JPS63269635A - Underwater communication system - Google Patents

Abstract

PURPOSE:To attain underwater transmission/reception simply and accurately by adopting communication under water through an ultrasonic wave transmission medium, receiving a coded signal corresponding to a message at a message destination station to apply signal processing and demodulating the signal as voice or significant character information according to the correspondence processing. CONSTITUTION:A data signal corresponding to a message is sent from a ship installation 3, a prescribed signal is added to the data signal by a controller 3b and the resulting signal is sent to a repeater 8 as a radio signal. The repeater receives a radio wave signal and sends it to a controller 6b via an underwater ultrasonic wave transducer 8b. Then the reception of the data is informed to a diver 6 through vibration delivery such as skin stimulation or bone conduction in the incoming function of the controller 6b. Then the data signal is received as voice by a voice synthesizer or significant character information by a character converter corresponding to the message by means of a speaker or a display device.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a communication system between a plurality of underwater diving sounds and between a diver and the surface of the water.

(Conventional technology and its problems) The principle of underwater communication using ultrasonic waves is well known;
In order to improve communication capabilities, improvements have been made to communication devices equipped with spherical radiators (Japanese Patent Application Laid-Open No. 50-92604), but all of these devices transmit and receive audio as is. However, when transmitting audio, it is considerably more difficult and physically demanding for divers to emit audio than on land, due to limited oxygen supply and high water pressure.

Furthermore, the environment is such that it is difficult for audio to be transmitted correctly, such as breathing noise and noise from the air coming out of the scuba unit's air demand valve, which has a larger amplitude than the audio signal, and there is also multipath noise during reception. There is a strong possibility that this will occur. To briefly explain multipath noise here, for example, when communicating underwater as shown in Fig. 5, in addition to the direct transmission path S1 from the sending side to the receiving side, there is a A transmission path S to S4 is generated due to reflection. Multipath noise is the occurrence of a plurality of transmission paths (multipaths) as described above, which causes propagation interference and makes communication difficult.

As described above, due to the various reasons mentioned above, the level of communication between humans has become quite low, and there has been a problem in that there are limitations as a means of accurate information transmission.

(Objective of the Invention) Therefore, an object of the present invention is to provide an underwater communication system that can easily and accurately transmit and receive communications between multiple stations including underwater divers.

(Means for Achieving the Object) In order to achieve the above object, the underwater communication system according to the present invention provides communication between multiple stations including underwater divers.
Underwater, using an ultrasonic transmission path, a message destination station receives a coded signal with message correspondence attached in advance and transmitted from a communication device of one of the stations, performs signal processing, and makes the correspondence. Communication is performed by demodulating voice or meaningful text information according to the above.

(Embodiment) FIG. 1 is a schematic configuration diagram showing an overall image of an embodiment of an underwater communication system according to the present invention. In the figure, the service area 1.2 of the system is shown. Each of the service areas 1 and 2 corresponds to the air and the water, respectively.

Service area 1 secures a transmission path using radio waves, and service area 2 secures a transmission path using ultrasonic waves.

Service areas 1 and 2 have stations (equipment or divers)
3 to 7 is assumed. Station 3 in service area 1
The devices 3a to 5a are, for example, an input device such as a keyboard, a printer, and a display.

This may be an output device such as a speaker, a memory device, or the like, and may also be a measuring device or the like if necessary.

Equipment 6a, 7 for divers 6, 7 in service area 2
a is an input device such as a keyboard, an output device such as a display, a speaker, or a measurement device. The number and arrangement of devices shown in FIG. 1 are merely examples, and they may be provided in appropriate numbers and arranged as appropriate depending on actual needs.

Controllers 6b, 7 for divers 6, 7. When the caller b receives a signal from the other party, it has a call receiving function such as applying stimulation to the skin or bone conduction in order to clearly notify the person in question.

Controllers 3b to 7b are connected to the devices 3a to 7a, respectively, by connection cables (not shown). Data transmission between each station is carried out wirelessly (the transmission path is radio waves in the air, and ultrasonic waves in water). Each controller 3b
7b have a data communication exchange function, and establishment of a wireless transmission path between arbitrary stations is performed by the functions of controllers 3b to 7b. The repeater 8 has a radio wave antenna 8a for the service area 1, and a transducer 8b for transmitting and receiving ultrasonic waves for the service area 2.

According to experiments, it is known that multipath noise occurs near a certain depth, and the transducer 8b is installed at a depth where multipath noise is unlikely to occur, avoiding the vicinity of that depth. The repeater 8 works as a radio wave transmitter/receiver and an ultrasonic wave transmitter/receiver. These transceivers have data processing functions such as a data error self-correction function.

Now, consider the case where a signal is transmitted from the ship equipment 3 to the equipment 6a of the diver 6. A data signal with message correspondence is sent from the ship equipment 3. For example, when the data signal is a 2-byte signal, the following message correspondences can be considered as the data signal to which message correspondence is attached.

01..."Ascend"02..."Descent"03..."Staystill"04..."Is there enough air?"05..."Is there anything abnormal?" As mentioned above A signal corresponding to a message addressed to a diver is a data signal to which message correspondence is attached.

This data signal is added with predetermined signals such as a synchronization signal, an address signal, and a check bit for error checking in the controller 3b, and is sent to the repeater 8 as a wireless signal. Note that in service area 1, messages can also be transmitted using voice signals.

The repeater 8 receives the radio wave signal and self-corrects data errors occurring on the transmission path by checking check bits. The error-corrected data signal is sent to the controller 6b via the underwater ultrasonic transducer 8b. The controller 6b receives the wireless signal and again self-corrects data errors occurring in the wireless ultrasound transmission path.

Further, the diver 6 is informed that data has been received by vibration transmission by skin stimulation bone conduction in the call receiving function of the controller 6b. Then, the error-corrected data signal is output as voice by a voice synthesizer or as meaningful character information by a character converter to each speaker in accordance with the above-mentioned message correspondence.

Receive on display etc. The display may be attached to the elbow or wrist, or may be displayed by specially processing the glass surface of underwater goggles.

Also, voice signals may be used as the transmission means for stations 3 to 5, but in this case, the voice signals are sent as they are without the above-mentioned message-compatible encoding, and furthermore, the voice signals themselves are free from data errors. Since it is transmitted without any correction, considering the noise of radio waves in the air, the noise of waves hitting the coastline, etc., it seems more accurate to transmit the encoded data signal.

Data transmission other than that described above, such as between the diver 6 and the diver 7, is also performed by the same operation as described above.

Radio line control such as call control is performed by the functions of controllers 3b to 7b. As a means of transmission, as a substitute for the hand signal transmission means normally used by fellow divers,
For example, a removable keyboard attached to the arm, elbow, etc., that can send messages such as ``Rise up'' and ``Descent'' with a single key operation as a ``-'' data signal is conceivable. When sending messages using the keyboard, there is no need for fellow divers to constantly monitor each other compared to sending messages using hand signals, and even when they cannot see each other, messages can be easily sent by pressing a single key on the keyboard. .

Furthermore, by combining messages that have traveled faster, even more complex messages can be transmitted.

Relay and reception can be carried out in the same manner as the communication from the ship equipment 3 to the diver 6 described above, but the following information can be considered on the display to be given to the diver at the time of reception. For example, the water depth of each diver (measured with a water pressure gauge, etc.)
By displaying information such as the relative positional relationship between divers (calculated by integrating twice the value measured by an acceleration sensor, etc.), it is also possible to constantly check the positional information of each diver. .

Furthermore, the memory devices of the devices 3a to 5a of the stations 3 to 5 can also store the contents of communication between each station. In this case, a coded data signal requires less storage capacity.

In the system according to an embodiment of the present invention, data transmission is carried out via a radio wave and ultrasonic wireless transmission path, but due to the noise of radio waves in the air, the sound of underwater work, and the noise of waves crashing on the coastline, etc. , 2 is a communication channel with a considerable error rate. The error characteristics of a wireless line are considered to be a mixture of burst (continuous) errors and random errors. Therefore, in one embodiment of the present invention, an error self-correcting code system is adopted for random errors, and a bit interleave system is adopted for burst groups, thereby improving the data error rate.

Due to the use of the repeater 8, the wireless transmission section always has two spans during operation of this system, and data transmission errors are doubled on average for a unit section. Therefore, in the present invention, the repeater 8 is provided with a data error self-correction function. Furthermore, by installing the ultrasonic transducer at a depth where multipath noise is less likely to occur, multipath noise propagation disturbances are kept to a minimum. Therefore, regardless of the use of the repeater 8, it is possible to obtain line reliability equivalent to direct communication between stations (1 span of radio section).

In addition, by performing communication using a coded data signal as described above, a message can be sent by simply pressing a voice-comparison button, and there is no interference from noises such as breathing. Furthermore, information can be accurately transmitted by performing error correction during relay and reception. Furthermore, by increasing the efficiency of encoding, it becomes possible to convey a considerable amount of information. As a matter of course,
It is easy to add audio as a means of transmission for the diver. Although it cannot be used on a practical level, it may be possible to use it for extremely simple signals.

FIG. 2 is a schematic block diagram showing an example of the controllers 3b to 7b shown in FIG. 1. The power necessary for the operation of the controller shown in FIG. 1 is supplied from a power supply section (not shown).

The devices 3a to 7a are connected to the interface section 9 through connection cables (not shown). The electrical conditions of the interface section 9 are preferably R3- shown in JIs.
Designed based on 2320.

Data provided through the interface section 9 is input to the error self-correction section 10 under the control of the communication control section 13. In the error self-correction section 10, predetermined check bits are added to the input data. The data to which the check bit has been added is processed by the memory write/read control unit 12.
, and are written into the memory section 11 and interleaved. The memory unit 11 also has a data buffer function.

The data in the memory section 11 is addressed by the memory write/read control section 12, read out to the communication control section 13, and given to the data modulation/demodulation section 14 with a predetermined synchronization header and index added thereto. The index includes a transmitting station address, a receiving station address, and other information necessary for communication control.

The binary value signal given to the data modulation/demodulation section 14 is preferably first-order modulated using the MSK modulation method. MSK
The modulation method refers to the FSK (continuous phase) modulation method in which the modulation index is 0.5.

FSK modulators are increasingly being integrated into ICs, and have the advantage of being able to implement modulation and demodulation at low cost.

The MSK modulated signal is given to the modulator input point X of the radio unit 15 in the equipments 3b to 5b. In the radio unit 15, secondary modulation is performed using an FM modulation method. FM is mainly used as secondary modulation in S/
This is because in order to improve N, and because the distance between in-phase q is indefinite, it is necessary to provide an AGC section with a wide dynamic range in other modulation methods. The FM modulated signal is radiated to the service area 1 (in the air) via the antenna 16.

In addition, in the divers 6b and 7b, there is an ultrasonic modulation/demodulation section as a part corresponding to the radio unit 15, and an ultrasonic transducer (indicated by a dotted line in the figure) as a part corresponding to the antenna 16. The transmitted signal is sent to service area 2 (underwater) via an ultrasonic transducer.
is radiated to.

The communication control unit 13 provides a press signal (usually a DC signal) to the radio unit (ultrasonic modulation/demodulation unit) 15 to control transmission. By turning on and off this DC signal, the power of the transmitting circuit in the radio section (ultrasonic modulation/demodulation section) 15 is turned on and off. The received signal received from the antenna (ultrasonic transducer) 16 is transmitted to the radio unit (ultrasonic modulation/demodulation unit) 1
5, the received demodulated signal is FM demodulated and provided to the data modulation/demodulation section 14 from the received demodulated signal output point Rx. Carrier detection section 1
7 generates a DC signal when a signal is received by the radio section (ultrasonic modulation/demodulation section) 15.

The communication control unit 13 performs call control based on this DC signal. For example, if the station that sent the message detects the carrier before its own transmission carrier starts up, or if the carrier is not detected at the appropriate time after the own station's own carrier starts up, then it repeats the transmission sequence again.

Furthermore, if the response frame does not appear even after the reception limit time has passed, the communication control unit 13 retransmits the message.

The received signal demodulated by the data modulation/demodulation section 14 is provided to the communication control section 13, where bit synchronization and frame synchronization are achieved. Data is memory write/read control unit 1
2 and written into the memory section 11. At this time, burst errors occurring in the interleaved data are converted to random errors. Memory section 11
The data therein is timing-controlled by the communication control section 13, addressed by the memory write/read control section 12, and read out to the error self-correction section 10.

In the error self-correction unit 10, errors occurring in input data are self-corrected by a predetermined calculation. The error-corrected data is provided to the computer or peripheral device through the interface section 9.

In addition, the diver is provided with a call receiving device 18 (indicated by a dotted line in the figure), which has the function of physically notifying the diver of a confirmation signal upon receipt of the signal through the interface section 9. ing.

FIG. 3 is a schematic block diagram showing an example of the repeater 8 shown in FIG. 1. The radio connection section 19 has impedance matching and level matching functions. The power necessary for the operation of the repeater 8 is supplied from a power supply unit (not shown). The received signal from the radio unit 20a (stations 3 to 5) or the ultrasonic radio unit 20b (stations 6, 7) is sent to the radio connection unit 1.
9 to the data demodulation section 21. Further, a carrier detection signal indicating signal reception is separated at the radio device connection section 19 and given to the transmission/reception control section 22 .

Accordingly, the transmission/reception control unit 22 controls timing necessary for data processing.

The input signal subjected to MSK demodulation in the data demodulation section 21 is written into the memory section 24 via the synchronization detection/data writing section 23 under timing control of the transmission/reception control section 22 . This writing is performed after bit synchronization and frame synchronization are established in the synchronization detection/data writing section 23, and an address is specified by the data writing control section 25. By writing to the memory unit 24, burst errors occurring in interleaved data are converted into random errors. The memory section 24 also acts as a data buffer.

The data in the memory section 24 is addressed and read out by the data read control section 26. The data read control section 26 is given a write address from the data write control section 25, and specifies a read address based on it. The timing of the operation is controlled by the transmission/reception control section 22. When the data read control section 26 starts operating, a press signal is given to the radio connection section 19 via the press signal section 27. This press signal activates the transmitting section of the radio section 20a or the ultrasonic radio section 20b depending on the case.

The data read from the memory section 24 is provided to a data read/error correction/synchronization signal generation section 28 activated by timing information from the data read control section 26. There, data errors are self-corrected by predetermined calculations, and a synchronization signal is newly generated and added.

The input data processed in this manner is subjected to MSK modulation again in the data modulation section 29 and is provided to the radio device connection section 19 and the radio device section 20a, or the ultrasonic radio device section 20b. The transmitter of either the radio unit 20a or the ultrasonic radio unit 20b is activated by a press signal, and the signal is FM-modulated again and transmitted from the antenna 30a to space or the ultrasonic transducer 2.
It is radiated into the water from 0b.

FIG. 4 shows a schematic block diagram showing an example of a case where a CPU is used in the repeater 8. In the figure, the radio unit 31a corresponds to the radio unit 20a in FIG. 3, the radio unit 31b corresponds to the ultrasonic radio unit 20b in FIG.
2 corresponds to the radio device connection section 19 in FIG. modem 33
are the data demodulating section 21 and the data modulating section 29 in FIG.
corresponds to An MSK modem is used as the modem 33,
Delay detection is performed during demodulation, and a synchronization signal of received data is regenerated by a PLL circuit.

When the signal is received by the radio unit 31a, a carrier detection signal is output, separated by the radio connection unit 32, and provided to the interrupt control circuit 35 via the I10 port 34. The synchronization signal clock reproduced by the modem 33 is given to the interrupt control circuit 35 via the I10 port 34. The interrupt control circuit 35 receives these carrier detection signals and synchronization signal clocks and provides timing instructions for the operation of the CPU 36. Interrupt generation is performed based on the carrier detect signal and the actual timing of the data is provided based on the synchronization signal clock.

The received data MSK demodulated in the modem 33 is taken into the CPtJ 36 from the terminal RX via the I10 port 34. The CPU 36 has a ROM 37 and a RAM 38.
is used to perform data processing such as error correction on the given received data as described above with respect to the repeater shown in FIG. The processed data is again given to the modem 33 via the I10 port 34, where it is MSK-modulated again and given from the TX terminal via the radio connection section 32 to the radio section 31a or the radio section 31b.

When the processed data is sent out again, a press signal is given from the CPU 36 to the radio unit 31a or 31b via the I10 port 34 and the radio connection unit 32. As a result, the transmitting section within the radio section 31a or the radio section 31b is activated. F in the transmitter
The M-modulated signal is again radiated into space or water from the antenna 39a or the ultrasonic transducer 39b.

In this invention, since data is transmitted using a wireless transmission path, it is expected that establishing synchronization will be difficult. If synchronization is not achieved, the data received will be meaningless. Normal synchronization includes bit synchronization and room synchronization, and received data becomes meaningful only after bit synchronization is achieved and frame synchronization is established. The synchronization signal includes a bit sync BS for bit synchronization and a frame sync F'S for frame synchronization. In data transmission using a wireless system, there are many interferences from the external environment such as noise and interference, and with a short synchronization signal like in a wired system, there are extremely few opportunities to establish synchronization. Therefore, when using a conventional synchronization signal, it is generally necessary to send a long synchronization signal, although it depends on the transmission speed and operating conditions.

Furthermore, as for the frame sync pattern, it is necessary to select an appropriate one, as has been devised in various ways in the past.

(Effects of the Invention) As explained above, according to the present invention, communication between a plurality of stations including underwater divers can be performed accurately in the cylinder during transmission and reception.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the overall configuration of an embodiment of the present invention, FIG. 2 is a schematic block diagram showing an example of the controller shown in FIG. 1, and FIG. 3 is a schematic block diagram showing an example of the controller shown in FIG. Figure 4 is a schematic block diagram showing an example of a repeater in which a CPU is used. Figure 5 is a diagram showing the principle of multipath noise. be. 3-7... Station (equipment and diver), 3a-7a... Equipment, 3b-7b... Controller, 8... Repeater

Claims (4)

[Claims] (1) A communication system between multiple stations including underwater divers, in which communication is carried out underwater via an ultrasonic transmission path, and messages sent from the communication device of one of the stations are processed in advance. An underwater communication system characterized in that a message destination station receives a coded signal, processes the signal, and demodulates it as voice or meaningful character information in accordance with the correspondence, thereby performing communication. (2) The underwater communication system according to claim 1, further comprising a relay device that repeatedly relays the transmitted signal, and wherein the relay device has a data error self-correction function. (3) The relay device has an ultrasonic transducer for an ultrasonic transmission line under the water surface and an antenna for a wireless transmission line in the air, enabling communication between stations underwater and in the air. An underwater communication system according to claim 2. (4) The underwater communication system according to claim 3, wherein the ultrasonic transducer is installed at a depth below the water surface where no multipath noise occurs.