JP2016071619A - Underwater sound observation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an underwater sound observation device installed at a correct position when a structure and the like are sunk and built in water.SOLUTION: An underwater sound observation device transmits a state of an underwater state replaced with a time difference between two digital sound signals to an on-board ship station. The underwater state transmits two sound digital signals having a prescribed time difference determined by the state of the structure in water to the on-board ship station in a one-way direction. The on-board ship station receives the time difference between the two digital sound signals from transmitted from the underwater station by the on-board ship station. A reception signal recovery circuit in the on-board ship station measures the time difference between the two digital sound signals, and recovers the state based on the time difference between the sound digital signals. The structure can correctly and quickly grasp the state in water in the underwater station by performing a one-way communication with the on-board ship station from the underwater state, and as a result, the work and the like in water can be correctly performed in a short time.SELECTED DRAWING: Figure 1

Description

  In the present invention, when a structure (object) is submerged and constructed in water (for example, the sea, a port, the vicinity of a breakwater, a river, a lake, etc., hereinafter simply referred to as underwater) The present invention relates to an underwater acoustic observation apparatus when installed at a position. The present invention relates to an underwater acoustic observation apparatus that can be installed in a correct orientation when a structure, a wave-dissipating apparatus, or the like (for example, Tetrapot-Trademark) is built in the water. The present invention relates to the orientation, temperature, position, orientation, etc. of a structure in water (hereinafter, all objects submerged in water are simply referred to as structures) between the shipboard station and the underwater station. The present invention relates to an underwater acoustic observation apparatus that can be immediately known in real time without handshaking.

  Since radio waves or light does not reach the water accurately, it is difficult to accurately observe the state of the structure in the water. The underwater structure can be measured by receiving a reply signal of an acoustic signal emitted from the shipboard station toward the underwater station. For communication between the shipboard station and the underwater station, a system called an acoustic modem is used, and a system for transmitting 0 or 1 digital data by transmitting and receiving a modulated acoustic signal in both sides is adopted. ing.

  FIG. 3 is a diagram for explaining a conventional example, and is a diagram for knowing the orientation of a structure using an acoustic signal. FIG. 4 is a diagram for explaining a conventional example, and is a diagram for explaining a method for sinking a tetrapot to an accurate position in water using an acoustic signal. In FIG. 3, the structure 14 ′ on the ship in a harbor or river is lowered to the water 10 by the crane 31. Since the structure 14 that has entered the water is difficult to see directly with the eyes, it is necessary to make it possible to monitor the direction by the underwater sensor 112 using an acoustic signal or the like.

  The direction determined by the underwater sensor 112 is received as an acoustic signal by the receiving device 121 on the ship. When the structure 14 is continuously installed, it is usually connected and fixed by at least one uneven portion (not shown). The structure 14 or the like is always required to be installed by fitting the concave and convex portions to each other at an accurate position based on real-time information.

  FIG. 4 is for sinking a wave-absorbing device such as a tetrapot. In FIG. 4, the tetrapots 41 ′ are stacked at a predetermined position by the crane 31. The tetrapot 41 'has a great difference in the wave-dissipating effect depending on the orientation and the way of stacking. The direction sensor 112 attached to the structure 14 or the tetrapot 41 can be accurately installed at a desired position by exchanging information with the shipboard station 12.

  For example, in the invention according to Japanese Patent Application No. 2013-102097 (filed on May 14, 2013) proposed by the present applicant, the communication between the shipboard station and the plurality of underwater stations is the same ID code and the same distance measurement. Signals were sent all at once, and a different ID code and the same ranging signal were returned from the maritime station to the shipboard station. The underwater acoustic positioning system has mutual communication regulations when transmission / reception is performed, and can obtain accurate data. However, it takes time to exchange data according to the communication regulations, and the work in the harbor or the like. There were many problems when doing.

Japanese Patent Application No. 2013-102097 (filed on May 14, 2013)

  In the invention described in the aforementioned Japanese Patent Application No. 2013-102097 (filed on May 14, 2013), before the shipboard station and the submarine station transmit the data, before the communication conditions are determined between them, Processing was necessary, and the time required for this was several seconds to several tens of seconds. The submarine station generally uses a battery as a power source, and starts measurement after changing from a normal sleep state to a wakeup state. The time required for this was further required from several seconds to several tens of seconds.

  In order to carry digital data by an acoustic signal, it is necessary to transmit / receive an acoustic signal having a pulse length proportional to the total number of bits of the digital data to be transmitted. As the number of bits increases, the transmission / reception time of acoustic pulses also increases, and the degree of influence by environmental noise and surrounding structures increases. As a result, data transmission errors increase and a transmission delay time due to retry processing occurs.

  In addition, since transmission of an acoustic signal requires transmission / reception of a signal having a pulse length proportional to the total number of bits of digital data to be transmitted, one data transmission process takes time. Therefore, it cannot cope with data transmission in a short cycle (<1 second) required for real-time data monitoring. An acoustic pulse signal having a length proportional to the number of bits to be transmitted consumes power proportional to the data capacity to be transmitted. That is, there is a problem that the battery is consumed quickly.

  In order to solve the above-described problems, the present invention does not employ a method of transmitting digital data itself used by an existing acoustic modem on a carrier wave, but transmits a digital value to be transmitted as two acoustic pulse signals. It is an object of the present invention to provide an underwater acoustic observation apparatus that transmits an acoustic digital signal from an underwater station. In the shipboard station, the time difference between the two received acoustic digital signals is correlated and precisely measured, and the time difference between the two digital signals is inversely converted into a digital value so that the direction in water can be quickly determined. An object of the present invention is to provide an underwater acoustic observation apparatus for obtaining accurately.

(First invention)
The underwater acoustic observation apparatus according to the first aspect of the invention can observe the state of the underwater station and transmit it to the shipboard station as a one-way acoustic signal, and has a certain time difference determined by the state of the underwater station. An underwater station that transmits two acoustic digital signals to the shipboard station, and two received digital acoustic signals transmitted from the underwater station, and a reception signal restoration that restores a state based on a time difference between the acoustic digital signals And an onboard station having a circuit.

(Second invention)
The underwater acoustic observation apparatus according to the second aspect of the invention can collect azimuth data of the underwater station by transmitting two acoustic signals from the underwater station to the shipboard station, and has a certain time difference determined by the direction. Receiving the two acoustic digital signals to the shipboard station and receiving the two digital acoustic signals transmitted from the underwater station and restoring the angle based on the time difference between the acoustic digital signals It is at least comprised from the shipboard station provided with the signal restoration circuit.

(Third invention)
The underwater acoustic observation apparatus according to a third aspect of the invention is characterized in that the interval between the two acoustic digital signals is divided into 0.00 to 359.99.

(Fourth invention)
In the underwater acoustic observation apparatus according to a fourth aspect of the present invention, the time interval between the two acoustic digital signals can represent any one of azimuth, temperature, position, and orientation.

(Fifth invention)
In the underwater acoustic observation apparatus according to the fifth aspect of the invention, the time interval representing the two-dimensional data is two sets of two acoustic digital signals.

(Sixth invention)
In the underwater acoustic observation apparatus according to the sixth aspect of the present invention, the time interval representing the three-dimensional data is a set of two acoustic digital signals.

  According to the present invention, since the underwater direction information can be expressed by only two acoustic digital signals, the time required for the handshake time (pre-processing time) between the underwater station and the shipboard station becomes unnecessary. The time until communication is possible and the communication time are shortened.

  According to the present invention, since it is not necessary to encode all bits constituting digital data and transmit them as an acoustic digital signal, the transmission time of the two acoustic digital signals is remarkably shortened, and the data transmission cycle is shortened. Can do.

  According to the present invention, since transmission / reception is not switched for one transducer, unlike an acoustic modem, no extra acoustic communication time occurs before and after data transmission. That is, since the present invention is a one-way communication from the underwater side to the upper side of the ship, not only handshaking processing is unnecessary, but also data transmission time can be shortened and data transmission accuracy can be achieved.

  When using a conventional acoustic modem, if the sensor data output cycle is fast, a large amount of data is accumulated in the transmission buffer, and these data are temporarily sent to the shipboard side, so that data can be observed at a fixed cycle. On the other hand, according to the present invention, since the communication processing time is short, buffering of transmission data is not required, so that it is possible to monitor data in real time on the shipboard station side. That is, according to the present invention, it is suitable for work for installing a structure that requires real-time work in water.

  According to the present invention, since correlation processing is performed using an acoustic digital signal that uses an M-sequence or Bent-sequence pseudo-random sequence code, an error in transmission data can occur even in an environment affected by noise or multipath. Can be kept low.

  According to the present invention, data of a plurality of azimuth sensor units can be sequentially transmitted to the shipboard station side by properly using types of pseudo-random number sequence codes such as an M sequence and a Bent sequence. Also, multi-channel simultaneous data transmission is possible by giving different modulation codes to transmission data of a plurality of transmission channels.

  According to the present invention, in principle, the resolution (accuracy) of data transmission can be easily improved by lengthening the delay time for transmitting two acoustic digital signals. Since the data transmission cycle and the data resolution are contradictory, flexible operation settings corresponding to the required conditions can be easily realized without changing the hardware.

  According to the present invention, by transmitting two short digital audio signals, it is possible to transmit with a reduced data capacity to be transmitted, so that not only the power (battery) on the underwater station side is reduced, but also after the work is finished, It is possible to replace the battery with other underwater stations.

  According to the present invention, a plurality of sets of two acoustic digital signals can be transmitted to transmit a plurality of sets of two-dimensional or three-dimensional data. Can be transmitted.

FIG. 1 is an embodiment of the present invention and is a schematic diagram for explaining an example when an acoustic digital signal from an underwater structure is received by a shipboard station. FIG. 2 is a schematic diagram for explaining an example in which an acoustic digital signal is transmitted from an underwater station and received by a shipboard station according to an embodiment of the present invention. FIG. 3 is a diagram for explaining a conventional example, and is a diagram for knowing the orientation of a structure using an acoustic digital signal. FIG. 4 is a diagram for explaining a conventional example, and is a diagram for explaining a method for sinking a tetrapot into an accurate position in water using an acoustic digital signal. FIGS. 5A to 5D are diagrams for explaining the results of testing the underwater acoustic observation apparatus of the present invention in a water tank. FIG. 6 is a diagram for explaining a water tank test method when testing the underwater acoustic observation apparatus of the present invention in a water tank. FIG. 7 is a diagram for explaining the correlation of the results (part 1) of the water tank test of the underwater acoustic observation apparatus of the present invention. FIG. 8 is a diagram for explaining the correlation of the results (part 2) of the water tank test of the underwater acoustic observation apparatus of the present invention. 9 (a) to 9 (d) are diagrams for explaining actual water tank test photographs using the underwater acoustic observation apparatus of the present invention. FIG. 10 is a diagram for explaining an example in which the acoustic digital signal of the present invention is transmitted as a plurality of channels. 11A and 11B are diagrams for explaining an example in which the acoustic digital signal of the present invention is transmitted as a plurality of channels. FIG. 12 (a) is a diagram for explaining three-dimensional information by the method of the present invention. FIG. 2B is a diagram for explaining an example in which the three-dimensional information is expressed as two sets of information.

(First invention)
The underwater acoustic observation apparatus according to the first aspect of the invention replaces the state of the underwater station with a time difference between two digital acoustic signals and transmits the underwater station to the shipboard station. The underwater station transmits, for example, two acoustic digital signals having a certain time difference determined by the state of an underwater structure to the shipboard station in one way. The shipboard station receives the time difference between the two digital acoustic signals transmitted from the underwater station at the shipboard station.

  The reception signal restoration circuit in the shipboard station measures a time difference between the two digital acoustic signals and restores a state based on the time difference between the acoustic digital signals. Since the structure allows one-way communication from the underwater station to the shipboard station, it is possible to quickly and accurately grasp the underwater condition in the underwater station. It became possible to do exactly.

(Second invention)
The underwater acoustic observation apparatus according to the second aspect of the present invention transmits the orientation data of the structure to the shipboard station as a time difference between two digital acoustic signals using an orientation sensor attached to the underwater station. In the shipboard station, the direction data can be easily and quickly known by one-way communication. For example, the direction sensor attached to the structure is thrown into the water together with the structure by a crane or the like. The underwater station made of the structure unilaterally transmits two acoustic digital signals having a certain time difference determined by the angle of an attached direction sensor to the shipboard station.

  The shipboard station receives the two digital acoustic signals transmitted from the underwater station as a time difference. The reception signal restoration circuit in the shipboard station measures the time difference between the two digital acoustic signals and restores the angle based on the time difference between the acoustic digital signals. Underwater structures can be accurately assembled and placed because the exact angle is quickly known at the position lowered by the crane.

(Third invention)
The underwater acoustic observation apparatus of the third invention divides the interval between two acoustic digital signals into 0.00 to 359.99. That is, the acoustic digital signal is pulsed every 1.00 degrees such as 0.00, 1.00, 2.00, 3.00,... 357.00, 358.00, 3599.99. Therefore, the exact angle can be determined by measuring the time between the pulses.

(Fourth invention)
The underwater acoustic observation apparatus of the fourth aspect of the invention can know the state of the underwater station by associating the time interval of the acoustic digital signal with the azimuth, temperature, position, or orientation. Since the azimuth or temperature is one-dimensional, it is expressed by an interval between two acoustic digital signals. In the case of the position, it is two-dimensional information, but it is possible by providing the received signal restoration circuit with a time interval and a two-dimensional comparison table instead of the continuous acoustic digital signal of the first invention or the second invention. . Similarly, the posture is three-dimensional, but can be realized by providing the received signal restoration circuit with a time interval and a three-dimensional comparison table.

  In the present invention, since various states can be expressed by two acoustic digital signals, a handshake time is not required between the shipboard station and the underwater station, and data in various states can be processed in real time as well as communication. The device can be simplified. In particular, the installation of structures in the water (for example, the sea, harbors, near breakwaters, rivers, lakes, etc.) can be performed accurately in a short time.

(Fifth invention)
The fifth invention comprises, for example, two-dimensional data such as position information, and can be expressed by time intervals based on two sets of two-dimensional information, unlike one-dimensional orientation and temperature. Since the position is two-dimensional information represented by coordinate axes, for example, by setting two sets of data of X coordinate and Y coordinate (two sets of two acoustic digital signals), one point on the coordinate axes is obtained. Can be expressed.

(Sixth invention)
The sixth invention comprises, for example, three-dimensional data such as a posture, and is possible by using a solid coordinate composed of an X coordinate, a Y coordinate, and a Z coordinate. Three-dimensional data can be expressed by three sets of data composed of two acoustic digital signals representing the X coordinate, Y coordinate, and Z coordinate. In the fifth and sixth inventions, the amount of data is slightly increased compared to the first to fourth inventions. However, since the communication is one-way and each communication processing time is short, buffering of transmission data is unnecessary. It becomes possible to exchange data in real time.

  FIG. 1 is an embodiment of the present invention, and is a schematic diagram for explaining an example when an onboard station receives an acoustic signal from an underwater structure. In FIG. 1, the underwater acoustic observation apparatus of the present invention attaches an underwater station 11 (described later) to a structure (object) 14 to be put in the water, for example, when revetment work is performed, and is transmitted from the underwater station 11. The shipboard station 12 receives the signal. The shipboard station 12 can determine the direction of the structure (object) 14 accurately and quickly (in real time) by analyzing the received signal.

  The underwater station 11 transmits two acoustic digital signals 16 at predetermined intervals. The shipboard station 12 receives the two acoustic digital signals 16 transmitted from the underwater station 11, and analyzes the current direction of the structure based on the interval between the two acoustic digital signals. Can be performed accurately and quickly.

  The underwater station 11 includes, for example, a power supply unit 111, an orientation sensor unit 112 that detects an orientation, an acoustic transmission unit 113 that transmits an acoustic digital signal, and a transmitter 114 that transmits the acoustic digital signal to the shipboard station 12. And is detachably mounted on the structure 14. For example, the structure 14 is placed on the seabed 15 and the shipboard station 12 is informed by the acoustic digital signal transmitted from the acoustic transmitter 113 whether the position (orientation) is in a desired state. . The azimuth sensor unit 112 checks whether or not the azimuth sensor unit 112 is deviated from the reference position.

  The azimuth sensor unit 112 is provided with a reference line outside a storage container (not shown) attached to the underwater station 11. The reference line is used as a reference for the direction sensor unit 112. The reference line of the azimuth sensor unit 112 of the underwater station 11 defines a correlation with the shipboard station 12, and does not need to define a precise azimuth.

  The azimuth obtained by the azimuth sensor 112 is converted into two predetermined acoustic digital signals by the acoustic transmitter 113 and oscillated from the transmitter 14 into the sea. The shipboard station 12 includes, for example, at least a receiver 121, an acoustic reception unit and signal processing unit 122, and a personal computer (including a sensor value display unit) 123. The personal computer 123 processes the two acoustic digital signals received by the receiver 121 by the acoustic receiver and the signal processor 122 to know the correct orientation of the structure 14.

  FIG. 2 is a schematic diagram for explaining an example in which an acoustic digital signal is transmitted from an underwater station and received by a shipboard station according to an embodiment of the present invention. The underwater station 11 and the shipboard station 12 in FIG. 2 are the same as those in FIG. 1, but will be described in more detail. The underwater station 11 includes an azimuth sensor unit (for example, azimuth) 112, an A / D converter (hereinafter simply referred to as ADC) 21 that converts analog data of the azimuth sensor unit 112 into digital data, and a digital value generation unit 22. And a transmission signal generation circuit 23, an external I / F circuit 24, a transmission circuit 25, a transmitter 114, and a power supply unit 111.

  The digital value generation unit 22 converts the direction detected by the direction sensor unit 112 into a digital value. For example, an angle of 360 degrees is assigned to a number from 0.00 to 359.99. The digital value generator 22 generates a digital value of 123.45 when the orientation is 123.45 degrees. For example, when the azimuth is 45.450 degrees, a digital value of 45.450 is generated. The digital value has a resolution of two decimal places.

  When the value of the azimuth sensor unit 112 is, for example, 123.45 degrees, the digital data converted by the ADC is generated by the transmission signal generation circuit 23 as two acoustic digital signals 16 having a predetermined interval. . The transmission signal generation circuit 23 can be set by an external I / F circuit 24. For example, the digital value of 123.45 generates two acoustic digital signals having a time difference of 123.45 sec. The two acoustic digital signals 16 are transmitted underwater through the transmission circuit 25 and the transmitter 114.

  The shipboard station 12 includes a receiver 121, a reception circuit 26, a reception signal restoration circuit 122, a correlation signal unit 1222, and an external IF circuit 27. The receiving circuit 26 includes, for example, a band pass filter (BPF), an automatic gain control circuit (AGC), and an A / D converter (hereinafter simply referred to as ADC). The receiving circuit 26 removes noise and generates two acoustic digital signals 16 having a predetermined bandwidth and gain.

  The reception signal restoration circuit 122 reproduces an acoustic digital signal having two intervals based on the direction generated by the underwater station 11. The correlation processing unit 1222 is associated with the interval of 123.45 μsec in the above example being azimuth 123.45 degrees. The external I / F circuit 27 performs the internal setting of the onboard station 12 and outputs the number of directions on the screen.

  Position information composed of two-dimensional data can be expressed by time intervals based on two sets of two-dimensional information. Since the position information is one point in the X coordinate and the Y coordinate, the X coordinate can be represented by two acoustic digital signals and the Y coordinate can be represented by two acoustic digital signals. For example, assuming that the coordinate positions of the coordinate axes x and y are x (0,20) and y (30,0), they can be expressed as follows. That is, two sets of acoustic digital signals can be expressed by two sets of acoustic digital signals (0, 20) and (0, 30). The two sets of acoustic digital signals can represent accurate positions by setting the first two acoustic digital signals as the X axis and the next acoustic digital signal as the Y axis.

  Similarly, for example, even if it is composed of three-dimensional data such as a posture, a solid coordinate composed of an X coordinate, a Y coordinate, and a Z coordinate can be handled in the same manner as the two-dimensional information. The two-dimensional data or the three-dimensional data can be expressed by two or three sets of data composed of two acoustic digital signals representing the X coordinate, the Y coordinate, and the Z coordinate, as well as the orientation or temperature. The two-dimensional data or the three-dimensional data has a slightly larger amount of data, but since no handshake time is required, information can be sent in real time.

  As the power source of the underwater station 11, a battery pack (power supply unit 111) having a necessary and sufficient capacity for the continuous operation time of the underwater station 11 is used. The underwater station 11 has a structure in which the power supply unit 111 can be attached to and detached from the structure 14. For example, in the structure 14, the underwater station 11 (with built-in azimuth sensor) is first attached to a reference plane. Next, the structure 14 is lowered into the water using a crane of a work ship (not shown).

  The receiver 121 of the shipboard station 12 is hung in the water from the side of a work ship (not shown) (it is hung to a depth deeper than the bottom of the work ship). Receive and monitor the current orientation of the structure 14. The underwater station 11 is removed from the underwater station 11 by a diver after the structure 14 is installed on the seabed in a desired direction, and is collected on the work boat.

  The acoustic digital signal transmitted from the underwater station 11 is modulated by a pseudo-random code such as an M series. On the other hand, the acoustic digital signal received by the shipboard station 12 includes, in addition to noise generated from a work ship, etc. when transmitted from the underwater station 11, and multiple reflection signals (multipath) due to the seabed or quay. ing. Correlation processing is required to accurately detect rising edges of the two acoustic digital signals transmitted by the underwater station 11 from the received signals subjected to the noise and distortion, and to calculate the time interval between them.

  In the correlation processing, it is necessary to obtain a correlation function on the time axis by using the same modulated signals as the two acoustic digital signals transmitted by the underwater station 11 for the two acoustic digital signals received by the shipboard station 12. Two peaks should appear in the correlation function, and the time interval between the two peaks is the value of the direction sensor unit 112 of the underwater station 11.

  The M-sequence code is a pseudo-random signal generated based on an artificial rule. These signals have the property that the autocorrelation value shows a sharp peak and at the same time the correlation value with other than itself is extremely low. Therefore, the signal has an advantage that the propagation time can be correctly determined by the correlation processing even when the received signal is unclear due to ambient noise or the like.

Hereinafter, processing in the reception signal restoration circuit 122 will be described.
(1) Fast Fourier transform a waveform (correlation reference) modulated with a specific M-sequence code transmitted by the underwater station 11. (Only the first time) As a result, real power and imaginary power are obtained for each frequency component.
(2) A / D-convert the acoustic digital signal received by the shipboard station 12. (Convert to digital data)
(3) Perform fast Fourier transform (FFT) on the received signal. It is assumed that real and imaginary powers are obtained for each frequency component.
(4) The complex number B (X + jY) and complex conjugate (X−jY) obtained in (3) above are obtained, and A is multiplied by the complex conjugate. The result is C.
(5) When inverse Fourier transform (IFFT) is performed on C represented on the frequency axis, a correlation function on the time axis is obtained.

  FIGS. 5A to 5D are diagrams for explaining the results of testing the underwater acoustic observation apparatus of the present invention in a water tank. FIG. 6 is a diagram for explaining a water tank test method when testing the underwater acoustic observation apparatus of the present invention in a water tank. In FIG. 6, a test water tank 66 filled with fresh water 67 is provided with a transmitting hydrophone 68, a receiving hydrophone 69, and a noise generating hydrophone 70.

  The aquarium test apparatus includes a processing apparatus 61 that generates an acoustic code database and received waveform data, a processing apparatus 62 that performs processing for performing the aquarium test, a transmission apparatus 63, a reception apparatus 64, and It is comprised from the noise generator 65. The water tank test apparatus generates the first pulse and the second pulse shown in FIG. 5 (a), and the generated noise and the pulse that is the two acoustic digital signals are received as shown in FIG. 5 (b). ing. The first pulse and the second pulse are transmitted and received as shown in FIGS. As shown in FIG. 5D, the first pulse and the second pulse are delayed by ΔT seconds at the time of transmission and reception.

  The first pulse M1 and the second pulse M2 shown in FIG. 5 are transmitted from the transmission device 63 in FIG. 6 to the transmission hydrophone 68 shown in FIG. 6 with a free time of 500,000 μsec. The noise generated from the noise generator 65 shown in FIG. 6 is received by the receiving device 64 through the receiving hydrophone 69 together with the first pulse M1 and the second pulse M2 as in the actual case. . The first pulse M1 and the second pulse M2 received by the receiving device 64 are received at the shipboard station in the state shown in FIG.

  The processing device 62 shown in FIG. 6 performs correlation processing of the first pulse M1 and the second pulse M2, and measures the idle time between pulses. The processor 62 measures an error ΔT with respect to the free time given in FIG.

  FIG. 7 is a diagram for explaining the correlation of the results (part 1) of the water tank test of the underwater acoustic observation apparatus of the present invention. FIG. 7A shows a received waveform received by the processing device 62. FIG. 7 (b) shows the idle time of the first pulse M1 and the second pulse M2, and indicates that, for example, the error ΔT = + 3 μsec.

  FIG. 8 is a diagram for explaining the correlation of the results (part 2) of the water tank test of the underwater acoustic observation apparatus of the present invention. As in FIG. 7, the error ΔT = + 13 μsec. The processing device 62 can determine the time between actual acoustic digital signals in consideration of the error ΔT, and know the correct orientation.

  9 (a) to 9 (d) are diagrams for explaining actual water tank test photographs using the underwater acoustic observation apparatus of the present invention. 9A, the test water tank 911 has a length of 2650 mm, a width of 1750 mm, and a depth of 620 mm, for example. The test water tank 911 is provided with an output unit 912, a noise output unit 913, and a transmission signal and noise reception unit 914 of the transmission device. FIG. 9C is a diagram showing the received waveform and the correlation. FIG. 9D shows a noise generator 917 and a processing device 918 used in the experiment.

  FIG. 10 is a diagram for explaining an example in which the acoustic digital signal of the present invention is transmitted as a plurality of channels. The transmission signal from the underwater station in FIG. 10 is obtained by switching the transmission code in order and transmitting two acoustic digital signals, so that the values of a plurality of different sensors, for example, four channels M1 to M4 are sequentially transmitted to the shipboard station. An example that can be transmitted is shown. For example, M1 can represent orientation, M2 can represent pitch, M3 can represent roll, and M4 can represent temperature.

  11A and 11B are diagrams for explaining an example in which the acoustic digital signal of the present invention is transmitted as a plurality of channels. FIGS. 11A and 11B show a case where a plurality of underwater stations are installed in the structure. The plurality of underwater stations can secure more transmission channels by assigning different transmission code systems.

  FIG. 12 (a) is a diagram for explaining three-dimensional information by the method of the present invention. FIG. 2B is a diagram for explaining an example in which the three-dimensional information is expressed as two sets of information. FIG. 12 (a) is a diagram for explaining a case where the azimuth, roll, and pitch are measured as three-dimensional information. FIG. 12B shows an example in which the orientation No. 1 roll, pitch No. 2 and roll No. 3 are used. As described above, according to the present invention, information such as the interval between two acoustic digital signals can be easily transmitted in one-way without a shake hand.

  As mentioned above, although the Example of this invention was explained in full detail, this invention is not limited to the said Example. The present invention can be modified in various ways without departing from the scope of the claims. The shipboard station and underwater station, transmission / reception apparatus, data processing apparatus, etc. of the present invention are constituted by known communication engineering and acoustic engineering techniques, and can be modified without departing from the scope of the claims. is there.

10 ... Underwater 11 ... Underwater station 111 ... Power supply unit 112 ... Direction sensor unit 113 ... Acoustic transmission unit 114 ... Transmitter 12 ... Boat station 121 ... Receiver 122... Acoustic signal restoration circuit 1221 .. Two acoustic signals 1222 .. Correlation processing unit 123... Host personal computer 13... Underwater 14. .... Acoustic digital signal 21 ... ADC
22 ··· Digital value generating unit 23 ··· Transmission signal generating circuit 24 ··· External I / F circuit 25 ··· Transmitting circuit 26 ··· Reception circuit 27 ··· External I / F F circuit

(First invention)
The underwater acoustic observation apparatus according to the first aspect of the present invention can observe an azimuth using an azimuth sensor provided in the structure and transmit the unidirectional acoustic signal to the shipboard station . The state of the structure is measured by the azimuth sensor . An underwater station composed of the structure that is transmitted to the shipboard station in place of two acoustic digital signals having a certain fixed time difference, and the two digital acoustic signals having a certain time difference transmitted from the underwater station And a shipboard station provided with a received signal restoration circuit that restores the position of the structure in the water based on the time difference of the acoustic digital signal.

(Second invention)
The underwater acoustic observation apparatus according to the second aspect of the present invention can observe the direction by the direction sensor provided in the structure and transmit it to the shipboard station as a one-way acoustic signal . The state of the structure is determined by the direction sensor . An underwater station composed of the structure that is transmitted to the shipboard station in place of two acoustic digital signals having a certain fixed time difference, and the two digital acoustic signals having a certain time difference transmitted from the underwater station And a shipboard station provided with a received signal restoration circuit that restores the angle state of the structure in the water based on the time difference of the acoustic digital signal.

(Fourth invention)
In the underwater acoustic observation apparatus according to a fourth aspect of the present invention, the time interval between the two acoustic digital signals can represent any one of azimuth, temperature, position, or orientation by having a two-dimensional comparison table. .

Claims (6)

In the underwater acoustic observation device that can observe the state of the underwater station and transmit it as a one-way acoustic signal to the shipboard station,
An underwater station that transmits two acoustic digital signals with a certain time difference determined by the state of the underwater station to the shipboard station;
A shipboard station provided with a reception signal restoration circuit that receives the two digital acoustic signals transmitted from the underwater station and restores a state based on a time difference between the acoustic digital signals;
An underwater acoustic observation apparatus characterized by comprising at least. In the underwater acoustic observation apparatus capable of collecting the azimuth data of the underwater station by transmitting two acoustic signals from the underwater station to the shipboard station,
An underwater station that transmits two acoustic digital signals having a certain time difference determined by the direction to the shipboard station;
An onboard station provided with a reception signal restoration circuit that receives the two digital acoustic signals transmitted from the underwater station and restores an angle based on a time difference between the acoustic digital signals;
An underwater acoustic observation apparatus characterized by comprising at least.   The underwater acoustic observation apparatus according to claim 2, wherein an interval between the two acoustic digital signals is divided into 0.00 to 359.99.   The underwater acoustic observation according to any one of claims 1 to 3, wherein the time interval between the two acoustic digital signals can represent any of azimuth, temperature, position, and orientation. apparatus.   5. The underwater acoustic observation apparatus according to claim 1, wherein the time interval representing the two-dimensional data includes two sets of two acoustic digital signals.   The underwater acoustic observation apparatus according to any one of claims 1 to 5, wherein the time interval representing the three-dimensional data includes two sets of two acoustic digital signals.