JPS6344180B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to measuring temperature distribution in the depth direction underwater.

Conventionally, temperature sensing elements such as thermistors have often been used as devices for measuring temperature in water.
This type of measuring device can measure temperature with relative accuracy, but it can only measure local areas, and in order to measure a wide range of temperature distribution, it must measure temperature at many different points. Not necessarily,
It has the disadvantage that measurement takes a long time.

The present invention provides an apparatus for measuring trends in temperature gradients in water by transmitting ultrasonic pulses into water and measuring the propagation time.

One embodiment of this invention will be described below.

In FIG. 1, 1 and 2 are ultrasonic transducers installed on the bottom of a ship 3. The ultrasonic transducer 1 transmits and receives ultrasonic pulses from the bottom of the ship to the seabed directly below. Also, when the ship 3 is sailing in the direction of arrow A, the ultrasonic transducer 2 is set at θ with respect to the seabed directly below.
It sends and receives ultrasonic pulses toward the ocean floor behind it.

The ultrasonic transducer 1 periodically transmits ultrasonic pulses of frequency f ₁ based on the transmitter 19 . The reflected wave from the seabed immediately below is received by the transducer 1 and then guided to the receiver 4 where it is amplified and detected. The output of receiver 4 is sent to counter 5. The counter 5 counts clock pulses from the clock pulse source 20 every time the transmitter 19 excites the transducer 1, and stops counting when the receiver 4 detects a seabed reflected wave. The counted value is then sent to the latch circuit 6, where it is latched until the next counted value is sent out from the counter 5.

The count value of the latch circuit 6 is sent to the storage circuit 7, and when the output from the range meter 8 is sent out, the count value is stored. The range meter 8 measures the distance traveled by the ship 3, and sends out an output every time the ship 3 travels a certain distance (unit distance). The storage circuit 7 sequentially stores the latch values of the latch circuit 6 every time the range meter 8 sends an output, and after the storage capacity is exceeded, the oldest stored value is stored while being updated in order. Therefore, the memory circuit 7 stores depth data while the ship 3 travels a certain distance _L0 .

On the other hand, the ultrasonic transducer 2 transmits ultrasonic pulses in the θ direction based on the transmitter 9 and receives reflected waves from the ocean floor. Then, the seabed reflected wave is detected by the receiver 10 and then sent to the counter 11.

The counter 11 counts the clock pulse train of the clock pulse source 21 every time the transmitter 9 excites the transducer 2, and when the receiver 10 detects a submarine pulse, the counted value is sent to the latch circuit 12 and latched. be done. The latch value of the latch circuit 12 is θ
It corresponds to the time it takes for a sound wave sent in a direction to return.

In the above, the direction θ in which the ultrasonic transducer 2 transmits and receives ultrasonic pulses is controlled by the directivity angle control circuit 13, and the directivity angle control circuit 13 transmits data corresponding to the directivity angle θ to the horizontal distance calculation circuit 14. Send to. The horizontal distance calculation circuit 14 converts the ultrasonic pulse into θ
Calculate the horizontal distance L to the seabed when transmitting waves in the direction. The calculation result is sent to the storage circuit 7, and among the stored numerical values in the storage circuit 7, the stored numerical value D ₀ corresponding to the horizontal distance L calculated above is read out.
Therefore, the stored numerical value read out from the storage circuit 7 corresponds to the depth of the seabed position in the θ direction from the current position of the ship 3.

The depth data D ₀ read from the storage circuit 7 is sent to the propagation time calculation circuit 16 together with the distance data L sent from the horizontal distance calculation circuit 14 .

The propagation time calculation circuit 16 calculates the time it takes for an ultrasonic pulse transmitted in the θ direction to be reflected on the ocean floor in the θ direction and return. For example, the straight line distance R to the seabed in the θ direction can be found from R = √ ₀ ² + ² , so by dividing this straight line distance R by the propagation speed C of the sound wave, the theoretical distance to the sea bed in the θ direction can be calculated as follows. The round trip time of the sound wave can be found. Note that the propagation velocity C of the sound wave is determined to correspond to the water temperature of the surface layer.

However, in reality, water temperature is not uniform but changes with depth, and generally the water temperature becomes lower as the depth increases. In this case, the ultrasonic pulse transmitted in the θ direction is refracted as indicated by the dotted line B and reflected from the seabed slightly different from the theoretical seabed point. For this reason,
The time it takes for the reflected wave to return to the ultrasonic transducer 2 is shorter than the theoretical time, and this degree increases as the tendency of water temperature change increases. Also, when the water temperature increases with depth, the ultrasonic waves transmitted and received in the θ direction will move along the dotted line C, contrary to the above.
As a result of the refraction, the time it takes for the reflected wave to actually return is longer than the theoretical time.

The calculation result of the propagation time calculation circuit 16 is sent to the comparison circuit 1.
7 and the actual measurement time during which the latch circuit 12 is latched is calculated. and,
The comparison result is sent to the display 18 and displayed. Therefore, as is clear from the above, it is possible to know the tendency of the water temperature change from the value displayed on the display 18. Further, since the transmission/reception direction θ of the ultrasonic pulse can be arbitrarily varied, changes in water temperature can be observed in more detail by making measurements while varying the transmission/reception direction θ.

As explained above, according to the present invention, trends in water temperature changes can be determined simply by transmitting and receiving ultrasonic pulses from a sailing ship, making it possible to obtain an extremely useful device for use in searching for fishing grounds, etc. can.

In the above, the ultrasonic transducers 1 and 2 are configured to receive reflected waves from the seabed, but it is also possible to similarly detect water temperature change trends by using underwater reflected waves instead of seabed reflected waves. be able to.
In other words, a part of the sound waves transmitted into water is reflected near the boundary where the water temperature changes, and the sources of reflection are often widely distributed toward the water surface, so even if these reflected waves are used, the above cannot be achieved. In the same way, it is possible to know the tendency of changes in water sound.

Moreover, in the above, it is also possible to measure the water temperature based on the change tendency of the measured water sound.
That is, if a sound sensing element 22 is installed on the bottom of the boat 3 and the water temperature near the transducers 1 and 2 is measured with a water thermometer 23, and the water temperature change based on this water sound is calculated from the water temperature change trend described above, You can know the water temperature at each depth.

[Brief explanation of the drawing]

FIG. 1 shows an embodiment of the invention.

Claims (1)

[Claims] 1. A depth measuring device that measures the depth of a reflection source based on the time it takes to transmit an ultrasonic pulse from the bottom of a ship in a direction almost directly below and receive a reflected wave; and the depth measuring device. θ with respect to the ultrasonic wave transmission and reception direction of
an ultrasonic transceiver device that transmits ultrasonic pulses in a direction and measures the time it takes to receive a reflected wave from a reflection source at a depth measured by the depth measuring device; and a depth measured by the depth measuring device. and the transmission direction θ of the ultrasonic pulse of the ultrasonic transceiver device, the measurement depth in the θ direction and the theoretical time required for the ultrasonic pulse transmitted in the θ direction to return after being reflected. 1. A water temperature measuring device, comprising: calculating means, and measuring a tendency of change in water temperature based on a comparison between the calculating time and the measuring time of the ultrasonic wave transmitting/receiving device. 2 Ultrasonic wave transmission/reception direction θ of the ultrasonic wave transmission/reception device
2. The water temperature measuring device according to claim 1, wherein the temperature can be changed arbitrarily. 3. A depth measuring device that measures the depth of the reflection source based on the time it takes to transmit an ultrasonic pulse almost directly below the bottom of the ship and receive the reflected wave; and ultrasonic wave transmission and reception of the depth measuring device. θ with respect to the direction
an ultrasonic transceiver device that transmits ultrasonic pulses in a direction and measures the time it takes to receive a reflected wave from a reflection source at a depth measured by the depth measuring device; and a depth measured by the depth measuring device. and the transmission direction θ of the ultrasonic pulse of the ultrasonic transceiver device, the theoretical time it takes for the ultrasonic pulse transmitted in the θ direction to be reflected at the measurement depth in the θ direction and return. means for calculating, a water temperature measuring device for measuring water temperature near the depth of the transducer for transmitting and receiving the ultrasonic pulses, and calculating a ratio between the depth measured by the depth measuring device and the calculation time of the calculating means. A water temperature measuring device further comprising a calculation means for calculating the water temperature based on the ratio and the measured value of the water temperature measuring device. 4 Ultrasonic wave transmission/reception direction θ of the ultrasonic wave transmission/reception device
4. The water temperature measuring device according to claim 3, wherein the temperature can be changed arbitrarily.