CN105823548A - Sound velocity profiler based on TOF technology - Google Patents

Abstract

The invention relates to a sound velocity profiler based on a TOF technology, comprising a time and temperature measurement module with a TDC_GP22 chip as the core, an external transducer, and a temperature sensor. The TDC_GP22 chip sends a pulse signal to the transducer, the transducer emits ultrasonic waves, receives an echo signal and returns the echo signal to the TDC_GP22 chip, the needed echo signal is detected through a first wave detection function of the chip to get the round-trip time of echo, and time measurement is thus completed; and the TDC_GP22 chip carries discharge time measurement to get the resistance change of the temperature sensor, and temperature measurement is thus completed. The sound velocity profiler adopts the TOF technology, and is realized by the TDC_GP22 chip. By detecting the round-trip time of echo, the sound velocity can be calculated. As the chip has very high time detection resolution 'ps level', the data accuracy of single measurement is higher than the average data accuracy of multiple measurements using a 'sing-around method'.

Description

A kind of Sound speed profile instrument based on TOF technology

Technical field

The present invention relates to a kind of Sound speed profile instrument, a kind of Sound speed profile instrument based on TOF technology.

Background technology

Sound speed profile instrument is a kind of to measure the fine measuring instrument of different depth acoustic wave propagation velocity in water, the data such as the velocity of sound of current water layer, temperature, the degree of depth can be recorded fast and accurately by devices such as internal temperature, pressure transducers, a wherein measured important parameter needed for sound velocity data sonar especially, is widely used in the work such as water-depth measurement.But, along with the upgrading of various sonars, it is more and more higher to the required precision of the velocity of sound, and the most traditional instrument based on " ring ring method " measurement velocity of sound cannot meet the requirement of high accuracy acoustic velocity measutement.

In order to improve the certainty of measurement of Sound speed profile instrument, Sound speed profile instrument based on " time leap " technology no longer uses traditional " ring ring method " to carry out acoustic velocity measutement, but use the most state-of-the-art " time leap (TimeOfFlight) " technology to carry out acoustic velocity measutement, TOF (TimeofFlight) measuring principle is also known as echo ranging principle, it is a kind of method of non-contact distance-measurement, is currently widely used in level gauging.Its principle is: the transducer being arranged on Sound speed profile instrument pedestal launches ultrasound wave to reflecting surface, when in ultrasonic propagation to reflecting surface, reflects and returns to be received on transducer.

Summary of the invention

The technical problem to be solved in the present invention is to overcome existing defect, it is provided that a kind of Sound speed profile instrument based on TOF technology, can improve acoustic velocity measutement precision.

In order to solve above-mentioned technical problem, the invention provides following technical scheme:

A kind of Sound speed profile instrument based on TOF technology of the present invention, this Sound speed profile instrument includes the time with TDC_GP22 chip as core, temperature-measuring module, external transducer, temperature sensor, TDC_GP22 chip emission pulse signal is to transducer, transducer is launched ultrasound wave and receives echo-signal, returns to TDC_GP22 chip, detects Function detection to required echo-signal by the first wave of TDC_GP22 chip, drawing the two-way time of echo, the deadline measures；TDC_GP22 chip draws the resistance change of temperature sensor by measurement discharge time, completes temperature survey.

Further, this Sound speed profile instrument also includes the data processing module with single-chip microcomputer as core, is used for controlling TDC_GP22 chip operation, measure of time result is returned to single-chip microcomputer and carries out the accurate calculating of acoustic velocity value.

Further, during measure of time, transmitting and the reception of ultrasound wave use and share a transducer.

Further, TDC_GP22 chip has the temperature measurement unit on a PICOSTRAIN basis.

Further, the computing formula of temperature value is as follows:

$T=\frac{-R_0*A+\sqrt{{(R_0*A)}^2-4*R_0*B*(R_0-R_{RTD})}}{2*R_0*B}$

Wherein, A and B is the known parameters of platinum resistance, and its magnitude is respectively 10^-3With 10^-7, R₀The resistance value of platinum resistance, R when being 0 DEG C_RTDBeing the resistance value of platinum resistance under Current Temperatures, T is intended to the temperature surveyed.

Beneficial effects of the present invention: this Sound speed profile instrument uses TOF technology, and this technology realizes especially by TDC_GP22 chip, by detection ultrasound wave two-way time, so that it may calculate acoustic velocity value；Owing to TDC_GP22 chip has high time detecting resolution " ps level ", therefore, the only data precision of single measurement, just averagely obtained than changing " ring ring method " repetitive measurement data precision is high.

Accompanying drawing explanation

Fig. 1 is that the present invention uses TOF technology to carry out the schematic diagram of acoustic velocity measutement；

Fig. 2 is the circuit theory sketch of Sound speed profile instrument of the present invention.

Detailed description of the invention

Embodiment cited by the present invention; it is only intended to help and understands the present invention; should not be construed as limiting the scope of the present invention; for those skilled in the art; without departing from the inventive concept of the premise; can also make improvements and modifications the present invention, these improve and modification also falls in the range of the claims in the present invention protection.

1, the measurement of time

The measurement of time is the key that Sound speed profile instrument is measured, and this time resolution determines acoustic velocity measutement precision.TDC_GP22 chip 1 is the High-precision time-to-digital converter of latest generation.This chip has the certainty of measurement of ps level, and is being internally integrated tranmitting frequency and the most adjustable pulse generator of phase place, therefore uses this chip can meet high precision design requirement.

In Sound speed profile instrument based on TOF technology, in order to simplify structure, launch and receive the method using a shared transducer 2, and utilizing TOF know-why to carry out the measurement of the velocity of sound.Concrete grammar is as follows:

As shown in Figure 1, a plane of reflection 4 is fixed at distance transducer 2S, under the control of peripheral single-chip microcomputer, TDC_GP22 chip sends out frequency, the pulse signal that number is certain, this signal is received retroreflection plane 4 by transducer 2 and launches ultrasound wave, ultrasound wave is reflected plane 4 reflection and generates echo-signal and return to TDC_GP22 chip by transducer 2, Function detection is detected to required echo-signal by the first wave of chip, thus draw the two-way time of echo, acoustic velocity value C=2S/T, wherein S is the transducer 2 distance to the plane of reflection 4, T is the time that ultrasound wave once comes and goes.

2, the measurement of temperature

Temperature is used for calibrating the acoustic velocity value recorded as an important parameter of Sound speed profile instrument, because the velocity of sound and temperature have the biggest relation, the most high-precision temperature survey is very important in the design process of Sound speed profile instrument.TDC_GP22 chip 1 has the temperature measurement unit on a PICOSTRAIN basis, can realize the temperature survey of high accuracy and low-power consumption.Its principle is mainly based upon resistance to discharge time of electric capacity.Owing to the resistance value of temperature sensor RTD3 has direct relation with temperature, TDC_GP22 chip 1 will directly measure the resistance change of temperature sensor RTD3, is completed by internal point-device measure of time.During actual measurement, the reference resistance of a temperature stabilization and the resistance of temperature sensor RTD3 can be selected respectively same electric capacity to be carried out discharge and recharge, ratio according to they discharge times can show that the resistance of temperature sensor RTD3, concrete calculating process are shown in formula (1):

$R_{RTD}=\frac{(\frac{T_{RTD}}{T_{\mathrm{Re}f}}-1)*R_0}{ga\inf actor}---\left(1\right)$

Internal comparator is when 3.0V, and gain correction coefficient gainfactor is 0.9931, R₀The resistance value of platinum resistance when being 0 DEG C.

Resistance value according to platinum resistance thermometer and the relation equation below (2) of temperature:

R_RTD=R₀*(1+A*T-B*T²)(2)

Can draw:

$T=\frac{-R_0*A+\sqrt{{(R_0*A)}^2-4*R_0*B*(R_0-R_{RTD})}}{2*R_0*B}---\left(3\right)$

Wherein, A and B is regime values, and its magnitude is respectively 10^-3With 10^-7, it is all known for regular these parameters of platinum resistance product.R_RTDBeing the resistance value of platinum resistance under Current Temperatures, T is intended to the Celsius temperature surveyed.By the i.e. available required temperature value of above computing formula.

3, the circuit design of Sound speed profile instrument based on TOF technology

The circuit design of Sound speed profile instrument based on TOF technology is broadly divided into two parts, and Part I is the time with TDC_GP22 chip 1 as core, temperature-measuring module, needs the peripheral components such as external transducer 2, temperature sensor RTD3.Part II is the data processing module with STM32 single-chip microcomputer as core, and this part is mainly responsible for controlling TDC_GP22 chip 1 and is worked, and measure of time result is returned to single-chip microcomputer and carries out the accurate calculating of acoustic velocity value.

Owing to TDC_GP22 chip 1 is internal by highly integrated for the function of each unit, detect function, high-resolution hydrocode unit including first wave, pulse generator, analog switch, comparator, window function and clock demarcation etc., it is only necessary to outside adds a simple single-chip microcomputer just can carry out high-precision measurement.Therefore can accomplish in application process that hardware designs simplifies, and accomplishes minimum by the quantity of external component, thus the size of circuit board can be accomplished the least.

Fig. 2 is simple hardware designs schematic diagram.The temperature-measuring module peripheral circuit of TDC_GP22 chip 1 is simple, is primarily due to it and has been internally integrated a Schmidt trigger.In figure, R1 is temperature stabilized reference resistance, C1 is charge and discharge capacitance, PT1000 is the temperature sensor RTD3 selected, by the effective setting to TDC_GP22 depositor, transmitting terminal can send out transmitting signal, the analogue signal passed back is converted into digital signal through a comparator being internally integrated, and is given to stop input.TDC_GP22 chip 1 also has a time delays window, and this function can filter the noise of STOP signal leading portion.Add this chip and there is first wave detection function, can effectively record the pulse of first ripple, thus just can obtain the effective echo flight time.

Whole hardware designs has carried out preliminary experiment after completing, the standard velocity of sound that have chosen sound velocity data under 11 groups of different temperatures and corresponding temperature in experimentation contrasts, and result shows that data are attained by designing requirement in terms of stability, exact value and certainty of measurement.Wherein the precision of measured temperature can reach ± 0.05 DEG C, and resolution can reach 0.001 DEG C, and the certainty of measurement of the velocity of sound can reach 0.03m/s, and resolution can reach 0.001 meter per second.Therefore, present invention Sound speed profile based on TOF technology instrument, its hardware designs is simply easily achieved, and experimental data is preferable, can apply in the Sound speed profile instrument design of higher precision.

Claims (5)

1. a Sound speed profile instrument based on TOF technology, it is characterized in that: described Sound speed profile instrument includes with the TDC_GP22 chip (1) time as core, temperature-measuring module, external transducer (2), temperature sensor (3), TDC_GP22 chip (1) launches pulse signal to transducer (2), transducer (2) is launched ultrasound wave and receives echo-signal, return to TDC_GP22 chip (1), Function detection is detected to required echo-signal by the first wave of TDC_GP22 chip (1), draw the two-way time of echo, deadline measures；TDC_GP22 chip (1) draws the resistance change of temperature sensor (3) by measurement discharge time, completes temperature survey.

Sound speed profile instrument based on TOF technology the most according to claim 1, it is characterized in that: described Sound speed profile instrument also includes the data processing module with single-chip microcomputer as core, for controlling TDC_GP22 chip (1) work, measure of time result is returned to single-chip microcomputer and carries out the accurate calculating of acoustic velocity value.

Sound speed profile instrument based on TOF technology the most according to claim 1, it is characterised in that: during described measure of time, transmitting and the reception of ultrasound wave use and share a transducer (2).

Sound speed profile instrument based on TOF technology the most according to claim 1, it is characterised in that: described TDC_GP22 chip (1) has the temperature measurement unit on a PICOSTRAIN basis.

Sound speed profile instrument based on TOF technology the most according to claim 1, it is characterised in that: the computing formula of described temperature value is as follows:

$T=\frac{-R_0*A+\sqrt{{(R_0*A)}^2-4*R_0*B*(R_0-R_{RTD})}}{2*R_0*B}$

Wherein, A and B is the known parameters of platinum resistance, and its magnitude is respectively 10^-3With 10^-7, R₀The resistance value of platinum resistance, R when being 0 DEG C_RTDBeing the resistance value of platinum resistance under Current Temperatures, T is intended to the temperature surveyed.