JPS581732B2 - Vertical water temperature distribution measurement method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a vertical water temperature distribution measuring method.

As a device for measuring the vertical distribution of water temperature, a tipping thermometer, BT (Bathythermoqraph),
STD (Salinity Temperature)
Depth) and XBT (Expendable B
athythermoqraph) etc. have been used so far.

Although tip-over thermometers have high accuracy in water temperature measurement, they have the disadvantage that they cannot measure temperature continuously and must be measured at each depth, which requires a lot of time to determine the vertical water temperature distribution. have.

Furthermore, since the mercury thermometer is suspended in water using a rope, it is difficult to handle and it is difficult to measure the water temperature in deep places.

Although BT and SDT require a shorter measurement time than an inversion thermometer, they still require a long time for actual measurement.

Moreover, since it is suspended in water using a relatively thick rope, it has the same drawbacks as a tipping thermometer.

Furthermore, both the temperature sensor and the depth sensor used are expensive, and the need for good watertightness also makes the measurement device quite expensive.

The three types of vertical water temperature distribution measurement devices described above are used by suspending the water temperature measurement section with a relatively thick rope, so they are difficult to use when the water current at the measurement site is strong or when the measurement boat is moving. Another major drawback is that it is difficult to measure.

XBT throws an object containing a temperature sensor into water,
Since the device uses a thin and long conductor to obtain water temperature information detected while descending through the water, it is an inexpensive and quick device that can measure water temperature.

However, since it is a wired system, troubles related to the conductor wires are likely to occur and handling thereof is complicated.

Furthermore, since the depth information is calculated on the assumption that the free falling speed of an object falling through water is constant, changes in the falling speed remain as measurement errors.

The present invention can solve the various drawbacks mentioned above, and is configured so that accurate depth information can be obtained without using a pressure sensor by transmitting information using ultrasonic waves and utilizing the Doppler effect. This provides a vertical water temperature distribution measuring device that has good measurement accuracy, is easy to handle, and is inexpensive.

Hereinafter, practical examples of the method of the present invention will be explained using the drawings.

This vertical water temperature distribution measuring device detects the water temperature while freely falling in the water, and has a wave transmitter that emits water temperature information to an external medium with ultrasonic waves, and a vertical water temperature distribution measuring device that receives and processes the radiation signal. The wave receiving section that obtains the water temperature distribution can be roughly divided into two elements.

FIG. 1 is a block diagram of the wave transmitting section, and FIG. 2 is a timing chart showing the signal relationship of each part of the wave transmitting section. First, the configuration and operation of the transmitting section will be explained using these figures.

In the figure, 1 is a thermistor for detecting water temperature, and is used as a resistance element that determines the oscillation frequency of the astable multivibrator 2.

The signal S1 shows the output waveform of the astable multivibrator 2, and the pulse interval changes depending on the water temperature.

3 is a monostable multivibrator which operates at the rising edge of S1 and generates a pulse signal with a constant time width.

Reference numerals 4 and 5 designate monostable multivibrators, which operate at the falling edge of the output signals of the preceding monostable multivibrators 3 and 4, respectively, and generate pulse signals with a constant time width.

The output signals of the monostable multivibrators 3 and 5 are ORed in an OR circuit 6 to generate a signal S2.

7 is a crystal excavation circuit, and its output signal is frequency-divided by a frequency dividing circuit 8 to become an ultrasonic carrier wave signal.

The carrier wave signal is ANDed with the signal S2 by the AND circuit 7, and becomes the signal S3.

Therefore, this signal S3 has a pulse interval Tti that changes depending on the water temperature, and has a carrier wave of a constant frequency within the pulse signal.

10 is a count circuit whose enable terminal is connected to the output terminal of the monostable multivibrator 5, and when the output signal of the monostable multivibrator 5 is applied, the output signal of the crystal oscillation circuit 7 is output at the falling edge of the output signal of the monostable multivibrator 5. When counting of a certain number of objects is completed, the monostable multivibrator 11 is operated to output a signal S4.

The time interval Td of the signal S4 has the same stability as that of the output signal of the crystal excavation circuit 7.

Reference numeral 12 denotes an AND circuit, which takes the logical sum of the signal S4 and the output signal of the frequency dividing circuit 8 to generate a signal S5.

Reference numeral 13 denotes an OR circuit, which takes the OR of the signals S 3 and S 5 to generate a signal S6.

Therefore, this signal S6 includes a pulse signal whose pulse interval changes depending on the water temperature, and a pulse signal whose time interval is constant depending on the stability of the pulse signal and crystal oscillation.

A power amplifier 14 amplifies the signal S6 and supplies it to the ultrasonic transmitter 15.

The ultrasonic transmitter 15 has the role of converting the supplied electric signal into an acoustic signal and emitting it into the water.

The above-mentioned wave transmitter is dropped into the water from a measurement boat, and the wave receiver described below receives the radiated signal and electrically processes it to obtain the vertical distribution of water temperature.

FIG. 3 is a block diagram of the wave receiving section, and FIG. 4 is a timing chart of signals in each wave receiving section.

The configuration and operation of the receiving part will be explained using these figures.

In the figure, reference numeral 16 denotes an ultrasonic receiver for receiving the ultrasonic signal sent from the transmitter, and the shape of the receiving wave is as shown in signal S7.

17 is an amplifier that amplifies the signal S7 and sends it to the waveform shaping circuit 1.
Supply to 8.

The output signal of the waveform shaping circuit 18 becomes the signal S8 33 1
9 is a monostable multivibrator, which is activated by the falling edge of the pulse of signal S8, is longer than T1 of signal S8, and has T2
A pulse signal S9 having a pulse width shorter than that is output.

20 is an AND circuit which takes the AND of the signals S8 and S9 and extracts the signal S10 having only temperature information.

Reference numeral 21 denotes a single-female fixed multivibrator which operates at the rising edge of the pulse of signal S10 and outputs a pulse signal S11 having a shorter pulse width than T3.

22 is an AND circuit that takes the AND of the signals Sll and S8 and extracts a pulse signal S12 that does not include temperature information.

A flip-flop circuit 23 has a set terminal applied with a signal S10, a reset terminal applied with a signal S12, and a signal S13 taken out from its output terminal.

The pulse width of the signal S13 is independent of temperature and changes only due to the Doppler effect caused by the falling speed of the wave transmitter.

24 is a flip-flop circuit which performs a toggle operation at the falling edge of the pulse of signal S12, and outputs signals S14 and S15 from two output terminals, respectively.

These signals contain both water temperature information and the Doppler effect in their pulse widths.

If the pulse interval Tti of the transmission signal is expressed by the functional form of a known function F1 with water temperature t as an independent variable, it can be expressed by the following equation.

From the received signals S13, S14, and S15, Tt of the transmitted signal
The equivalents of i and Td are found, and these are expressed as Tti'
, Td', this is due to the Doppler effect.

Here, both the falling velocity of the wave transmitter and the sound velocity are Y within Td time.
Assuming that the average and the average within Tti time are not significantly different, then.

Td in equation (2) can be determined from a measured value when the wave transmitter is stationary with respect to the receiver, without adjusting the crystal oscillation frequency when manufacturing the wave transmitter.

From equation (2), the Dotsubra effect can be expressed as Td and Td as shown in the following equation.
It can be found from i'.

Therefore, the value Tti obtained by removing the Doppler effect from the receiving pulse interval Tti' can be determined, and from this and equation (1), the accurate water temperature can be determined.

The speed of sound Vi is a function of water temperature and depth, and if the depth is ΣDi, then the following equation is obtained.

If ■1 is found by the above equation, the falling F speed 1 of the sending part can be found from equation (6).

■If 1 is found, the depth De p th is It can be found by

Here, α is the short distance that the transmitter falls before the first pulse signal is emitted.

By repeating the above operations, the vertical distribution of water temperature can be determined accurately.

However, when calculating the initial sound speed Vi, the depth ΣD
Calculate Vi by setting i to 0, calculate i from this value, substitute this into equation (9) to calculate ΣDi, and calculate the value of Vi by (8)
Find it from the formula and use it as the initial speed of sound.

Specifically, the falling speed of the wave transmitter is approximately 2 m/s, and in order to obtain depth information with an error of 1%, the detection of the falling speed is set to 1%.
An example of a design for a device determined by the error is shown below.

The ultrasonic carrier frequency is 100 KHz. From equation (2), the change in pulse interval Td due to the Doppler effect ΔTdi
The differential value with respect to the velocity is expressed as Vi == 1 5 0 om/sec,
122 m/sec.

Since the value of Td'i when receiving Td is determined by the presence or absence of the carrier wave frequency, the error in Td measurement is considered to be one wave of the carrier wave, and if it is 1.0 x 10' seconds, the drop due to Td measurement is From the condition that the time that corresponds to the resolution of speed detection is shorter than this, the following equation is obtained, and the pulse width Tti including the temperature information is calculated with a slight margin in mind.

If each pulse width is TI)ttTp2 in Fig. 2, then it is possible to distinguish between signals that include temperature information and signals that do not, and if Tp1-・Tp2=1-:IJ seconds, then (
13) From formula.

Here, (Tti)min is the value of Tti when the water temperature is the minimum value in the measurement temperature range.If the measurement range is 0 to 40℃, To = 844 milliseconds from equation (14), with a slight margin. Take To-1 second in anticipation.

Therefore, in a place where the water temperature is 20°C, measurements must be taken once every 2m.

The effects of the present invention described above will be listed below.

(1) Since information is transmitted using the ultrasonic method, it is easier to handle than the wired method.

It is also less susceptible to the effects of water currents and the movement of the measurement vessel.

(2) Since no pressure sensor is used to obtain depth information, the device is small and inexpensive.

(3) Since the depth is calculated by detecting the falling speed, the measurement accuracy is good.

(4) It is only necessary to increase the stability of the crystal oscillation circuit in the wave transmitting section, and there is no need to adjust the emission frequency.

(5) Since the Dotsubura effect is measured based on the pulse interval, if the pulse interval is made longer, small changes can be measured with high accuracy, and the accuracy of depth information is good.

(6) Since the time for emitting a signal can be shortened by shortening the pulse width, effective power consumption can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the wave transmitting section in an embodiment of the vertical water temperature distribution measuring method of the present invention, FIG. 2 is a timing chart of signals of each transmitting section, and FIG. 3 is the configuration of the wave receiving section. FIG. 4 is a timing chart of signals in each part of the wave receiving section. 1... Thermistor, 2, 3, 4.5...
・Monostable multivibrator, 6...OR circuit, 7...Crystal oscillation circuit, 8...Divide circuit, 9...AND circuit, 10... Count circuit, 11... Monostable multivibrator, 12... AND circuit, 13... OR circuit, 14...・Power amplifier, 15...
...Ultrasonic generator, 16...Ultrasonic receiver, 1
7... Amplifier, 18... Waveform shaping circuit, 19... Simple constant multivibrator, 20...
...AND circuit, 21...Monostable multivibrator, 22...AND AND circuit, 23,2
4...Flip-flop circuit.

Claims (1)

[Claims] 1. An object that emits ultrasonic waves to an external medium, a first pulse signal whose pulse interval changes depending on the water temperature, and a second pulse signal whose pulse interval is a fixed time interval from the above pulse signal, is free-falling underwater. The ultrasonic pulse signal is received just below the water surface, the Doppler effect is determined from the change in the interval between the first and second pulse signals, and the water temperature is calculated from the pulse interval obtained by subtracting the Doppler effect from the pulse interval of the first pulse signal. A vertical water temperature distribution measurement method characterized by determining the falling speed of an object from the water temperature and the Dotsupura effect. 2. Vertical water temperature distribution measuring method 1, 3 according to claim 1, characterized in that a difference in pulse width, pulse waveform, or pulse level is used to distinguish between the first pulse signal and the second pulse signal. When the object that emits the ultrasonic pulse signal is stationary relative to the receiver, the first
2. The vertical water temperature distribution measuring method according to claim 1, wherein the interval value of the second pulse is used as a standard value for measurement.