Offshore electric field detection equipment based on corona current measurement

Abstract

The present invention discloses an offshore electric field detection device based on corona current measurement, comprising a floating platform, a corona probe, a counterweight, a multi-parameter detection unit, a data processing unit, a Beidou communication module, and a composite power supply system. The floating platform is made of corrosion-resistant composite materials and has a built-in sealed cabin. A corona probe is installed on the top, and the corona probe adopts a multi-level gradient structure and a hydrophobic coating, which significantly improves the resistance to salt spray corrosion. The electric field detection equipment integrates sensors such as corona current, salt spray concentration, wind speed, and attitude, and collects environmental and platform motion data in real time. The electric field strength is calculated through a dynamic coupling correction algorithm of corona current and salt spray, wind speed, and platform attitude. Combined with adaptive filtering and data compression technology, the interference of the environment and platform motion is suppressed to achieve high-precision measurement of the sea surface electric field strength. Data compression and Beidou encrypted transmission technology are used to achieve ultra-long-distance data transmission.

Description

Technical Field

[0001] The present invention relates to the field of atmospheric physics and ocean electric field technology, and in particular to an offshore electric field detection device based on corona current measurement, which is used to monitor the electric field intensity on the sea surface in real time and improve the electric field measurement accuracy and equipment reliability through dynamic correction of multiple environmental parameters. Background Art

[0002] Lightning activity is a direct result of dramatic changes in the atmospheric electric field. Land-based lightning detection technology has matured over decades of development. Fixed electric field meter networks and ground-based radar systems enable real-time monitoring and early warning of lightning activity, predicting the charge distribution of thunderstorm clouds by measuring changes in the ground electric field intensity gradient. However, the development of lightning detection technology in marine environments is seriously lagging behind. Statistics show that global marine lightning activity is frequent and significantly more intense than on land. Currently, forecasting marine thunderstorms primarily relies on monitoring changes in sea surface electric field intensity. Existing technologies have significant shortcomings in real-time sea surface electric field detection. Existing technologies often rely on monitoring vessels equipped with mobile electric field detection equipment to intermittently sample localized sea areas, indirectly inferring the charge distribution of thunderstorm clouds by measuring sea surface electric field intensity. This method requires significant manpower and resources, is costly, and, due to limitations in speed and maneuverability, cannot achieve continuous monitoring over large areas and over long periods. Furthermore, inclement weather often forces ships to return to port for shelter, leading to interruptions in data collection during periods of peak lightning activity. Drones equipped with micro-electric field sensors can quickly reach target sea areas, but their flight time is typically less than two hours, and their wind resistance is limited to winds below force 5. In severe convective weather, drones are prone to losing control and crashing into the sea due to rainfall and turbulence, making their practical application scenarios extremely limited. Traditional buoy-based monitoring devices, while capable of fixed-point deployment, primarily focus on general parameters such as wind speed and water temperature, lacking specialized equipment for detecting electric field intensity. A few studies have employed moored buoys integrated with electric field sensors, but these designs suffer from fundamental flaws. Traditional spherical electric field probes are easily covered by salt spray, resulting in reduced corona discharge stability and large drift errors in measured data. The buoy's attitude changes caused by wave motion can significantly alter the distance between the probe and the sea surface, generating false electric field signals. The buoys lack the ability to simultaneously correct multiple parameters, making it impossible to remove environmental interference such as wind speed and salt spray concentration, resulting in low data reliability. Data transmission is wireless, but due to the limitations of wireless communication equipment, transmission distance is limited, limiting electric field detection to nearshore areas. These technical shortcomings severely restrict their application in critical scenarios such as marine thunderstorm warning and lightning path prediction. It is necessary to develop a high-precision offshore electric field detection equipment that is resistant to environmental interference, can be self-powered for a long time, and supports dynamic correction to fill the technical gap in the field of marine lightning monitoring. It is very necessary to detect offshore electric fields in the distant seas and study the changes in electric field intensity gradients to predict thunderstorm weather through Beidou short message remote data transmission. Summary of the Invention

[0003] The present invention aims to provide an offshore electric field detection device based on corona current measurement. The device comprises a floating platform, a corona probe, a counterweight, a multi-parameter detection unit, a data processing unit, a Beidou satellite communication module, and a power supply unit. The floating platform is constructed of corrosion-resistant composite materials and features a sealed cabin. A corona probe is mounted on top, featuring a multi-level gradient structure and a hydrophobic coating, significantly enhancing its resistance to salt spray corrosion. The device integrates sensors for corona current, salt spray concentration, wind speed, and platform attitude, collecting real-time environmental and platform motion data. The device calculates electric field strength using a dynamic coupling correction algorithm based on corona current, salt spray, wind speed, and platform attitude. Adaptive filtering and data compression techniques are used to suppress environmental and platform motion interference, enabling high-precision measurement of sea surface electric field strength. Data compression and Beidou encrypted transmission technology enable ultra-long-distance data transmission. The device utilizes a photovoltaic cell, wave generator, and battery-powered composite power supply system for long-term endurance. The device is suitable for marine electromagnetic environment monitoring and meteorological early warning applications, offering the advantages of flexible deployment, high reliability, and low cost.

[0004] The present invention is implemented through the following technical solution: an offshore electric field detection device based on corona current measurement, comprising: a floating platform 1, a corona probe 2, a counterweight 3, a detection unit 4, a data processing unit 5, a Beidou satellite communication module 6, and a power supply unit 7. The floating platform 1 is made of corrosion-resistant composite materials, has a sealed interior, and a mounting base for the corona probe 2 is provided on top. The corona probe 2 is vertically mounted on the top of the floating platform 1 at a height of ≥1 meter. The counterweight 3 is suspended below the floating platform 1, and the symmetrical arrangement ensures the balance of the floating platform 1. The detection unit 4 includes a corona current detection module 41, a salt spray detection module 42, a seawater conductivity detection module 43, a temperature detection module 44, a wind speed detection module 45, an acceleration detection module 46, and a three-axis attitude detection module 47. The data processing unit 5, integrated within the sealed cabin, measures the corona discharge current of the corona probe 2 and calculates the sea surface electric field intensity through the corona current detection module 41. The salt spray detection module 42 corrects the effect of the air salt spray concentration above the sea surface on the electric field intensity. The wind speed detection module 45 corrects the effect of wind speed on the electric field intensity. The acceleration detection module 46 detects the height of the floating platform 1, and the three-axis attitude detection module 47 detects the inclination angle of the floating platform 1. The effects of the height and inclination angle of the floating platform 1 on the electric field intensity are corrected. The seawater conductivity detection module 43 and the temperature detection module 44 are used to analyze the relationship between the seawater conductivity and the air salt spray concentration.

[0005] The data processing unit 5 performs signal filtering, compression and outlier marking algorithms on the detection data of the detection unit 4 to calculate the electric field strength on the sea surface. EThe BeiDou satellite communication module 6 obtains the coordinate position, marks the timestamp, and transmits the electric field strength data, air salt spray concentration and platform coordinates through short messages. The monitoring center generates a thermal map based on the returned electric field strength and air salt spray concentration and the BeiDou coordinate superposition data.

[0006] The electric field strength E , calculated using the following formula:

[0007] ,

[0008] in, α The correction coefficient is 0.5~0.8, n is the number of free electrons per unit volume (unit: m −3 ), q is the charge of a single electron (1.602×10 −19 coulomb), m is the electron mobility (the mobility of electrons in air is about 1.3×10 −4 m 2 / V⋅s), A is the effective area of the probe (unit: m 2 );

[0009] Effects of air salt spray concentration, wind speed, and floating platform 1 posture on electric field strength, and corrected electric field strength E co The following formula is used for calculation:

[0010] ,

[0011] in: The height difference Δ between the corona probe 2 and the sea surface caused by the ups and downs of the floating platform 1 h ( t ), h 0 is the characteristic scale of corona discharge; To correct the swing angle, i ( t ) is the platform inclination angle; is the wind speed correction, v ( t ) is the wind speed, β The empirical coefficient is 0.1. v 0 is the reference wind speed, which is 1m / s; Corrected for salt spray, c ( t ) is the salt spray concentration, coefficient c Take 0.2, the base concentration c 0 = 1 mg / m 3 The acceleration detection module 46 obtains the acceleration a, calculate Δ by the following formula h ( t ), , the three-axis attitude detection module 47 obtains the platform tilt angle i ( t ), the wind speed detection module 45 obtains the wind speed v ( t ), the salt spray detection module 42 obtains the salt spray concentration c ( t ). h 0. β 、 c Determined by laboratory simulation or fitting of offshore measured data, the correction factor is substituted into the formula to dynamically calculate the corrected electric field strength. E co , and Kalman filtering suppresses high-frequency noise.

[0012] The floating platform 1 has a support 11 on its top, made of carbon fiber and coated with a DSAN coating with a hydrophobic angle greater than 150°. An anchor ring 12 is provided at the bottom of the floating platform 1, connected to an anchor 14 by a Kevlar cable 13.

[0013] The tip of the corona probe 2 is a tungsten alloy needle structure with a diameter of ≤0.1mm, which is installed at the top of the bracket 11. The tip of the corona probe 2 adopts a multi-level gradient structure, and the diameter from the root to the tip gradually decreases from 2mm to 0.1mm. The tungsten alloy tip is electron beam polished and the surface roughness Ra≤0.05 m m, the surface of which is coated with a salt spray resistant tungsten alloy film, the corona probe 2 is connected to the corona current detection module 41 and is connected to the data processing unit 5 using a cable with a Teflon insulation tape shielding layer.

[0014] The salt fog detection module 42 uses a laser scattering method to measure the salt fog concentration. By measuring the scattering signal of the laser by the salt particles in the flowing air, the content and particle size distribution of the salt particles are obtained, and the level of salt fog content in the air is obtained in real time. The salt fog detection module 42 has a salt fog particle concentration measurement range of 0~10mg / m³ and a particle size distribution measurement range of 0.5~10 m m.

[0015] The data processing unit 5 has a built-in coordinated power supply and low-power sleep mode. It can automatically activate all detection modes according to a set start-up threshold. If the start-up threshold is lower than the threshold, it automatically enters sleep mode and performs only corona current detection. The data processing unit 5 obtains raw data from the detection unit 4 and uses sliding average and Kalman filtering algorithms to remove noise and improve data accuracy. It also uses bit-splitting data compression to reduce data volume, reduce the workload of the communication module, and improve transmission efficiency. The data processing unit 5 is equipped with an adaptive filtering module that uses a band-stop filter based on the wave spectrum, with a center frequency locked at 0.1-0.3Hz. This eliminates low-frequency interference signals caused by wave motion and effectively suppresses electric field measurement errors caused by platform shaking. The data processing unit 5 uses a sliding window median or isolation forest algorithm to identify and mark abnormal data to ensure data accuracy and reliability. The processed data is packaged into a complete data packet, compressed into a binary package, and transmitted as a short message via the Beidou satellite communication module 6.

[0016] The power supply unit 7 includes a photovoltaic panel 71, a wave generator 72, and a battery 73. The photovoltaic panel 71 uses a monocrystalline silicon cell, and the wave generator 72 uses a pendulum-type small generator. The photovoltaic panel 71 and the wave generator 72 are connected to the battery 73 inside the platform through the BMS battery management system. The battery 73 uses a lithium battery pack.

[0017] The Beidou satellite communication module 6 is encrypted with AES-256 and transmitted through the Beidou RDSS channel. The capacity of a single message is 1200 bytes, and a short message is sent once every 5 minutes.

[0018] The beneficial effects of the present invention are as follows: the error is greatly reduced by dynamically correcting the electric field strength through salt spray concentration, wind speed, platform height and inclination. The anti-salt spray design of the corona probe adopts a gradient structure, hydrophobic coating and tungsten alloy coating to effectively prevent the probe from being corroded by seawater. The adaptive filtering band-stop filter based on the wave spectrum eliminates 0.1~0.3Hz low-frequency interference. Through dynamic correction formulas and Kalman filtering, the electric field strength solution error is ≤5%; the composite power supply system can work continuously under no light conditions. Using Beidou encrypted short message transmission, data return is not subject to distance restrictions, realizing ultra-long-distance data return. The equipment cost is low and can be deployed in batches in offshore areas. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a vertical view of the present invention;

[0020] Figure 2 Plan view of the present invention;

[0021] Figure 3 This is a block diagram of the electric field strength detection principle of the present invention.

[0022] In the figure: 1- floating platform, 2- corona probe, 3- counterweight, 4- detection unit, 5- data processing unit, 6- Beidou satellite communication module, 7- power supply unit, 11- bracket, 12- anchor ring, 13- cable, 14- anchor, 31- counterweight support rod, 32- cross brace, 41- corona current detection module, 42- salt spray detection module, 43- seawater conductivity detection module, 44- temperature detection module, 45- wind speed detection module, 46- acceleration detection module, 47- three-axis attitude detection module, 71- photovoltaic panel, 72- wave generator, 73- battery. DETAILED DESCRIPTION

[0023] In order for those skilled in the art to better understand the present invention, Figure 1~Figure 3 To further explain the present application, in the description of the present invention, the terms "up", "down", "left", "right", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or directions or positional relationships commonly understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the components or parts referred to must have a specific direction, be constructed and operated in a specific direction. The contents mentioned in the implementation manner are not limitations of the present invention.

[0024] The marine electric field detection device based on corona current measurement of the present invention comprises: a floating platform 1, a corona probe 2, a counterweight 3, a detection unit 4, a data processing unit 5, a Beidou satellite communication module 6, and a power supply unit 7. Figure 1 , the plan view of the present invention is shown in Figure 2 The electric field strength detection principle block diagram of the present invention is shown in Figure 3. The floating platform 1 is made of corrosion-resistant composite materials. Specifically, the floating platform 1 uses glass fiber reinforced epoxy resin composite materials to make the shell, and the interior is filled with polyurethane foam material. The floating platform 1 is provided with a sealed cabin inside. The sealed cabin has a waterproof level of IP68 and is used to place the data processing unit 5 and the Beidou satellite communication module 6. The top of the floating platform 1 is provided with a corona probe 2 mounting seat. The corona probe 2 is vertically installed on the top of the floating platform 1 at a height of ≥1 meter. The top surface of the floating platform 1 is provided with a bracket 11. The bracket 11 is made of carbon fiber material and the outer layer is coated with a DSAN coating with a hydrophobic angle of >150°. The balance hammer 3 is suspended below the floating platform 1 and is arranged symmetrically. A lead counterweight is used to ensure that the platform inclination angle is ≤5° to ensure the balance of the floating platform 1. The balance hammer 3 is cantilevered outward using a balance hammer strut 31 to increase the anti-overturning ability of the floating platform 1. The balance hammer struts 31 are connected and fixed with a cross brace 32 to increase the strength of the balance hammer struts 31. The balance hammer strut 31 and cross brace 32 use steel pipes as support components, and are wrapped with carbon fiber material to seal and prevent seawater erosion. An anchor ring 12 is provided at the bottom of the floating platform 1, and a cable 13 made of Kevlar is used to connect it to the anchor 14. The length of the cable 13 should be determined according to the depth of the sea area to be detected, and a margin of 10% to 20% should be reserved compared to the seawater depth. The floating platform 1 can float and move freely without being drifted away by the waves. If the purpose of the detection is to study the free floating trajectory of the floating platform 1 with the waves and currents, and randomly detect the electric field strength of the ocean, the cable 13 and anchor 14 can be omitted.

[0025] The tip of the corona probe 2 is a tungsten alloy needle structure with a diameter of ≤0.1mm, which is installed at the top of the bracket 11. The tip of the corona probe 2 adopts a multi-level gradient structure, with the diameter gradually decreasing from 2mm to 0.1mm from the root to the tip. The tungsten alloy tip is electron beam polished and the surface roughness Ra≤0.05 m The corona probe 2 and the corona current detection module 41 are connected to the data processing unit 5 using a cable with a Teflon insulation tape shielding layer.

[0026] The detection unit 4 includes a corona current detection module 41, a salt spray detection module 42, a seawater conductivity detection module 43, a temperature detection module 44, a wind speed detection module 45, an acceleration detection module 46, and a three-axis attitude detection module 47. The salt spray detection module 42 is used to correct the influence of the salt spray concentration in the air above the sea surface on the electric field strength. The salt spray detection module 42 uses a laser scattering method to measure the salt spray concentration. By measuring the scattering signal of the laser by the salt particles in the flowing air, the content and particle size distribution of the salt particles are obtained, and the level of salt spray content in the air is obtained in real time. The salt spray concentration meter model MHY-YW6 is used. The salt spray particle concentration measurement range is 0~10mg / m³ and the particle size distribution measurement range is 0.5~10 mm. Wind speed detection module 45 is used to correct for the effects of wind speed on the electric field strength. It utilizes a mechanical anemometer with a range of 0–50 m / s. Acceleration detection module 46 detects the ups and downs of the floating platform 1. It uses a VSA001 model with a detection range of ±25g and an accuracy of ±0.2%. Three-axis attitude detection module 47 detects the inclination of the floating platform 1. It uses a YIS106 model. It detects inclinations of ±60° for roll and pitch, and ±180° for heading, with an accuracy of 0.1° for roll and pitch, and 0.5° for heading. The data processing unit 5 corrects for the effects of salt spray concentration, wind speed, and the platform's ups and downs and inclination on the electric field strength. The seawater conductivity detection module 43 and temperature detection module 44 are used to analyze the relationship with air salt spray concentration.

[0027] Power supply unit 7 comprises photovoltaic panels 71, wave generators 72, and batteries 73. PV panels 71 utilize monocrystalline silicon cells, while wave generators 72 utilize a small pendulum-type generator. These panels are connected to the platform's internal battery 73 via a battery management system (BMS). Battery 73 utilizes a lithium-ion battery pack. PV panels 71 have a power output of 50W, wave generators 72 have an output power of 30W, and battery 73 has a capacity of 500Wh. Power management prioritizes photovoltaic power generation over wave power generation. When light intensity exceeds 200W / m², photovoltaic power is prioritized. The wave generator activates when the platform's swing frequency exceeds 0.2Hz, and non-core modules are shut down when the remaining battery charge drops below 20%.

[0028] The corona current detection module 41 measures the corona discharge current of the corona probe 2 and calculates the sea surface electric field strength through the corona current detection module 41. E . Corona discharge occurs near the tip electrode. When the electric field strength is high enough, the gas molecules are ionized, generating a large number of positive ions and secondary electrons, forming a non-self-sustaining discharge. The corona discharge current is nonlinearly positively correlated with the electric field strength. By measuring the corona discharge current, the magnitude of the electric field strength can be inferred. The data processing unit 5 performs signal filtering, compression and outlier marking algorithms on the detection data of the detection unit 4 to calculate the electric field strength on the sea surface. E Calculate the electric field strength by corona current E , calculated using the following formula:

[0029] ,

[0030] in, α The correction coefficient is 0.5~0.8, n is the number of free electrons per unit volume (unit: m −3 ), at standard atmospheric pressure, the number of free electrons in air is n About 10 9 m−3 , q is the charge of a single electron (1.602×10 −19 coulomb), m is the electron mobility (the mobility of electrons in air is about 1.3×10 −4 m 2 / V⋅s), A is the effective area of the probe (unit: m 2 ).

[0031] The swing of floating platform 1 will accelerate the air flow and wind speed v Affecting the electric field through two mechanisms changes the electron mobility m Positively correlated with wind speed, accelerating the diffusion of salt spray aerosols and affecting the free electron density n Therefore, the electric field strength needs to be E Correction is made. The influence of air salt spray concentration, wind speed, and the attitude of floating platform 1 on the electric field strength is corrected using the following formula:

[0032] ,

[0033] in: The height difference Δ between the corona probe 2 and the sea surface caused by the ups and downs of the floating platform 1 h ( t ), h 0 is the characteristic scale of corona discharge, h 0 is a characteristic attenuation scale that describes the change of electric field intensity with height. Its physical nature is related to the vertical distribution characteristics of the atmospheric electric field. h 0 determines the platform height fluctuation Δ h ( t ) on the electric field measurement, h The larger 0 is, the slower the electric field decays with height (the more uniform the ambient electric field distribution); h The smaller 0 is, the more significant the attenuation of the electric field with height (the electric field is concentrated in the area near the sea surface). h 0 Usually 10~50 meters, closely related to the following factors, atmospheric conductivity (salt spray, humidity increase conductivity, may increase h 0); spatial charge distribution (the thickness of the charge layer under a thunderstorm cloud affects the vertical gradient of the electric field); turbulent mixing (turbulent diffusion in the ocean boundary layer leads to a uniform electric field distribution). To correct the swing angle, i ( t ) is the platform inclination angle; is the wind speed correction, v ( t ) is the wind speed, β The empirical coefficient is 0.1. v0 is the reference wind speed, which is 1m / s; Corrected for salt spray, c ( t ) is the salt spray concentration, coefficient c Take 0.2, the base concentration c 0 = 1 mg / m 3 .

[0034] In the above correction, the acceleration detection module 46 obtains the height change Δ of the corona probe 2 h ( t ), the core principle of the acceleration detection module 46 sensor to measure the height of the ups and downs is to deduce the displacement change through the integral operation of acceleration and combine it with the dynamic compensation algorithm to eliminate the error. According to Newton's second law F = yes , Newton's second law and acceleration integral, the acceleration detection module 46 obtains the instantaneous acceleration by measuring the inertial force on the mass block a , the displacement change Δ can be obtained by two integration operations h , calculated by the following formula: , represents the displacement Δ h is the acceleration a About time t The three-axis attitude detection module 47 obtains the platform tilt angle i ( t ). The wind speed detection module 45 obtains the wind speed v ( t ). The salt spray detection module 42 obtains the salt spray concentration c ( t ). h 0. β 、 c Determined by laboratory simulation or fitting of offshore measured data, the correction factor is substituted into the formula to dynamically calculate the corrected electric field strength. E co , and Kalman filtering suppresses high-frequency noise.

[0035] Data processing unit 5 utilizes an STM32H7 processor and integrates filtering, algorithms, compression, and outlier marking for electric field intensity, salt spray concentration, seawater conductivity, temperature, wind speed, acceleration, and triaxial attitude. All components of data processing unit 5 are integrated onto a single PCB, sealed with melt adhesive and housed within a sealed cabin. Data processing unit 5 acquires raw data from detection unit 4 and utilizes sliding average and Kalman filtering algorithms to remove noise and improve data accuracy. Bit-stitching data compression reduces data volume, lowers the workload of the communication module, and improves transmission efficiency. Data processing unit 5 includes an adaptive filtering module that employs a band-stop filter based on the ocean wave spectrum, with a center frequency locked between 0.1 and 0.3 Hz. This eliminates low-frequency interference signals caused by ocean wave motion and effectively suppresses electric field measurement errors caused by platform sway. Data processing unit 5 uses a sliding window median or isolation forest algorithm to identify and flag outliers, ensuring data accuracy and reliability. The Beidou satellite communication module 6 obtains the coordinate position, marks the timestamp, and transmits it to the data processing unit 5. The data processing unit 5 packages the processed data with the coordinate position and time information into a complete data packet, compresses it into a binary packet, and sends it through the Beidou satellite communication module 6 short message.

[0036] The data processing unit 5 has built-in coordinated power supply and a low-power sleep mode. It automatically activates all detection modes based on a set activation threshold. If the threshold falls below, it automatically enters sleep mode, performing only corona current detection and disabling all other non-core modules. The activation threshold is based on 1.5 to 2 times the average current detected by the corona current detection module 41 on clear weather. The data processing unit 5 also has a built-in self-diagnostic protocol. If a battery anomaly or sensor failure occurs, the fault code is proactively reported via short messages.

[0037] The data is transmitted through the Beidou RDSS channel after AES-256 encryption. The capacity of a single message is 1200 bytes. A short message is sent every 5 minutes. The electric field strength data, air salt spray concentration and platform coordinates are transmitted through short messages. The monitoring center generates a thermal map based on the returned electric field strength and air salt spray concentration and the Beidou coordinate superposition data.

[0038] Example 1: The floating platform 1 has a diameter of 2 meters. The upper bracket 11 is 1 meter higher than the top surface of the platform. The corona probe 2 is a cylinder with a lower diameter of 5 mm and a cone with a top diameter of 0.1 mm and a height of 50 mm. The surface area of the combined probe is 0.0033066 m 2 The floating platform 1 weighs 50 kg (excluding the weight of the counterweight 3), and the center of gravity height is H 平台 =0.25m, 4 counterweights are arranged symmetrically, with a horizontal distance from the center of the platform r =2m (extended outwards through the balance hammer support rod 31), single hammer weight m锤 =8kg, bottom distance of suspended floating platform 1 h =−2m. Total center of gravity height H 总 calculate:

[0039] , the total center of gravity is located 0.628 meters below the bottom of the platform, which enhances the anti-overturning ability of the floating platform 1 and improves its stability;

[0040] Restoring torque calculation:

[0041] , calculate the wind speed that can be resisted as v ≈20.73m / s wind, wind speed and wind level comparison table, 20.73m / s wind speed corresponds to approximately level 8 wind;

[0042] Buoyancy calculation: The bottom of floating platform 1 is hemispherical. Based on its deadweight of 50 kg and four counterweights weighing 32 kg, the platform displacement is 1.57 m 3 , buoyancy (density of water r =1000kg / m 3 ): F 浮 =1000×1.57×9.8≈15386N, total weight (platform + counterweight): W 总 =(50+32)×9.8=803.6N, <15386N, sufficient buoyancy, safe design.

[0043] Example 2: The detected electric field strength is E=25.62kV / m. Considering the fluctuation and tilt of the floating platform caused by the waves, the influence of the salt spray concentration and temperature of the air on the electric field strength, the detected electric field strength is E Make corrections:

[0044] ,

[0045] The platform rises and falls, causing the height difference between the probe and the sea surface to change Δ h ( t ) is calculated as 2m after acceleration, characteristic scale h 0 Based on experience, take 25m, and adjust for height fluctuations The platform's three-axis attitude detection tilt angle is 30°, and the swing angle correction The wind speed detection module 45 measures the wind speed to be v =15m / s, empirical coefficient β ≈0.1, reference wind speed v 0=1m / s, wind speed correction The salt spray detection module 42 detects the salt spray concentration. c=1.4mg / m 3 ,coefficient c Take 0.2, salt spray correction The calculated correction factor is 1.5995. Substituting E=25.62kV / m, the corrected electric field strength is E co =40.98 kV / m.

[0046] The above embodiments are only examples for explaining the present invention. The relationship between corona current and electric field strength needs to be determined through experiments, data collection and regression, and the correlation between the two. h 0. Experience coefficient β , Salt spray coefficient c Determined by laboratory simulation or fitting of offshore measured data.

[0047] The present invention is a one-way communication detection device. The electric field strength results detected by the offshore electric field detection device are transmitted back via Beidou short messages. The monitoring center receives and demodulates the transmitted data via the Beidou navigation system. The monitoring center cannot send instructions to the offshore electric field detection device. Using this device, the detection device can be placed in a predetermined sea area using a ship. Multiple devices can form a detection network. Data is transmitted back via short messages from the Beidou navigation system. Data can be transmitted back in any area covered by the Beidou navigation system, making it suitable for offshore electric field strength detection.

[0048] The description and drawings of this application are only a specific implementation method and are not restrictive. Under the guidance of this application, those skilled in the art can make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the scope of protection of this application.

Claims

1. A marine electric field detection device based on corona current measurement, characterized in that: include: A floating platform (1), a corona probe (2), a counterweight (3), a detection unit (4), a data processing unit (5), a Beidou satellite communication module (6), and a power supply unit (7); the floating platform (1) is made of corrosion-resistant composite materials, has a sealed cabin inside, and a corona probe (2) mounting seat on the top, and the corona probe (2) is vertically mounted on the top of the floating platform (1) at a height of ≥1 meter; the counterweight (3) is suspended below the floating platform (1) and symmetrically arranged to ensure the balance of the floating platform (1); the detection unit (4) includes a corona current detection module (41), a salt spray detection module (42), a seawater conductivity detection module (43), a temperature detection module (44), a wind speed detection module (45), an acceleration detection module (46), and a three-axis attitude detection module (47). Module (47); the data processing unit (5) is integrated in the sealed cabin, and the sea surface electric field strength is obtained by measuring the corona discharge current of the corona probe (2) and calculating it through the corona current detection module (41); the salt spray detection module (42) is used to correct the influence of the air salt spray concentration above the sea surface on the electric field strength; the wind speed detection module (45) is used to correct the influence of the wind speed on the electric field strength; the acceleration detection module (46) is used to detect the height of the floating platform (1) up and down; the three-axis attitude detection module (47) is used to detect the inclination angle of the floating platform (1) and correct the influence of the attitude of the floating platform (1) on the electric field strength by the height and inclination angle of the floating platform (1); the seawater conductivity detection module (43) and the temperature detection module (44) are used to judge the relationship with the air salt spray concentration; The data processing unit (5) performs signal filtering, compression and outlier marking algorithms on the detection data of the detection unit (4) to calculate the electric field intensity on the sea surface. E The BeiDou satellite communication module (6) obtains the coordinate position, marks the timestamp, and transmits the electric field strength data, air salt spray concentration and platform coordinates through short messages. The monitoring center generates a thermal map based on the returned electric field strength and air salt spray concentration and the BeiDou coordinate superposition data.

2. The marine electric field detection device based on corona current measurement according to claim 1, characterized in that: The electric field strength E , calculated using the following formula: ， in, α The correction coefficient is 0.5~0.8, n is the number of free electrons per unit volume, q is the charge of a single electron, μ is the electron mobility, A is the effective area of the probe; Effects of air salt spray concentration, wind speed, and floating platform (1) posture on electric field strength, and corrected electric field strength E co The following formula is used for calculation: ， in: The height difference between the corona probe (2) and the sea surface caused by the ups and downs of the floating platform (1) is Δ h ( t ), h 0 is the characteristic scale of corona discharge; To correct the swing angle, θ ( t ) is the platform inclination angle; is the wind speed correction, v ( t ) is the wind speed, β The empirical coefficient is 0.

1. v 0 is the reference wind speed, which is 1m / s; Corrected for salt spray, c ( t ) is the salt spray concentration, coefficient γ Take 0.2, the base concentration c 0 = 1 mg / m 3 ; The acceleration detection module (46) obtains the acceleration a , calculate Δ by the following formula h ( t ), , the three-axis attitude detection module (47) obtains the platform tilt angle θ ( t ), the wind speed detection module (45) obtains the wind speed v ( t ), the salt spray detection module (42) obtains the salt spray concentration c ( t ); h 0. β 、 γ Determined by laboratory simulation or fitting of offshore measured data, the correction factor is substituted into the formula to dynamically calculate the corrected electric field strength. E co , and Kalman filtering suppresses high-frequency noise.

3. The marine electric field detection device based on corona current measurement according to claim 1, characterized in that: The top surface of the floating platform (1) is provided with a bracket (11), the bracket (11) is made of carbon fiber material, and the outer layer is coated with a DSAN coating with a hydrophobic angle greater than 150 degrees; the bottom of the floating platform (1) is provided with an anchor ring (12), which is connected to the anchor (14) by a cable (13) made of Kevlar.

4. The marine electric field detection device based on corona current measurement according to claim 1 or 2, characterized in that: The corona probe (2) has a tip that is a tungsten alloy needle structure with a diameter of ≤0.1 mm and is mounted on the top of the bracket (11). The tip of the corona probe (2) adopts a multi-level gradient structure, with the diameter gradually decreasing from 2 mm to 0.1 mm from the root to the tip. The tungsten alloy tip is electron beam polished, and the surface roughness Ra is ≤0.05 μ m, the surface of which is coated with a salt spray resistant tungsten alloy film, the corona probe (2) is connected to the corona current detection module (41) and is connected to the data processing unit (5) using a cable with a Teflon insulation tape shielding layer.

5. The marine electric field detection device based on corona current measurement according to claim 1, characterized in that: The salt fog detection module (42) uses a laser scattering method to determine the salt fog concentration. By measuring the scattering signal of the laser by the salt particles in the flowing air, the content and particle size distribution of the salt particles are obtained, and the level of the salt fog content in the air is obtained in real time. The salt fog detection module (42) has a salt fog particle concentration measurement range of 0~10mg / m³ and a particle size distribution measurement range of 0.5~10 μ m.

6. The marine electric field detection device based on corona current measurement according to claim 1, characterized in that: The data processing unit (5) has a built-in coordinated power supply and low-power sleep mode, and can automatically start all detection modes according to a set start-up threshold value. When the start-up threshold value is lower than the start-up threshold value, it automatically enters the sleep mode and only performs corona current detection. The data processing unit (5) obtains raw data from the detection unit (4), removes noise using a sliding average and Kalman filter algorithm to improve data accuracy, and uses a bit splicing method to compress data to reduce the amount of data, reduce the workload of the communication module, and improve transmission efficiency. The data processing unit (5) is provided with an adaptive filtering module, which uses a band-stop filter based on the wave spectrum, with the center frequency locked at 0.1~0.3Hz, to eliminate low-frequency interference signals caused by wave motion and effectively suppress electric field measurement errors caused by platform shaking. The data processing unit (5) identifies and marks abnormal data through a sliding window median or isolation forest algorithm to ensure the accuracy and reliability of the data, packages the processed data into a complete data packet, compresses it into a binary packet, and sends it as a short message through the Beidou satellite communication module (6).

7. The marine electric field detection device based on corona current measurement according to claim 1, characterized in that: The power supply unit (7) comprises a photovoltaic panel (71), a wave generator (72), and a battery (73). The photovoltaic panel (71) adopts a monocrystalline silicon cell, and the wave generator (72) adopts a pendulum-type small generator. The photovoltaic panel (71) and the wave generator (72) are connected to the battery (73) inside the platform through a BMS battery management system. The battery (73) adopts a lithium battery pack.

8. The marine electric field detection device based on corona current measurement according to claim 1, characterized in that: The BeiDou satellite communication module (6) has a built-in encryption chip, which is encrypted using AES-256 and then transmitted through the BeiDou RDSS channel. The capacity of a single message is 1200 bytes, and a short message is sent once every 5 minutes.

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