A marine multi-depth water quality data acquisition system based on pressure sensing

Abstract

This invention relates to the field of marine environmental monitoring technology and discloses a pressure-sensing-based multi-depth marine water quality data acquisition system, aiming to solve the problem of in-situ synchronous acquisition and precise depth correlation of water quality parameters at different depths in the ocean. The system includes a multi-depth detection carrier structure with several longitudinally distributed sensor mounting chambers inside, each chamber equipped with a pressure balancing channel; multiple sets of water quality sensor components, each housed in its respective sensor mounting chamber, for collecting water quality parameters such as dissolved oxygen, pH, conductivity, and turbidity; and a depth sensing module located at the top of the carrier, which senses water pressure through a pressure-sensitive element and converts it into a depth signal. This application, through the integrated design of the multi-depth detection carrier and multiple sensor sets, combined with depth sensing and data fusion technology, achieves synchronous acquisition and precise depth correlation of multi-depth water quality parameters in the vertical profile of the ocean, significantly improving monitoring efficiency and accuracy, and is suitable for long-term in-situ monitoring of the marine environment.

Description

Technical Field

[0001] This invention relates to the field of marine environmental monitoring technology, specifically to a marine multi-depth water quality data acquisition system based on pressure sensing. Background Technology

[0002] Marine environmental monitoring is a crucial foundation for marine scientific research, marine resource development, and marine ecological protection. Multi-depth synchronous acquisition of water quality data is key to understanding the vertical structure of the ocean. With the continuous development of marine observation technologies, obtaining water quality parameters such as dissolved oxygen, pH, turbidity, and conductivity at different depths has become a core requirement for marine environmental assessment. Current technologies primarily rely on independent sensor units distributed at different depths, with each unit recording water quality parameters at its location. However, this distributed acquisition model inherently suffers from limitations in the accuracy of data timestamps.

[0003] Due to limitations imposed by internal sensor clock skew and data transmission delays, water quality data recorded by sensors at different depths often correspond to different times, resulting in a lack of strict temporal consistency among the data at different depths. When the marine environment undergoes rapid changes or when precise analysis of the vertical profile characteristics of water bodies is required, inconsistent water quality data will severely affect the accuracy of subsequent data fusion and marine process analysis. In sea areas with dramatic tidal changes or distinct water stratification, this data correlation error caused by temporal asynchrony is particularly pronounced.

[0004] In this context, existing technologies are insufficient to meet the demand for high-precision synchronous acquisition of ocean water quality data at multiple depths, resulting in a significant deficiency in the detailed characterization of the evolution of the vertical water body structure in the ocean. There is an urgent need for a technical solution that can achieve precise time-synchronous acquisition of water quality data at multiple depths. Summary of the Invention

[0005] This application provides a pressure-sensing-based ocean multi-depth water quality data acquisition system, which aims to achieve in-situ synchronous acquisition and precise depth correlation of water quality parameters at different ocean depths.

[0006] The first aspect of this application provides a pressure-sensing-based ocean multi-depth water quality data acquisition system, comprising: The multi-depth detection carrier structure has several longitudinally distributed sensor installation chambers inside. Each sensor installation chamber has a pressure equalization channel in its chamber wall to achieve pressure balance between the inside of each sensor installation chamber and the external seawater environment. Multiple sets of water quality sensor components are installed in each sensor installation chamber. Each set of water quality sensor components includes a dissolved oxygen sensor, a pH sensor, a conductivity sensor, and a turbidity sensor, which are used to collect water quality parameter data at corresponding depth locations in real time. The depth sensing module is located at the top of the multi-depth detection carrier structure. It includes a pressure-sensitive element and a signal conditioning circuit. The pressure-sensitive element is used to sense the water pressure signal of the external seawater environment and convert the water pressure signal into an electrical signal. The signal conditioning circuit is used to amplify and filter the electrical signal to obtain a depth signal that is proportional to the depth. The data fusion processing unit is located inside the multi-depth detection carrier structure and is electrically connected to each group of water quality sensor components and depth sensing module. It is used to receive water quality parameter data collected by each group of water quality sensor components and depth signals output by the depth sensing module, and to add corresponding depth tags to the water quality parameter data of each group of water quality sensor components according to the depth signals to obtain water quality data with depth information. The wireless communication module, electrically connected to the data fusion processing unit, is used to wirelessly transmit water quality data with depth information to an external receiving terminal.

[0007] In one optional embodiment, each sensor mounting compartment is provided with an openable and closable door at its end. The door is sealed to the compartment wall by a sealing ring, and the outer surface of the door is provided with an anti-bioadhesion coating.

[0008] In one optional embodiment, the pressure balancing channel includes a first channel section and a second channel section. The first channel section extends horizontally through the wall of the sensor mounting compartment, and the second channel section is connected to the first channel section vertically. The outlet end of the second channel section is positioned downwards towards the multi-depth detection carrier structure.

[0009] In one optional embodiment, the multi-depth detection carrier structure further includes a counterweight balancing system, which is disposed at the bottom of the multi-depth detection carrier structure and includes a counterweight block and a counterweight adjustment mechanism. The counterweight adjustment mechanism is used to adjust the position of the counterweight block relative to the multi-depth detection carrier structure to achieve vertical attitude adjustment of the multi-depth detection carrier structure in water.

[0010] In one optional implementation, the data fusion processing unit includes an analog-to-digital converter, a storage module, and a main control processor. The analog-to-digital converter is electrically connected to each group of water quality sensor components and the depth sensing module, respectively, and is used to convert the analog signals output by each water quality sensor component and the analog signals output by the depth sensing module into digital signals. The storage module is used to cache the water quality parameter data collected by each water quality sensor component and the depth signal output by the depth sensing module. The main control processor is electrically connected to the analog-to-digital converter and the storage module, respectively, and is used to read the water quality parameter data and the depth signal in the storage module, and to tag the water quality parameter data with the corresponding depth according to the depth signal.

[0011] In one alternative implementation, the wireless communication module includes a modulation circuit, a power amplifier, and an antenna. The modulation circuit modulates the digital signal output by the data fusion processing unit into a radio frequency signal, the power amplifier amplifies the radio frequency signal, and the antenna radiates the amplified radio frequency signal to an external receiving terminal.

[0012] In one optional implementation, each group of water quality sensor components further includes a temperature sensor, which is used to collect seawater temperature data at corresponding depth locations in real time. The data fusion processing unit is also used to receive the temperature data collected by the temperature sensor and associate the temperature data with depth tags as a component of the water quality parameter data.

[0013] In one alternative embodiment, the outer wall of the multi-depth probe carrier structure is provided with a corrosion-resistant protective layer, which is made of polyethylene or titanium alloy.

[0014] In one optional implementation, the depth sensing module further includes a temperature compensation unit, which is used to perform temperature compensation on the depth signal based on the collected seawater temperature data, so as to eliminate the influence of temperature changes on the output accuracy of the pressure-sensitive element.

[0015] In one optional implementation, the data fusion processing unit is further provided with a time synchronization module. The time synchronization module is used to provide a unified time reference for the acquisition time of each group of water quality sensor components and the sensing time of the depth sensing module, so as to ensure the temporal consistency between water quality parameter data and depth signals.

[0016] In the pressure-sensing-based multi-depth marine water quality data acquisition system provided in this application, the multi-depth detection carrier structure, by setting up several longitudinally distributed sensor mounting chambers, enables the simultaneous mounting of multiple sets of water quality sensor components on the same carrier. By setting pressure balancing channels in each sensor mounting chamber, the pressure balance between the inside of each sensor mounting chamber and the external seawater environment is ensured, avoiding the problem of chamber sealing failure due to depth changes. The depth sensing module accurately senses the external water pressure signal through pressure-sensitive elements and works in conjunction with each set of water quality sensor components, enabling the data fusion processing unit to accurately label the water quality parameter data of each set of water quality sensor components according to the depth signal, realizing in-situ synchronous acquisition and accurate depth correlation of multi-depth water quality data. The wireless communication module wirelessly transmits the water quality data with depth information to the external receiving terminal, meeting the real-time requirements of marine environmental monitoring.

[0017] Compared with the prior art, the beneficial effects achieved by the present invention are: By integrating a multi-depth detection carrier structure with multiple sets of water quality sensor components, simultaneous monitoring of water quality parameters at multiple depth points on a vertical ocean profile is achieved, significantly improving monitoring efficiency compared to traditional single-point monitoring methods. Through the cooperation of the depth sensing module and the data fusion processing unit, precise binding of water quality parameter data with depth information is realized, solving the problem of inaccurate correspondence between water quality data and depth information in existing technologies. The design of the pressure balancing channel ensures the sealing reliability of the sensor installation chamber in deep-water environments, extending the system's service life. Temperature compensation units correct depth signals, improving the accuracy of depth measurements and ensuring the precision of the correspondence between water quality data and depth labels. The entire system is compact and highly integrated, suitable for long-term in-situ monitoring tasks in marine environments, and can provide high-quality multi-depth water quality data support for marine ecological research, marine resource development, and marine environmental protection. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall technical solution flow of the data acquisition system of this invention; Figure 2 This is a flowchart illustrating the collaborative operation of the depth perception module and the data fusion processing unit in this invention. Figure 3 This is a schematic diagram of the sensor mounting chamber and pressure balancing channel inside the multi-depth detection carrier structure in this invention. Figure 4 This is a schematic diagram of the data acquisition and tag association process between multiple water quality sensor components and the depth sensing module in this invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Reference Figure 1 , Figure 1 This is a schematic diagram of the overall technical architecture of a pressure-sensing-based marine multi-depth water quality data acquisition system proposed in one embodiment of this application. As shown in the figure, the system includes: a multi-depth detection carrier structure, multiple sets of water quality sensor components, a depth sensing module, a data fusion processing unit, and a wireless communication module.

[0021] In this embodiment, the working principle of the pressure-sensing-based multi-depth ocean water quality data acquisition system is as follows: The multi-depth detection carrier structure, through several longitudinally distributed sensor mounting chambers within it, enables the arrangement of multiple depth points on the vertical profile of the ocean. Water quality sensor components within each sensor mounting chamber are responsible for real-time acquisition of water quality parameter data at the corresponding depth location. The depth sensing module accurately senses the water pressure signal of the external seawater environment through pressure-sensitive elements and converts the water pressure signal into an electrical signal proportional to the depth. The data fusion processing unit receives the water quality parameter data collected by each group of water quality sensor components and the depth signal output by the depth sensing module, and assigns corresponding depth tags to the water quality parameter data of each group of water quality sensor components based on the depth signal, obtaining water quality data with depth information. The wireless communication module wirelessly transmits the water quality data with depth information to an external receiving terminal. This application, through the collaborative work of the above modules, achieves in-situ synchronous acquisition and precise depth correlation of multi-depth water quality data, solving the problem in the prior art where water quality data and depth information are difficult to accurately correspond.

[0022] In one embodiment, this application also provides a pressure-sensing-based ocean multi-depth water quality data acquisition system. In this system, a number of longitudinally distributed sensor installation chambers are arranged inside the multi-depth detection carrier structure. The walls of each sensor installation chamber are provided with pressure balancing channels to achieve pressure balance between the inside of each sensor installation chamber and the external seawater environment.

[0023] In this embodiment, the multi-depth detection carrier structure adopts a cylindrical or spindle-shaped design, and its outer shell is made of high-strength, corrosion-resistant materials, such as titanium alloy or reinforced polyethylene, to ensure structural strength and sealing performance in deep-water environments. Sensor mounting compartments are uniformly arranged along the axial direction of the multi-depth detection carrier structure, and the spacing between adjacent sensor mounting compartments can be set according to actual monitoring requirements, typically ranging from 0.5 meters to 2 meters. The walls of each sensor mounting compartment employ a double-layer sealing structure, with an inner O-ring seal and an outer V-ring seal to ensure sealing reliability under high-pressure environments.

[0024] In this embodiment, the design principle of the pressure balance channel is as follows: Since electronic components and sensor probes need to be installed inside the sensor mounting compartment, the air pressure inside the compartment is typically atmospheric pressure or slightly higher. When the multi-depth exploration carrier structure descends to different depths, the external seawater pressure increases with depth. (Based on seawater density...) For example, at a depth of When the external seawater pressure P is measured in meters, the formula for calculating the external seawater pressure P is:

[0025] in, This is the atmospheric pressure at sea level (approximately 101.325 kPa). The acceleration due to gravity is approximately 9.8 m / s². At a depth of 100 meters, the external seawater pressure is approximately 1.11 MPa; at 1000 meters, the pressure is approximately 10.3 MPa. Under such high pressure, if the sensor installation compartment is completely sealed, the pressure difference between the inside and outside will reach several megapascals, which could lead to structural deformation or even failure of the compartment.

[0026] To address this issue, this application incorporates pressure balancing channels within the bulkhead of each sensor mounting compartment. The cross-sectional shape of these channels can be circular, elliptical, or slit-shaped, with a diameter or width typically ranging from 1 mm to 5 mm. The channels are filled with an elastic sealing material, such as silicone or fluororubber. This material maintains a sealed state under normal pressure, preventing seawater from entering the compartment. When the external seawater pressure exceeds a preset threshold, the elastic sealing material is compressed, forming a tiny channel that gradually balances the pressure inside and outside the compartment. The preset threshold is typically set between 0.1 MPa and 0.5 MPa, with the specific value depending on the volume of the sensor mounting compartment and the elastic modulus of the sealing material.

[0027] In this embodiment, the pressure balancing channel specifically includes a first channel section and a second channel section. The first channel section penetrates the wall of the sensor mounting compartment horizontally, with its inlet end located on the outer surface of the wall and its outlet end located near the inner surface of the wall. The second channel section connects to the first channel section vertically, with its outlet end facing downwards towards the multi-depth detection carrier structure. The purpose of this L-shaped bend structure is as follows: First, the horizontal first channel section can utilize the wall thickness as a pressure buffer distance, reducing the possibility of direct seawater impact; second, the downward-facing outlet end design can prevent air bubbles and suspended particles from entering the sensor mounting compartment; third, the L-shaped structure can effectively prevent marine life from entering the compartment.

[0028] In one embodiment, each sensor mounting compartment is provided with an openable and closable door at its end. The door is sealed to the compartment wall by a sealing ring, and the outer surface of the door is provided with an anti-biofouling coating.

[0029] In this embodiment, the hatch employs a hinged or snap-on opening and closing structure, facilitating the installation, maintenance, and replacement of sensors. The sealing ring uses an O-ring or rectangular ring made of corrosion-resistant silicone rubber or fluororubber, with a compression ratio typically between 15% and 25% to ensure sealing performance under high pressure. The anti-biofouling coating uses a self-polishing copolymer (SPC) coating containing copper oxide or tributyltin, effectively preventing marine organisms such as barnacles, oysters, and seaweed from adhering to the hatch surface, avoiding difficulties in opening and closing the hatch and a decrease in sealing performance due to biofouling. The thickness of the anti-biofouling coating is typically between 50 and 200 micrometers, requiring maintenance recoating every six months to one year.

[0030] In one embodiment, the multi-depth detection carrier structure further includes a counterweight balancing system, which is disposed at the bottom of the multi-depth detection carrier structure and includes a counterweight block and a counterweight adjustment mechanism. The counterweight adjustment mechanism is used to adjust the position of the counterweight block relative to the multi-depth detection carrier structure to achieve vertical attitude adjustment of the multi-depth detection carrier structure in water.

[0031] In this embodiment, the working principle of the counterweight balancing system is as follows: Since the multi-depth detection carrier structure houses multiple sensor mounting compartments, a data fusion processing unit, a wireless communication module, and other components, its overall center of gravity is typically biased towards the upper half of the structure. Without counterweight adjustment, the carrier will be top-heavy underwater, causing the sensor mounting compartments to fail to accurately reach the predetermined depth, thus affecting the accuracy of the water quality data.

[0032] The counterweight balancing system adjusts the center of gravity of the vessel by adjusting the position of the counterweight blocks. The counterweight blocks can be made of lead or stainless steel, and their weight is determined based on the total weight of the vessel and the designed diving depth, typically ranging from 5% to 20% of the vessel's weight in air. The counterweight adjustment mechanism includes a threaded adjusting rod and a locking nut. Operators can drive the threaded adjusting rod using a winch or electric actuator to move the counterweight blocks up and down along a vertical guide rail. The adjustment range of the counterweight blocks is typically 0.3 meters to 0.5 meters, with an adjustment accuracy of ±5 millimeters. By precisely adjusting the position of the counterweight blocks, the vessel can maintain a vertical attitude underwater, with the tilt angle controlled within ±3°.

[0033] In one embodiment, this application also provides a pressure-sensing-based ocean multi-depth water quality data acquisition system. In this system, multiple sets of water quality sensor components are correspondingly installed in each sensor installation chamber. Each set of water quality sensor components includes a dissolved oxygen sensor, a pH sensor, a conductivity sensor, and a turbidity sensor, which are used to collect water quality parameter data at each corresponding depth location in real time.

[0034] In this embodiment, each sensor in each water quality sensor assembly adopts a digital output interface, such as an RS485 interface or an SDI-12 interface, supporting multi-point communication and long-distance transmission. The working principle and key technical parameters of each sensor are as follows: Dissolved oxygen sensors employ either fluorescence quenching or polarography. The fluorescence quenching method works as follows: the sensor probe surface is coated with a fluorescent material, which emits red light when excited by blue light. When the fluorescent material comes into contact with dissolved oxygen in the water, oxygen molecules quench the fluorescence, leading to a decrease in fluorescence intensity and a shortened fluorescence lifetime. By measuring the change in fluorescence intensity or lifetime, the concentration of dissolved oxygen in the water can be calculated. The measurement range of the fluorescence quenching method is typically 0 to 20 mg / L, with an accuracy of ±0.1 mg / L and a response time of less than 30 seconds. The polarography method works as follows: the sensor probe contains a cathode and an anode, with a stable voltage applied between them. Dissolved oxygen in the water undergoes a reduction reaction on the cathode surface, generating a limiting current proportional to the dissolved oxygen concentration. By measuring the magnitude of this limiting current, the concentration of dissolved oxygen can be calculated. The measurement range of the polarography method is typically 0 to 15 mg / L, with an accuracy of ±0.2 mg / L.

[0035] pH sensors employ either the glass electrode method or the ISFET (Inductively Coupled Field-Effect Transistor) method. The glass electrode method works as follows: the sensor probe is filled with a pH-stable electrolyte solution, and the inner and outer surfaces of the glass membrane create a potential difference with the water sample and the internal electrolyte solution, respectively. This potential difference has a linear relationship with the pH value of the water sample; the pH value can be obtained by measuring this potential difference. The glass electrode method typically has a measurement range of 0 to 14, an accuracy of ±0.02, and a response time of less than 60 seconds. The ISFET method works as follows: the sensor probe integrates an ISFET, whose gate voltage changes with the pH value of the water sample; the pH value can be calculated by measuring the change in gate voltage. The ISFET method has the advantages of small size, fast response speed, and high mechanical strength.

[0036] Conductivity sensors employ either the four-electrode method or the electromagnetic induction method. The four-electrode method works as follows: the sensor probe contains two current electrodes and two voltage electrodes; a stable alternating current is applied to the current electrodes, and the voltage electrodes measure the potential difference between the two electrodes; based on Ohm's law and electrode geometry, the conductivity of the water sample can be calculated. The four-electrode method typically has a measurement range of 0 to 100 mS / cm, an accuracy of ±0.5%FS, and a response time of less than 30 seconds. The electromagnetic induction method typically has a measurement range of 0 to 500 mS / cm, an accuracy of ±1%FS, and is suitable for measuring water bodies with high conductivity.

[0037] Turbidity sensors employ either optical scattering or transmission methods. The optical scattering method works as follows: a light source inside the sensor probe emits a beam of light of a specific wavelength. This beam scatters upon contact with suspended particles in the water sample; the scattered light is received by a photodetector, and the intensity of the scattered light is directly proportional to the turbidity of the water sample. The measurement range of the optical scattering method is typically 0 to 1000 NTU, with an accuracy of ±2%FS or ±0.3 NTU (whichever is greater), and a response time of less than 10 seconds. The transmission method works as follows: a light source inside the sensor probe emits a beam of light, which passes through the water sample and is received by a photodetector; the intensity of the light after it penetrates the water sample is negatively correlated with the turbidity of the water sample. The turbidity can be calculated by measuring the attenuation of the light intensity.

[0038] In one embodiment, each group of water quality sensor components also includes a temperature sensor, which is used to collect seawater temperature data at each corresponding depth location in real time. The data fusion processing unit is also used to receive the temperature data collected by the temperature sensor and associate the temperature data with depth tags as a component of the water quality parameter data.

[0039] In this embodiment, the temperature sensor uses a platinum resistance thermometer (Pt1000) or a thermistor (NTC / PTC). The working principle of a platinum resistance thermometer is as follows: the resistance of platinum metal changes approximately linearly with temperature, and its temperature coefficient of resistance is approximately 0.385 Ω / ℃. By measuring the resistance of the platinum resistance thermometer, the water temperature can be accurately calculated. The measurement range of a platinum resistance thermometer is typically -5 to 35℃, with an accuracy of ±0.1℃. The working principle of a thermistor is as follows: the resistance of a thermistor changes non-linearly with temperature, but it has high sensitivity. By calibrating the resistance-temperature curve of the thermistor, temperature measurement can be achieved. The measurement range of a thermistor is typically -10 to 50℃, with an accuracy of ±0.2℃.

[0040] In this embodiment, incorporating temperature data collected by a temperature sensor into the water quality parameter data is of great significance. The reasons are as follows: First, the physical properties of water, such as density, viscosity, and solubility, are closely related to temperature; for example, the dissolved oxygen saturation concentration in water decreases as temperature increases. Second, the measurement results of water quality sensors usually require temperature compensation; for example, the measurement values ​​of pH sensors are significantly affected by temperature, and the measurement values ​​of conductivity sensors are positively correlated with temperature. Third, the temperature distribution of seawater is an important indicator of marine physical processes and is closely related to seawater density stratification, upwelling, and ocean circulation.

[0041] In one embodiment, this application also provides a pressure-sensing-based ocean multi-depth water quality data acquisition system, in which the outer wall of the multi-depth detection carrier structure is provided with a corrosion-resistant protective layer, which is made of polyethylene material or titanium alloy material.

[0042] In this embodiment, the main function of the corrosion-resistant protective layer is to prevent corrosion and biofouling of the multi-depth probe structure during long-term immersion in seawater. Polyethylene material has excellent corrosion resistance and low cost, but its mechanical strength is relatively low, and it is usually used in shallow sea or short-term monitoring scenarios. Titanium alloy material has extremely high corrosion resistance and mechanical strength, but its cost is high, and it is usually used in deep sea or long-term monitoring scenarios. The thickness of the corrosion-resistant protective layer is typically 2 mm to 10 mm, with the specific thickness determined based on the operating environment and design life.

[0043] In one embodiment, this application also provides a pressure-sensing-based ocean multi-depth water quality data acquisition system. In this system, a depth sensing module is disposed at the top of the multi-depth detection carrier structure and includes a pressure-sensitive element and a signal conditioning circuit. The pressure-sensitive element is used to sense the water pressure signal of the external seawater environment and convert the water pressure signal into an electrical signal. The signal conditioning circuit is used to amplify and filter the electrical signal to obtain a depth signal that is proportional to the depth.

[0044] In this embodiment, the depth sensing module is positioned at the top of the multi-depth detection carrier structure. Its purpose is to allow the pressure-sensitive element to directly sense the water pressure of the external seawater environment, avoiding the influence of the pressure balance channel within the carrier structure on the measurement. The pressure-sensitive element employs a piezoresistive pressure sensor or a capacitive pressure sensor. The working principle of the piezoresistive pressure sensor is as follows: a Wheatstone bridge consisting of four strain resistors is integrated on a silicon diaphragm inside the sensor. When external water pressure acts on the silicon diaphragm, the diaphragm deforms, causing a change in the resistance of the strain resistors. By measuring the output voltage of the bridge, the magnitude of the external water pressure can be calculated. The measurement range of the piezoresistive pressure sensor is typically 0 to 2 MPa (corresponding to a depth of approximately 0 to 200 meters) or 0 to 10 MPa (corresponding to a depth of approximately 0 to 1000 meters), with an accuracy of ±0.1%FS to ±0.5%FS and a response time of less than 1 millisecond. The working principle of a capacitive pressure sensor is as follows: The sensor contains a fixed electrode and a movable electrode, with a capacitance formed between them. When external water pressure is applied to the movable electrode, the electrode spacing changes, causing a change in the capacitance value. By measuring the change in capacitance, the magnitude of the external water pressure can be calculated. Capacitive pressure sensors have advantages such as good temperature stability and high sensitivity, making them suitable for high-precision depth measurement applications.

[0045] In this embodiment, the signal conditioning circuit preprocesses the electrical signal output by the pressure-sensitive element to make it suitable for subsequent analog-to-digital conversion and processing. The signal conditioning circuit typically includes the following components: The first-stage amplifier circuit uses an instrumentation amplifier or differential amplifier to amplify the weak electrical signal (typically in the millivolt range) output by the pressure-sensitive element to the volt range. The amplifier gain is typically set between 10 and 100 times, depending on the sensitivity of the pressure-sensitive element and the input range of the subsequent circuitry. The common-mode rejection ratio (CMRR) of the amplifier is typically greater than 80 dB to suppress common-mode interference.

[0046] Low-pass filter: A second- or fourth-order active low-pass filter is used, with a cutoff frequency typically set between 10Hz and 100Hz, to filter out high-frequency noise and pressure fluctuations. The passband ripple of the low-pass filter is typically less than 0.5dB, and the stopband attenuation is typically greater than 40dB / octave.

[0047] Temperature compensation circuit: Employs a thermistor or integrated circuit temperature sensor to monitor the operating temperature of the pressure-sensitive element in real time, and compensates for the measurement results based on a pre-calibrated temperature-pressure curve. The temperature compensation algorithm can employ linear interpolation, polynomial fitting, or table lookup methods.

[0048] Reference voltage source: Employs a precision reference voltage chip to provide a stable reference voltage for the signal conditioning circuit. The accuracy of the reference voltage is typically ±0.1% to ±0.5%, and the temperature drift is typically less than 10 ppm / ℃.

[0049] The output signal of the signal conditioning circuit is typically an analog voltage signal of 0 to 5V or 0 to 10V, or a current signal of 4 to 20mA. The relationship between the output signal and depth can be expressed by the following formula:

[0050] in, This is the output voltage of the signal conditioning circuit. and These are the output voltages corresponding to depths of 0 and maximum depth, respectively. This represents the maximum measurable depth.

[0051] In one embodiment, the depth sensing module further includes a temperature compensation unit, which is used to perform temperature compensation on the depth signal based on the collected seawater temperature data, so as to eliminate the influence of temperature changes on the output accuracy of the pressure-sensitive element.

[0052] In this embodiment, the working principle of the temperature compensation unit is as follows: The output signal of the pressure-sensitive element is affected by temperature changes mainly in two aspects: first, the zero-point drift and sensitivity drift of the pressure-sensitive element itself; and second, the measurement error caused by the volume expansion coefficient of the sealing material (such as silicone oil). Taking a piezoresistive pressure sensor as an example, its zero-point temperature coefficient is typically ±0.01%FS / ℃ to ±0.05%FS / ℃, and its sensitivity temperature coefficient is typically -0.1%FS / ℃ to -0.3%FS / ℃. This means that under a temperature change of 10℃, without temperature compensation, the depth measurement error may reach 1% to 3%.

[0053] The temperature compensation unit is implemented as follows: First, the pressure-sensitive element is calibrated across the entire temperature range before leaving the factory. Calibration temperature points are typically 0℃, 10℃, 20℃, and 30℃. At each temperature point, its output signal is measured under known pressure, establishing temperature-zero offset curves and temperature-sensitivity offset curves. Second, during actual use, the temperature compensation unit receives seawater temperature data collected by the temperature sensor in real time. Based on the temperature-zero offset curves and temperature-sensitivity offset curves, it calculates the zero-point offset and sensitivity offset at the current temperature. Finally, the depth signal is corrected based on the calculation results, using the following correction formula:

[0054] in, This is the corrected depth value. This is the original depth value. The temperature coefficient of sensitivity. The zero-point temperature coefficient, This is the difference between the current temperature and the reference temperature.

[0055] In one embodiment, this application also provides a pressure-sensing-based marine multi-depth water quality data acquisition system. In this system, a data fusion processing unit is disposed inside the multi-depth detection carrier structure and is electrically connected to each group of water quality sensor components and a depth sensing module. It is used to receive water quality parameter data collected by each group of water quality sensor components and depth signals output by the depth sensing module, and to label the water quality parameter data of each group of water quality sensor components with corresponding depth tags according to the depth signals, thereby obtaining water quality data with depth information.

[0056] In this embodiment, the data fusion processing unit is the core processing unit of the entire system, responsible for coordinating the working sequence of each sensor, collecting sensor data, performing data fusion, and associating tags. The structure and function of the data fusion processing unit will be described in detail below.

[0057] In one embodiment, this application also provides a pressure-sensing-based marine multi-depth water quality data acquisition system. In this system, the data fusion processing unit includes an analog-to-digital converter, a storage module, and a main control processor. The analog-to-digital converter is electrically connected to each group of water quality sensor components and a depth sensing module, respectively, and is used to convert the analog signals output by each water quality sensor component and the analog signals output by the depth sensing module into digital signals. The storage module is used to cache the water quality parameter data acquired by each water quality sensor component and the depth signals output by the depth sensing module. The main control processor is electrically connected to the analog-to-digital converter and the storage module, respectively, and is used to read the water quality parameter data and depth signals in the storage module, and to tag the water quality parameter data with corresponding depth labels according to the depth signals.

[0058] In this embodiment, the workflow of the data fusion processing unit is as follows: The first step is system self-test and initialization. After the main control processor is powered on, it first executes a self-test program to check the power supply voltage, operating current, and communication status of each module. If the self-test passes, the main control processor initializes the operating parameters of each sensor, including sampling frequency, measurement range, calibration coefficient, etc. After initialization, the main control processor sends a start command to each sensor to enable each sensor to enter continuous operation or timed operation.

[0059] The second step is data acquisition and analog-to-digital conversion. Each water quality sensor component acquires water quality parameter data in real time according to a preset sampling frequency (typically 1Hz to 10Hz), and transmits the acquired analog signals to the analog-to-digital converter (ADC) via signal lines. The depth sensing module also acquires depth signals in real time according to a preset sampling frequency (typically 10Hz to 100Hz), and transmits the analog signals to the ADC. The ADC converts the received analog signals into digital signals, with a conversion accuracy typically between 12 and 16 bits. The ADC can use either synchronous sampling or time-division sampling: synchronous sampling means that all channels sample simultaneously, suitable for scenarios requiring precise time synchronization; time-division sampling means that each channel samples sequentially, suitable for cost-sensitive scenarios.

[0060] The third step is data caching and storage. The digital signal output from the analog-to-digital converter is first stored in the buffer of the storage module. The storage module typically uses an SD card, eMMC, or NAND Flash, with a storage capacity usually ranging from 8GB to 128GB, which can meet the data storage needs of continuous operation for several months to several years. The storage module uses a circular buffer or a first-in-first-out (FIFO) mechanism, automatically overwriting the oldest data when the storage space is full.

[0061] The fourth step is data fusion and tag association. The main control processor reads data from the storage module at preset time intervals (usually 1 to 60 seconds) and performs data fusion processing. First, the main control processor aligns the water quality parameter data and depth signals from the same or similar times. Then, it determines the current depth position of each sensor installation chamber based on the depth signal value. Based on the correspondence between depth values ​​and sensor installation chamber positions, the main control processor assigns a corresponding depth tag to the water quality parameter data of each group of water quality sensor components. The specific tag association algorithm is as follows: The main control processor pre-stores the calibration depth positions of each sensor mounting compartment. For example, the calibration depth of sensor mounting compartment A is... The calibration depth of sensor installation compartment B is And so on. When the main control processor reads the depth signal... At that time, calculate the depth signal Distance from each calibrated depth position:

[0062] in, Indicates the first Each sensor is installed in a separate compartment. The main control processor correlates water quality parameter data with the calibration depth location closest to the target depth; that is, if... If the value is the smallest, then the current water quality parameter data is assumed to come from the sensor installation compartment. and label it as depth .

[0063] The fifth step is data encapsulation and output. The main control processor encapsulates the water quality data with depth tags according to a predetermined data format, forming data packets. The data packet format typically includes: a packet header (fixed bytes, used to identify the start of the data packet), a timestamp (Unix timestamp or relative time), depth tags, water quality parameter data (dissolved oxygen, pH, conductivity, turbidity, temperature, etc.), a checksum (CRC or checksum), and a packet trailer. The main control processor transmits the encapsulated data packets to the wireless communication module via the internal bus.

[0064] In one embodiment, the data fusion processing unit is further provided with a time synchronization module. The time synchronization module is used to provide a unified time reference for the acquisition time of each group of water quality sensor components and the sensing time of the depth sensing module, so as to ensure the temporal consistency between water quality parameter data and depth signals.

[0065] In this embodiment, the time synchronization module works as follows: The time synchronization module typically uses a real-time clock (RTC) chip or a GPS clock module. The RTC chip has a built-in independent timing circuit and backup battery, maintaining accurate timing even in the event of a power outage; its timing accuracy is typically ±2 seconds / day to ±10 seconds / day. The GPS clock module obtains precise time information by receiving GPS satellite signals, achieving a time accuracy of ±1 microsecond to ±100 nanoseconds, suitable for high-precision synchronization scenarios.

[0066] The time synchronization module provides a unified time reference for the data fusion processing unit, ensuring that the data collected by each sensor has an accurate timestamp. The time synchronization module is also responsible for triggering all sensors to simultaneously acquire data at predetermined times, achieving precise time alignment between water quality parameter data and depth signals. The trigger signal for the time synchronization module can be implemented through hardware interrupts or software timers, with a trigger accuracy typically ranging from ±1 millisecond to ±10 milliseconds.

[0067] The time synchronization module also supports external time synchronization protocols, such as NTP (Network Time Protocol) or PTP (Precision Time Protocol), which can synchronize time with external data centers to ensure the time consistency of the entire monitoring system.

[0068] In one embodiment, this application also provides a pressure-sensing-based ocean multi-depth water quality data acquisition system, in which a wireless communication module is electrically connected to a data fusion processing unit for wirelessly transmitting water quality data with depth information to an external receiving terminal.

[0069] In this embodiment, the wireless communication module serves as the interface for data exchange between the entire system and external systems, responsible for wirelessly transmitting water quality data containing depth information to external receiving terminals. The wireless communication module typically employs the following communication methods: Underwater acoustic communication: Underwater acoustic communication is the most commonly used wireless communication method for underwater equipment. Its working principle is as follows: The transmitting end modulates a digital signal onto a sound wave of a specific frequency, and then transmits the sound wave into the water through an underwater acoustic transducer. After propagating in the water, the sound wave is received by the transducer at the receiving end, which demodulates the sound wave to reconstruct the digital signal. The communication distance of underwater acoustic communication is typically 1 to 10 kilometers, the communication rate is typically 1 kbps to 10 kbps, and the carrier frequency is typically 10 kHz to 100 kHz. The advantages of underwater acoustic communication are its long propagation distance, while its disadvantages include limited bandwidth, high latency, and susceptibility to noise interference.

[0070] Underwater electromagnetic wave communication: The working principle of underwater electromagnetic wave communication is the same as that of radio communication in the air. However, due to the high conductivity of seawater, electromagnetic waves attenuate rapidly in water, and it is usually only suitable for short-range (less than 10 meters) communication. The advantages of underwater electromagnetic wave communication are high bandwidth and low latency, while the disadvantage is its extremely short propagation distance.

[0071] Surface buoy relay communication: The working principle of surface buoy relay communication is as follows: The multi-depth probe structure transmits data to the surface buoy via underwater acoustic communication or wired cable; the surface buoy then forwards the data to an external receiving terminal via radio communication (such as 4G, 5G, or satellite communication). This method combines the advantages of underwater and aerial communication and is currently the most widely used solution.

[0072] In one embodiment, this application also provides a pressure-sensing-based ocean multi-depth water quality data acquisition system. In this system, the wireless communication module includes a modulation circuit, a power amplifier, and an antenna. The modulation circuit is used to modulate the digital signal output by the data fusion processing unit into a radio frequency signal. The power amplifier is used to amplify the power of the radio frequency signal, and the antenna is used to radiate the amplified radio frequency signal to an external receiving terminal.

[0073] In this embodiment, the specific workflow of the wireless communication module is as follows: Data Modulation: The modulation circuit converts the digital signal output from the data fusion processing unit into a radio frequency signal suitable for wireless transmission. Modulation methods can include ASK (Amplitude Shift Keying), FSK (Frequency Shift Keying), PSK (Phase Shift Keying), or QAM (Quadrature Amplitude Modulation). For low-speed data transmission, FSK modulation is typically used due to its strong anti-interference capability; for high-speed data transmission, QAM modulation is typically used due to its higher spectral efficiency.

[0074] Power Amplification: The power of modulated RF signals is typically only a few milliwatts to tens of milliwatts, which is insufficient for long-distance transmission. Power amplifiers amplify the power of RF signals to 100mW to 10W, with the specific power level depending on the communication distance and antenna gain. Power amplifiers typically employ linear amplifiers to maintain the signal modulation characteristics unchanged.

[0075] Signal transmission: The amplified radio frequency signal is radiated into space through the antenna. The antenna type can be a whip antenna, helical antenna, or patch antenna, depending on the operating frequency band and installation space. The antenna gain is typically 0 dBi to 10 dBi, and the radiation mode can be designed to be omnidirectional or directional.

[0076] Signal reception: The wireless communication module also needs to be able to receive external commands to enable remote parameter configuration, firmware upgrades, and other functions. The signal reception link includes a low-noise amplifier, demodulation circuit, and decoding circuit.

[0077] In this embodiment, the communication protocol of the wireless communication module typically adopts a custom protocol or a standard protocol, such as TCP / IP, UDP, MQTT, etc. The communication frequency band can be the ISM band (433MHz, 868MHz, 915MHz, 2.4GHz) or a satellite communication band. The communication distance is typically 1 to 10 kilometers under line-of-sight conditions, and will decrease in the presence of obstacles.

[0078] Based on the above embodiments, the workflow of the pressure-sensing-based ocean multi-depth water quality data acquisition system proposed in this application can be summarized as follows: First, the multi-depth probe structure is adjusted to a vertical attitude by a counterweight balancing system and descends to the target depth at a set rate. During the descent and after reaching the target depth, the depth sensing module continuously collects the water pressure signal of the external seawater and processes it through a signal conditioning circuit and a temperature compensation unit to obtain an accurate depth signal.

[0079] Secondly, under the control of the main control processor, the water quality sensor components in each sensor installation chamber synchronously collect water quality parameter data such as dissolved oxygen, pH, conductivity, turbidity, and temperature at each depth location according to the set sampling frequency; the analog signals output by each sensor are converted into digital signals by an analog-to-digital converter and stored in the storage module.

[0080] Third, the main control processor of the data fusion processing unit reads water quality parameter data and depth signals from the storage module, and adds corresponding depth tags to the water quality parameter data of each group of water quality sensor components according to the depth signals to obtain water quality data with depth information; the data fusion processing unit is also equipped with a time synchronization module to ensure the time consistency between water quality parameter data and depth signals.

[0081] Fourth, the wireless communication module encapsulates water quality data with depth information according to a predetermined data format, and wirelessly transmits the data to an external receiving terminal through a modulation circuit, power amplifier, and antenna; the external receiving terminal can be a coastal base station, an ocean monitoring vessel, a satellite relay station, or a cloud platform server.

[0082] The pressure-sensing-based ocean multi-depth water quality data acquisition system proposed in this application has the following significant advantages: First, it achieves in-situ synchronous acquisition of water quality data at multiple depths: Through the integrated design of the multi-depth detection carrier structure and multiple sets of water quality sensor components, the system can simultaneously carry multiple sets of water quality sensor components on the same carrier, realizing the simultaneous monitoring of water quality parameters at multiple depth points on the vertical profile of the ocean, which greatly improves the monitoring efficiency compared with the traditional single-point monitoring method.

[0083] Second, it achieves precise binding of water quality parameter data and depth information: through the cooperation of the depth sensing module and the data fusion processing unit, the system can accurately label the water quality parameter data of each group of water quality sensor components according to the depth signal, which solves the problem that water quality data and depth information are difficult to accurately correspond in the existing technology.

[0084] Third, it ensures the sealing reliability of the sensor installation chamber in deep water environment: through the design of the pressure balance channel, the system can achieve pressure balance between the inside of the sensor installation chamber and the external seawater environment under different depth conditions, avoiding the problem of chamber sealing failure caused by depth changes and extending the service life of the system.

[0085] Fourth, it improves the accuracy of depth measurement: by correcting the depth signal through the temperature compensation unit, the system can eliminate the influence of temperature changes on the output accuracy of the pressure-sensitive element, ensuring the accuracy of the correspondence between water quality data and depth labels.

[0086] Fifth, the entire system has a compact structure and high integration, making it suitable for long-term in-situ monitoring tasks in marine environments. It can provide high-quality multi-depth water quality data support for fields such as marine ecological research, marine resource development, and marine environmental protection.

[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A pressure-sensing-based ocean multi-depth water quality data acquisition system, characterized in that, include: The multi-depth detection carrier structure has several longitudinally distributed sensor installation chambers inside. Each sensor installation chamber has a pressure equalization channel in its chamber wall to achieve pressure balance between the inside of each sensor installation chamber and the external seawater environment. Multiple sets of water quality sensor components are installed in each sensor installation chamber. Each set of water quality sensor components includes a dissolved oxygen sensor, a pH sensor, a conductivity sensor, and a turbidity sensor, which are used to collect water quality parameter data at corresponding depth locations in real time. The depth sensing module is located at the top of the multi-depth detection carrier structure. It includes a pressure-sensitive element and a signal conditioning circuit. The pressure-sensitive element is used to sense the water pressure signal of the external seawater environment and convert the water pressure signal into an electrical signal. The signal conditioning circuit is used to amplify and filter the electrical signal to obtain a depth signal that is proportional to the depth. The data fusion processing unit is located inside the multi-depth detection carrier structure and is electrically connected to each group of water quality sensor components and depth sensing module. It is used to receive water quality parameter data collected by each group of water quality sensor components and depth signals output by the depth sensing module, and to add corresponding depth tags to the water quality parameter data of each group of water quality sensor components according to the depth signals to obtain water quality data with depth information. The wireless communication module, electrically connected to the data fusion processing unit, is used to wirelessly transmit water quality data with depth information to an external receiving terminal.

2. The ocean multi-depth water quality data acquisition system based on pressure sensing according to claim 1, characterized in that, Each sensor installation compartment has an openable and closable door at its end. The door is sealed to the compartment wall by a sealing ring, and the outer surface of the door is coated with an anti-bioadhesion coating.

3. The ocean multi-depth water quality data acquisition system based on pressure sensing according to claim 1, characterized in that, The pressure balance channel includes a first channel section and a second channel section. The first channel section runs horizontally through the wall of the sensor mounting compartment, and the second channel section is connected to the first channel section vertically. The outlet end of the second channel section is set towards the bottom of the multi-depth detection carrier structure.

4. The ocean multi-depth water quality data acquisition system based on pressure sensing according to claim 1, characterized in that, The multi-depth detection carrier structure also includes a counterweight balancing system, which is located at the bottom of the multi-depth detection carrier structure. The counterweight balancing system includes a counterweight block and a counterweight adjustment mechanism. The counterweight adjustment mechanism is used to adjust the position of the counterweight block relative to the multi-depth detection carrier structure so as to achieve vertical attitude adjustment of the multi-depth detection carrier structure in the water.

5. The ocean multi-depth water quality data acquisition system based on pressure sensing according to claim 1, characterized in that, The data fusion processing unit includes an analog-to-digital converter, a storage module, and a main control processor. The analog-to-digital converter is electrically connected to each group of water quality sensor components and the depth sensing module, respectively, and is used to convert the analog signals output by each water quality sensor component and the analog signals output by the depth sensing module into digital signals. The storage module is used to cache the water quality parameter data collected by each water quality sensor component and the depth signal output by the depth sensing module. The main control processor is electrically connected to both the analog-to-digital converter and the storage module, and is used to read the water quality parameter data and depth signal from the storage module, and to tag the water quality parameter data with the corresponding depth based on the depth signal.

6. The ocean multi-depth water quality data acquisition system based on pressure sensing according to claim 1, characterized in that, The wireless communication module includes a modulation circuit, a power amplifier, and an antenna. The modulation circuit is used to modulate the digital signal output by the data fusion processing unit into a radio frequency signal. The power amplifier is used to amplify the power of the radio frequency signal. The antenna is used to radiate the amplified radio frequency signal to an external receiving terminal.

7. The ocean multi-depth water quality data acquisition system based on pressure sensing according to claim 1, characterized in that, Each water quality sensor assembly also includes a temperature sensor, which is used to collect seawater temperature data at corresponding depth locations in real time. The data fusion processing unit is also used to receive the temperature data collected by the temperature sensor and associate the temperature data with depth tags as part of the water quality parameter data.

8. The ocean multi-depth water quality data acquisition system based on pressure sensing according to claim 1, characterized in that, The outer wall of the multi-depth probe structure is equipped with a corrosion-resistant protective layer, which is made of polyethylene or titanium alloy.

9. The ocean multi-depth water quality data acquisition system based on pressure sensing according to claim 7, characterized in that, The depth sensing module also includes a temperature compensation unit, which is used to compensate the depth signal based on the collected seawater temperature data in order to eliminate the impact of temperature changes on the output accuracy of the pressure-sensitive element.

10. The ocean multi-depth water quality data acquisition system based on pressure sensing according to claim 1, characterized in that, The data fusion processing unit is also equipped with a time synchronization module, which provides a unified time reference for the acquisition time of each group of water quality sensor components and the sensing time of the depth sensing module, ensuring the temporal consistency of water quality parameter data and depth signals.

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