JPS59226842A - Water temperature measuring device - Google Patents

Abstract

PURPOSE:To improve reliability of a detected underwater temperature by detecting in advance a reflecting point of an ultrasonic pulse, receiving a reflected wave from a detected reflecting point in a pulse transmitted from other point, and making a theoretical propagation path coincide with a measured propagation path. CONSTITUTION:A temperature variation boundary H1 is set to an optional depth, and a water temperature above H1 and a water temperature below it are denoted deg.C1 and deg.C2, respectively. A sound wave reflected by a point R1 emitted from a Q point is refracted at H1 and reach to the Q point. An incident angle theta1 and a refractive angle theta2 are determined by water temperatures deg.C1, deg.C2, therefore, a refractive path of the sound wave extending from the point R1 to a Q1 point can be calculated. When a calculated time coincides with a measurement time, it is known that a temperature is varied from deg.C1 to deg.C2. After detecting a temperation variation to the R1 point, a temperation variation to R2 and R3 is detected. In this way, by detecting a water temperature by which the propagation time coincides with the measurement time, a temperature variation to an R4 point can be detected, and a water temperature can be measured exactly.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field of the Invention) The present invention relates to a device for measuring temperature in water, and in particular, to a device for measuring temperature in water.
The present invention relates to a device that measures the temperature of water by transmitting and receiving ultrasonic waves into the water.

(Prior Art) In general, there is a close relationship between fishing grounds and water temperature, and therefore, by detecting water temperature, it is possible to discover good fishing grounds.

Water temperature is most commonly detected using a temperature sensing element such as a thermistor. However, such measuring devices
Although it is relatively easy to measure surface water temperature, it is not suitable for measuring temperature at a specific depth underwater.

Therefore, recently, a device has been proposed that uses ultrasonic waves to measure the temperature of water without using a temperature-sensitive element as described above.

Currently proposed devices of this type attempt to measure water temperature by simultaneously receiving sound waves along different paths and utilizing the difference in reception time caused by the difference in path length.

For example, ultrasonic pulses are transmitted obliquely underwater from a point a certain distance away, and the reflected waves that are diffusely reflected in the water are received by a receiver installed at another point. At this time, if a plurality of receivers with slightly different pointing directions are installed to receive the reflected waves, the reflected waves with slightly different propagation paths will be received with different times corresponding to the path difference. Therefore, by comparing the time difference caused by the theoretical path difference with the measured time difference, it is possible to calculate the change in the sound wave propagation velocity, and therefore the rate of change in the propagation velocity or the temperature change can be known. However, in such measurement methods, the theoretical propagation path and the actual propagation path do not match. In other words, while sound waves in water propagate while being refracted according to changes in water temperature, the theoretical propagation path should ignore such refraction and emit a-, so there is a difference between the actual propagation path and the theoretical propagation path. It does not correspond at all. Therefore, even if the time difference comparison as described above is performed, the water temperature cannot be measured.

(Objective of the Invention) The present invention addresses the above-mentioned drawbacks and makes it possible to accurately measure water temperature by detecting the actual propagation path of the sound waves and measuring the propagation time of the sound waves. Realize the device.

(Principle of the Invention) In FIG. 1, an ultrasonic pulse of frequency f1 is transmitted and received from the transducer Z□ at point P toward the seabed directly below.

At this time, a sharp beam with pencil-like directivity is used as the ultrasonic pulse.

The ultrasonic pulses transmitted from the transducer Z1 are reflected by floating objects such as bubbles R, J, , R8, R4, etc. in the water, resulting in underwater reflected waves Ar, A as shown in Fig. 2a.
2, As, A1, etc. are received.

On the other hand, the distance from point P. Ultrasonic receivers at Q points that differ by 2. is provided and transmits an ultrasonic pulse of frequency f2. The wave receiver Z2 has directivity in a relatively wide range of directions including the wave transmitting/receiving area of the wave transmitter/receiver Z1.

Therefore, the receiver Z2 detects the underwater floating objects R1, R,, 几8, 几 out of the ultrasonic pulses transmitted from the transducer Z. The reflected wave reflected in the directional direction of the receiver Z is received by the receiver Z. Therefore, when transmitting ultrasonic pulses from the transducer Z1, the underwater floating objects R0 and R7 received by the transducer Z2
, R8, & are the received signals B1, R8, & in Fig. 2.
As shown as B2, B8, B, ΔT1 for the received signals A1, A,2, A,8, A4 of the transducer Z1.
, 2, △T8. The wave is received with a delay of 671 hours.

As is clear from the above, this delay time ΔT1.1hT2.1hTI11 ear 4 is from point Q to floating objects R1, R2 in the water.
, R8, and the propagation of ultrasonic waves up to R4.

The distance from point Q to underwater floating objects R1, R2, R8, and R4 is the distance between PQ. and floating objects R□, R2 from point P
, R8, and B4. In addition, the distance from point P to the floating object in the water is the distance from the transducer Z.
Transmit ultrasonic pulses from 1 to remove floating objects R□, 几2, 几8
, R4 can be calculated by measuring the time until the reflected waves of R4 are received.

Therefore, when the distances from point Q to underwater floating objects R1, R2, R8, and R4 are calculated, from point Q to underwater floating objects R51,
Since the sound wave propagation time up to R2, R8, and R4 can be calculated, the calculated time is the measurement time ΔT0 in FIG.
It is sufficient to detect a water temperature that matches 46m'f, , ΔT.

This water temperature detection can be performed as follows.

In Figure 3, from point Q, floating objects R,'! ', set the temperature change boundary H1 at an arbitrary depth during the propagation of the ultrasonic wave, set the water temperature above the boundary H1 to Q, and the water temperature below C1 to C.
Set it to 7°. Therefore, the sound wave reflected at point R1 is at the boundary H
The incident angle θ1 and the refraction angle θ when the sound wave is refracted at the boundary are determined by the water temperatures C1° and C2°. Therefore, by setting the water temperatures C,0, C,O, the refraction path of the sound wave from point R1 to point 91 can be calculated, and thereby the propagation time of the sound wave from point R51 to point 91 can be calculated. . When the calculation time matches the measurement time △T in Fig. 2, the boundary part I (□
It can be seen that the temperature change at 010° to 02°. In the above, the temperature change boundary H2 is a virtual point, but by detecting the distance to the floating object at a small distance, the temperature change due to the virtual point is set to be almost similar to the actual temperature change. be able to.

After detecting the temperature change up to point R1 as described above,
Detecting the temperature change up to point R2 8' In this case, in the same way as above, set the temperature change boundary H, and set the water temperature above the boundary H2 as Q, and the water temperature below Q1 as 08°, and then set the voltage. The propagation path of the sound wave from the point to the 92nd point is calculated.

Then, the propagation time of the propagation path is the measurement time Δ in Figure 2.
1゛, water temperature 02', CB. Detect.

Thereafter, temperature changes up to point R8 and point R are detected by setting temperature change boundaries H,,l-I4 in the same way.

(Embodiment of the Invention) In FIG. 4, Z indicates an ultrasonic transducer, and A2 and Zs indicate an ultrasonic receiver.

The ultrasonic transducer Z1 has sharp directivity similar to the ultrasonic transducer Z1 shown in FIG. Then, as shown in Figure 5a, underwater reflection points R61, R2, and 8
, receives reflected waves A1, A7, A8, and A4 from the electric current.

Also, the ultrasonic receivers Z2 and A8 are at a distance from the ultrasonic transducer Z. They are arranged symmetrically in different positions.

Then, similarly to the ultrasonic receiver Z in Fig. 1, the reflection point 1 is
, Island, Uma, receives the reflected waves from R6. Figure 5 b1 is the received signal of the ultrasonic receiver Z2, R2 is the ultrasonic receiver Z8.
The received signal is shown.

The received signal of the ultrasonic transducer Z1 is amplified and detected by the receiver 2, and then converted into digital data by the A/D converter 5. The converted digital data is then input to the microprocessor 5 via the input/output converter 4. The microprocessor 5 sends the captured received signal data together with time data until reception of the received signal to the storage circuit 6 for storage.

On the other hand, the received signals from the ultrasonic receivers Z2 and A8 are amplified and detected by the respective receivers 7 and 8, and then sent to the A/D converters 9.
10, it is converted into a digital signal. Then, in the same manner as described above, the data is input to the microprocessor 5 via the input/output converters 11.12, and then stored in the storage circuit 13.14 together with the time data.

Therefore, the memory circuit 6 stores the received signal of FIG. 5a, and the memory circuits 13 and 14 store the received signals of FIG. 5 b1, b.

Microprocessor-5 includes memory circuit 6 and 13.1
After storing each received signal data in 4, each stored data is read out and the time difference signal 1 in FIG.
1, △Tz, th'f y, OK 1 Ibe 2□, △T4,
Measure △1゛3, ゛, and 4.

This time difference measurement is performed based on the received signal of the ultrasonic transducer z1 (Fig. 5a).
, R, are detected. Then, calculate the distances from points Ql and Q9 to reflection points R1, R2, R8, and R4,
Theoretical propagation time ΔT□, △ for a sound wave to propagate that distance
'p,,48.6T41i! Output L, ultrasonic receiver E receiver Z
x, Z, from among the received signals (Fig. 5 b1, b,),
At the time of calculation, the received signals I3□1, horse, BIJ % B14, island, B22, B'2g, and B, which appear closest to ear 1, female 2, ΔT8, and ΔT4, are selected. and,
After selection, the time differences Δ'I'11, ΔT! with respect to the corresponding received signals A1, A, , AB, A! 2, △Ttg, △T1
Calculate each of △T'n %△T22, Δ'1゛8, and △T, and calculate the time difference data △Tuz△T12, △T1
B, △T14, to the memory circuit 13, and the time difference data △T
21, △T22, ゛, 8, △T24 are stored in the storage circuit 14.

After storing the time difference data in the storage circuits 13 and 14 as described above, the microprocessor-5 reads out the respective time difference data and averages the corresponding time differences. That is, the time difference ΔT21 corresponding to the time rdJ difference ΔTu is averaged with respect to each other. Similarly, the time differences △T+'2 and △T22 are changed to the time differences △Tag and △'r
, 8, and the time differences T14 and ΔT24 are respectively averaged. Then, the averaged time difference data is stored in the storage circuit 15.

In FIG. 4, ultrasonic receivers Z2 and A8 are arranged symmetrically with respect to ultrasonic receiver Z. Therefore, Z□,
When A2 and ZB stop at fixed positions and transmit and receive ultrasonic waves, the arrival time of the sound waves from the underwater reflection points R□, R2, R8 and the electric waves to the ultrasonic wave receivers Z2 and Z8 are equal to each other.

However, the ultrasonic transducer Z-engine and the ultrasonic receiver Z2,
When measuring water temperature while moving with Z8 mounted on the bottom of a ship, the ultrasonic signal is subject to the Doppler effect, so R1, Kame, R
8. The time for the sound wave to reach the ultrasonic wave receiver Z2 from the reflection point of R4 is slightly different from the time for the sound wave to reach the ultrasonic wave receiver Z8. Therefore, by averaging both time differences as described above, the influence of the Doppler effect can be canceled and the ultrasonic wave receiver Z
2 or Z8 can be measured accurately.

Microprocessor-5 has reflection points R1J, , R8, R
6 to the ultrasonic receiver Z2 or Z8 in the storage circuit 15, the water temperature detector 1
The water temperature data is taken in from 6 through the input/output converter 17.

Note that the water temperature detector 16 uses, for example, a temperature sensing element,
Measure water surface temperature.

The microprocessor 5 receives the water temperature data from the water temperature detector 16 and the reflection points R4, R2, and 8 obtained from the storage circuit 6.
, depth data of □, distance between PQ or PQ2. Based on the data, Q
The sound wave propagation path from the point to the reflection points R, R2, R8, and R4 is calculated. And temperature change boundaries H1, H2, Ha
, H4, and calculated the propagation paths in which the temperature changes were sequentially changed, and out of the sound wave propagation time of each propagation path, the measurement times △T□0, △T12, △T1B, △T14 and (△ A propagation path that matches the averaging time of T2□, △T22, △T2B, and △T44 is detected, and the set temperature for calculating the propagation path is displayed on the display 18.
The water temperature data guided to the display 18 is input to the input/output converter 19.
guided through. Also, 29 minutes apart. If the data is known in advance, it may be stored in the memory circuit in advance.

(Effects of the Invention) As is clear from the above description, the present invention transmits ultrasonic pulses, detects the reflection points of the ultrasonic pulses in advance, and reflects the ultrasonic pulses transmitted from other points. Among them, the reflected waves from the detected reflection points are received. Therefore, since the reflection points of the ultrasonic waves are specified in advance, it is possible to match the theoretical propagation path and the actually measured propagation path extremely accurately. Therefore, the detected water temperature can be made extremely reliable.

(Other embodiments of the invention) In FIG. 4, an ultrasonic transducer P and an ultrasonic receiver Z
2. Z8 is designed to transmit ultrasonic pulses from the sea surface to the seabed, but the ultrasonic transducer Z1 and ultrasonic receivers Z2 and Zs are arranged as if being towed underwater.
Ultrasonic pulses may be transmitted and received in the direction of the water surface.

[Brief explanation of drawings]

Fig. 1 is a diagram for explaining the details of this invention, Fig. 2 is a diagram for explaining the transmission and reception of ultrasonic waves, Fig. 3 is a diagram for explaining calculation of water temperature, Fig. 4 5 shows an embodiment of the present invention, and FIG. 5 shows a waveform diagram for explaining its operation. 1... Transmitter, 2... Transmitter, 3...
...A/D converter, 4...Input/output converter,
5...Microprocessor-16...
Memory circuit, 7.8...Receiver, 9.10...
... A/D converter, 11.12... Input/output converter, 13, 14.15... Memory circuit, 16.
...Water temperature detector, 17...Input/output converter, 18
... Display device, 19 ... Input/output converter Applicant Furuno Electric Co., Ltd.

Claims (1)

[Scope of Claims] An ultrasonic transducer that transmits sharp ultrasonic pulses with pencil-like directivity in a substantially vertical direction and receives reflected waves returning from various points in water, and the ultrasonic transducer distance from. first and second ultrasonic receivers that are respectively provided at different symmetrical positions and have directivity angles that include the wave transmitting and receiving area of the ultrasonic transducer and receive the reflected waves; The reflected waves received by the transducer and the first and second
First and second time difference measurement circuits that measure reflected waves arriving from a common reflection point among the reflected waves received by each ultrasonic receiver; and measurement by the first and second time difference measurement circuits. An averaging circuit that mutually averages the time difference between reflected waves arriving from a common reflection point, and a temperature change boundary between the common reflection point and the surface layer, and A propagation path from the corresponding common reflection point to the first or second ultrasonic receiver is calculated, and a temperature change boundary where the sound wave propagation time of the propagation path coincides with the averaging time of the averaging circuit is determined. A water temperature measuring device comprising a detection arithmetic circuit.