JPH1186175A - Data transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a data transmission system, which can easily transmit the measurement data through such conductive medium as seawater, lake water, or earth, etc., by transmitting induced electromagnetic waves of impulse waves having widths of a specific range into the medium, receiving the electromagnetic waves transmitted through the medium, and then transmitting the measurement data into the medium. SOLUTION: A measurement device 10 and a transmitter 20 are placed on the seabed ground 1. Even if the seabed is reclaimed by the earth 2, the measurement data on the ground 1 are transmitted onto the surface of the sea through a seawater 3 and the earth 2 and then received by a receiver 30 mounted on a measurement ship 4 working near the surface of the sea. A transmission means uses the electromagnetic waves of impulse waves, having a width of about 0.3 μs to 80 μs. The transmitted pulses propagate through a medium such as the seawater 3 or the earth 2, etc., and received by a receiving antenna 31 of the receiver 30. The receiver 30 extracts the measurement data from the received pulses. Thus, the measurement data can be transmitted without the use of a cable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for transmitting measurement data of the ground at the bottom of the sea or lake, or the ground under the ground.

[0002]

2. Description of the Related Art For example, when continuously measuring the state of the seabed at a water depth of about 30 m, a measuring instrument such as an earth pressure gauge or a water pressure gauge is arranged on the seabed to measure the state of the seabed such as earth pressure or subsidence of the ground. However, there is a method of transmitting the measurement data to the ground by a long cable drawn to the sea floor.

However, when burying the seabed while measuring the state of the ground on the seabed, the cable is often cut due to the embankment put into the seawater or the subsidence of the seabed ground due to the embankment.

As another transmission method, ultrasonic waves can be considered. However, it is impossible to transmit ultrasonic waves through embankments such as mountain sand that has been put into seawater.

As another method, the use of radio waves for communication is not possible due to attenuation of radio waves by seawater. Also, depending on the condition of the radio wave, even if the signal can be received, it interferes with other communication radio waves, and conversely cannot be used for interference.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a system for easily transmitting measurement data through electrically conductive seawater, lake water and soil media.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a data transmission system for transmitting measurement data in electrically conductive seawater, lake water, or soil media, wherein the impulse wave has a pulse width of about 0.3 .mu.s to about 80 .mu.s. A transmitter for transmitting the induced electromagnetic wave into the medium, a receiver for receiving the electromagnetic wave propagating in the medium, and a measuring device having a sensor, and transmitting the measurement data of the measuring device into the medium by the transmitter. Receiving at a receiver, and propagating through a medium, a data transmission system, or, in the data transmission system, installing an antenna of a transmitter at the bottom of a sea or a lake, and placing an antenna of the receiver near a water surface A data transmission system or a transmitter in the data transmission system, characterized in that measurement data is transmitted from the bottom of the sea or the lake and received near the water surface. Data transmission characterized in that the antenna is installed at the bottom of the sea or lake, buried in landfill embankment, the antenna of the receiver is placed near the water surface, the measurement data is transmitted from the bottom of the sea or the lake, and received near the water surface. In the system.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

<A> Outline of Data Transmission System The data transmission system of the present invention transfers data via a medium having a slight electrical conductivity such as seawater, lake water, or the ground. As described above, the measuring device 10 and the transmitter 20 are arranged on the seafloor ground 1 having a depth of 40 m, and even when the seafloor is buried with the landfill embankment, the measurement data of the seafloor ground is transmitted on the sea surface through the seawater 3 and the landfill embankment 2. , Is received by the receiver 30 mounted on the measurement work boat 4 near the sea surface.

<B> Transmission means The transmission means uses an impulse electromagnetic wave having at least one pulse (peak) having a pulse width of about 0.3 μs to about 80 μs. Number of pulses is 1
Not only the number but also a plurality may be provided. This low frequency electromagnetic wave can propagate in seawater, lake water and soil without much attenuation.

Also, since the dielectric constant of water is very high compared to 82 and 1 of air, the reception voltage of electromagnetic waves transmitted in seawater is about 10 times higher than in air, and the transmission voltage in seawater is Reception is easy. Also, the transmission frequency in water is lower than in air. In the sea, an ordinary radio wave of a high frequency attenuates at a shallow position in seawater and does not reach a receiving antenna used for transmission.

In addition, it is not usually possible to receive a guided impulse electromagnetic wave of a transmission means transmitted from the sea floor in a space above the sea surface. Also, even if this electromagnetic wave may leak to the external space on the water surface, the impulse electromagnetic wave is not a continuous wave and its properties to radiate far into the space are inferior. It's easy to do.

When transmitting measurement data using this electromagnetic wave, various methods of expressing the measurement data by pulses are known. For example, the measurement data is expressed by the number of pulses, or expressed by a pulse interval. You can also.

Since this electromagnetic wave is an impulse wave, its frequency is ambiguous and it is not strict to convert it to a frequency. However, an electromagnetic wave having a pulse width of about 0.3 μs to about 80 μs has a frequency of about 5 to 150 kHz. Is equivalent to

<C> Transmitter and Receiver The transmitter transmits electromagnetic waves having a pulse width of about 0.3 μs to about 80 μs in the sea. In order to adjust the transmission frequency and transmission voltage, the specifications of the transmitter were drastically changed, and to a small extent, the transmission linear antenna type was changed to a spiral side-fi helical antenna type. Adjust by changing the number of turns. When the transmitter receives measurement data from a measuring device provided with a sensor for measuring the state of the ground such as earth pressure, the transmitter receives the measurement data by a system controller 22 having a central processing unit (CPU) as shown in FIG. The data is expressed by the number of pulses, the interval between pulses, and the like, and transmitted from the transmitting antenna 21 by the pulse generator 23. The earth of the receiver 30 uses a heavy metal insulated from seawater such as on a ship.

The transmitted pulse is transmitted to the landfill embankment 2 or seawater 3
, And is received by the receiving antenna 31 of the receiver 30 several tens of meters away. The received signal is passed through the receiver 30 through an amplifier such as 1000 times if amplification is required.
Conveyed to. Thus, the receiver 30 extracts measurement data from the received pulse.

An embodiment of pulse propagation will be described below.

<A> Pulse Propagation Experiment (Part 1) In order to propagate a pulse in seawater and perform an experiment of pulse attenuation, a water channel 5 filled with seawater as shown in FIG. 3 is used. A dipole-type transmitting antenna 21 having a length of 4 m is arranged in the middle of the waterway 5 and the receiving antenna 31 is arranged at a predetermined distance. The receiving antenna 31 may be of the same dipole type or monopole type. The receive voltage is low and use enough amplifiers.

FIG. 4 shows a reception waveform transferred at a distance of 10 m between the transmitting antenna 21 and the receiving antenna 31. The pulse width is 30 μs, and the pulse width of one pulse having an amplitude of about 1 mV before amplification is shown. It is a waveform. FIG. 5 shows a case where the distance between the transmitting antenna 21 and the receiving antenna 31 is 22 m. There is no particular difference from the waveform at the time of 10 m, and electromagnetic inductive electromagnetic waves can be received.

<B> Pulse Propagation Experiment (Part 2) Similarly, a sea surface as shown in FIG. 6 is used to conduct a pulse propagation experiment in seawater and a pulse attenuation. The transmitter 20 and the receiver 30 are arranged on the ship 4 and the transmitting antenna 2
1 and the receiving antenna 31 are arranged at predetermined intervals in seawater.

FIG. 7 shows a reception waveform transmitted at a distance of 5 m between the transmitting antenna 21 and the receiving antenna 31, and having a pulse width of about 0.5 μs and a maximum amplitude of about 200 mV. Although the received pulse waveform is attenuated and continuous with respect to one transmitted pulse waveform, the pulse waveform can be sufficiently received.

FIG. 8 shows the transmitting antenna 21 and the receiving antenna 3
1 is a reception waveform whose distance is 10 m, and the pulse width and amplitude are similar to those in FIG. 7. In this case, the pulse waveform can be sufficiently received.

[0023]

According to the present invention, the following effects can be obtained. <B> Lake water, which is generally considered not to propagate radio waves,
Even in seawater or soil, measurement data can be transmitted without using a cable. <B> Since transmission can be performed using impulse electromagnetic waves with a wide range of pulse widths to some extent, the contents of the electromagnetic waves to be used are adjusted in consideration of the environment of external radio waves, the magnitude of the received voltage, and the life of the power supply. can do.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a system for transferring measurement data from the sea floor.

FIG. 2 is a block diagram of a transmitter.

FIG. 3 is an experimental diagram of electromagnetic wave propagation 1

FIG. 4 is a waveform diagram of a pulse propagated 10 m in the sea.

FIG. 5 is a waveform diagram of a pulse propagated 22 m in the sea.

FIG. 6 is an experimental diagram of the second electromagnetic wave propagation.

FIG. 7 is a diagram of a pulse waveform propagated 5 m in the sea.

FIG. 8 is another pulse waveform diagram propagated 10 m in the sea.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Submarine ground 2 ... Reclaimed embankment 3 ... Seawater 4 ... Measuring work boat 5 ... Waterway 10 ... Measurement device 20 ... Transmitter 21 ... Transmission antenna 22 ... System controller 23 ..Pulse generator 30.Receiver 31.Reception antenna

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Fumio Marumo 2-4-6 Kanda Awaji-cho, Chiyoda-ku, Tokyo Inside Toyoko Hermes Tokyo Office (72) Inventor Taizo Sano Four wards in Nishinasuno-machi, Nasu-gun, Tochigi 154-1 Machi, Goyo Construction Co., Ltd. (72) Inventor Bunji Shigematsu 153-1, Nishi-Nasuno-cho, Nasu-gun, Tochigi Prefecture 153-1 Goyo Construction Co., Ltd. (72) Inventor Bunshi Kato Hiroshima, Hiroshima 1-665-1, Fukuda, Higashi-ku, Yokohama-shi

Claims (3)

[Claims] 1. A data transmission system for transmitting measurement data into an electrically conductive medium of seawater, lake water or soil, wherein an induced electromagnetic wave of an impulse wave having a pulse width of about 0.3 μs to about 80 μs is transmitted into the medium. And a receiver for receiving the electromagnetic wave propagating in the medium, and a measuring device having a sensor, the measurement data of the measuring device is transmitted into the medium by the transmitter, and received by the receiver, A data transmission system characterized by being propagated in a medium. 2. The data transmission system according to claim 1, wherein an antenna of the transmitter is installed on the bottom of a sea or a lake, an antenna of the receiver is arranged near the surface of the water, and measurement data is transmitted from the bottom of the sea or the bottom of the lake. A data transmission system characterized by receiving near. 3. The data transmission system according to claim 1, wherein an antenna of the transmitter is installed on a seabed or a lake bottom, buried in a landfill embankment, an antenna of a receiver is arranged near the water surface, and measurement is performed from the seabed or the lake bottom. A data transmission system that transmits data and receives it near the water surface.