Global environmental monitoring cube satellite system

Abstract

The application provides a global environment monitoring CubeSat system, which is composed of three non-coplanar CubeSats, the CubeSat adopts a 6u size rectangular body and a configuration of an unfolded solar wing, has a three-axis stable attitude control capability, and comprises a comprehensive information management module, an attitude control module, a power module and a data processing and transmission module. The system can monitor the concentration and source of greenhouse gases of the earth, and simultaneously monitor the ocean nuclear pollution of the earth.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of environmental monitoring, and particularly relates to a global environmental monitoring cubic satellite system capable of monitoring marine nuclear pollution and atmospheric greenhouse gases. BACKGROUND

[0002] Marine resources are important resources essential for human survival. The most widely used application of atomic energy is nuclear power generation. Nuclear power plants have advantages such as low pollution and high energy, and have great development prospects and are valued by countries around the world. However, once an accident occurs in a nuclear power plant, radioactive substances inside the nuclear power plant will be released, which will bring serious disaster to the environment around the nuclear power plant and even the world. Once the radioactive substances are released and enter the ocean, they will cause great harm to the marine ecosystem, and will also cause fatal radioactive substances to enter the human body through drinking water, marine products and the like, directly endangering human life and health. Therefore, marine nuclear pollution is a kind of environmental problem with great threat, and rapid environmental monitoring of marine nuclear pollution is imperative.

[0003] In addition, global warming is caused by the continuous accumulation of the greenhouse effect, which leads to an imbalance between the energy absorbed and emitted by the geosystem, and the energy is continuously accumulated in the geosystem, thereby causing temperature rise and global warming. Global warming may lead to great changes in global precipitation distribution, melting of glaciers and permafrost, rising of sea level, and increase in extreme weather events. The main greenhouse gas in the atmosphere is carbon dioxide. With the expansion of industrial production, the increase in the number of motor vehicles and other reasons, the emission of greenhouse gases is increasing day by day. Therefore, it is particularly important to monitor carbon dioxide in the atmosphere in real time. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a global environmental monitoring cubic satellite system, which utilizes satellite remote sensing technology to monitor marine nuclear pollution and atmospheric greenhouse gas concentration, and aims to solve the problem that marine nuclear pollution and atmospheric carbon dioxide concentration cannot be monitored in all directions and at all times at the present stage.

[0005] To solve the above technical problem, the present application provides a global environmental monitoring cubic satellite system, which can monitor the concentration and source of greenhouse gases on the earth, and simultaneously monitor marine nuclear pollution on the earth.

[0006] The specific technical solution is as follows: a global environmental monitoring cubic satellite system, characterized in that the system is composed of three non-coplanar cubic satellites, the cubic satellite adopts a 6u-sized rectangular body and a deployed solar wing configuration, has a three-axis stable attitude control capability, and comprises a comprehensive information management module, an attitude control module, a power module, and a data processing and transmission module.

[0007] Further, the integrated information management module is responsible for the management and control of the on-orbit flight mission of the CubeSat, which is composed of multiple plug-in computer processing boards.

[0008] Further, the attitude control module is responsible for the attitude control of the CubeSat, including one sun sensor, two star sensors, three reaction flywheels and one mechanical gyroscope.

[0009] Further, the power module is responsible for the power management and distribution of the CubeSat, including a deployable solar panel, a power management single-chip microcomputer and a storage battery, wherein the storage battery adopts a multifunctional lithium battery structure integrated with the side cabin plate, effectively increasing the space inside the satellite.

[0010] Further, the data processing and transmission module is responsible for the preprocessing of the ground image information obtained by the camera load.

[0011] Further, the payload of the CubeSat includes a visible light and infrared integrated multi-spectral camera and an Internet of Things load, the multi-spectral camera can detect the spectral information of the target, obtain continuous, narrow-band image data with high spectral resolution, and monitor the growth of marine organisms such as seaweed, changes in seawater color, and the absorption of CO2 in the atmosphere to special spectrum; the Internet of Things load terminal is an ultra-long distance wireless transmission scheme based on spread spectrum technology.

[0012] Further, the monitoring of the growth of marine organisms such as seaweed in the ocean, the change of seawater color mainly refers to the fact that marine algal plants have a greater impact on the color of seawater, including diatoms, green algae, blue-green algae, red algae and brown algae. When nuclear pollution radioactive substances enter the ocean, the enrichment of radionuclides causes marine organisms to suffer from internal or external radiation and die, causing eutrophication of seawater. At the same time, since most blue-green algae have strong resistance to nuclear radiation, diatoms, green algae and red algae are relatively weak. Eutrophic seawater allows blue-green algae to multiply rapidly, and blue-green algae are prokaryotes and rich in chlorophyll. The large number of blue-green algae makes the chlorophyll in the ocean reach about 1.5-2 times the original level, causing the color of the ocean water to change, resulting in a strong absorption in the blue-green band and a strong scattering in the red and near-infrared bands, thus presenting a characteristic brown color. Therefore, the multi-spectral camera using blue, green and red and near-infrared optical channels for ocean imaging can indirectly observe the distribution of radioactive substances in the ocean, and thus can realize the monitoring of nuclear radiation water pollution changes.

[0013] Further, in the Internet of Things load, the CubeSat system Internet of Things terminal in the LoRa-based satellite Internet of Things scheme adopts LoRa modulation technology and is adaptively modified according to the communication situation.

[0014] Further, the satellite-borne LoRa Internet of Things payload includes a memory, an MCU, a power module, a power amplifier / LNA module, a CAN communication interface, a 28V power supply interface, and a UART data interface. The LoRa module implements a data modulation and demodulation function and a self-organizing network function. The memory implements a function of storing received data. The power amplifier / LNA is a bidirectional amplifier and can undertake a power amplification function during transmission and a low-noise amplification function during reception. The MCU implements a function of reading and writing data streams and configuring parameters of the LoRa module.

[0015] Further, the system mainly has three operation modes.

[0016] 1) Global survey mode

[0017] During daily operation, the system is in the global survey mode. In the global survey mode, the cube star system operates in a predetermined orbit, the cube star controls the remote sensing payload through side swing to perform nadir track scanning, monitors the global in a maximum ground coverage mode, and transmits data to the ground station responsible for collecting remote sensing data of each orbit of the overhead satellite to generate a global greenhouse gas concentration distribution map, a global ocean radioactive material content distribution map, and other processed advanced data.

[0018] 2) Regional detailed survey mode

[0019] When it is necessary to conduct carbon emission survey on a specific country or region, or to conduct special monitoring on the sea area near a hidden nuclear power station, the system operates in the regional detailed survey mode. In the regional detailed survey mode, the cube star system operates in a predetermined orbit, the cube star autonomously plans a regional scanning attitude sequence, controls the attitude, and conducts detailed survey on a specific region to achieve the longest time monitoring of the target region within the reentry period. Specifically, first, the cube star scanning attitude sequence is planned for the target region. Then, the ground station injects relevant attitude instructions to the satellite. The ground station is responsible for collecting remote sensing data and buoy data of each orbit of the overhead satellite to generate a greenhouse gas concentration distribution map of the target region, a regional ocean radioactive material content distribution map, and estimated carbon emission data in a specific time interval.

[0020] 3) Emergency response mode

[0021] When a certain area is affected by volcanic eruption, forest fire, explosion accident, or nuclear sewage leakage of a coastal nuclear power plant, the emergency response mode is triggered manually through the ground station, in the emergency response mode, the cubic star system runs on a predetermined orbit, the cubic star performs staring observation on the hot spot area through attitude control, the longest time monitoring of the hot spot area in the reentry period is realized, then the ground station sends the staring imaging instruction to the satellite or the satellite autonomously plans to perform staring imaging on the area where the corresponding buoy is located, the ground data processing subsystem generates the greenhouse gas concentration distribution map, the ocean radioactive material content distribution map, the greenhouse gas propagation prediction map and the ocean radioactive material propagation prediction map of the accident area in combination with the collected over-the-top satellite per-orbit remote sensing data and buoy data.

[0022] Compared with the prior art, the application has the following advantages: the advantages of high precision, fast response ground monitoring means and wide coverage of the cubic star system are combined, the nuclear leakage accident that may occur globally can be quickly and effectively warned, and the diffusion and propagation path of the nuclear pollution radioactive material can be accurately predicted. The functions of ocean nuclear pollution monitoring and atmospheric carbon dioxide concentration monitoring are integrated, more functions are realized with smaller satellites. And the root supply of realizing the corresponding functions is met.

[0023] Firstly, the combination of rapid warning and long-period monitoring of ocean nuclear radiation is realized

[0024] Secondly, the combination of ocean nuclear radiation monitoring and atmospheric greenhouse gas monitoring is realized

[0025] Thirdly, the satellite is small in envelope and mass, and is convenient for launching. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a schematic diagram of a global environment monitoring cubic star system;

[0027] Figure 2 is a schematic diagram of a cubic star;

[0028] Figure 3 is a schematic diagram of a cubic star system;

[0029] Figure 4 is a schematic diagram of a star-borne LoRa Internet of Things load.

[0030] The drawing comprises: 1, a measurement and control antenna, 2, a measurement and control unit, 3, an Internet of Things antenna, 4, a data transmission unit, 5, a camera main load, 6, a power module, 7, a gyroscope, 8, a flywheel, 9, a comprehensive information management module, 10, a data processing and transmission module, 11, a star sensor, 12, a sun sensor, 13, a cubic star constellation system, 14, an ocean, 15, an atmosphere, 16, an Internet of Things load, 17, a visible light infrared integrated camera, 18, atmospheric greenhouse gas monitoring, 19, ocean nuclear pollution monitoring. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with accompanying drawings of the embodiments of the present application. Figures 1-4 The technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with accompanying drawings of the embodiments of the present application.

[0032] To construct a global greenhouse gas and marine pollution monitoring constellation system with high timeliness and high precision, and to meet the working condition requirements of cameras and Internet of Things loads, in combination with the overall mission design of the constellation, the satellite constellation design should meet the following index requirements:

[0033] (1) To realize the coverage monitoring of global greenhouse gases and marine environment, realize greenhouse gas diffusion analysis and emission source positioning, the constellation needs to meet the following requirements: the global atmosphere is observed within 24 hours, the ground coverage rate is greater than 90%, and the global land (except polar regions) coverage rate reaches 100%;

[0034] (2) To realize the monitoring, early warning and pollution source positioning of global marine pollution, especially nuclear pollution, the constellation needs to meet the following requirements: all global nuclear power plants are fully covered within 12 hours, and the single observation time is greater than 5 seconds;

[0035] (3) To meet the observation and communication requirements of camera, Internet of Things antenna and other loads, the satellite orbit height is not more than 550km.

[0036] On the basis of the basic index requirements, to reduce the system cost and operation and maintenance expenses, the constellation configuration design should be optimized on the basis of fully utilizing the satellite maneuvering observation capability and fully considering the target distribution characteristics. The satellite attitude maneuvering and stability performance and the load observation capability are examined, and it is determined that a single satellite has 45° side swing observation capability, that is, a single satellite has an equivalent field of view with a half field of view of 45°.

[0037] Global geographic information and nuclear power plant location information are imported, the coverage performance is iteratively calculated by using an optimization method, and the minimum constellation of three cubic stars is obtained. The satellite constellation is composed of three groups of non-coplanar cubic stars, and the orbit elements are shown in Table 1.

[0038] Table 1 Orbit elements of the constellation

[0039] Symbol Number of orbits Parameter a Semi-major axis 6928.137 km e Eccentricity 0 i Orbital inclination 78° ΔΩ Longitude of ascending node 26.098° Δω Argument of perigee 0° △f True anomaly 140.662°

[0040] That is, the right ascension difference of the ascending node between adjacent orbital planes is 26.098°, and the phase difference of the perigee angle between the cubic stars corresponding to the serial numbers of the adjacent orbital planes is 140.662°.

[0041] The observation capability of the constellation is verified, and the observation coverage capability of the constellation is simulated and verified at the epoch time t0 of UTC time 0 o'clock on January 1, 2022. The space position of the constellation at the epoch time is shown in Table 2.

[0042] Table 2 Epoch time constellation space position

[0043] Serial number Longitude of ascending node Argument of perigee True anomaly 1 47° 0° 0° 2 73.098° 0° 140.662° 3 99.196° 0° 281.324°

[0044] According to the simulation results, the 3 CubeSat constellation achieves global greenhouse gas coverage observation within 24 hours, with an observation coverage rate of 92%, and the observation coverage rate of land areas below 84 degrees latitude reaches 100%, meeting the overall mission requirements of the constellation.

[0045] According to the simulation results, the 3 CubeSat constellation achieves global nuclear power plant coverage within 12 hours, with a single nuclear power plant coverage time of more than 5 seconds, meeting the overall requirements of the constellation design.

[0046] A global environmental monitoring CubeSat system, which is composed of 3 non-coplanar CubeSats, adopts a 6u-sized rectangular body and an unfolded solar wing configuration, and has three-axis stable attitude control capability. The system includes a comprehensive information management module 9, an attitude control module, a power module 6, and a data processing and transmission module 10. The performance indicators of the CubeSat are shown in Table 3 below.

[0047] Further, the comprehensive information management module 9 is responsible for the management and control of the CubeSat on-orbit flight mission, which is composed of multiple plug-in computer processing boards.

[0048] Further, the attitude control module is responsible for the attitude control of the CubeSat, including 1 sun sensor 12, 2 star sensors 11, 3 reaction flywheels 8 and 1 mechanical gyroscope 7.

[0049] Further, the power module 6 is responsible for the power management and distribution of the CubeSat, including an unfolded solar cell panel, a power management single-chip microcomputer and a storage battery, wherein the storage battery adopts a multifunctional lithium battery structure integrated with the side cabin plate, effectively increasing the space inside the star.

[0050] Further, the data processing and transmission module 10 is responsible for preprocessing the ground image information obtained by the camera main load 5.

[0051] Table 3 Main performance indicators of CubeSat (6u)

[0052]

[0053] Further, the payload of the CubeSat includes a visible-infrared integrated multi-spectral camera 17 and an Internet of Things payload 16. The multi-spectral camera can detect spectral information of a target, acquire continuous, narrow-band image data with high spectral resolution, monitor growth of marine organisms such as seaweed, changes in water color of seawater, and absorption of CO2 in the atmosphere to special spectrum; and the Internet of Things payload terminal 16 is an ultra-long distance wireless transmission scheme based on spread spectrum technology.

[0054] Principle of detection of greenhouse gases:

[0055] Gases such as CO2, CH4, and H2O in the atmosphere have different absorption capacities for light of different spectral bands, so a multi-spectral camera can be used to observe light reflected by the ground in spectral bands located at the center of the strong absorption band and the weak absorption band of the monitored gas, while the light of the sun in the two spectral bands is calibrated. By comparing the intensity information of the two spectral bands, the information about the concentration of the monitored gas can be extracted by using the method of path integral differential absorption.

[0056] Table 4: Infrared spectral absorption bands of main atmospheric molecules

[0057] Gas composition Strong absorption band center wavelength / μm Weak absorption band center wavelength / μm H2O 1.4 / 1.9 / 2.7 / 6.3 / 13.0-10000 0.9 / 1.1 CO2 2.7 / 4.3 / 14.7 1.4 / 1.6 / 2.0 / 5.0 / 9.4 / 10.4 O3 4.7 / 9.6 / 14.1 3.3 / 3.6 / 5.7 CH4 3.3 / 3.8 / 7.7 None [N2O] 4.5 / 7.8 3.9 / 4.1 / 9.6 / 17.0 CO 4.7 2.3

[0058] Taking CO2 gas monitoring as an example, the concentration of CO2 can be calculated by comparing the ratio of the ground reflected light intensity in the high absorption rate spectral band of CO2 in the infrared spectrum and the ground reflected light intensity in the low absorption rate spectral band of CO2, and according to the initial values of each spectrum calibrated by the sun. The concentration of CO2 at the subsolar point. For a single spectral band, the formula is as follows:

[0059]

[0060] In the formula, I(λ) is the real-time value of the spectrum, I0(λ) is the initial value of the spectrum, λ is the wavelength, L is the optical path, σi(λ) and σi'(λ) respectively represent the "wideband" absorption cross section which changes slowly with wavelength and the "wideband" absorption cross section which changes rapidly, σi'(λ) is also called differential absorption cross section, c i is the concentration of the measured gas, and εR(λ) and εM(λ) are the Rayleigh scattering and Mie scattering coefficients, respectively.

[0061] In order to exclude the influence of other gas components, a double-spectral band differential method can be used to correct the calculated concentration data to obtain more accurate CO2 concentration.

[0062] Furthermore, the monitoring of the growth of marine organisms such as algae and changes in seawater color mainly refers to the significant impact of marine algae on seawater color. These include diatoms, green algae, cyanobacteria, red algae, and brown algae. When radioactive substances from nuclear contamination enter the ocean, the accumulated nuclides cause marine organisms to suffer from internal or external radiation, leading to disease and death, and causing eutrophication of seawater. Simultaneously, because most cyanobacteria have strong resistance to nuclear radiation, while diatoms, green algae, and red algae are relatively weaker, eutrophic seawater causes cyanobacteria to proliferate. Cyanobacteria are prokaryotes, rich in chlorophyll. The proliferation of cyanobacteria can increase the chlorophyll content in the ocean to approximately 1.5-2 times the original level, causing a change in ocean water color. Strong absorption occurs in the blue-green band, while strong scattering occurs in the red and near-infrared bands, resulting in a characteristic brown color. Therefore, using a multispectral camera with blue, green, red, and near-infrared optical channels to image the ocean can indirectly observe the distribution of radioactive substances in the ocean, thereby enabling the monitoring of changes in nuclear radiation water pollution. Specifically, the following steps are included:

[0063] 1) When radioactive materials from nuclear contamination enter the ocean, the enriched nuclides cause marine organisms to suffer from internal or external radiation, resulting in disease and death, and causing eutrophication of seawater. Most cyanobacteria have strong resistance to nuclear radiation, and the eutrophication of seawater causes cyanobacteria to multiply in large quantities. The large-scale proliferation of cyanobacteria will cause the chlorophyll a in the ocean to reach about 1.5-2 times the original level, causing the color of the ocean water to change. Strong absorption occurs in the blue-green band, and strong scattering occurs in the red and near-infrared bands, thus exhibiting a characteristic brown color.

[0064] 2) Install a multispectral camera with blue, green, red, and near-infrared optical channels on the satellite to image the ocean, and process the image data transmitted back to the ground by the multispectral camera on the satellite.

[0065] 3) Use the processed multispectral camera image data transmitted back to the ground to retrieve the chlorophyll a concentration in the ocean water;

[0066] Chlorophyll a is a pigment commonly found in marine phytoplankton, and its concentration can reflect the biomass of marine phytoplankton to a certain extent. When the chlorophyll concentration on the sea surface increases, the reflectance intensity of the 685nm band increases. The processed image data is converted into remote sensing reflectance values, and then the chlorophyll a concentration information in the ocean water is calculated using a standard empirical algorithm.

[0067] 4) Invert the concentration of nuclear radiation in ocean water based on the chlorophyll a concentration;

[0068] The blue algae breeding in the sea can be simplified as an S-shaped curve. When the biomass reaches a certain degree, the population quantity is affected by the total amount of nutrients, and the population quantity has the maximum capacity K allowed by the environment. When the population quantity reaches K, the population quantity will stop growing, that is, the growth rate at this time is 0. Sometimes it will be relatively stable above and below the maximum value. Due to the pollution of nuclear waste water in the sea, other organisms die, and the nutrients in the sea increase, so the K value increases, which is reflected in the increase of chlorophyll a content;

[0069] After the satellite is put into orbit, the k value is calibrated by observing and inverting the sea color of each place. When the k value of a certain sea area is more than twice the normal value, combined with the actual situation of the local area, it is judged whether the marine water body is polluted by nuclear waste water;

[0070] If there is nuclear pollution, the concentration A(x) of nuclear radiation in the marine water body is calculated by using the following function:

[0071] A(x) = bf(y) + c

[0072] Where A(x) represents the concentration of nuclear radiation in the marine water body, f(y) is the concentration of chlorophyll a in the marine water body, and b and c are coefficients.

[0073] Further, the method for processing the image data transmitted by the multispectral camera on the satellite to the ground is as follows:

[0074] A. The image data transmitted by the multispectral camera on the satellite to the ground is radiometrically calibrated. Radiometric calibration is the process of converting the gray value DN recorded by each detection unit of the multispectral camera into actual physical radiation brightness of the actual ground object. The observation count value DN of the satellite multispectral camera can be converted into equivalent apparent radiation brightness data by using the following formula:

[0075] L = C·DN + B

[0076] Where L is the radiation brightness after conversion of a certain spectral band, DN is the gray value of the satellite multispectral camera; C is the calibration slope, B is the calibration intercept, and C and B are constants;

[0077] B. Atmospheric correction is performed on the radiometrically calibrated data

[0078] The data after radiation calibration needs to be corrected by atmosphere, and after the atmospheric correction, the error caused by atmospheric scattering, absorption and reflection can be eliminated to obtain the actual reflectivity. The sea surface spectrum curve after atmospheric correction is closer to the true value. The FLAASH atmospheric correction model is used to correct the data after radiation calibration. The FLAASH atmospheric correction model first corrects the adjacent pixel effect and then calculates the visibility of the whole radiation image. The FLAASH atmospheric correction model can generate a classification image of cirrus and thin clouds, smooth the spectrum and eliminate noise. After atmospheric correction by the FLAASH atmospheric correction model, the image will become clear, the color will be more realistic, and the spectral line will be closer to the real object spectrum line. According to the image information of the multi-spectral camera, the parameters are set, and the image atmospheric correction result is output.

[0079] C. Marine area extraction

[0080] The whole image after atmospheric correction includes marine area and land area, and only the marine area is needed to participate in the calculation in the inversion calculation process, so the marine area range needs to be extracted. The normalized difference marine water index method is used to extract the marine water range.

[0081] The normalized difference marine water index is based on the fact that the reflectivity of marine water is very high in the green band and is very strong in the infrared band. Therefore, the normalized marine water index is proposed:

[0082] (GREEN-NIR) / (GREEN+NIR)>T

[0083] GREEN represents the green band, NIR represents the infrared band, and T represents the extraction threshold.

[0084] Further, in the open sea area, the reflectivity of cyanobacteria in the near-infrared band is high, and the reflectivity in the red light is low. The normalized difference marine water index, as one of the main monitoring bands for monitoring marine water color, can better reflect the steep slope effect and improve the monitoring efficiency.

[0085] Further, in the near-shore sea area, because the water is shallow, the underwater sediment will also affect the reflection of the red light and the near-infrared spectrum. At the same time, because of the leakage of radioactive substances from the coastal nuclear power plant, the first affected area is the near-shore sea area. In addition, the change in the number of plants in other marine areas will also cause changes in the normalized difference marine water index. Cyanobacteria contain a large amount of chlorophyll a, and in addition to the near-infrared spectrum, chlorophyll a has an absorption peak in the 433nm-453nm wavelength spectrum, and is a high reflection area in the 480nm-500nm, 510nm-530nm, 555nm-575nm wavelength spectrum. Therefore, the above spectrum can be used to observe the near-shore sea area.

[0086] Further, in the Internet of Things payload 16, the LoRa-based satellite Internet of Things solution adopts LoRa modulation technology in the Internet of Things terminal of the CubeSat system, and is adapted according to the communication situation.

[0087] Table 5 Performance parameters of the Internet of Things communication system

[0088] Item Index parameter Operating frequency 470-510 MHz Operating bandwidth 500 kHz Spreading factor 9 Coding efficiency 4 / 5 Data rate (before / after coding) 8789 / 7031 Reception sensitivity -122 dBm Reception demodulation signal-to-noise ratio -12.5 dB Satellite-ground communication distance More than 2100 km

[0089] Further, the satellite-borne LoRa Internet of Things payload includes a memory, an MCU, a power module, a power amplifier / LNA module, a CAN communication interface, a 28V power supply interface and a UART data interface, the LoRa module realizes the functions of data modulation and demodulation and self-organizing network; the memory realizes the function of storing the received data; the power amplifier / LNA is a bidirectional amplifier, which can undertake the functions of power amplification during transmission and low-noise amplification during reception, and the MCU realizes the functions of reading and writing data streams and configuring parameters of the LoRa module.

[0090] Further, the space-ground integrated environmental monitoring system based on the CubeSat constellation has three operation modes:

[0091] 1) Global survey mode

[0092] During daily operation, the system is in the global survey mode. In the global survey mode, the CubeSat system operates in a predetermined orbit, and the CubeSat performs nadir scanning by side swing control of the remote sensing payload to monitor the global in the maximum ground coverage mode, and transmits data to the ground station responsible for collecting remote sensing data of each orbit of the over-the-top satellite to generate global greenhouse gas concentration distribution maps, global marine radioactive material content distribution maps and other refined advanced data.

[0093] 2) Regional detailed survey mode

[0094] When it is necessary to conduct carbon emission survey in a specific country or region, or to conduct special monitoring of the sea area near a certain hidden nuclear power station, the system operates in the regional detailed survey mode. In the regional detailed survey mode, the CubeSat system operates in a predetermined orbit, and the CubeSat autonomously plans a sequence of scanning attitudes and controls the attitudes to conduct detailed survey of a specific region to achieve the longest time monitoring of the target region within the re-entry period. Specifically, first, a sequence of scanning attitudes of the CubeSat is planned for the target region; then, the ground station sends relevant attitude instructions to the satellite; the ground station collects remote sensing data and buoy data of each orbit of the over-the-top satellite to generate greenhouse gas concentration distribution maps of the target region, regional marine radioactive material content distribution maps and carbon emission estimation data in a specific time interval.

[0095] 3) Emergency response mode

[0096] When a certain area is affected by volcanic eruption, forest fire, explosion accident, or nuclear waste leakage of a coastal nuclear power plant, the emergency response mode is triggered manually through the ground station. In the emergency response mode, the cube satellite system operates in a predetermined orbit. The cube satellite performs staring observation on the hot spot area through attitude control, realizes the longest time monitoring of the hot spot area in the reentry period, and then the ground station sends the staring imaging instruction to the satellite or the satellite autonomously plans to perform staring imaging on the area where the corresponding buoy is located. The ground data processing subsystem generates the greenhouse gas concentration distribution map, the marine radioactive material content distribution map, the greenhouse gas propagation prediction map and the marine radioactive material propagation prediction map of the accident area in combination with the collected over-the-top satellite per-orbit remote sensing data and buoy data.

[0097] The above merely describes the preferred embodiments of the present application, and does not limit the patent scope of the present application. Any equivalent structural transformation, direct / indirect application in other related technical fields, or the like made under the inventive concept of the present application, and in combination with the content of the specification and drawings, is included in the patent protection scope of the present application.

Claims

1. A global environmental monitoring CubeSat system, characterized by, The system is composed of three non-coplanar cube satellites, which have the ability of three-axis stabilization attitude control, and includes an integrated information management module, an attitude control module, a power module, and a data processing and transmission module. The payload of the cube satellite includes a visible-infrared integrated multi-spectral camera and an Internet of Things payload. The multi-spectral camera can detect the spectral information of the target, obtain high-spectral resolution continuous and narrow-band image data, monitor the growth of seaweed in the ocean, changes in seawater color, and the absorption of CO2 in the atmosphere on special spectra. The system has three main operating modes: 1) Global survey mode During routine operation, the system is in global survey mode. In this mode, the cube satellite system operates on a predetermined orbit, and the cube satellite controls the remote sensing payload through side swing to perform nadir track scanning, thereby monitoring the global area in the maximum ground coverage mode and transmitting data to the ground station for collection of per-orbit remote sensing data from the overhead satellite to generate global greenhouse gas concentration distribution maps, global ocean radioactive material content distribution maps, and other processed high-level data. 2) Regional detailed survey mode When regional detailed survey is required, the system operates in regional detailed survey mode. In this mode, the cube satellite system operates on a predetermined orbit, and the cube satellite autonomously plans the regional scanning attitude sequence and controls the attitude to conduct detailed survey of a specific area, thereby achieving the longest time monitoring of the target area within the reentry period. First, the cube satellite scans the target area to plan the attitude sequence; then, the ground station uploads relevant attitude instructions to the satellite; and finally, the ground station collects per-orbit remote sensing data and buoy data from the overhead satellite to generate greenhouse gas concentration distribution maps of the target area, regional ocean radioactive material content distribution maps, and carbon emission estimation data within a specific time interval. 3) Emergency response mode When emergency response is required, the ground station manually triggers the emergency response mode. In this mode, the cube satellite system operates on a predetermined orbit, and the cube satellite controls the attitude to conduct staring observation of a hot area, thereby achieving the longest time monitoring of the hot area within the reentry period. Then, the ground station uploads or the satellite autonomously plans the staring imaging instructions for the area where the corresponding buoy is located, and the ground data processing subsystem generates greenhouse gas concentration distribution maps, ocean radioactive material content distribution maps, greenhouse gas propagation prediction maps, and ocean radioactive material propagation prediction maps of the accident area based on the collected per-orbit remote sensing data and buoy data from the overhead satellite.

2. A global environmental monitoring CubeSat system according to claim 1, wherein, The integrated information management module is responsible for the management and control of the cube satellite during on-orbit flight missions and is composed of multiple plug-in computer processing boards.

3. A global environmental monitoring CubeSat system according to claim 1, wherein, The attitude control module is responsible for the attitude control of the cube satellite and includes one sun sensor, two star sensors, three reaction flywheels, and one mechanical gyroscope.

4. A global environmental monitoring CubeSat system according to claim 1, wherein, The power module is responsible for power management and distribution of the cube satellite and includes deployable solar panels, a power management single-chip microcomputer, and a storage battery. The storage battery adopts a multifunctional lithium battery structure integrated with the side cabin plate, effectively increasing the space inside the satellite.

5. A global environmental monitoring cubesat system according to claim 1, wherein, The data processing and transmission module is responsible for preprocessing of the ground image information obtained by the camera payload.

6. A global environmental monitoring cubesat system according to claim 1, wherein, In the Internet of Things payload, the LoRa-based satellite Internet of Things scheme adopts LoRa modulation technology in the Internet of Things terminal of the CubeSat system, and is adapted according to the communication situation.

7. A global environmental monitoring CubeSat system according to claim 6, wherein, The satellite-borne LoRa Internet of Things payload includes a memory, an MCU, a power module, a power amplifier / LNA module, a CAN communication interface, a 28V power supply interface and a UART data interface, the LoRa module realizes the functions of data modulation and demodulation and self-organizing network, the memory realizes the function of storing the received data, the power amplifier / LNA is a bidirectional amplifier, which can undertake the functions of power amplification during transmission and low-noise amplification during reception, and the MCU realizes the functions of reading and writing operation on the data stream and configuration of the parameters of the LoRa module.

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