of a portion of Fig. 1, particularly a detailed block diagram of a transmitter and a transmit-receive switch unit, Fig. 3 shows a schematic ~lock diagram of a portion of Fig. l, particularly a detailed block diagram of a beam-former, Fig. 4 shows a schematic block diagram of the ~'~6~
coordinate converter used in Fig. l, and Fig. 5 shows an explanatory diagram for explaining the operation of the undçrwater detection system shown in Fig. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
. .
Referring to Fig. l, a clock pulse generator l supplies clock pulses to a sector counter 2 and a direc-tion counter 3. A controller 5 supplies a start signal to the sector counter 2, the direction counter 3 and a transmitter 4. The transmitter 4 produces in response to the start signal signals of a frequency as amplitude-modulat~d by a pulse, and supplies the pulse signals to a transmitting and receiving unit 7 through a transmit-receive switch unit 6. The transmitting and receiving unit 7 radiates an ultrasonic wave pulse in response to the pulse signals applied thereto into the water in a sector of for example 30 degrees. As illustrated in Fig. 2, the transmitter 4 comprises a pulse signal generator 4' and delay circuits 4B through 4E. The pulse signal generator 4' produces in response to the start signal the signal of a frequency as amplitude-modulated by the pulse, and supplies the pulse signal to the delay circuits 4B through 4E each of which comprises counters.
The delay circuits 4B and 4E delay the output pulse signal from the pulse signal generator 4' by the same amount. The delay circuits 4C and 4D delay the output pulse signal from the pulse signal generator 4' by the same amount which, however, is larger than the amount of delay by tne delay circuits 4B and 4E. The transmit-receive switch unit 6 comprises transmit-receive switches 6A through 6F. The transmitting and receiving unit 7 comprises six transducers 7A through 7F which are disposed on a horizontal straight line. The output pulse signal from the pulse signal generatox 4' is directly supplied to the transducers 7A and 7F through the transmit-receive switches 6A and 6~'~ respectively. The delayed output pulse signals from the delay circuits 4B and 4E
are supplied to the transducers 72 and 7E through the transmit-receive switches 6B and 6E, respectivelyO The delayed output pulse signals from the delay circuits 4C
and 4D are respectively supplied to the transducers 7C
and 7D through -the transmit-receive switches 6C and 6D.
As a result, the transmitting and receiving unit 7 radiates an ultrasonic wave pulse into a wide sector of 30 degrees, Reception signals caught by the transducers 7A
through 7F are supplied to a beam-former 10 through the transmit-receive switch 6A through 6F, respectively. The beam-former 10 successively forms at a high speed six directional reception beams in different azimuthal direc-tions at a uniform angular distance within the sector of 30 degrees, so that echoes from substantially the same ~Z~6~ii8~
range are caught by the respective reception beams. A
reception beam is forrned by appropriately phase-shifting the reception signals from the transducers 7A through 7F
with respect to one another and combining the phase~
shifted signals together. A reception beam can be turned within the sector of 30 degrees by varying the phase delay of the reception signals. The beam-former 10 comprises six mixers, a phase control device, a combining circuit and a filter as illustrated in Fig. 3.
Output signals from the transmit-receive switches 6A
through 6F are suppliad to one input of each of mixers llA through llF, respectively. The phase control device 12 produces six pulse trains of a frequency at its six output terminals Tl through T6 and supplies the pulse trains to the other input of each of the mixers llA
through llF, respectively, the pulse trains being pro-gressively phase-shifted with respect to the foregoing ones. The mixer llA modulates the reception signal from the transmit-receive switch 6A with the pulse train from the output terminal Tl of the device 12. Similarly, the mixers llB through llF respectively modulate the recep-tion signals with the pulse trains supplied thereto through the output terminals T2 through T6. Output signals from the mixers llA through llF are supplied to the inputs of the cor~ining circuit 13. The combining circuit 13 cor~ines together output signals rom the ~2~ 5~33 mixers and produces combined output signals to a ~ilter 14. The filter 14 may comprise a low pass filter and passes the frequency difference components of output signals from the mixers. The phase diE~erence amounts between the pulse trains produced by the phase control device 12 are desirably varied in response to the output signal ~rom the direction counter 3. The principle of turning a reception beam in an angular direction by the beam-former 10 has been explained in U.5. Patent No, 4,117,487. The output signal from the Eilter 14 is supplied to an analog-digital converter 15.
A turning unit 16 comprises a pulse motor and is mechanically coupled to the transmitting and receiving unit 7 and controlled by the controller 5 to turn the transmitting and receiving unit 7 in a clockwise or an anticlockwise direction. A search range setting unit 18 sets the direction and angular range of the sector to be searched into the controller 5. The controller 5 comprises a microprocessor and supplies pulse signals and a rotational direction signal to the turning unit 16, thereby turning the transmitting and receiving unit 7 in a direction. A sensor 19 detects the pointing direction of the transmitting and receiving unit 7 and transmits a signal representing the direction of the unit 7 to the controller 5. The sensor 19 comprises a S1~3 circular plate having a plurality of groups of four holes in radial directions and a plurality of four photointer-rupters placed adjacent to the holes, with the circular plate coupled to the rotating shaft of the transmitting and receiving unit 7 and rotated in synchronism with the rotation of the unit 7. The controller 5 also supplies a direction signal representing the pointing direction of the transmitting and receiving unit 7 at a time when the unit is search.ing a sector, to a gate signal generator 20. The sector counter 2 starts in response to the start signal applied thereto to count the clock pulses from the clock pulse generator 1 and produces an output pulse each time it counts up the number of clock pulses corxesponding to the angle of half of the sector to be searched. The gate signal generator 20 produces gate pu~ses.at...a time interval each having a pulse ~idth ~ corresponding to the angle of the sector to be searched : based on the output pulse from the sector counter 2 and the direction signal from the controller 5. A gate 21 passes output signals from the analog-digital converter 15 to a memory unit 22 during the time period the gate pulse is applied thereto.
The direction counter 3 starts in response to the start signal to count the clock pulses from the clock pulse generator 1, and produces an output pulse to a distance counter 23 and is cleared to zero every time g ~2~6S1 33 its count reaches a count value corresponding to an angle of 360 degrees, and supplies its count value to the beam-former 10 and a coordinate converter 24. The distance counter 23 increases its count in response to an output pulse from the direction counter 3, and supplies the count value representing the distance from the transmitting and receiving unit 7 to detected objects, to the coordinate converter 2~, and is cleared to zero in count value when its count reaches to a value corresponding to the detec-tion range. The coordinate converter 24 produces X- and Y-address signals and supplies these signals to the memory unit 22 through an address switch 25. The con-struction and operation of the coordinate converter 24 will be explained hereinafter. The memory unit 22 includes m xn semiconductor RA~ (random access memory) elements arranged in m columns and n rows~ ~ith the number of RAM elements being the same as that of the picture elements of the screen of the CRT 26 wherein the picture elements are also arranged in m columns and n rows.
Each memory element of the memory unit 22 consists of three bits. The memory unit 22 writes the output signal from the gate 21 into the storage location determined by X- and Y-address signals supplied from the coordinate converter 24. A clock pulse generator 27 supplies clock pulses toan X-axis counter 28, the address switch 25 and the read/write terminal of the memory unit 22. The ~q~658~
frequency of the clock pulses from the clock pulse generator 27 is set higher than that of clock pulses from the cloclc pulse generator 1~ The X-axis counter 28 repetitiously counts m clock pulses and transmits an output pulse to a Y-axis counter 29 every time its count reaches m, and supplies its eount to the memory unit 22 through the address switeh 25, and also supplies horizontal synehronous signals to a deflection circuit 30. The Y-axis eounter 29 repetitiously counts n clock pulses, supplies its eount to the memory unit 22 through the address switeh 25, and further supplies vertical synchro-nous signals to the deflection circuit 30~ The memory unit 22 reads a stored signal from the memory element determined by the count outputs from the X-axis and Y-axis counters 28 and 29. The address switch 25 comprises an eleetric switching device, and supplies either the X- and Y-address signals from the coordinate canverter 24 or the counts from the X-axis and Y-axis counters depend-ing on the polarity of the elock pulses from the clock pulse generator 27. When the X- and Y-address signals are supplied to the memory unit 22 and a write signal is applied to the read/write terminal of the memory unit 22 from the clock pulse generator 27, the output signal from the gate 21 is written into a memory element deter-mined by the X- and Y-address signals. On the other hand, when the count outputs from the X-axis and Y-axis -- 11 ~
~I~Z~6583 counters 28 and 29 are supplied to the memory unit 22 through the addres switch ~5 and a read signal is applied to the read/write terminal of the memory unit 22, the stored signal is read out from the memory element determined by the count outputs from the X-axis and Y-axis counters and fed to a color converter 31. The color converter 31 performs the necessary color conversion for displaying a predetermined color on the screen of the CRT in accordance with the level o~ the digital signal supplied from the memory u~it 22. The red, green and blue electron guns of the color cathode ray tube 26 are controlled by the output signals from the color converter 31. The deflection circuit 30 deflects electron beams of the CRT horizontally in synchronism with the horizontal synchronous signal and deflects them vertically in synchro-nism with the vertical synchronous signal, thereby sweeping the electron beams over the whole screen of the CRT.
Referring to Fig. 4, the output signal from the direction counter 3 is supplied to one input of a memory unit 35 which comprises a read only memory. The output signal frorn the direction counter 23 is supplied to the other input of the memory unit 35 and to one input of an adder 36. The memory unit 35 stores pairs (~x, Qy) of predetermined binary numerical values at memory elements corresponding to all points in a polar coordinates, and reads out and supplies a pair of numerical values (Qx, ay) according to the signals from the direction counter 3 and distance counter 23, to one input of a x address counter 38 and of a y address counter 39. The x and y address counters 38 and 39 comprise up or down counters.
The numerical value Xo of X component of the origin of the CRT is supplied to the other input of the adder 36.
The adder 3~ adds the value Xo and output signal from the direction counter 23 to one another, and sets the resultant value to the x address counter 38. The x address counter 38 starts counting from the preset value, and increases its count by "1" if Q~ supplied is "1", and holds its count if Qx supplied is "0". The numerïcal value Yo of Y component of the origin of the CRT is preset into the y address counter 39~ The y address counter 39 starts counting from the preset value, and increases its count by "1" if Qy supplied is "1", and does not increase its count if Qy supplied is "0". The count outputs from the x and y address counters are supplied to the memory unit 22 through the address switch 25.
In operation, assuming that a sector of 90 degrees from a direction of 315 degrees through a direction of 45 degrees is searched as illustrated in Fig. 5, the transmitting and receiving unit 7 is firstly directed to a direction of 330 degrees. A start signal from the - 13 _ ~L2~65~3 controller 5 is supplied to the transmitter 4, the sector counter 2 and direction counter 3. The pulse signals are transmitted from the transmitter 4 to the transmitting and recelving unit 7 through the transmit-receive switch unit 6. The ultrasonic wave pulse is radiated into the water in a sector of as large as 30 degrees. The recep-tion signals received by the transmitting and receiving unit 7 are transmitted to the beamformer 10. A reception beam is repeatedly turned at a high speed from left to right in the sector of 30 degrees, so that echo signals from the pointing directions of the reception beam are caught and supplied to the memory unit 22 through the analog-digital converter 15 and gate 21. The signals supplied to the.memory unit 22 are written into the memory elements determined by X- and Y-address signals supplied from the coordinate converter 24. The stored signals are successively read out from the memory elements selected by the count outputs from the X-axis and Y-axis counters 28 and 29, and are supplied to the CRT ~6 through the color converter 31. The searched sector of 30 degrees is displayed on the screen of the CRT 26 in a direction of 330 degrees, since the electron beams are repeatedly horizontally and vertically scanned over the screen in synchronism with the reading operation. On completion of the search over the sector from the direc-tion of 315 degrees through the direction of 345 degrees, the transmitting and receiving unit 7 is turned by the turning unit 16 by 30 degrees and then is directed in a direction of 0 degree. A start signal is again trans-mitted to the transmitter 4, the sector counter 2 and S direction counter 3. In the same way as described above, the ultrasonic wave pulse is radiated into the water in response to the pulse signals from the transmitter 4 into the sector of 30 degrees from a direction of 345 degrees through a direction of 15 degrees. The echo signals caught by the turning reception beam are supplied to the memory unit 22 through the analog-digital converter 15 and gate 21 and are written into the memory elements determined by the ~ and Y-address signals from the coordinate converter 24. The stored signals are lS successively read out from the memory elements selected by the count outputs from the X-axis and Y-axis counters 28 and 29, and are supplied to the CRT 26. The searched sector of 60 degrees is displayed on the screen of the CRT 26 ~rom the direction of 315 degrees through the direction of 15 degrees. On completion of the search over the sector from the direction of 345 degrees through the direction of 15 degrees, the controller 5 instructs the turning unit 16 to rotate the transmitting and receiv-ing unit 7 by 30 degrees and directs it in a direction of 30 degrees. A strat signal is ayain transmitted to the transmitter 4, the sector counter 2 and diraction counter 3. In the same way, the ultrasonic wave pulse is radiated into the water, and echo signals received are supplied to the memory unit 22. The stored signals read out from the memor~ eleme~ts are supplied to the CRT 26. As a result, the searched sector oE 90 degrees is displayed on the screen of the CRT 26 from the direction of 315 degrees through the direction of 45 degrees. ~hen the search over the wide sector of 90 degrees has been completed, the turning unit 16 controlled by the controller S turns the transmitting and receiving unit 7 in an anticloc~wise direction by 60 degrees and directs the unik 7 in the direction of 330 degrees. In the same way as described above, a start signal is supplied to the transmitter 4 from the controller ~ and, thereafter, the same operation as described above follows. The echo signals supplied to the memory unit 22 replace the signals stored in the memory elements.
It should be noted that although reception beams are successively formed in different azimuthal directions by the beam-former in the foregoing embodiment, a plurali-ty of previously formed reception beams may be successively selected one after another to accomplish the same object.
It should also be noted although a cathode-ray tube is used in the foregoing embodiment, a so-called plasma display or an array of light-emitting diodes can also be used.
It should further be noted that a sector of 30 degrees is searched by the transmitting and receiving unit 7 at a time in the foregoing embodiment, a sector of a smaller or larger angles can be searched by the unit 7 at a time.
It should further be noted that although the trans-ducers are disposed on a straight line in the foregoing embodiment, the transducers may be disposed on an arc of a circle. In this case, th~ delay circuits are not necessary to be incorporat~d.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be appar~nt to one skilledin the art that vaxious changes and modifications can be made therein without departing lS Erom the spirit and scope of the invention.
This invention relates to an underwater detection system for searching the wa~er within a wide angular range. Particularly it relates to a system which has a transmitting and receiving unit for transmitting an ultrasonic wave pulse into the water within a narrow sector of a predetermined angle and receiving echo signals by a plurality of r~ception beams, and turns ~he transmitting and receiving unit by a predetermined angle to search another narrow sector each time the search within the preceding narrow sector is completed, thereby searching the water within a wide angular range.
As one of prior art underwater detection systems, a PPI sonar has been widely used. A PPI sonar is disclosed in U.S. patent No. 2,759,783. The PPI sonar slowly rotates a transducer which radiates an ultrasonic wave pulse into the water in a direction and receives echo signals therefrom with a reception beam, thereby trans-mitting ultrasonic wave pulses in successive different directions and hence searching the water within a wide angular range. One of the drawbacks of the PPI sonar is its slow speed of searching. Assuming now that the beam width of a transmission beam and a reception beam is six degrees and the detection range of the sonar is 12~ iS~3 750 meters, it takes one second to search the water in a given direction and hence it takes sixty seconds to complete the search in all directions i.e., 360 degrees.
Since the saarch in each direction is made every sixty seconds and the ship which is equipped with ~he P~I
sonar advances, there will be areas where the search is not made.
Another prior art underwater detection system as disclosed in U.S. patent No. 4,045,766 has also been widely used. The prior art system has a plurality of transducers disposed on a circle and successively forms a series of directional reception beams along a circum-ferential direction a~ high speed, ~hereby searching the water in all directions very rapidly. A narxow reception beam is formed in a direction by appropriately phase-shifting the reception signals caught by each of selected gxoups of transducers. Reception beams will be succes-sively formed in a circumferential direction by selecting different groups of transducers. But the construction of such a system will be complicated and the system inevitably will be bulky and costly.
SUMMARY OF THE INVENTION
Accordingly, an object of this invention is to provide an underwater detection system which is capable of searching the water within a wide angular range at a relatively high speed.
~Z~'~S~3 Another object of this invention is to provide an underwater Aetection system which successively searches the water within each of a plurality of narrow sectors, thereby searching the water within a wide angular range.
Another object of this invention is to provide an underwater detection system which has a transmitting and receiving unit Eor radiating an ultrasonic wave pulse into the water in a narrow sector of a predetermind angle and receiving echo signals by a plurali~y of reception beams formed within the sector, and turns the transmitting and receiving unit by a prdetermined angle to search another narrow sector each time the search within the preceding narrow sector is completed, thereby searching the water within a wide angular range.
To this end there is provided an underwater detection system comprising: a. transmitting means for transmitting an ultrasonic wave pulse into the water at least in a sector of an angle smaller than 36 degrees, b. a plurality of transducers, c. receiving means for forming directional reception beams in different azimuthal directions within the sector and producing echo signals successively obtained by the directional reception beams, each of the directional reception beams being formed by utiliæing the echo signals received by said plurality of transducers, d. turning means for turning said transmitting and receiving means by a i ~2~6~83 predetermined angle after a search within said sector is completed, thereby searching another sector, e. an indi-cator for displaying the signals received by said receiving means in sector form at portions corresponding to said search sector, f. a memory unit for storing the signals supplied from said rèceiving means, g. coordinate con-verting means for producing output signals based on the dixection and range of the echo signals, h. writing means for writing output signals from said receiving means into said memory unit controlled by the output signals from said coordinate converting means, and i. reading means for reading out stored signals from said memory unit and supplying them to said indicatorO
~IEF DESCRIPTI N OF THE DRAWINGS
In the drawings:
Fig. 1 shows a schematic block diagram of an under-water detection system according to an embodiment of the invention, Fig. 2 shows a schematic block diagram of a portion of Fig. 1, particularly a detailed block diagram of a transmitter and a transmit-receive switch unit, Fig. 3 shows a schematic ~lock diagram of a portion of Fig. l, particularly a detailed block diagram of a beam-former, Fig. 4 shows a schematic block diagram of the ~'~6~
coordinate converter used in Fig. l, and Fig. 5 shows an explanatory diagram for explaining the operation of the undçrwater detection system shown in Fig. 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
. .
Referring to Fig. l, a clock pulse generator l supplies clock pulses to a sector counter 2 and a direc-tion counter 3. A controller 5 supplies a start signal to the sector counter 2, the direction counter 3 and a transmitter 4. The transmitter 4 produces in response to the start signal signals of a frequency as amplitude-modulat~d by a pulse, and supplies the pulse signals to a transmitting and receiving unit 7 through a transmit-receive switch unit 6. The transmitting and receiving unit 7 radiates an ultrasonic wave pulse in response to the pulse signals applied thereto into the water in a sector of for example 30 degrees. As illustrated in Fig. 2, the transmitter 4 comprises a pulse signal generator 4' and delay circuits 4B through 4E. The pulse signal generator 4' produces in response to the start signal the signal of a frequency as amplitude-modulated by the pulse, and supplies the pulse signal to the delay circuits 4B through 4E each of which comprises counters.
The delay circuits 4B and 4E delay the output pulse signal from the pulse signal generator 4' by the same amount. The delay circuits 4C and 4D delay the output pulse signal from the pulse signal generator 4' by the same amount which, however, is larger than the amount of delay by tne delay circuits 4B and 4E. The transmit-receive switch unit 6 comprises transmit-receive switches 6A through 6F. The transmitting and receiving unit 7 comprises six transducers 7A through 7F which are disposed on a horizontal straight line. The output pulse signal from the pulse signal generatox 4' is directly supplied to the transducers 7A and 7F through the transmit-receive switches 6A and 6~'~ respectively. The delayed output pulse signals from the delay circuits 4B and 4E
are supplied to the transducers 72 and 7E through the transmit-receive switches 6B and 6E, respectivelyO The delayed output pulse signals from the delay circuits 4C
and 4D are respectively supplied to the transducers 7C
and 7D through -the transmit-receive switches 6C and 6D.
As a result, the transmitting and receiving unit 7 radiates an ultrasonic wave pulse into a wide sector of 30 degrees, Reception signals caught by the transducers 7A
through 7F are supplied to a beam-former 10 through the transmit-receive switch 6A through 6F, respectively. The beam-former 10 successively forms at a high speed six directional reception beams in different azimuthal direc-tions at a uniform angular distance within the sector of 30 degrees, so that echoes from substantially the same ~Z~6~ii8~
range are caught by the respective reception beams. A
reception beam is forrned by appropriately phase-shifting the reception signals from the transducers 7A through 7F
with respect to one another and combining the phase~
shifted signals together. A reception beam can be turned within the sector of 30 degrees by varying the phase delay of the reception signals. The beam-former 10 comprises six mixers, a phase control device, a combining circuit and a filter as illustrated in Fig. 3.
Output signals from the transmit-receive switches 6A
through 6F are suppliad to one input of each of mixers llA through llF, respectively. The phase control device 12 produces six pulse trains of a frequency at its six output terminals Tl through T6 and supplies the pulse trains to the other input of each of the mixers llA
through llF, respectively, the pulse trains being pro-gressively phase-shifted with respect to the foregoing ones. The mixer llA modulates the reception signal from the transmit-receive switch 6A with the pulse train from the output terminal Tl of the device 12. Similarly, the mixers llB through llF respectively modulate the recep-tion signals with the pulse trains supplied thereto through the output terminals T2 through T6. Output signals from the mixers llA through llF are supplied to the inputs of the cor~ining circuit 13. The combining circuit 13 cor~ines together output signals rom the ~2~ 5~33 mixers and produces combined output signals to a ~ilter 14. The filter 14 may comprise a low pass filter and passes the frequency difference components of output signals from the mixers. The phase diE~erence amounts between the pulse trains produced by the phase control device 12 are desirably varied in response to the output signal ~rom the direction counter 3. The principle of turning a reception beam in an angular direction by the beam-former 10 has been explained in U.5. Patent No, 4,117,487. The output signal from the Eilter 14 is supplied to an analog-digital converter 15.
A turning unit 16 comprises a pulse motor and is mechanically coupled to the transmitting and receiving unit 7 and controlled by the controller 5 to turn the transmitting and receiving unit 7 in a clockwise or an anticlockwise direction. A search range setting unit 18 sets the direction and angular range of the sector to be searched into the controller 5. The controller 5 comprises a microprocessor and supplies pulse signals and a rotational direction signal to the turning unit 16, thereby turning the transmitting and receiving unit 7 in a direction. A sensor 19 detects the pointing direction of the transmitting and receiving unit 7 and transmits a signal representing the direction of the unit 7 to the controller 5. The sensor 19 comprises a S1~3 circular plate having a plurality of groups of four holes in radial directions and a plurality of four photointer-rupters placed adjacent to the holes, with the circular plate coupled to the rotating shaft of the transmitting and receiving unit 7 and rotated in synchronism with the rotation of the unit 7. The controller 5 also supplies a direction signal representing the pointing direction of the transmitting and receiving unit 7 at a time when the unit is search.ing a sector, to a gate signal generator 20. The sector counter 2 starts in response to the start signal applied thereto to count the clock pulses from the clock pulse generator 1 and produces an output pulse each time it counts up the number of clock pulses corxesponding to the angle of half of the sector to be searched. The gate signal generator 20 produces gate pu~ses.at...a time interval each having a pulse ~idth ~ corresponding to the angle of the sector to be searched : based on the output pulse from the sector counter 2 and the direction signal from the controller 5. A gate 21 passes output signals from the analog-digital converter 15 to a memory unit 22 during the time period the gate pulse is applied thereto.
The direction counter 3 starts in response to the start signal to count the clock pulses from the clock pulse generator 1, and produces an output pulse to a distance counter 23 and is cleared to zero every time g ~2~6S1 33 its count reaches a count value corresponding to an angle of 360 degrees, and supplies its count value to the beam-former 10 and a coordinate converter 24. The distance counter 23 increases its count in response to an output pulse from the direction counter 3, and supplies the count value representing the distance from the transmitting and receiving unit 7 to detected objects, to the coordinate converter 2~, and is cleared to zero in count value when its count reaches to a value corresponding to the detec-tion range. The coordinate converter 24 produces X- and Y-address signals and supplies these signals to the memory unit 22 through an address switch 25. The con-struction and operation of the coordinate converter 24 will be explained hereinafter. The memory unit 22 includes m xn semiconductor RA~ (random access memory) elements arranged in m columns and n rows~ ~ith the number of RAM elements being the same as that of the picture elements of the screen of the CRT 26 wherein the picture elements are also arranged in m columns and n rows.
Each memory element of the memory unit 22 consists of three bits. The memory unit 22 writes the output signal from the gate 21 into the storage location determined by X- and Y-address signals supplied from the coordinate converter 24. A clock pulse generator 27 supplies clock pulses toan X-axis counter 28, the address switch 25 and the read/write terminal of the memory unit 22. The ~q~658~
frequency of the clock pulses from the clock pulse generator 27 is set higher than that of clock pulses from the cloclc pulse generator 1~ The X-axis counter 28 repetitiously counts m clock pulses and transmits an output pulse to a Y-axis counter 29 every time its count reaches m, and supplies its eount to the memory unit 22 through the address switeh 25, and also supplies horizontal synehronous signals to a deflection circuit 30. The Y-axis eounter 29 repetitiously counts n clock pulses, supplies its eount to the memory unit 22 through the address switeh 25, and further supplies vertical synchro-nous signals to the deflection circuit 30~ The memory unit 22 reads a stored signal from the memory element determined by the count outputs from the X-axis and Y-axis counters 28 and 29. The address switch 25 comprises an eleetric switching device, and supplies either the X- and Y-address signals from the coordinate canverter 24 or the counts from the X-axis and Y-axis counters depend-ing on the polarity of the elock pulses from the clock pulse generator 27. When the X- and Y-address signals are supplied to the memory unit 22 and a write signal is applied to the read/write terminal of the memory unit 22 from the clock pulse generator 27, the output signal from the gate 21 is written into a memory element deter-mined by the X- and Y-address signals. On the other hand, when the count outputs from the X-axis and Y-axis -- 11 ~
~I~Z~6583 counters 28 and 29 are supplied to the memory unit 22 through the addres switch ~5 and a read signal is applied to the read/write terminal of the memory unit 22, the stored signal is read out from the memory element determined by the count outputs from the X-axis and Y-axis counters and fed to a color converter 31. The color converter 31 performs the necessary color conversion for displaying a predetermined color on the screen of the CRT in accordance with the level o~ the digital signal supplied from the memory u~it 22. The red, green and blue electron guns of the color cathode ray tube 26 are controlled by the output signals from the color converter 31. The deflection circuit 30 deflects electron beams of the CRT horizontally in synchronism with the horizontal synchronous signal and deflects them vertically in synchro-nism with the vertical synchronous signal, thereby sweeping the electron beams over the whole screen of the CRT.
Referring to Fig. 4, the output signal from the direction counter 3 is supplied to one input of a memory unit 35 which comprises a read only memory. The output signal frorn the direction counter 23 is supplied to the other input of the memory unit 35 and to one input of an adder 36. The memory unit 35 stores pairs (~x, Qy) of predetermined binary numerical values at memory elements corresponding to all points in a polar coordinates, and reads out and supplies a pair of numerical values (Qx, ay) according to the signals from the direction counter 3 and distance counter 23, to one input of a x address counter 38 and of a y address counter 39. The x and y address counters 38 and 39 comprise up or down counters.
The numerical value Xo of X component of the origin of the CRT is supplied to the other input of the adder 36.
The adder 3~ adds the value Xo and output signal from the direction counter 23 to one another, and sets the resultant value to the x address counter 38. The x address counter 38 starts counting from the preset value, and increases its count by "1" if Q~ supplied is "1", and holds its count if Qx supplied is "0". The numerïcal value Yo of Y component of the origin of the CRT is preset into the y address counter 39~ The y address counter 39 starts counting from the preset value, and increases its count by "1" if Qy supplied is "1", and does not increase its count if Qy supplied is "0". The count outputs from the x and y address counters are supplied to the memory unit 22 through the address switch 25.
In operation, assuming that a sector of 90 degrees from a direction of 315 degrees through a direction of 45 degrees is searched as illustrated in Fig. 5, the transmitting and receiving unit 7 is firstly directed to a direction of 330 degrees. A start signal from the - 13 _ ~L2~65~3 controller 5 is supplied to the transmitter 4, the sector counter 2 and direction counter 3. The pulse signals are transmitted from the transmitter 4 to the transmitting and recelving unit 7 through the transmit-receive switch unit 6. The ultrasonic wave pulse is radiated into the water in a sector of as large as 30 degrees. The recep-tion signals received by the transmitting and receiving unit 7 are transmitted to the beamformer 10. A reception beam is repeatedly turned at a high speed from left to right in the sector of 30 degrees, so that echo signals from the pointing directions of the reception beam are caught and supplied to the memory unit 22 through the analog-digital converter 15 and gate 21. The signals supplied to the.memory unit 22 are written into the memory elements determined by X- and Y-address signals supplied from the coordinate converter 24. The stored signals are successively read out from the memory elements selected by the count outputs from the X-axis and Y-axis counters 28 and 29, and are supplied to the CRT ~6 through the color converter 31. The searched sector of 30 degrees is displayed on the screen of the CRT 26 in a direction of 330 degrees, since the electron beams are repeatedly horizontally and vertically scanned over the screen in synchronism with the reading operation. On completion of the search over the sector from the direc-tion of 315 degrees through the direction of 345 degrees, the transmitting and receiving unit 7 is turned by the turning unit 16 by 30 degrees and then is directed in a direction of 0 degree. A start signal is again trans-mitted to the transmitter 4, the sector counter 2 and S direction counter 3. In the same way as described above, the ultrasonic wave pulse is radiated into the water in response to the pulse signals from the transmitter 4 into the sector of 30 degrees from a direction of 345 degrees through a direction of 15 degrees. The echo signals caught by the turning reception beam are supplied to the memory unit 22 through the analog-digital converter 15 and gate 21 and are written into the memory elements determined by the ~ and Y-address signals from the coordinate converter 24. The stored signals are lS successively read out from the memory elements selected by the count outputs from the X-axis and Y-axis counters 28 and 29, and are supplied to the CRT 26. The searched sector of 60 degrees is displayed on the screen of the CRT 26 ~rom the direction of 315 degrees through the direction of 15 degrees. On completion of the search over the sector from the direction of 345 degrees through the direction of 15 degrees, the controller 5 instructs the turning unit 16 to rotate the transmitting and receiv-ing unit 7 by 30 degrees and directs it in a direction of 30 degrees. A strat signal is ayain transmitted to the transmitter 4, the sector counter 2 and diraction counter 3. In the same way, the ultrasonic wave pulse is radiated into the water, and echo signals received are supplied to the memory unit 22. The stored signals read out from the memor~ eleme~ts are supplied to the CRT 26. As a result, the searched sector oE 90 degrees is displayed on the screen of the CRT 26 from the direction of 315 degrees through the direction of 45 degrees. ~hen the search over the wide sector of 90 degrees has been completed, the turning unit 16 controlled by the controller S turns the transmitting and receiving unit 7 in an anticloc~wise direction by 60 degrees and directs the unik 7 in the direction of 330 degrees. In the same way as described above, a start signal is supplied to the transmitter 4 from the controller ~ and, thereafter, the same operation as described above follows. The echo signals supplied to the memory unit 22 replace the signals stored in the memory elements.
It should be noted that although reception beams are successively formed in different azimuthal directions by the beam-former in the foregoing embodiment, a plurali-ty of previously formed reception beams may be successively selected one after another to accomplish the same object.
It should also be noted although a cathode-ray tube is used in the foregoing embodiment, a so-called plasma display or an array of light-emitting diodes can also be used.
It should further be noted that a sector of 30 degrees is searched by the transmitting and receiving unit 7 at a time in the foregoing embodiment, a sector of a smaller or larger angles can be searched by the unit 7 at a time.
It should further be noted that although the trans-ducers are disposed on a straight line in the foregoing embodiment, the transducers may be disposed on an arc of a circle. In this case, th~ delay circuits are not necessary to be incorporat~d.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be appar~nt to one skilledin the art that vaxious changes and modifications can be made therein without departing lS Erom the spirit and scope of the invention.
Claims (3)
1. An underwater detection system comprising:
a. transmitting means for transmitting an ultrasonic wave pulse into the water at least in a sector of an angle smaller than 36 degrees, b. a plurality of transducers, c. receiving means for forming directional reception beams in different azimuthal directions within the sector and producing echo signals successively obtained by the directional reception beams, each of the directional reception beams being formed by utilizing the echo signals received by said plurality of transducers, d. turning means for turning said transmitting and receiving means by a predetermined angle after a search within said sector is completed, thereby searching another sector, e. an indicator for displaying the signals received by said receiving means in sector form at portions corresponding to said search sector, f. a memory unit for storing the signals supplied from said receiving means, g. coordinate converting means for producing output signals based on the direction and range of the echo signals, h. writing means for writing output signals from said receiving means into said memory unit controlled by the output signals from said coordinate converting means, and i. reading means for reading out stored signals from said memory unit and supplying them to said indicator.
a. transmitting means for transmitting an ultrasonic wave pulse into the water at least in a sector of an angle smaller than 36 degrees, b. a plurality of transducers, c. receiving means for forming directional reception beams in different azimuthal directions within the sector and producing echo signals successively obtained by the directional reception beams, each of the directional reception beams being formed by utilizing the echo signals received by said plurality of transducers, d. turning means for turning said transmitting and receiving means by a predetermined angle after a search within said sector is completed, thereby searching another sector, e. an indicator for displaying the signals received by said receiving means in sector form at portions corresponding to said search sector, f. a memory unit for storing the signals supplied from said receiving means, g. coordinate converting means for producing output signals based on the direction and range of the echo signals, h. writing means for writing output signals from said receiving means into said memory unit controlled by the output signals from said coordinate converting means, and i. reading means for reading out stored signals from said memory unit and supplying them to said indicator.
2. An underwater detection system as defined in Claim 1 wherein the receiving means forms directional reception beams in different azimuthal directions in a sector of 30 degrees.
3. An underwater detection system as defined in Claim 1 or 2 further comprising a color converter interposed between the memory unit and the indicator.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP56-191410 | 1981-11-27 | ||
| JP56191410A JPS5895276A (en) | 1981-11-27 | 1981-11-27 | Underwater detecting device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1206583A true CA1206583A (en) | 1986-06-24 |
Family
ID=16274137
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000419663A Expired CA1206583A (en) | 1981-11-27 | 1983-01-18 | Underwater detection system |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5895276A (en) |
| CA (1) | CA1206583A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60115884A (en) * | 1983-11-29 | 1985-06-22 | Marine Instr Co Ltd | Ultrasonic detecting method |
| JP2008043928A (en) * | 2006-08-21 | 2008-02-28 | Asahipen Corp | Container for roller-type application tool |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5868680A (en) * | 1981-10-20 | 1983-04-23 | Koden Electronics Co Ltd | Echo indicator for several sectors |
-
1981
- 1981-11-27 JP JP56191410A patent/JPS5895276A/en active Pending
-
1983
- 1983-01-18 CA CA000419663A patent/CA1206583A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5895276A (en) | 1983-06-06 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4154113A (en) | Ultrasonic imaging system | |
| US3012222A (en) | System for displaying sonic echoes from underwater targets | |
| US4155258A (en) | Ultrasonic imaging system | |
| US6711953B2 (en) | Method of and apparatus for controlling beams produced by a cylindrical transducer | |
| US4119938A (en) | Methods and devices for ultrasonic imaging | |
| US3967233A (en) | Sonar system for classifying submerged objects | |
| US4425634A (en) | Detection system | |
| GB1529304A (en) | Imaging system | |
| US4118703A (en) | Pulse radar apparatus | |
| US4045766A (en) | Ultrasonic detection system | |
| CA1206583A (en) | Underwater detection system | |
| US5061935A (en) | Three-dimensional display radar | |
| US6192006B1 (en) | Device for and a method of determining the angle of incidence of a received signal and a scanning sonar | |
| US4672589A (en) | Underwater detection system | |
| US3950724A (en) | Horizontal fish detection sonar | |
| US3465337A (en) | Beam scanning device of sonic or electric wave or the like | |
| US4471473A (en) | Direction finding circuit arrangement | |
| US2486197A (en) | Three-dimensional proximity indication system | |
| US2697822A (en) | Sound detecting and indicating system | |
| US2587610A (en) | Directional radar system | |
| GB2134256A (en) | Underwater detection system | |
| JPH0479583B2 (en) | ||
| JPH0136155Y2 (en) | ||
| US3378839A (en) | Radiolocation system | |
| JPH01118791A (en) | Signal processor of ultrasonic sonar |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |