Self-cleaning marine suspended matter concentration measurement device and method based on Beidou navigation

Abstract

The invention discloses a self-cleaning marine suspended matter concentration measuring device and method based on Beidou navigation. The measuring device comprises: a data processing module, a sensor module, a power supply module, a Beidou short message and navigation module, a motor and a transmission module; the measuring method process is as follows: firstly, the measuring device is operated to a predetermined position, and a transducer is lowered to a target depth, an ARM / DSP generates a signal with specific parameter configuration, and transmits and receives the signal through an A / D converter and a D / A converter and a pair of transceiver transducers, calculates the statistical characteristics of the received signal, derives a Bayesian decision threshold, and judges the corresponding concentration according to an experience table and the Bayesian decision criterion.

Description

Technical Field

[0001] The present invention relates to the technical field of marine suspended matter detection, and in particular to a self-cleaning marine suspended matter concentration measuring device and method based on Beidou navigation. Background Art

[0002] The concentration of suspended matter in the ocean is an important indicator for measuring the quality of the marine environment. The current mainstream methods for monitoring suspended matter concentration include filtration mass method, optical method, remote sensing technology and acoustic method. The acoustic method mainly constructs the corresponding suspended matter inversion model by measuring the backscattering intensity of suspended matter in the water body, such as CN201910118786.X, CN201610229384.3 and other methods, but the above methods also have some problems: First, because the water body itself absorbs the energy of the transmitted signal, it is necessary to use the power spectrum of the signal passing through the target water body under the condition of no suspended matter, which is difficult to obtain in actual ocean detection; second, it can only measure the suspended matter concentration at a fixed depth, which cannot meet the needs of multi-depth measurement in the ocean; third, the measurement device of the acoustic measurement method needs to be placed manually, and the data cannot be retrieved in real time, which has low flexibility; fourth, there are many organisms in the ocean, and attaching to the device will reduce the accuracy of the device or even damage the device. Summary of the invention

[0003] The purpose of the present invention is to solve the shortcomings of existing suspended matter concentration measurement methods and defects in ocean measurement scenarios, and to provide a self-cleaning ocean suspended matter concentration measurement device and method based on Beidou navigation.

[0004] The first object of the present invention can be achieved by adopting the following technical solutions:

[0005] A self-cleaning marine suspended matter concentration measuring device based on Beidou navigation, the measuring device comprising a data processing module, a sensor module, a Beidou short message and navigation module, a power module, and a motor and transmission module;

[0006] The data processing module is composed of an ARM / DSP, a D / A converter, and an A / D converter. The data processing module is connected to a sensor module, a Beidou short message and a navigation module, and a motor and a transmission module; the ARM / DSP is the control center of the measuring device, the D / A converter is used to convert the digital signal generated by the ARM / DSP into an analog signal used by the transmitting transducer, and the A / D converter is used to convert the analog signal received by the receiving transducer into a digital signal that can be processed by the ARM / DSP; the data processing module is used to receive commands from a remote control center transmitted by the Beidou short message and the navigation module, and control other modules, generate a transmitting signal according to the remote control center command and hand it over to the transmitting transducer for transmission, and process the data sent back by the receiving transducer;

[0007] The Beidou short message and navigation module includes a Beidou receiver. The remote control center transmits the command to the Beidou receiver through the Beidou short message system. The Beidou receiver transmits the command to the data processing module for processing. The data processing module mobilizes the concentration measurement device to the specified coordinates, and estimates the suspended matter concentration, performs ultrasonic cleaning on the concentration measurement device, and lowers the signal transceiver transducer to the specified depth through the motor and transmission module according to the command of the remote control center. After the measurement is completed, the data processing module transmits the measurement data back to the remote control center through the Beidou receiver; and synchronizes the location information to the data processing module and the remote control center.

[0008] The sensor module includes an ultrasonic cleaning sensor and a signal transceiver sensor, wherein the ultrasonic cleaning sensor is composed of two high-power ultrasonic transmitters; the signal transceiver sensor is composed of two hydroacoustic transducers, one as a transmitting transducer and the other as a receiving transducer, the transmitting transducer is connected to the D / A converter, the receiving transducer is connected to the A / D, and the hydroacoustic transducers are fixed by an adjustable hard beam to maintain the relative positions between the transducers; the ultrasonic cleaning sensor is connected to the data processing module, waiting for the data processing module to command to perform ultrasonic cleaning operations, ultrasonic waves cause high-frequency vibrations in the seawater and produce cavitation effects at the bottom of the measuring instrument and the device, the cavitation effect produces a large number of bubbles on the surface of the device, and the bubbles produce high temperature and high pressure at the moment of collapse to impact the surface of the device, thereby causing dirt or marine life to fall off; the transmitting transducer in the signal transceiver sensor sends the analog model generated by the D / A converter under the control of the data processing module, and the receiving transducer receives the signal data passing through the target waters and transmits it to the A / D converter in the data processing module;

[0009] The motor and transmission module is composed of a motor and a transducer fixed shaft, the circumference of the fixed shaft is L, and after the data processing module obtains the depth information d, it calculates that the motor needs to rotate num=d / L times, and the data processing module controls the motor to lower the transducer fixed shaft to make the underwater acoustic transducer reach a predetermined depth;

[0010] The power supply module is connected to the data processing module, the Beidou short message and navigation module, the motor and the transmission module and provides power.

[0011] Furthermore, the power module is composed of a solar panel and a storage battery, and the solar panel continuously charges the storage battery when there is sufficient sunlight during the day. The combination of the solar panel and the storage battery ensures its long-term working ability.

[0012] Furthermore, the Beidou receiver in the Beidou short message and navigation module communicates with the remote control center through the Beidou satellite, receives commands and transmits data, and transmits the commands of the remote control center to the data processing module for processing; the data processing module transmits the measured data back to the remote control center, and synchronizes the location information to the data processing module and the remote control center. China's Beidou satellite navigation system has global short message communication capabilities. When communicating, the receiver's transmission power is only 1 to 3 watts, and the single communication capacity is 14,000 bits. It can still communicate when there is no base station signal in the marine environment, improving the robustness of the device.

[0013] Another object of the present invention can be achieved by adopting the following technical solutions:

[0014] A method for measuring the concentration of suspended matter in a self-cleaning ocean based on a Beidou navigation-based self-cleaning ocean suspended matter concentration measuring device, the concentration measuring method comprising the following steps:

[0015] S1. The concentration measurement device is connected to the remote control center through the Beidou short message and navigation module, and determines the longitude and latitude (lon, lat) of its own position, and sends its longitude and latitude to the remote control center, where lon is the longitude of the current position and lat is the latitude of the current position;

[0016] S2. After the remote control center confirms the device location, it will t ,lat t ) is sent to the concentration measuring device, lon t is the target location longitude, lat t is the target location latitude;

[0017] S3, the concentration measurement device receives the coordinates sent by the remote control center through the Beidou short message and navigation module and performs navigation;

[0018] S4. The depth measurement device arrives at the designated location to transmit and collect signals at a specific depth, and estimate the suspended matter concentration. The process is as follows:

[0019] S41, use Beidou short message and navigation module to navigate the concentration measurement device to the target longitude and latitude (lon t ,lat t ), after arrival, the concentration measurement device uses Beidou short message and navigation module to communicate with the remote control center to determine the detection depth d, and the data processing module lowers the signal transceiver sensor to the measurement depth d through the motor and transmission module;

[0020] S42, the data processing module generates a transmission signal and transmits it through the transmitting transducer. After the transmission signal passes through the target water area, it is received by the receiving transducer, and the obtained signal is processed by the data processing module;

[0021] S43, estimate the concentration of suspended matter;

[0022] S5. The concentration measurement device sends the measurement result to the remote control center through the Beidou short message and navigation module;

[0023] S6: Does the remote control center need to measure the concentration of suspended matter at different depths at the coordinates? If yes, repeat step S4; otherwise, proceed to step S7;

[0024] S7: Does the remote control center need to measure the concentration of suspended matter at other coordinates? If yes, repeat steps S3 to S4; otherwise, proceed to step S8;

[0025] S8. The remote control center determines whether to perform ultrasonic cleaning on the concentration measuring device. If yes, a high-power ultrasonic transmitter is used for cleaning. Otherwise, the remote control center enters the end state.

[0026] Furthermore, the process of step S42 is as follows:

[0027] S42-1, generate the transmission signal: Use the baseband signal of the Sa function as the transmission signal, which can make full use of the bandwidth of the transmitting transducer and the receiving transducer. S , T generates the baseband signal, where A is the signal amplitude, f is the signal frequency, which should satisfy f = B / 2, B is the bandwidth of the transducer, N s is the total number of sampling points in one continuous cycle of the signal, T = 1 / F DA The sampling rate is F DA The sampling interval of the D / A converter is T = 1 / F DA , the baseband signal Sa(n) of Sa function is as follows, where n is a value from 1 to N s Sampling points:

[0028]

[0029] Because the Sa function baseband signal has 0 as the center frequency and is not at the center frequency of the transmitting transducer, the Sa function baseband signal needs to be modulated to the center frequency f of the transmitting transducer using a cosine function signal. c At, the modulated signal x(n)

[0030]

[0031] S42-2, transmitting signals and collecting data: the transmitting transducer can transmit analog signals, the ARM / DSP transmits the modulated signal to the D / A converter and converts it into an analog signal x(t), and x(t) is transmitted to the transmitting transducer;

[0032] The signal is transmitted from the transmitting transducer after t = dt / c after the signal reaches the receiving transducer, signal reception begins, c is the speed of sound in the ocean, d t is the distance between the transducers; the emission duration is K*T*N s , K is the number of transmission signal cycles, and the receiving duration is K*T*N s ARM / DSP processes the digital signal, and the analog signal y(t) received by the receiving transducer is sampled at a rate of F AD The A / D converter converts the received signal into a digital signal to obtain the received signal y(l), l = 1, 2, ..., K*N r , l is the sampling point, and the total number of sampling points for one cycle of the received signal is N r =F AD / F DA *N s .

[0033] Furthermore, the process of step S43 is as follows:

[0034] Calculate the energy mean of a single cycle of the received signal y(l)

[0035]

[0036] Where k is the number of cycles;

[0037] According to the empirical table generated by laboratory measurement data, the current suspended solids concentration value is judged by comparing with the empirical table. When the suspended solids concentration is different, the transmitted signal will have different degrees of amplitude attenuation when passing through the target sea area. Specifically, the higher the suspended solids concentration, the greater the attenuation of the signal amplitude, which makes the energy of the received signal smaller. When the energy of the received signal is less than m1, the suspended solids concentration is judged to be c1. When the energy of the received signal is greater than m J When the suspended solids concentration is c J , when the energy of the received signal is m j With m j+1 When the Bayesian decision criterion is used, the following decision threshold is derived for judgment, where c j 、c j+1 Respectively represent the jth and j+1th concentrations, m j 、m j+1 Respectively represent the energy mean of a single cycle of the measurement signal at the jth and j+1th concentrations, represents the energy variance of a single cycle of the measured signal at the jth and j+1th concentrations, j=1,...,J is the concentration sequence number, assuming that the probability of the jth and j+1th concentrations appearing is 0.5 respectively, the cost of correct judgment is 0, and the cost of wrong judgment is 1, the following judgment threshold can be derived;

[0038] when hour

[0039] When the following conditions are met, the suspended matter concentration is judged to be c j+1 ;

[0040]

[0041] When the following conditions are met, the suspended matter concentration is judged to be c j ;

[0042]

[0043] when hour

[0044] When the following conditions are met, the suspended matter concentration is judged to be c j+1 ;

[0045]

[0046] When the following conditions are met, the suspended matter concentration is judged to be c j ;

[0047]

[0048] Furthermore, after entering the end state, the concentration measuring device enters a sleep state, waiting for the next remote control center to request a connection. The sleep mechanism saves power and is conducive to extending the battery life of the concentration measuring device.

[0049] Furthermore, the empirical table contains J rows of data, representing the statistical characteristics of the received signal energy at J different concentrations from small to large, j is the concentration number from 1 to J, and each row of data contains 3 parameters c j 、m j , c j represents the jth concentration, m j represents the energy mean of a single cycle of the measured signal at the jth concentration, represents the energy variance of a single cycle of the measured signal at the jth concentration. The energy of a single cycle of the received signal has the characteristics of normal distribution. The probability density function of the energy of a single cycle of the signal can be obtained from the statistical characteristics of the energy of the received signal. When it is between the energy means of two adjacent concentration signals, a decision can be made using the derived decision threshold.

[0050] Table 1. Experience table

[0051]

[0052] Compared with the prior art, the present invention has the following advantages and effects:

[0053] 1. The present invention has a wide range of adaptability. The statistical characteristics of the attenuation of ocean water acoustic energy are combined with an empirical table to detect the concentration of suspended matter. When the energy of the signal is in two energy distributions with different concentrations, the derived Bayesian decision criterion can be used to distinguish the current concentration, and avoid using the received signal in a non-suspended matter environment as a reference signal, which meets actual needs.

[0054] 2. The present invention has high flexibility. The concentration measurement device integrates a motor and a transmission module, which can control the transducer to be accurately lowered to any position at a certain depth through the data processing module, thus realizing multi-depth measurement.

[0055] 3. The present invention has high integration. The concentration measuring device uses the Beidou navigation system, which can not only perform navigation, but also has the function of sending and receiving short messages, so that the remote control center can send commands to the Beidou receiver through the Beidou satellite, and the Beidou receiver then transmits the commands to the data processing module for processing, thereby realizing remote control of the concentration measuring device, and the data measured by the concentration measuring device can be sent to the remote control center, which improves flexibility, eliminates the need for additional remote communication modules, and reduces costs.

[0056] 4. The present invention has long-term monitoring capability. A solar panel is covered on the top of the concentration measuring device to continuously charge the battery module when there is sunlight. Due to the omnidirectional coverage, the probability of the sun failing to charge in a specific direction is reduced, thereby improving the charging efficiency.

[0057] 5. The present invention has strong robustness. The concentration measuring device is equipped with a high-power ultrasonic transmitter to clean the measuring device. The remote control center can issue cleaning commands to the concentration measuring device at any time through Beidou short messages and navigation modules, reducing the attachment of marine organisms and marine debris to the sensor, which may lead to the measurement accuracy of the concentration measuring device. Considering the corrosive effect of minerals and salt in seawater on the transducer, the present invention uses full-transmission protective materials to protect the sensor module and cable to prevent damage and ensure its long-term working stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0059] Figure 1 It is a specific structural diagram of the self-cleaning marine suspended matter measuring device based on Beidou navigation disclosed in the present invention;

[0060] Figure 2It is a front view of the self-cleaning marine suspended matter measuring device based on Beidou navigation disclosed in the present invention;

[0061] Figure 3 It is a side view of the self-cleaning marine suspended matter measuring device based on Beidou navigation disclosed in the present invention;

[0062] Figure 4 It is a top view of the self-cleaning marine suspended matter measuring device based on Beidou navigation disclosed in the present invention;

[0063] Figure 5 It is a structural diagram of the self-cleaning marine suspended matter measuring device based on Beidou navigation disclosed in the present invention;

[0064] Figure 6 It is a flow chart of the self-cleaning ocean suspended matter measurement method based on Beidou navigation disclosed in the present invention. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0066] Example 1

[0067] This embodiment discloses a self-cleaning marine suspended solids measurement system based on Beidou navigation. The concentration measurement device includes a data processing module 2, a sensor module 5, a power module 1, a Beidou short message and navigation module 3, a motor and a transmission module 4, and the connection diagram is shown in FIG. Figure 5 shown.

[0068] The data processing module is composed of TI's ARM chip AM3352 and corresponding peripheral circuits and A / D converters, D / A converters. In this embodiment, the A / D converter and D / A converter use the AD9280 module, which supports high-speed A / D and D / A conversions. The data processing module is used to receive commands, control other modules, generate signals, and process received signals. The data processing module is connected to the sensor module, power module, Beidou short message and navigation module, motor and transmission module.

[0069] The sensor module consists of two parts. The first part is the ultrasonic cleaning sensor, which includes two high-power ultrasonic transmitters T186UEQ. The second part is the signal transceiver sensor, which includes a transmitting transducer DYW-1M-01E and a receiving transducer DYW-1M-01E. The sensor module is connected to the power module, data processing module, motor and transmission module. The data processing module generates a transmitting signal according to the command of the remote control center, and generates an analog signal through the D / A converter and sends it to the transmitting transducer. The receiving transducer transmits the receiving signal to the A / D converter to convert it into a digital signal, and the converted signal is then sent to the ARM for processing; when cleaning is required, the ultrasonic cleaning sensor transmits high-power ultrasonic waves to the concentration measuring device to make the attached organisms and garbage fall off, so as to achieve the purpose of cleaning.

[0070] The power module consists of solar panels and large-capacity batteries. It is connected to the data processing module, sensor module, Beidou short message and navigation module, motor and transmission module to provide power for these modules.

[0071] The Beidou short message and navigation module consists of the Beidou short message communication integrated device PD06 and the Beidou system transceiver antenna, and is responsible for communication and navigation with the remote control center.

[0072] The motor and transmission device consists of a motor and a transducer fixed shaft. The transducer fixed shaft consists of Figure 1 As shown, ARM receives the measured depth information d, divides d by the circumference L of the fixed axis of the transducer to obtain the number of revolutions num that the motor needs to make, and controls the motor to lower the transducer to the designated location.

[0073] Figure 1 The inner cavity of the device shown in the figure includes: the battery of the power module, the data processing module, the Beidou short message communication integrated machine of the navigation module, and the motor and transmission device for controlling the lifting and lowering of the sensor.

[0074] Example 2

[0075] The flow chart of the method for detecting suspended matter concentration by using the attenuation of ocean water acoustic energy in this embodiment is as follows: Figure 6 As shown, the specific steps include:

[0076] S1. The concentration measurement device is connected to the control center through the Beidou short message and navigation module, and determines the longitude and latitude of its own position (23.1571306°, 113.3416493°), and sends its longitude and latitude to the remote control center.

[0077] S2. After the remote control center confirms the position of the concentration measuring device, it sends the target longitude and latitude (23.1568995°, 113.3413786°) to the concentration measuring device.

[0078] S3. The concentration measurement device receives the coordinates sent by the remote control center through the Beidou short message and navigation module and performs navigation.

[0079] S4. The depth measurement device arrives at the designated location to transmit and collect signals at a specific depth, and estimate the suspended matter concentration. The process is as follows:

[0080] S41. Arrive at the measurement location specified by the remote control center, and send your own latitude and longitude coordinates (23.1568995°, 113.3413786°) to the remote control center through the Beidou short message and navigation module. After the remote control center confirms that the concentration measurement device has arrived, it sends the detection depth d=1m to the concentration measurement device. The concentration measurement device obtains the measurement depth and lowers the transducer to the target depth through the motor and transmission module. In this example, the distance between the transceiver and the transmitter is d t =2cm, the center frequency of the transmitting transducer and the receiving transducer is f c =1MHz, bandwidth B=100KHz.

[0081] S42-1, use a 12-bit D / A converter, and the sampling frequency of the D / A converter is F D / A =32MHz, the data processing module uses equation [1][2] to generate the digital signal x(n),

[0082]

[0083] where f B =50kHz,f c =1MHz,N s =4096,A=2 12 -1,T=1 / F D / A =0.03125us.

[0084] After x(n) is converted into an analog signal x(t) by a D / A converter, a transmission signal is generated and waits for transmission.

[0085] S42-2, after the transmitting transducer transmits the signal, the receiving transducer starts receiving the signal at an interval of t=0.02m / 1500m / s=13us, and receives K*T*N s =10000*4096*0.03125us=1.28s later, the receiving transducer stops transmitting. The receiving transducer transmits the received analog signal y(t) to a 12-bit A / D converter with a sampling frequency of 20MHz to convert it into a digital signal. After the conversion, the number of points per cycle of the received signal is N. r =20MHz / 32MHz*4096=2560, and the final received signal y(n) is obtained.

[0086] S43, the data processing module uses formula [4] to calculate the energy mean of each cycle of the received signal, and the energy mean is In this embodiment, the empirical table is shown in Table 2. By comparing Table 2, the energy mean value is between the empirical table numbers 8 and 9. And the energy variance of sequence number 8 is greater than the energy variance of sequence number 9 The concentration corresponding to No. 8 is 0.8kg / m 3 , the concentration corresponding to No. 9 is 0.9kg / m 3 , m8=8.4387e6, m9=7.0473e6, Using formula [7], we get

[0087]

[0088] The concentration in the target area is determined to be the concentration corresponding to number 8, which is 0.8 kg / m 3 .

[0089] Table 2. Experience table

[0090]

[0091]

[0092] S5. The concentration measurement device sends the measurement results to the remote control center via Beidou short message and navigation module.

[0093] S6. The remote control center needs to measure the suspended matter concentration at the depth d=1.2m at the coordinate and repeat S4.

[0094] S7. The remote control center needs to measure the suspended matter concentration at the coordinates (23.1569988, 113.3412949) and repeat S3 and S4.

[0095] S8. The remote control center issues a command for ultrasonic cleaning and uses a high-power ultrasonic transmitter for cleaning.

[0096] After the measurement is finished, the concentration measuring device enters the sleep state and waits for the next connection request from the remote control center.

[0097] Example 3

[0098] The flow chart of the method for detecting suspended matter concentration by using the attenuation of ocean water acoustic energy in this embodiment is as follows: Figure 6 As shown, the specific steps include:

[0099] S1. The concentration measurement device is connected to the control center through the Beidou short message and navigation module, and determines the longitude and latitude of its own location (23.1568995°, 113.3413786°), and sends its longitude and latitude to the remote control center.

[0100] S2. After the remote control center confirms the position of the concentration measuring device, it sends the target longitude and latitude (23.1571938°, 113.3411082°) to the concentration measuring device.

[0101] S3. The concentration measurement device receives the coordinates sent by the remote control center through the Beidou short message and navigation module and performs navigation.

[0102] S4. The depth measurement device arrives at the designated location to transmit and collect signals at a specific depth, and estimate the suspended matter concentration. The process is as follows:

[0103] S41, arrive at the measurement position designated by the remote control center, send its own latitude and longitude coordinates (23.1571938°, 113.3411082°) to the remote control center through the Beidou short message and navigation module. After the remote control center confirms that the concentration measurement device has arrived, it sends the detection depth d=1.5m to the concentration measurement device. The concentration measurement device obtains the measurement depth and lowers the transducer to the target depth through the motor and transmission module. In this example, the distance between the transceiver and the transmitter is d t =2cm, the center frequency of the transmitting transducer and the receiving transducer is f c =1MHz, bandwidth B=100KHz.

[0104] S42-1, use a 12-bit D / A converter, and the sampling frequency of the D / A converter is F D / A =32MHz, the data processing module uses equation [1][2] to generate the digital signal x(n),

[0105]

[0106] where f B =50kHz,f c =1MHz,N s =4096,A=2 12 -1,T=1 / F D / A =0.03125us.

[0107] After x(n) is converted into an analog signal x(t) by a D / A converter, a transmission signal is generated and waits for transmission.

[0108] S42-2, after the transmitting transducer transmits the signal, the receiving transducer starts receiving the signal at an interval of t=0.02m / 1500m / s=13us, and receives K*T*N s=10000*4096*0.03125us=1.28s later, the receiving transducer stops transmitting. The receiving transducer transmits the received analog signal y(t) to a 12-bit A / D converter with a sampling frequency of 20MHz to convert it into a digital signal. After the conversion, the number of points per cycle of the received signal is N. r =20MHz / 32MHz*4096=2560, and the final received signal y(n) is obtained.

[0109] S43, the data processing module uses formula [4] to calculate the energy mean of each cycle of the received signal, and the energy mean is In this embodiment, the empirical table is shown in Table 3. By comparing Table 2, the energy mean is between the empirical table numbers 14 and 15. And the energy variance of sequence number 14 is smaller than the energy variance of sequence number 15 The concentration corresponding to No. 14 is 1.4 kg / m 3 , the concentration corresponding to number 15 is 1.5kg / m 3 , m 14 =2.3119e+06,m 15 =2.1952e+06, Using formula [4], we get

[0110]

[0111] The target area concentration is determined to be the concentration corresponding to sequence number 15, i.e. 1.5 kg / m 3 .

[0112] Table 3. Experience table

[0113] Serial number Signal energy mean Signal Energy Variance Suspended matter concentration 1 2.8695e+07 4.6675e+09 <![CDATA[0.1kg / m 3 ]]> 2 2.7432e+07 1.2363e+12 <![CDATA[0.2kg / m 3 ]]> 3 2.6508e+07 6.73e+09 <![CDATA[0.3kg / m 3 <!-- 9 -->]]> 4 2.0783e+07 7.8888e+10 <![CDATA[0.4kg / m 3 ]]> 5 1.6424e+07 3.7075e+09 <![CDATA[0.5kg / m 3 ]]> 6 1.3080e+07 1.4528e+11 <![CDATA[0.6kg / m 3 ]]> 7 1.0004e+07 8.399e+09 <![CDATA[0.7kg / m 3 ]]> 8 8.4387e+06 8.8199e+10 <![CDATA[0.8kg / m 3 ]]> 9 7.0473e+06 2.6341e+09 <![CDATA[0.9kg / m 3 ]]> 10 5.5910e+06 5.3613e+10 <![CDATA[1.0kg / m 3 ]]> 11 3.4946e+06 2.2123e+09 <![CDATA[1.1kg / m 3 ]]> 12 2.7774e+06 1.6701e+10 <![CDATA[1.2kg / m 3 ]]> 13 2.5580e+06 1.0884e+09 <![CDATA[1.3kg / m 3 ]]> 14 2.3119e+06 1.6583e+08 <![CDATA[1.4kg / m 3 ]]> 15 2.1952e+06 1.9045e+10 <![CDATA[1.5kg / m 3 ]]> 16 1.8327e+06 9.8731e+08 <![CDATA[1.6kg / m 3 ]]> 17 1.6220e+06 5.724e+09 <![CDATA[1.7kg / m 3 ]]> 18 1.5542e+06 3.5544e+09 <![CDATA[1.8kg / m 3 ]]> 19 1.1552e+06 4.4293e+09 <![CDATA[1.9kg / m 3 ]]>

[0114] S5. The concentration measurement device sends the measurement results to the remote control center via Beidou short message and navigation module.

[0115] S6. The measurement is completed and the measurement stops.

[0116] S7. There are no other measurement point tasks.

[0117] S8. The remote control center issues a command for ultrasonic cleaning and uses a high-power ultrasonic transmitter for cleaning.

[0118] After the measurement is finished, the concentration measuring device enters the sleep state and waits for the next connection request from the remote control center.

[0119] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A self-cleaning marine suspended matter concentration measuring device based on Beidou navigation, the measuring device comprising a data processing module, a sensor module, a Beidou short message and navigation module, a power module, and a motor and transmission module; The data processing module is composed of an ARM / DSP, a D / A converter, and an A / D converter. The data processing module is connected to a sensor module, a Beidou short message and a navigation module, and a motor and a transmission module; the ARM / DSP is the control center of the measuring device, the D / A converter is used to convert the digital signal generated by the ARM / DSP into an analog signal used by the transmitting transducer, and the A / D converter is used to convert the analog signal received by the receiving transducer into a digital signal that can be processed by the ARM / DSP; the data processing module is used to receive commands from a remote control center transmitted by the Beidou short message and the navigation module, and control other modules, generate a transmitting signal according to the remote control center command and hand it over to the transmitting transducer for transmission, and process the data sent back by the receiving transducer; The Beidou short message and navigation module includes a Beidou receiver. The remote control center transmits the command to the Beidou receiver through the Beidou short message system. The Beidou receiver transmits the command to the data processing module for processing. The data processing module mobilizes the concentration measurement device to the specified coordinates, and estimates the suspended matter concentration, performs ultrasonic cleaning on the concentration measurement device, and lowers the signal transceiver transducer to the specified depth through the motor and transmission module according to the command of the remote control center. After the measurement is completed, the data processing module transmits the measurement data back to the remote control center through the Beidou receiver; and synchronizes the location information to the data processing module and the remote control center. The sensor module includes an ultrasonic cleaning sensor and a signal transceiver sensor, wherein: The ultrasonic cleaning sensor is composed of two high-power ultrasonic transmitters; the signal transceiver sensor is composed of two hydroacoustic transducers, one as a transmitting transducer and the other as a receiving transducer. The transmitting transducer is connected to the D / A converter, and the receiving transducer is connected to the A / D. The hydroacoustic transducers are fixed by an adjustable hard crossbeam to maintain the relative position between the transducers; the ultrasonic cleaning sensor is connected to the data processing module, waiting for the data processing module to command to execute the ultrasonic cleaning operation. The ultrasonic wave causes the seawater to vibrate at a high frequency and produces a cavitation effect at the bottom of the measuring instrument and the device. The cavitation effect produces a large number of bubbles on the surface of the device. The bubbles generate high temperature and high pressure at the moment of collapse, which impacts the surface of the device, thereby causing dirt or marine life to fall off; the transmitting transducer in the signal transceiver sensor sends the analog model generated by the D / A converter under the control of the data processing module, and the receiving transducer receives the signal data passing through the target waters and transmits it to the A / D converter in the data processing module; The motor and transmission module is composed of a motor and a transducer fixed shaft, the circumference of the fixed shaft is L, and after the data processing module obtains the depth information d, it calculates that the motor needs to rotate num=d / L times, and the data processing module controls the motor to lower the transducer fixed shaft to make the underwater acoustic transducer reach a predetermined depth; The power supply module is connected to the data processing module, the Beidou short message and navigation module, the motor and the transmission module and provides power.

2. The self-cleaning marine suspended matter concentration measuring device based on Beidou navigation according to claim 1 is characterized in that: The power module is composed of a solar panel and a battery. When there is sufficient sunshine during the day, the solar panel continuously charges the battery.

3. The self-cleaning marine suspended matter concentration measuring device based on Beidou navigation according to claim 1 is characterized in that: The Beidou receiver in the Beidou short message and navigation module communicates with the remote control center through the Beidou satellite, receives commands and transmits data, and transmits the commands of the remote control center to the data processing module for processing; The data processing module transmits the measured data back to the remote control center, and synchronizes the location information to the data processing module and the remote control center.

4. A method for measuring the concentration of suspended solids in the self-cleaning ocean based on the Beidou navigation-based self-cleaning ocean suspended solids concentration measuring device according to any one of claims 1 to 3, characterized in that: The concentration measurement method comprises the following steps: S1. The concentration measurement device is connected to the remote control center through the Beidou short message and navigation module, and determines the longitude and latitude (lon, lat) of its own position, and sends its longitude and latitude to the remote control center, where lon is the longitude of the current position and lat is the latitude of the current position; S2. After the remote control center confirms the device location, it will t ,lat t ) is sent to the concentration measuring device, lon t is the target location longitude, lat t is the target location latitude; S3, the concentration measurement device receives the coordinates sent by the remote control center through the Beidou short message and navigation module and performs navigation; S4. The depth measurement device arrives at the designated location to transmit and collect signals at a specific depth, and estimate the suspended matter concentration. The process is as follows: S41, use Beidou short message and navigation module to navigate the concentration measurement device to the target longitude and latitude (lon t ,lat t ), after arrival, the concentration measurement device uses Beidou short message and navigation module to communicate with the remote control center to determine the detection depth d, and the data processing module lowers the signal transceiver sensor to the measurement depth d through the motor and transmission module; S42, the data processing module generates a transmission signal and transmits it through the transmitting transducer. After the transmission signal passes through the target water area, it is received by the receiving transducer, and the obtained signal is processed by the data processing module; S43, estimate the concentration of suspended matter; S5. The concentration measurement device sends the measurement result to the remote control center through the Beidou short message and navigation module; S6: Does the remote control center need to measure the concentration of suspended matter at different depths at the coordinates? If yes, repeat step S4; otherwise, proceed to step S7; S7: Does the remote control center need to measure the concentration of suspended matter at other coordinates? If yes, repeat steps S3 to S4; otherwise, proceed to step S8; S8. The remote control center determines whether to perform ultrasonic cleaning on the concentration measuring device. If yes, a high-power ultrasonic transmitter is used for cleaning. Otherwise, the remote control center enters the end state.

5. The method for measuring the concentration of suspended matter in the self-cleaning ocean according to the Beidou navigation-based self-cleaning ocean suspended matter concentration measuring device according to claim 4 is characterized in that: The process of step S42 is as follows: S42-1, generate a transmission signal: use the baseband signal of the Sa function as the transmission signal, according to the configuration parameters A, f, N S , T generates the baseband signal, where A is the signal amplitude, f is the signal frequency, which should satisfy f = B / 2, B is the bandwidth of the transducer, N s is the total number of sampling points in one continuous cycle of the signal, T = 1 / F DA The sampling rate is F DA The sampling interval of the D / A converter is T = 1 / F DA , the baseband signal Sa(n) of Sa function is as follows, where n is a value from 1 to N s Sampling points: The Sa function baseband signal is modulated to the transducer center frequency f using a cosine function signal. c The modulated signal x(n) is obtained S42-2, transmitting signal and performing data acquisition: ARM / DSP transmits the modulated signal to the D / A converter and converts it into an analog signal x(t), which is then transmitted to the transmitting transducer; The signal is transmitted from the transmitting transducer after t=d t / c after the signal reaches the receiving transducer, signal reception begins, c is the speed of sound in the ocean, d t is the distance between the transducers; the emission duration is K*T*N s , K is the number of transmission signal cycles, and the receiving duration is K*T*N s The analog signal y(t) received by the receiving transducer is sampled at a rate of F AD The A / D converter converts the received signal into a digital signal to obtain the received signal y(l), l = 1, 2, ..., K*N r , l is the sampling point, and the total number of sampling points for one cycle of the received signal is N r =F AD / F DA *N s .

6. The method for measuring the concentration of suspended matter in the self-cleaning ocean according to the Beidou navigation-based self-cleaning ocean suspended matter concentration measuring device according to claim 5, characterized in that: The process of step S43 is as follows: Calculate the energy mean of a single cycle of the received signal y(l) Where k is the number of cycles; According to the experience table generated by laboratory measurement data, the current suspended matter concentration value is determined by comparing the experience table. When the energy of the received signal is less than m1, the suspended matter concentration is determined to be c1. When the energy of the received signal is greater than m J When the suspended solids concentration is c J , when the energy of the received signal is m j With m j+1 When the Bayesian decision criterion is used, the following decision threshold is derived for judgment, where c j 、c j+1 Respectively represent the jth and j+1th concentrations, m j 、m j+1 Respectively represent the energy mean of a single cycle of the measurement signal at the jth and j+1th concentrations, represents the energy variance of a single cycle of the measured signal at the jth and j+1th concentrations, where j=1,...,J is the concentration sequence number; when hour When the following conditions are met, the suspended matter concentration is judged to be c j+1 ; or When the following conditions are met, the suspended matter concentration is judged to be c j ; and when hour When the following conditions are met, the suspended matter concentration is judged to be c j+1 ; and When the following conditions are met, the suspended matter concentration is judged to be c j ; or 7. The method for measuring the concentration of suspended matter in the self-cleaning ocean according to the Beidou navigation-based self-cleaning ocean suspended matter concentration measuring device according to claim 4, characterized in that: When entering the end state, the concentration measuring device enters a sleep state, waiting for the next remote control center to request a connection.

8. The method for measuring the concentration of suspended matter in the self-cleaning ocean according to the Beidou navigation-based self-cleaning ocean suspended matter concentration measuring device according to claim 6 is characterized in that: The empirical table contains J rows of data, representing the statistical characteristics of the received signal energy at J different concentrations from small to large, j is the concentration sequence from 1 to J, and each row of data contains 3 parameters c j 、m j , c j represents the jth concentration, m j represents the energy mean of a single cycle of the measured signal at the jth concentration, It represents the energy variance of a single cycle of the measured signal at the jth concentration.

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