CN117705257A - Measuring system, probe and sound velocity measuring method based on disposable sound velocity meter - Google Patents
Measuring system, probe and sound velocity measuring method based on disposable sound velocity meter Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H5/00—Measuring propagation velocity of ultrasonic, sonic or infrasonic waves, e.g. of pressure waves
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- Y02A90/30—Assessment of water resources
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Abstract
The embodiment of the invention discloses a measuring system, a probe and a sound velocity measuring method based on a disposable sound velocity meter. The method comprises the steps that a control instruction is generated by a pressure measurement module and a sound velocity measurement module in response to an acquisition unit, sound wave signals and pressure data of an underwater monitoring point are obtained, sound velocity data of the sound wave signals are determined by processing the sound wave signals, and the pressure data and the sound velocity data are uploaded to the acquisition unit; the acquisition unit receives sound velocity data and pressure data uploaded by the probe and sends the sound velocity data and the pressure data to the terminal processing unit; the terminal processing unit is used for receiving the pressure data and the sound velocity data sent by the acquisition unit, processing the pressure data to determine the depth data of the sound wave signals, generating sound velocity profile data based on the depth data and the sound velocity data, determining a sound velocity profile according to the sound velocity profile data and outputting the sound velocity profile data to the terminal display interface. By adopting the technical scheme, the accuracy of the sea water sound velocity profile data is improved.
Description
Technical Field
The invention relates to the field of sea water sound velocity measurement, in particular to a measurement system, a probe and a sound velocity measurement method based on a disposable sound velocity meter.
Background
The sound velocity measurement of the seawater relates to parameters such as the flow rate, temperature, salinity, sound velocity and the like of the seawater, and the parameters have very important significance for the safety and concealment of submarine navigation, underwater communication, underwater attack and the detection and anti-diving actions of water-surface ships and airplanes. The depth measurement of the sea water requires the probe to be submerged to a certain depth, and sound velocity data and depth data of the current submerged path are acquired.
When the sound velocity profile of a large-area water area needs to be measured, the sound velocity measuring sound velocity instrument is required to be capable of rapidly acquiring sound velocity data and depth data of a large number of sea water detection points, and the requirement of rapidly and accurately measuring the sound velocity profile of the large-area water area is met.
When the conventional disposable acoustic velocity meter measures underwater section data, the corresponding depth of the probe is often estimated by the time that the probe falls at a constant speed, so that the measured depth data are not accurate enough, and the accuracy of the acoustic velocity section data obtained based on the depth data is not high.
Therefore, how to stably and accurately acquire the seawater depth data becomes a technical problem to be solved when measuring the sound velocity profile of a large-area water area.
Disclosure of Invention
Aiming at the problem that the accuracy of sound velocity profile data obtained based on the depth data is low because the depth data obtained by measuring the sound velocity profile of a large-area water area in the prior art is not accurate, the embodiment of the invention provides a measuring system, a probe and a sound velocity measuring method based on a disposable sound velocity meter.
In a first aspect, the present invention provides a disposable acoustic velocimeter-based measurement system, the system comprising: the probe responds to the control instruction, obtains sound wave signals and pressure data of the underwater monitoring point through the pressure measurement module and the sound speed measurement module, processes the sound wave signals to determine sound speed data of the sound wave signals, and uploads the pressure data and the sound speed data to the acquisition unit; the acquisition unit is used for generating the control instruction, receiving the sound speed data and the pressure data uploaded by the probe and sending the sound speed data and the pressure data to the terminal processing unit; and the terminal processing unit is used for receiving the pressure data and the sound velocity data sent by the acquisition unit, processing the pressure data to determine the depth data of the sound wave signals, generating sound velocity profile data based on the depth data and the sound velocity data, determining a sound velocity profile according to the sound velocity profile data and outputting the sound velocity profile data to a terminal display interface.
In a second aspect, an embodiment of the present invention provides a probe based on a disposable acoustic velocity meter, including a control circuit board, an acoustic velocity sensor, a pressure sensor, and a transducer, where the control circuit board is connected to the acoustic velocity sensor and the pressure sensor, the acoustic velocity sensor is connected to the transducer, the transducer is configured to transmit an acoustic signal to a reflecting surface, the reflecting surface reflects the acoustic signal back to the transducer, and the transducer is fixedly connected to the reflecting surface through a support column.
In a third aspect, an embodiment of the present invention provides a method for measuring a sound velocity based on a disposable sound velocity meter, the method comprising: the acquisition unit wakes up the probe to perform power-on reset on the probe to finish initialization of the programmable device; the method comprises the steps that a control parameter sent by a terminal processing unit is received by an acquisition unit, and a control instruction is generated according to the control parameter; the probe obtains sound wave signals and pressure data of a plurality of underwater monitoring points according to the control instruction and sends the sound wave signals and the pressure data to the acquisition unit; the sound velocity data and the pressure data uploaded by the probe are received by the acquisition unit and are sent to the terminal processing unit; the terminal processing unit receives the pressure data and the sound velocity data sent by the acquisition unit, processes the pressure data to determine the depth data of the sound wave signals, generates sound velocity profile data based on the depth data and the sound velocity data, determines sound velocity profiles according to the sound velocity profile data of a plurality of underwater monitoring points and outputs the sound velocity profiles to a terminal display interface.
Compared with the prior art, the embodiment of the invention discloses a measuring system, a probe and a sound velocity measuring method based on a disposable sound velocity meter. The method comprises the steps that a control instruction is generated by a pressure measurement module and a sound velocity measurement module in response to an acquisition unit, sound wave signals and pressure data of an underwater monitoring point are obtained, sound velocity data of the sound wave signals are determined by processing the sound wave signals, and the pressure data and the sound velocity data are uploaded to the acquisition unit; the acquisition unit receives sound velocity data and pressure data uploaded by the probe and sends the sound velocity data and the pressure data to the terminal processing unit; the terminal processing unit is used for receiving the pressure data and the sound velocity data sent by the acquisition unit, processing the pressure data to determine the depth data of the sound wave signals, generating sound velocity profile data based on the depth data and the sound velocity data, determining a sound velocity profile according to the sound velocity profile data and outputting the sound velocity profile data to the terminal display interface. By adopting the technical scheme, the accuracy of the sea water sound velocity profile data is improved.
Drawings
FIG. 1 is a schematic illustration of a disposable acoustic velocity meter based measurement system according to an embodiment of the present invention;
FIG. 2 is a schematic structural view of a sound speed measurement module of the probe;
FIG. 3 is a schematic diagram of the structure of a transducer;
FIG. 4 is a schematic diagram of the relative pointing performance of a transducer;
FIG. 5 is a schematic diagram of the structure of the pressure measurement module;
FIG. 6 is a schematic diagram of the architecture of a system control module;
FIG. 7 is a schematic diagram of the structure of the acquisition unit;
FIG. 8 is an instruction protocol schematic of a control instruction;
FIG. 9 is a schematic diagram of the structure of a probe of a disposable sonic meter;
FIG. 10 is a flow chart of a sound velocity measurement method based on a disposable sound velocity meter according to an embodiment of the present application;
FIG. 11 is a schematic diagram of a probe continuously measuring sound speed data and pressure data;
FIG. 12 is a schematic diagram of an ultrasonic transmit pulse;
FIG. 13 is a schematic diagram of a primary amplified signal;
FIG. 14 is a schematic diagram of a two-stage filtered signal;
fig. 15 is a schematic diagram of the measurement result of the sound velocity in pure water;
fig. 16 is a schematic diagram of the measurement result of the actual sound velocity;
FIG. 17 is a schematic diagram of 200 sound speed values measured once at a temperature;
fig. 18 is a schematic diagram of measurement results after the measurement values of other acoustic velocity meters are set as standard values.
Detailed Description
The terms first, second and the like in the description and in the claims of the present application and in the above-described figures, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and are merely illustrative of the manner in which the embodiments of the application described herein have been described for objects of the same nature. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The sound velocity measurement of the seawater relates to parameters such as the flow rate, temperature, salinity, sound velocity and the like of the seawater, and the parameters have very important significance for the safety and concealment of submarine navigation, underwater communication, underwater attack and the detection and anti-diving actions of water-surface ships and airplanes. The depth measurement of the sea water requires the probe to be submerged to a certain depth, and sound velocity data and depth data of the current submerged path are acquired.
When the sound velocity profile of a large-area water area needs to be measured, the sound velocity measuring sound velocity instrument is required to be capable of rapidly acquiring sound velocity data and depth data of a large number of sea water detection points, and the requirement of rapidly and accurately measuring the sound velocity profile of the large-area water area is met.
Through years of research, the technology of XBT and a disposable salt-depth thermometer (XCTD) is mature, and at present, several companies in China can independently produce XBT and XCTD. The disposable sonic meter (XSV) has high technical difficulty, so that some problems in the research, development and production process need to be overcome, and the disposable sonic meter is always in a forbidden operation state, and no company can provide XSV products at home at present.
When the conventional disposable acoustic velocity meter measures underwater section data, the corresponding depth of the probe is often estimated by the time that the probe falls at a constant speed, so that the measured depth data are not accurate enough, and the accuracy of the acoustic velocity section data obtained based on the depth data is not high.
Therefore, how to stably and accurately acquire the seawater depth data by measuring the sound velocity profile of a large-area water area becomes a technical problem to be solved.
In order to achieve the purpose of improving the accuracy of measuring the sound velocity profile of a large-area water area, a measuring system, a probe and a sound velocity measuring method based on a disposable sound velocity meter are provided. By arranging the pressure sensor in the sound velocity measuring probe of the disposable sound velocity meter, the sea water pressure measuring precision is improved, and corresponding sea water depth data is obtained, so that the measuring accuracy of the sound velocity profile is improved. Meanwhile, the embodiment of the application also provides a high-precision sound velocity measurement and calibration scheme, and scheme verification is provided for a measurement system based on the disposable sound velocity meter.
Illustratively, fig. 1 shows a measurement system based on a disposable acoustic velocity meter according to an embodiment of the present invention, and as shown in fig. 1, the system includes a probe 100, an acquisition unit 200, and a terminal processing unit 300. The probe 100 and the acquisition unit 200 are interconnected by a first data channel, and the acquisition unit 200 is interconnected by a second data channel.
By way of example, but not limitation, the first data channel mode in the embodiment of the present application is not limited, and in order to ensure the communication quality of the channel of the wired communication system, the first data channel may be implemented by using the enameled wire of 485 bus protocol in the embodiment of the present invention to determine the drop distance of the disposable instrument.
By way of example, but not limitation, the second data channel mode is not limited in the embodiment of the present application, and in order to ensure the communication redundancy and the transmission speed of the channel of the wired communication system, the embodiment of the present invention may be implemented by adopting a USB (universal serial bus) to implement the second data channel, or may be implemented by a USB (UART (universal asynchronous receiver transmitter), an I2C (integrated circuit bus), an SPI (serial peripheral interface), or the like.
The probe 100 comprises a sound velocity measurement module 110, wherein the sound velocity measurement module 110 is used for acquiring sound velocity data of an underwater monitoring point; the pressure measurement module 120 is used for acquiring pressure data of the underwater monitoring point; the system control module 130, the system control module 130 is configured to receive and execute a control instruction generated by the acquisition unit 200; a power supply module 140, the power supply module 140 being configured to supply power to the probe 100; the communication module 150, the communication module 150 is configured to upload the acquired pressure data and sound velocity data to the acquisition unit 200.
Specifically, the probe 100 is powered by a battery, provides an output voltage of 6V, outputs ±3.3v through the power supply module 140, and supplies power to the singlechip, the sound velocity measurement module and the pressure measurement module. In order to improve the accuracy of measurement, +3.3V should be generated by using a linear voltage regulator (LDO) with good stability and small output ripple.
Specifically, the sound velocity and depth data are transmitted to the acquisition unit 200 in time for convenience. In this embodiment of the present application, the first data channel of the communication module 150 is implemented by using a 485 bus, and the 485 bus has the characteristics of stronger anti-interference capability and suitability for long-distance transmission.
The acquisition unit 200 comprises an instruction control module 210, wherein the instruction control module 210 is used for generating a control instruction to control the probe to work, stop and sleep; a data receiving module 220, wherein the data receiving module 220 is configured to receive the uploaded sound speed data and pressure data; a data transmission module 230, wherein the data transmission module 230 is configured to send the sound velocity data and the pressure data to the terminal processing unit 300.
The terminal processing unit 300 includes a communication module 310, where the communication module 310 is configured to receive the sound velocity data and the pressure data sent by the terminal processing unit, and in this embodiment, the communication module 310 is further configured to generate a control instruction to perform an instruction operation on the probe 100; a data processing module 320, where the data processing module 320 is configured to process the pressure data to determine depth data of the acoustic signal, and generate sound velocity profile data based on the depth data and the sound velocity data; the sound velocity profile drawing module 330 is used for determining sound velocity profiles according to sound velocity profile data of a plurality of underwater monitoring points; the display interface 340, where the terminal display interface 340 includes a communication setting page, a data display page, a file list page, and a sound velocity profile display page, and is used to display the sound velocity profile.
The embodiment shown in fig. 1 is merely illustrative. For example, the division of the modules is merely a logic function division, and there may be another division manner in actual implementation. For example, multiple modules or components may be combined or may be integrated into another system, or some features may be omitted, or not performed. Each functional module in each embodiment of the present application may be integrated into one processing module, or each module may exist alone physically, or two or more modules may be integrated into one module.
By way of example, fig. 2 shows a schematic structural diagram of a sound velocity measurement module of the probe, and as shown in fig. 2, the sound velocity measurement module 110 includes a time digital integrated circuit 111, where the time digital integrated circuit 111 is used for outputting a sound wave signal and receiving an echo signal; an amplifying circuit 112, the amplifying circuit 112 being configured to amplify the reflected echo signal; a filter circuit 113, wherein the filter circuit 113 is used for filtering the amplified echo signal; the transducer 114, the transducer 114 is used for generating sound wave according to the sound wave signal, receive echo.
Specifically, the time-to-digital integrated circuit 111 needs to be externally connected with two crystal oscillators, namely a 32.768KHz quartz crystal oscillator and a 4MHz ceramic crystal oscillator. The crystal oscillator frequency of 4MHz is used as a reference high-speed clock, the crystal oscillator frequency of 32.768KHz is used as a reference clock frequency for controlling the starting time of the reference high-speed clock frequency and calibrating the reference clock frequency, and the crystal oscillator frequency can also be independently used as another complete driver.
Pins 1110, 1111, 1112, 1113, 1114, 1115, 1116, 1117, 1118, 1119 are provided within the time-digital integrated circuit 111. The specific definition of the pin of the time digital integrated circuit in the embodiment of the application includes:
pin 1110: is a pulse transmitting port;
pin 1111: is a pulse receiving port;
pin 1112: outputting the echo signal to the amplifying circuit 112;
pin 1113: receiving the echo signal processed by the filter circuit 113;
pin 1114 and pin 1115: enabling the pin to receive control signals sent by the system control module 130 for the time digital integrated circuit 111 signal; the pin is high level enabled.
Pins 1116-1119: seven registers of the time digital integrated circuit 111 are configured for communication pins of the SPI through pins 1116-1119, so that control of the chip is realized.
In the embodiment of the present application, the time digital integrated circuit 111 further includes other pins related to clock, power supply and extension, so that the time digital integrated circuit 111 can implement the above functions, and other pin definitions are not limited herein.
Under ideal conditions, no external noise or very little noise will not affect the measurement accuracy, and the time-digital integrated circuit 111 can accurately determine the weak first wave signal in the echo. However, in a complex marine environment, the amplitude of the echo signal is smaller than that of the echo signal in an experimental environment, and is usually only tens of millivolts, and the signal to noise ratio is low, which seriously affects the accuracy of the first wave detection of the time digital integrated circuit 111, so that the echo signal needs to be processed, amplified and filtered, and a useful signal is reserved.
The amplifier circuit 112 preferably selects an operational amplifier having a high voltage conversion Rate (Slew Rate) and a large gain bandwidth product (Gain bandwidth product) in terms of operational amplifier selection. In the embodiment of the invention, the gain bandwidth product of the operation development device is 20MHz, the high common mode rejection ratio is 94dB, and the voltage swing is 30 v/mu s. The in-phase proportional amplification factor is controlled by adjusting the peripheral resistor, and the mathematical expression of the amplification factor is as follows:
the filter circuit 113 may set the center frequency of the band-pass filter, the passband amplification a, and the scaling factor K, and in the embodiment of the present invention, the center frequency of the second-order band-pass filter is about 1MHz.
More specifically, fig. 3 shows a schematic structural diagram of the transducer, and as shown in fig. 3, the transducer 114 includes a body 114, a support column 115, and a reflecting surface 116. In order to improve the measurement accuracy, in the embodiment of the invention, the transducer 114 is made of a circular piezoelectric ceramic plate with a center frequency of 1MHz and a diameter of 16 mm. Fig. 4 is a schematic diagram of the relative directional performance of the transducer, as shown in fig. 4, with the 3dB open angle of the transducer being only about 6 ° and having very good directivity. The support column 115 between the transducer 114 and the reflecting surface 116 is typically made of conventional metal materials such as carbon fiber, stainless steel, titanium alloy, etc., and in order to reduce the influence of temperature on measurement, in the embodiment of the present invention, the support column 115 is implemented by carbon fiber.
For example, fig. 5 shows a schematic structural diagram of a pressure measurement module, and as shown in fig. 5, the pressure measurement module 120 includes a pressure sensor 121, where the pressure sensor 121 is used to collect a pressure signal; a pressure amplifier 122, the pressure amplifier 122 being configured to amplify the collected pressure signal; the output ends of the first voltage compensation circuit 123 and the second voltage compensation circuit 124 are connected with a voltage follower formed by the pressure amplifier 122, and the voltage follower is used for providing bias voltage for a reference voltage pin of the pressure amplifier 122.
Specifically, when the pressure sensor 121 is selected, a pressure sensor with short response time, good linearity and small integrated error is selected as much as possible. In the embodiment of the invention, the ceramic pressure sensor is finally determined to be used through repeated experiments. Table 1 is a relevant parameter for the 100bar range of the pressure sensor, as shown in table 1.
Table 1 relevant parameters of the 100bar range of the pressure sensor
| Supply voltage | 2～30V | Precision of | 0.2～0.4％FS |
| Response time | <1ms | Temperature characteristics | ±0.015％FS/℃ |
| Stability of | <0.2% FS/year | Operating temperature | -40℃～+135℃ |
In the embodiment of the application, the range of the designed working depth is 0-1000 m, and pressure sensors with different measuring ranges can be selected according to different working depths.
In the embodiment of the invention, the pressure amplifier 122 adopts a micro-power consumption zero drift instrumentation amplifier, the gain error of the pressure amplifier 122 is 0.005%, the maximum value of input bias current is only 650pA, the voltage noise is only 68 nV/. V Hz, and the current noise is only 70 fA/. V Hz. The mathematical expression of the amplification gain G is as follows:
the pressure data are collected by the pressure measurement module 120 and uploaded to the terminal processing unit 300 through the collection unit 200, the data module of the terminal processing unit 300 processes the pressure data to finally determine depth data of a plurality of underwater detection points, and the mathematical expression for determining the depth data through the pressure data is as follows:
wherein z is depth, c 1 c 2 c 3 c 4 Is constant, c 1 ＝9.72659，c 2 ＝-2.2512*10 -5 ，c 3 ＝-2.279*10 -10 ，c 4 ＝-1.82*10 -15 ，γ′＝2.184*10 -6 ms -2 db， For the specific volume deviation, g (phi) = 9.780318 (1.0+5.2788 sin 2 (φ)-10 -5 *sin 4 (φ))[ms -2 ]。
For example, fig. 6 shows a schematic structural diagram of a system control module, and as shown in fig. 6, a system control module 130 is a control core of a circuit of an underwater probe part, and is used for performing sound velocity measurement and pressure measurement, packaging measured data, and transmitting the data to an emission acquisition unit through an enameled wire between the probe and the emission acquisition unit.
In the embodiment of the present invention, the system control module 130 includes a first programmable device 131, a peripheral circuit 132, and interfaces 133 to 138. The first programmable device 131 is configured to support FPU floating point operations and DSP instructions; can be externally connected with an external high-speed crystal oscillator with the frequency of 4-26M, and the highest working frequency can reach 168MHz. STM32F407 is abundant in peripheral equipment, has 144 IO pins, supports multiple communication protocols, can satisfy the design requirements of XSV (such as SPI communication, ADC acquisition, GPIO output and the like), supports SWD and JTAG interface downloading and debugging programs, and is convenient for system development.
The peripheral circuit 132 is used to provide functions such as start, reset, enable, clock, etc. to the time digital integrated circuit 111.
The interface 133 is configured to send control instructions to the sound speed measurement module 110.
The interface 134 is configured to receive sound speed data sent by the sound speed measurement module 110.
The interface 135 is used to send control instructions to the pressure measurement module 120.
The interface 136 is configured to receive a control instruction sent by the acquisition unit 200.
The interface 137 is used for sound speed data and pressure data sent to the acquisition unit 200.
In this embodiment of the present application, the probe 100 is a direct-reading instrument without a storage module, and cannot store collected data, where the data is transmitted to the water collection unit through the first data channel, and the water collection unit also sends an instruction to the probe through the first data channel, and after the system is powered on, initializes and configures GPIO pins and serial ports communications at first: setting the GPIO pin as a multiplexing function; the first data channel communication baud rate is set to 1000, the valid data bit is 8, a stop bit, no check is used, and the control is set to enable both reception and transmission. And configures the interrupt controller and enables USART to receive interrupts. USART has received the data and then executes the interrupt routine.
Illustratively, table 2 is a communication protocol in which the probe 100 transmits data, as shown in table 2. And packaging the acquired sound velocity and depth data in a data transmission program, transmitting a group of acquired data to a transmitting unit, and transmitting the acquired data to be acquired again.
Table 2 is a communication protocol for transmitting data by the probe 100
Fig. 7 is a schematic structural diagram of an acquisition unit, and as shown in fig. 7, the acquisition unit includes a second programmable device 210, and a peripheral circuit 220, where the second programmable device 210 further includes a firmware program, and the firmware is executed to send a control instruction to the probe 100, where the control instruction controls the probe to work. The peripheral circuit 220 is used to provide functions such as start, reset, enable, clock, etc. to the second programmable device 210.
For example, fig. 8 shows an instruction protocol schematic of a control instruction, and as shown in fig. 8, a specific definition of the instruction protocol is as follows:
5a01H (first instruction): communication test with the probe, wherein if the first response '00' is returned, the test is successful, if the first response 'DD' is returned, the sending timeout is indicated, if the third response 'EE' is returned, the receiving timeout is indicated, and if the first response 'FF' is returned, the data error is indicated;
5a02XXH (second instruction): notifying the probe to collect XX pressure data and displaying the data in a receiving text;
5a 03XXH (third instruction): notifying the probe to collect XX sound velocity data and displaying the data in a receiving text;
5a 04h (fourth instruction): informing the probe to enter a continuous working mode, and continuously uploading the collected pressure data and sound speed data;
5a 05h (fifth instruction): notifying the probe to stop collecting;
5a 09H (sixth instruction): and notifying the probe to sleep.
If the terminal sends '5A 01H' to the MCU, the data forwarding module and the probe perform communication test, the test is successful, the terminal returns '00', if the sending is overtime, returns 'DD', if the receiving is overtime, returns 'EEEE', if the receiving is overtime, returns 'FF'; if the terminal sends '5A02XXH', XX pressure data are sent to the probe, and the probe returns the pressure data to the water acquisition unit after the data are acquired. If the terminal sends '5A 03XXH', XX sound velocity data are sent to the probe, and the probe returns pressure data to the water acquisition unit after the data are acquired. If the terminal sends '5A 04H', a working signal is sent to the probe, the probe enters a continuous working mode, and the collected pressure and sound speed data are continuously uploaded; if the terminal sends '5A 20H', the probe is informed to stop acquisition, and the instruction is the same as pressing a stop receiving button; if the terminal sends '5A 09H', the probe is informed to sleep.
The foregoing is a related description of a disposable acoustic velocimeter-based measurement system. Based on the foregoing, the embodiment of the application provides a probe based on a disposable acoustic velocity meter.
Illustratively, fig. 9 shows a schematic diagram of the structure of a probe of a disposable sonic meter, which includes a control circuit board 131, a sonic sensor 111, a pressure sensor 121, and a transducer 114, as shown in fig. 9.
The control circuit board 131 is connected with the sound velocity sensor 111 and the pressure sensor 121, the sound velocity sensor 111 is connected with the transducer 114, the transducer 114 is used for transmitting sound wave signals to the reflecting surface 116, the reflecting surface 116 reflects the sound wave signals back to the transducer 114, and the transducer and the reflecting surface are fixedly connected through the supporting column 115.
Next, a topology generation method provided by the embodiment of the present application is described based on the above description. It will be appreciated that the method is set forth based on what has been described above, some or all of which may be found in the description above.
Referring to fig. 10, fig. 10 is a flowchart illustrating a sound velocity measurement method based on a disposable sound velocity meter according to an embodiment of the present application. It will be appreciated that the method is performed by the disposable sonic based system shown in fig. 1. As shown in fig. 10, the sound speed measurement method includes S10 to S30:
s10: and the acquisition unit wakes up the probe to perform power-on reset on the probe to finish the initialization of the programmable device.
In this embodiment, the acquisition unit 200 sends 5a01H (first instruction) to the probe 100, and performs a communication test with the probe, and if a first response "00" is returned, the test is successful, if a first response "DD" is returned, the sending timeout is indicated, if a third response "EE" is returned, the receiving timeout is indicated, and if a first response "FF" is returned, the data error is indicated;
s20: the acquisition unit waits for the control parameters sent by the terminal processing unit, generates control instructions according to the control parameters, and controls the probe to work.
In the embodiment of the present application, the acquisition unit 200 transmits 5a02xxh (second instruction) to the probe 100: notifying the probe to collect XX pressure data and displaying the data in a receiving text; 5a 03XXH (third instruction): notifying the probe to collect XX sound velocity data and displaying the data in a receiving text; 5a 04h (fourth instruction): informing the probe to enter a continuous working mode, and continuously uploading the collected pressure and sound speed data;
s30: and the probe acquires sound velocity data and pressure data according to the control instruction.
In the embodiment of the present application, the probe 100 collects sound velocity data and pressure data according to the control command in the aforementioned step S20.
If the instruction received by the probe 100 is the second instruction, XX pressure data are collected and returned to the collection unit 200;
if the instruction received by the probe 100 is the third instruction, XX sound velocity data are collected and returned to the collection unit 200;
if the instruction received by the probe 100 is the fourth instruction, the continuous acquisition phase is entered, and sound velocity data and pressure data are continuously returned to the acquisition unit.
Specifically, fig. 11 is a schematic diagram of the probe continuously measuring sound velocity data and pressure data, and as shown in fig. 11, continuous acquisition of sound velocity data and pressure data is completed through steps S31 to S34.
S31: after the probe 100 receives the fourth instruction, the sound speed measuring module 110 starts measuring the flight time of the sound wave, namely, sound speed data;
s32: after the measurement is finished, the first programmable device 131 generates an interrupt, and the second programmable device reads the measured time;
s33: the pressure measurement module 120 then begins the pressure measurement;
s34: after the pressure measurement is completed, the communication module 150 packages the sound velocity data and the pressure data and uploads them to the on-water collection unit 200.
The foregoing is a related description of a method for measuring sound velocity based on a disposable sound velocity meter according to an embodiment of the present application. The validation analysis of the feasibility and the reliability of the measuring system, the probe, the acquisition unit and the method of the disposable sound velocity meter is carried out, and the validation analysis is specifically as follows.
In the embodiment of the application, firstly, a sound velocity measurement module of a disposable sound velocity meter is debugged, and then a calibration scheme is formulated by analyzing factors influencing sound velocity measurement accuracy; finally, through a large number of experiments, the stability and the reliability of the disposable acoustic velocity meter are verified.
For example, fig. 12 is a schematic diagram of an ultrasonic wave transmitting pulse, and as shown in fig. 12, the main control chip acquisition unit 200 sends a single time measurement command (0 x 01) to the sound velocity measurement module 110, and the sound velocity measurement module 110 outputs a pulse signal driving the transducer to generate a frequency of 1MHz through the pin 1110.
In the embodiment of the application, the measuring system of the disposable acoustic velocity meter adopts the transducer integrating receiving and transmitting, and after the transducer sends out the pulse, the pulse is reflected by the reflecting surface after a period of time and finally received by the transducer. The amplitude of the echo signal is only tens of millivolts, and the echo signal contains high-frequency noise, and the original echo signal is shown in fig. 12, so that the first wave detection of the sound velocity measurement module 110 cannot be accurately judged. Fig. 13 is a schematic diagram of a first-stage amplified signal, and as shown in fig. 13, the signal amplitude of the waveform is increased after passing through the first-stage amplifying circuit. Fig. 14 is a schematic diagram of a two-stage filtered signal, as shown in fig. 14, where the signal of the waveform is flattened after passing through a bandpass filter circuit.
In this embodiment, the temperature of the seawater gradually decreases as the depth of the water increases during operation of the probe 100. The change of the ambient temperature can cause thermal expansion and contraction of mechanical components related to the measuring transducer and temperature drift of electronic components, so that the measuring accuracy is reduced.
Illustratively, table 2 is a table of the linear expansion coefficient of a common material, and as shown in table 2, the distance between the transducer 114 and the emission surface 116 is L, and the transmission distance of the acoustic wave during measurement is 2L. The temperature change can cause the support rod 115 between the transducer 114 and the emitting surface 116 to expand with heat and contract with cold, so that the distance L is changed, and the measurement accuracy is affected.
Table 2 table of the coefficient of linear expansion of common materials
| Material | Coefficient of thermal expansion (. Times.10-6/. Degree.C) |
| Copper (Cu) | 17.7 |
| Iron (Fe) | 13 |
| Carbon steel | 11.52 |
| Titanium alloy | 10.41 |
| Carbon fiber composite material | 7.12 |
As can be seen from table 2, the carbon fiber composite material has the smallest thermal expansion coefficient and the copper thermal expansion coefficient is the largest. Assuming that the length (sound propagation distance) of the support rod is 5cm, according to a thermal expansion coefficient formula Δl=a×l×Δt and v=2l/T, wherein Δl is a length change, a is a thermal expansion coefficient, L is a length, Δt is a change amount, assuming that sound velocity v=1500 m/s, Δt=30deg.C (sea water temperature change is typically between-2 ℃ and-30 ℃), an error introduced by the carbon fiber support rod is 0.030m/s, an error introduced by the copper support rod is 0.079m/s, and an error caused by the carbon fiber composite material is smaller.
For example, table 3 shows the circuit board temperature and the measurement result, and as shown in table 2, in addition to the influence on the structure of the probe 100, the temperature change may affect the chip, crystal oscillator, resistance-capacitance, etc. used in the measurement circuit, thereby affecting the measurement result. When designing the circuit, the critical part of the circuit should select the low temperature drift device, and the influence of temperature change on measurement should be verified. The method can be used for verifying by ensuring that external environmental factors are unchanged, only changing the temperature of the circuit board and observing the change of the measurement time.
TABLE 3 Circuit Board temperature and measurement results
From Table 3, it is seen that the trend of the temperature change and the measurement time result are substantially linear, the time measurement difference between the circuit board temperature at 10℃and the circuit board temperature at 30℃is 0.0006us, and the influence on the sound velocity measurement is about 0.015m/s.
Based on the above-mentioned influencing factors, assuming that the factors influencing the accuracy of the measurement time are only distance errors and circuit delays, it can be derived that:
t 1 ＝A*t+B
t＝k 1 *t 1 +k2
wherein k is 1 ＝1/A，k 2 ＝-B/A，t 1 For the time measured by the probe 100, t is a theoretical time value, A is the ratio of the actual propagation distance to the assumed propagation distance, and B is the circuit delay.
Measuring time t by a high-precision instrument, repeatedly measuring multiple groups of data, and obtaining t by matlab fitting 1 And t, and finally calculating the sound velocity value V=2S/t.
The calibration of the acoustic speed meter is mostly carried out in pure water, and in the embodiment of the application, the preliminary system test is carried out in pure water and is compared with the pure water acoustic speed meter for calibration. Fig. 15 is a schematic diagram of the measurement result of the sound velocity in pure water, and fig. 16 is a schematic diagram of the measurement result of the actual sound velocity. As shown in fig. 15 and 16, fitting by a least square method is performed to obtain a fitting formula t=1.9633×t 1 +1.2362, the sound velocity is calculated as v=1/t. The fitting formula is added into the acquisition unit 200, sound velocity data are acquired again and calculated, and compared with a pure water sound velocity meter, so that the relative error of sound velocity measurement is +/-0.07 m/s.
In the calibration process, due to the influence of circuit delay, environmental interference and the like, some errors exist in the measurement result by accident, fig. 17 shows a schematic diagram of 200 sound velocity values measured at a certain temperature in a single time, and as shown in fig. 17, the mathematical statistical mathematical expression of the sound velocity values is as follows:
wherein x is i For a single measurement of the sound speed value,mean value, S n Variance, σ is standard deviation. The average of 200 sound velocity values is 1507.486m/s, standard deviation σ= 01.75, +_according to the Laida criterion>The value is judged as an abnormal value and is removed. As can be seen from fig. 17, there are only 2 outliers in two hundred samples, demonstrating the stability of the measurement results.
In the embodiment of the application, due to the limitation of experimental conditions, the outfield system experiment adopts a simulation form, tests under the constant temperature condition, measures sound velocity values under different salinity, and adopts other sound velocity meters for calibration. After calibration, the fitting formulas of the two are added into the acquisition unit 200, sound velocity data are acquired again and calculated and compared with other sound velocity meters, fig. 18 shows a schematic diagram of measurement results obtained by taking measurement values of other sound velocity meters as standard values, and as shown in fig. 18, the relative error of sound velocity measurement is +/-0.2 m/s, so that the accuracy requirement of the disposable sound velocity meter is met.
The embodiment of the invention discloses a measuring system, a probe and a sound velocity measuring method based on a disposable sound velocity meter. The method comprises the steps that a control instruction is generated by a pressure measurement module and a sound velocity measurement module in response to an acquisition unit, sound wave signals and pressure data of an underwater monitoring point are obtained, sound velocity data of the sound wave signals are determined by processing the sound wave signals, and the pressure data and the sound velocity data are uploaded to the acquisition unit; the acquisition unit receives sound velocity data and pressure data uploaded by the probe and sends the sound velocity data and the pressure data to the terminal processing unit; the terminal processing unit is used for receiving the pressure data and the sound velocity data sent by the acquisition unit, processing the pressure data to determine the depth data of the sound wave signals, generating sound velocity profile data based on the depth data and the sound velocity data, determining a sound velocity profile according to the sound velocity profile data and outputting the sound velocity profile data to the terminal display interface. By adopting the technical scheme, the accuracy of the sea water sound velocity profile data is improved.
The foregoing description of the embodiments has been provided for the purpose of illustrating the general principles of the invention, and is not meant to limit the scope of the invention, but to limit the invention to the particular embodiments, and any modifications, equivalents, improvements, etc. that fall within the spirit and principles of the invention are intended to be included within the scope of the invention.
Claims (10)
1. A disposable acoustic speed meter-based acoustic speed measurement system, the system comprising:
the probe responds to the control instruction, obtains sound wave signals and pressure data of a plurality of underwater monitoring points through the pressure measurement module and the sound speed measurement module, processes the sound wave signals to determine sound speed data of the sound wave signals, and uploads the pressure data and the sound speed data to the acquisition unit;
the acquisition unit generates the control instruction according to the control parameter sent by the terminal processing unit, receives the sound velocity data and the pressure data uploaded by the probe and sends the sound velocity data and the pressure data to the terminal processing unit;
the terminal processing unit is used for receiving control parameters input by a terminal display interface, sending the control parameters to the acquisition unit, receiving the pressure data and the sound speed data sent by the acquisition unit, processing the pressure data to determine the depth data of the sound wave signals, generating sound speed profile data based on the depth data and the sound speed data, determining sound speed profiles according to the sound speed profile data of a plurality of underwater monitoring points, and outputting the sound speed profiles to the terminal display interface.
2. The sound speed measurement system of a disposable sound speed meter of claim 1, wherein the probe comprises:
the sound velocity measuring module is used for acquiring sound velocity data of the underwater monitoring point;
the pressure measurement module is used for acquiring pressure data of the underwater monitoring point;
the system control module is used for receiving and executing the control instruction generated by the acquisition unit;
the power supply module is used for supplying power to the probe;
the communication module is used for uploading the acquired pressure data and sound velocity data to the acquisition unit.
3. The sound speed measurement system of a disposable sound speed meter of claim 1, wherein the acquisition unit comprises:
the instruction control module is used for generating control instructions and controlling the probe to work, stop and sleep;
the data receiving module is used for receiving the uploaded sound speed data and pressure data;
and the data transmission module is used for transmitting the sound velocity data and the pressure data to a terminal processing unit.
4. The sound speed measurement system of the disposable sound speed meter according to claim 1, wherein the terminal processing unit 300 comprises:
the communication module is used for receiving the sound velocity data and the pressure data sent by the terminal processing unit;
the data processing module is used for processing the pressure data to determine depth data of the sound wave signals and generating sound velocity profile data based on the depth data and the sound velocity data;
the sound velocity profile drawing module is used for determining sound velocity profiles according to sound velocity profile data of a plurality of underwater monitoring points;
the terminal display interface comprises a communication setting page, a data display page, a file list page and a sound velocity profile display page, and is used for displaying the sound velocity profile.
5. The sound speed measurement system of a disposable sound speed meter of claim 4, wherein:
the data display page is used for receiving control parameters input by the page and outputting the control parameters to the acquisition unit;
the acquisition unit generates the control instruction according to the control parameter to control the probe to work.
6. The sound speed measurement system of a disposable sound speed meter of claim 1, wherein the control instructions comprise: a first control instruction for communication test with the probe; notifying the probe to collect a plurality of second control instructions of the pressure data; notifying the probe to acquire a plurality of third control instructions of the sound velocity data; a fourth control instruction for notifying the probe to continuously collect the pressure data and the sound velocity data; a fifth control instruction for notifying the probe to stop acquisition; and a sixth control instruction for notifying the probe to sleep.
7. The system of claim 5, wherein the probe returns a response to the acquisition module according to the first control command, the response comprising: a first response indicating that the test is successful, a second response indicating that the test instruction is overtime, a third response indicating that the test instruction is overtime, and a fourth response indicating that returned sound velocity data and pressure data have errors.
8. The utility model provides a probe based on disposable sound velocity appearance, includes control circuit board, sound velocity sensor, pressure sensor, transducer, its characterized in that:
the control circuit board is connected with the sound velocity sensor and the pressure sensor, the sound velocity sensor is connected with the transducer, the transducer is used for transmitting sound wave signals to the reflecting surface, the reflecting surface reflects the sound wave signals back to the transducer, and the transducer is fixedly connected with the reflecting surface through the supporting column.
9. The disposable acoustic velocity meter based probe of claim 8 wherein the support column is carbon fiber.
10. A method of measuring sound velocity based on a disposable sound velocity meter, the method comprising:
the method comprises the steps that a control parameter sent by a terminal processing unit is received by an acquisition unit, and a control instruction is generated according to the control parameter;
acquiring sound wave signals and pressure data of a plurality of underwater monitoring points by using a probe according to the received control instruction and sending the sound wave signals and the pressure data to the acquisition unit;
the sound velocity data and the pressure data uploaded by the probe are received by the acquisition unit and are sent to the terminal processing unit;
and receiving the pressure data and the sound velocity data sent by the acquisition unit by using the terminal processing unit, processing the pressure data to determine the depth data of the sound wave signals, generating sound velocity profile data based on the depth data and the sound velocity data, determining sound velocity profiles according to the sound velocity profile data of a plurality of underwater monitoring points, and outputting the sound velocity profiles to a terminal display interface.
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| CN118032110A (en) * | 2024-04-11 | 2024-05-14 | 国家海洋技术中心 | Disposable seawater sound velocity measuring probe and seawater sound velocity measuring system |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN118032110A (en) * | 2024-04-11 | 2024-05-14 | 国家海洋技术中心 | Disposable seawater sound velocity measuring probe and seawater sound velocity measuring system |
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