JP4358154B2 - Ultrasonic wave height meter - Google Patents

Description

  The present invention belongs to the technical field of an ultrasonic wave height meter that can measure the wave height with high accuracy in order to perform wave observation in a wide depth range from a deep sea area to a shallow sea area.

A conventional ultrasonic altimeter is installed in the sea or at the bottom of the sea, repeatedly transmits ultrasonic pulses from the ultrasonic transducer toward the sea surface at a faster cycle than the change of the wave, and is reflected by the sea surface. Measure the time to return to each pulse, convert this to the distance from the transducer to the sea level, and consider the change in this distance as the vertical change in the sea level. Is measured as the wave height.
However, the conventional ultrasonic altimeter does not include a means for identifying whether or not the received ultrasonic wave is a reflected wave from the sea surface (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 5-272777 ([0007], FIG. 1)

By the way, when an ultrasonic wave height meter transmits an ultrasonic wave toward the sea surface, it is not always the case that it is reflected only from the sea surface. When a fish school or other reflective object arrives or floats between the tide meter and the sea surface, or when bubbles caused by breaking waves such as when the sea gets rough, it is reflected from these.
Also, in shallow waters, the attenuation of sound waves is small, so that the ultrasonic waves reflected back from the sea surface re-reflect on the sea bottom and go back to the sea surface, and reflect back on the sea surface and return. Repeatedly, it may be reflected (repetitively reflected) from the sea surface multiple times for one pulse transmission.
Furthermore, although it is not a reflection, the ultrasonic wave of the ultrasonic sounding device may be transmitted toward the seabed from a ship that navigates near the wave height observation place, and may reach the wave height meter.

However, in the conventional ultrasonic wave height meter, as described above, the sound wave received is reflected from the sea surface, reflected from other reflecting objects, or reflected from the sea surface. Is not provided with a function for discriminating whether or not is the first reflection, whether it is a reflection of an ultrasonic wave generated by the altimeter itself, or a sound wave from another sound source.
Therefore, a processing operation for calculating the wave height is performed on the ultrasonic signal received after the transmission without distinction. As a result, there is a problem that the obtained data is not true sea level wave height data, or very inaccurate data is output.

  In view of the above-mentioned problems of the prior art, the problem of the present invention is that there are underwater bubbles due to arrival / floating and breaking waves of fish and other reflective objects, multiple reflections in shallow water areas, and sound emission from other sound sources. Even so, it is to provide an ultrasonic wave height meter capable of observing the original wave height data by avoiding erroneous measurement due to these disturbances with a high probability.

In order to solve the above problems, the present invention has the following configurations.
A first configuration of the present invention is an ultrasonic wave height meter including the following means.
(B) from the water pressure values measured by the pressure gauges (b) water pressure gauge for measuring the pressure of placed positions of water, water pressure, the ultrasound calculates the time T _P required to reciprocate the distance to the water surface receiving a transmission timing signal and the time data _{T P} time conversion unit (c) ultrasonic pulse, based on the transmission _{timing, (T} P -t ₁₎ from the time of _(T P + _{t 2)} time (where t ₁ and t ₂ are gate generators that generate a gate signal up to a time value determined by error and water surface condition) (d) The gate is generated in the middle of the signal passing path from the ultrasonic receiver to the recording / display device A gate circuit that receives the gate signal from the recorder and sends the received signal from the ultrasonic receiver to the recording / display unit for the duration of the gate signal.

A second configuration of the present invention is an ultrasonic wave height meter including the following means.
(B) from the water pressure values measured by the pressure gauges (b) water pressure gauge for measuring the pressure of placed positions of water, water pressure, the ultrasound calculates the time T _P required to reciprocate the distance to the water surface receiving said time data _{T P} and the transmission timing signal time conversion unit (c) ultrasonic pulse, based on the transmission _{timing, (T} P -t ₁₎ the time of the _(T P + _{t 2)} of the time (where t _1, t ₂ in the middle of the switching signal unit (d) signal transmitting path to record and display the ultrasonic receiver for outputting a switching signal to the time value) determined by the error and the water conditions, a switching signal unit receiving a switching signal from the (T P _{-t 1)} initiates a signal passed at the time, _(T P _{+ t 2)} signal passes through on-off circuit for cutting off the signal transmission at the time

The ultrasonic wave height meter of the present invention includes a water pressure gauge, and measures the water pressure at the depth or depth of the position where the ultrasonic wave height meter is installed. Although it is difficult to detect slight fluctuations in the water level, this water pressure value is completely affected by underwater bubbles caused by breaking waves, the presence of school of fish, repeated reflections, and sound emission of ultrasonic detectors of other ships. Since it is proportional to the water depth or depth, the distance to the water surface can be determined.
Accordingly Thus, ultrasound wave height meter emitted it is possible to calculate the time T _P for reciprocating the distance to the water surface. That time T _P corresponds to the distance to the water surface.
Therefore, ultrasonic pulses emitted from the wave height meter is time to come back after being reflected reaches the surface of the water, it comes to the vicinity of the time T _P.

In the present invention, _-t 1 before and after the time _{T P,} + _t provided _second width, the transmission timing of the ultrasonic pulse wave height meter (transmission time) and the time of _{(T P -t 1) (T} P + t _Since only the ultrasonic wave received at the time point between ₂ ) is sent to the recording / display device, only the reflected wave from the vicinity of the water surface is used by setting t ₁ and t _2. .
t ₁ and t ₂ take into account other water surface conditions such as the water pressure measurement error of the water pressure gauge and the difference due to the slow response speed of the water pressure measurement value relative to the vertical fluctuation of the water surface compared to the response speed of the ultrasonic round-trip time. Will be determined empirically.

  As described above, the range of ultrasonic waves received as wave height data is limited to those by reflected waves from the vicinity of the water surface. It does not sense reflections from bubbles, repeated reflections, or sounds emitted from other ship acoustic sounders. Even if these reflections and beeps may fall within the above range by chance, it is a very low probability, and as a whole, the accuracy of the wave height measurement of the wave height meter of the present invention will be greatly improved. There is.

The measurement accuracy of the ultrasonic wave height meter of the present invention in the case where there is reflection from other than the water surface, repetitive reflection, or transmission from another sound source depends on the setting of t ₁ and t ₂ . It is considered that deviates from the range reception time of the reflected sound from the water surface when set too small _{(T P -t 1) ~ (} T P + t 2), it is too large t 1, _{t 2} The probability of catching reflected sounds other than water surface reflections and sound emitted from other sound sources increases.
Therefore, it is desirable that it is as narrow as possible without departing from the reflected sound from the water surface.
Therefore, the setting of t ₁ and t ₂ is the time difference due to the difference in the calculation time error due to the water pressure measurement error of the water pressure gauge itself, the response speed of the water pressure measurement value with respect to the vertical fluctuation of the water surface, and the response speed of the ultrasonic round-trip time. It is the best mode to set the shortest possible range exceeding the sum of.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the ultrasonic wave height meter according to the first embodiment of the present invention.
FIG. 2 is a situation diagram in which an ultrasonic wave height meter is installed on the seabed. The ultrasonic transmitter 3 receives a transmission timing trigger signal having a fixed period from the timing circuit 5, generates an ultrasonic pulse electric signal, and sends the ultrasonic pulse electric signal to the ultrasonic transmitter / receiver 1. A pulse is transmitted toward the sea surface.

As shown in FIG. 2A, the ultrasonic pulse is reflected by the sea surface and returns to the ultrasonic wave height meter. This is received by an ultrasonic transmitter / receiver, converted into an electrical signal, sent to the ultrasonic receiver 4, where it is amplified and detected.
The speed of sound in water is approximately 1500 m / s although it varies depending on the water temperature and salt concentration. Since the underwater sound speed is known in this way, the distance from the wave height meter installation position to the sea surface can be determined by measuring the time from when the ultrasonic pulse is transmitted until it returns. Since the sea surface is moved up and down by the waves, changes in the sea surface up and down, that is, waves can be observed by repeating transmission and reception of ultrasonic pulses at a cycle shorter than the upper and lower cycles.

  As shown in FIG. 2 (b), if there is a floating reflector 10 such as underwater bubbles or a school of fish caused by breaking waves, the ultrasonic pulse is also reflected from this point and reaches the ultrasonic transducer 1 to generate ultrasonic waves. Amplified and detected by the receiver 4 and output.

FIG. 2C shows the case of repeated reflection.
On the other hand, the water pressure gauge 2 measures the water pressure at the location where the wave height meter is installed and sends a water pressure value signal to the water pressure / time converter 6. Although this water pressure value is difficult to detect slight fluctuations in the sea level, it is proportional to the water depth or depth, so it is possible to determine the distance to the sea surface. it is possible to calculate the time T _P. In terms of device 6 thus pressure-time by converting the water pressure value in the round trip time T _P sent to the gate generator 8. The gate generator 8 are subjected to transmission timing (transmission time) signal from the timing circuit 5, the transmission time by a time t ₁ which is set in advance from T _P as a reference short (early) time preset from the time point t ₂ The gate signal is generated up to the long (slow) time point.

FIG. 3 is a diagram showing a reflected signal and a gate signal with the horizontal axis as a time axis.
In (a), the sea surface reflection signal 11 appears at the position of the time required for the round trip to the sea surface of the ultrasonic wave, and the floating object reflection signal 12 is shown at a time position shorter than the sea surface reflection signal 11.
Also, in the shallow water area, since the sound wave is less attenuated, the ultrasonic wave that is reflected on the sea surface and returns to the sea bottom is reflected again on the sea floor, and is reflected again on the sea surface toward the sea surface and received again. It may appear at an integer multiple of the time position of the sea surface reflection signal.

(B) there is shown a gate signal 13 to both ends before and after _(T P -t ₁₎ time and _(T P + _{t 2)} when the round trip time _{T P} to sea level, which is converted from the water pressure value.
t ₁ and t ₂ are determined experimentally and statistically in consideration of the measurement error of the water pressure gauge and the tracking delay error (response error) resulting from the slow tracking of the water pressure value to the sea level change and the water surface condition.
This gate signal 13 is sent to the gate circuit 7, and the output signal of the ultrasonic receiver 4 is sent to the recording display 9 only during the gate width time of the gate signal 13, whereby the floating substance reflected signal 12 and the repeated reflected signal 16 are sent. Is to be removed.
Therefore, when the gate width is as narrow as possible in consideration of the measurement error and the tracking error, the probability of removing the floating object reflection signal 12 is increased.

In this way, only the received signal in a narrow range (within the gate width) in the vicinity of the first reflected wave reception signal from the sea surface is taken out, so as well as floating object reflection, repeated reflections and The received wave signal from the transmission of the sound sounding device is also removed, and the wave height can be reliably observed.
Note that the gate generator 8, the timing circuit 5, the water pressure / time converter 6, the recording display 9, the gate circuit 7 and the like in FIG. 1 can be constituted by a microcomputer or the like.

FIG. 4 is a block diagram showing the configuration of the second embodiment of the present invention.
The difference from the configuration of FIG. 1 is that a switching signal device 14 is substituted for the gate generator 8 of FIG. 1, and a signal passing on / off circuit 15 is substituted for the gate circuit 7 of FIG.
Switching signal 14 outputs an ON signal at the time of the FIG. 3 _{(b) (T P -t 1} ), and outputs an OFF signal at the time of _(T P + _{t 2).} Upon receiving the ON signal, the signal passing ON / OFF circuit 15 continues the state of passing the signal from the ultrasonic receiver 4 from the input side to the output side when receiving the ON signal, and passes when receiving the OFF signal. Works to stop. As in the case of FIG. 1, it will send (T P _{-t 1)} from the time _(T P _{+ t 2)} reflected received signal reception until the time the recording indicator 9.
The operation of the other parts is the same as in FIG.
The switching signal device 14 and the signal passing on / off circuit 15 can also be constituted by a microcomputer or the like.

It is a block diagram which shows the structure of the 1st Example of this invention ultrasonic wave height meter. It is a figure which shows the condition where an ultrasonic wave height meter is installed in the seabed and transmits a sound wave toward the sea surface. It is a figure which shows the reflected signal and gate signal which made the horizontal axis the time axis. It is a block diagram which shows the structure of the 2nd Example of this invention ultrasonic wave height meter.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic transmitter / receiver 2 Water pressure gauge 3 Ultrasonic transmitter 4 Ultrasonic receiver 5 Timing circuit 6 Water pressure / time converter 7 Gate circuit 8 Gate generator 9 Record display 10 Floating reflection object 11 Sea surface reflection signal 12 Floating object Reflected signal 13 Gate signal 14 Switching signal 15 Signal passing on / off circuit 16 Repeated reflected signal

Claims (2)

An ultrasonic wave height meter comprising the following means.
(B) from the water pressure values measured by the pressure gauges (b) water pressure gauge for measuring the pressure of placed positions of water, water pressure, the ultrasound calculates the time T _P required to reciprocate the distance to the water surface receiving a transmission timing signal and the time data _{T P} time conversion unit (c) ultrasonic pulse, based on the transmission _{timing, (T} P -t ₁₎ from the time of _(T P + _{t 2)} time (where t ₁ and t ₂ are gate generators that generate a gate signal up to a time value determined by error and water surface condition) (d) The gate is generated in the middle of the signal passing path from the ultrasonic receiver to the recording / display device A gate circuit that receives the gate signal from the recorder and sends the received signal from the ultrasonic receiver to the recording / display unit for the duration of the gate signal. An ultrasonic wave height meter comprising the following means.
(B) from the water pressure values measured by the pressure gauges (b) water pressure gauge for measuring the pressure of placed positions of water, water pressure, the ultrasound calculates the time T _P required to reciprocate the distance to the water surface receiving said time data _{T P} and the transmission timing signal time conversion unit (c) ultrasonic pulse, based on the transmission _{timing, (T} P -t ₁₎ the time of the _(T P + _{t 2)} of the time (where t _1, t ₂ in the middle of the switching signal unit (d) signal transmitting path to record and display the ultrasonic receiver for outputting a switching signal to the time value) determined by the error and the water conditions, a switching signal unit receiving a switching signal from the (T P _{-t 1)} initiates a signal passed at the time, _(T P _{+ t 2)} signal passes through on-off circuit for cutting off the signal transmission at the time

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