JPS5852178B2 - How to get underwater temperature and depth information - Google Patents

Description

Detailed Description of the Invention The present invention records frequency changes due to the Doppler effect and changes in sound speed due to changes in water temperature together with standard signals, performs signal processing at any time after measurement, and provides highly accurate underwater temperature information. and a method for obtaining depth information.

BACKGROUND ART Various types of measuring instruments have conventionally been used to obtain underwater temperature information and depth information.

These measuring instruments use both a pressure sensor, a temperature sensor, or only a temperature sensor, and therefore measurement accuracy is determined by the performance of these sensors, and high accuracy requires complicated, expensive, and expensive measuring instruments. Moreover, it had the disadvantage of being large in size.

In addition, the accuracy of depth information was a problem with measuring instruments that only used temperature sensors.

Furthermore, measurement results are often recorded on paper, which is inconvenient for effective use.

The present invention is intended to solve the above-mentioned problems, and its purpose is to obtain underwater temperature and depth information without using any sensors such as temperature sensors or pressure sensors, and to provide the measurement results in a faithful form. The objective is to present a method for recording data at any time and processing it with high accuracy.

Hereinafter, the present invention will be described in detail with reference to the drawings of embodiments.

FIG. 1 is a block diagram of the measurement system, and FIG. 2 is a diagram showing transmission signals and standard signals.

In Figure 1, 1 is a stable oscillation circuit, 2 is a pulse modulation circuit for converting the oscillation signal into a burst signal, 3 is a power amplifier circuit for amplifying the burst signal modulated by the pulse modulation circuit 2, and 4 is an amplified circuit. A conversion element converts the signal into an acoustic signal, 5 is a receiver for receiving the transmitted signal, 6 is a standard signal generator, and 7 is a data recorder for simultaneously recording the signals from 5 and 6.

In FIG. 2, fl represents the carrier frequency, tp represents the pulse interval, and f2 represents the frequency of the standard signal.

First, by measuring the temperature just below the water surface, the speed of sound at that point can be determined.

If the pulse interval tp is small, the distance that the falling object falling in the transmitting system falls while the first burst signal is sent is short, so the water temperature change during this period can be considered small, and the first burst signal Speed of sound at the signal transmission point■1'
can be approximated by the above sound speed.

Also, if the change in carrier frequency at this point is Ifl, and the falling speed of the object is 1, then this is due to the Doppler effect.

In other words, the change in carrier frequency of the first pulse Jf
By measuring , the falling velocity V1 of the object at that point can be calculated.

Furthermore, assuming that the falling speed v1 of the object does not change significantly between the transmission of the first and second pulses, the falling distance y1 of the object during that time is yl p l °' °°°° °°°゛°°°
°°°°°°°°° (3).

The difference (At1-ip) between the received pulse interval time At1 and the standard pulse interval is the propagation time of the sound wave.

Therefore, here, (1) is the average speed of sound during the transmission of the first and second pulses.

Next, if the change in sound speed between the first and second pulse transmissions is small, the sound speed at the next point can be approximated by the average sound speed (1).

In other words, v'=v...
・・・・・・・・・・・・(6)1.

In other words, the pulse width is made small enough that the change in sound speed can be ignored during this time, and the falling speed of the object is calculated during this time.
Calculate the average sound speed between points 1 and 2 at this speed, approximate the average sound speed to the sound speed at the second position, and use the change in the carrier frequency of the second pulse to calculate the velocity of the object at the second position. Calculating the falling speed.

By repeating this sequentially, the depth y and the water temperature at that point T T =T c, V i' t Y +ρ)...
・・・・・・・・・・・・・・・・・・(8) is issued.

where ρ is the density of water in the sea or lake.

If we write these in general It is.

However, i: means the first signal, and also indicates the position of the falling object to which the signal is sent.

vH: Falling speed of the falling object at i.

V%: Average sound speed f1 between sound speed Vl'l at i and (t + 1): Carrier frequency Jfi: Carrier frequency fi of the signal sent from i
Difference between and fl Jti: Pulse sent from i and (t +1)
This is the time interval between pulses sent from

If the data recorder records not only the transmitted pulse signal from the falling object but also the standard signal on a separate channel as in the present invention, errors caused by uneven rotation of the data recorder and distortion of the tape can be eliminated as shown below. Since it can be calibrated, accurate vertical temperature distribution of water temperature can be obtained.

If the reproduction frequency of the standard signal corresponding to the pulse width is f2', the rate of change due to uneven rotation of the data recorder and distortion of the tape, If2', is Jf□-(f2'-f2)/f2...・・・・・・
・・・・・・α■.

If the carrier regeneration frequency in the pulse is fi/, then the true carrier frequency f· is given by the formula for α.

Similarly, if the reproduction frequency of the standard signal within the pulse interval is f2'', the rate of change Af2 is.

The reproduction time of the pulse interval, Jti (from formula 151, the true pulse interval [, (ti is given).

If you record a stable standard signal of frequency f2 from the standard oscillator 6 along with the signal as described above, and process it while always calibrating the rotation unevenness of the data recorder and tape distortion with this standard signal, you can record the signal at any time. It is possible to obtain exactly the same amount of information as during measurement.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a measurement system implementing the method of obtaining underwater temperature and depth information according to the present invention, and FIGS. 2a and 2b are diagrams showing waveforms of a transmitted signal and a standard signal. 1... Oscillation circuit, 2... Pulse modulation circuit, 3... Amplification circuit, 4... Conversion element, 5... Wave reception equipment, 6... standard signal generator, 7... data recorder.

Claims (1)

[Claims] 1 A falling object having an oscillation circuit, a pulse modulation circuit that converts the oscillation signal of the oscillation circuit into a burst signal, and an electroacoustic exchange unit that converts the burst signal into an acoustic signal is dropped into water, and the sound from the falling object is An acoustic pulse signal is received underwater and recorded by a recording device, and at the same time a stable standard signal is recorded by the recording device, and at an arbitrary time after recording, the standard signal and the acoustic pulse signal are recorded. Accurate carrier frequency and pulse interval are obtained by reproducing and calibrating errors in the carrier frequency and pulse interval of the acoustic pulse signal caused by the recording device and recording medium using the frequency difference between reproduction and recording of the standard signal. A method for obtaining underwater temperature and depth information, characterized in that the underwater temperature and depth information is obtained from the Doppler effect of the carrier frequency and the change of the pulse interval due to the water temperature.