A dual-payload device for autonomous onboard identification and detection of methane point sources

Abstract

The present invention discloses a dual-payload device for autonomous identification and detection of methane point sources on a satellite, comprising a payload body, wherein a methane source identification sensor (with a forward tilt angle) and a methane concentration detection sensor (connected to the payload body through a swing arm structure) are respectively installed at the front and rear positions of the bottom of the payload body; the methane source identification sensor has dual detection channels (strong and weak absorption bands); the payload body includes a satellite computer module, which is used to obtain detection data of the methane source identification sensor, identify suspected methane emission sources through a ratio threshold method and determine coordinate information, generate attitude adjustment instructions for the swing arm structure, and generate detection instructions for the methane concentration detection sensor after the adjustment is completed; the methane concentration detection sensor is used to detect high-precision methane column concentration products. The device of the present invention can effectively and autonomously identify methane emission sources on a satellite and can successfully complete the detection task, and can improve the satellite's ability to detect and invert methane source strength with high precision.

Description

Technical Field

[0001] The present invention relates to the field of methane satellite monitoring, and in particular to a dual-load device for autonomous identification and detection of methane point sources on a satellite. Background Art

[0002] Methane is a powerful greenhouse gas, and its emission will lead to a bad ecological environment. Satellite monitoring is an effective means of monitoring methane emissions.

[0003] The document "Medium- and Long-Term Development Plan for Ecological and Environmental Satellites" issued by the Ministry of Ecology and Environment encourages the development of small satellite constellations with commercial models, expands the monitoring scope from key areas to the whole country, and increases the monitoring frequency from annual and quarterly to monthly, weekly and daily, comprehensively improving satellite monitoring capabilities in the field of ecological environment.

[0004] In recent years, commercial small satellites have gradually developed, and many companies or local governments have begun to plan to develop independent satellites or satellite constellations. Compared with large satellites, small satellites have the characteristics of small size, relatively lower cost, and short development cycle. However, due to cost control, volume control and weight control, small satellites have certain limitations in sensor performance, storage, computing power and other aspects, and their lifespan is relatively short. Therefore, small satellite technology pays more attention to high efficiency, flexibility, lightweight, constellation combination and highly integrated technology.

[0005] For methane monitoring, traditional satellite detection mission planning mainly relies on ground control, which determines the detection area, coordinates resources, generates detection mission instructions, and sends them to the satellite. However, this traditional method is highly dependent on transmission between the satellite and the ground, lacks autonomy and flexibility, and is difficult to meet the growing demand for intelligence. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a dual-payload device for autonomous identification and detection of methane point sources on board, so that it can effectively and autonomously identify methane emission sources on board and successfully complete the detection mission, so as to enhance the satellite's ability to detect and invert methane source strength with high precision, thereby overcoming the problems of poor autonomy and flexibility in existing technologies.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A dual-payload device for autonomous identification and detection of methane point sources on a satellite, comprising a payload body for being carried on a satellite platform; a methane source identification sensor and a methane concentration detection sensor are respectively installed at the front and rear positions of the bottom of the payload body along the flight direction of the satellite, the methane source identification sensor has a forward tilt angle, and the methane concentration detection sensor is connected to the payload body through a swing arm structure with extension and angle conversion;

[0009] The methane source identification sensor has dual detection channels, which are two spectral channels of a methane strong absorption band and a methane weak absorption band;

[0010] The payload body includes a satellite computer module, which is used to obtain detection data of a methane source identification sensor, identify a suspected methane emission source through a ratio threshold method, and determine coordinate information of the suspected methane emission source, and then generate an attitude adjustment instruction of the swing arm structure according to the coordinate information of the suspected methane emission source, and generate a detection instruction to the methane concentration detection sensor after the adjustment is completed;

[0011] The methane concentration detection sensor is a hyperspectral sensor, which is used to start the target detection mode according to the detection instruction, continuously image the suspected methane emission source, and detect high-precision methane column concentration products.

[0012] As a further improvement of the present invention, the central wavelengths of the two spectral channels of the methane strong absorption band and the weak absorption band are 3.31 μm and 1.65 μm respectively.

[0013] Furthermore, the central wavelength of the methane concentration detection sensor is 1.64 μm, the bandwidth is 35 nm, the spectral resolution is 0.125 nm, and the signal-to-noise ratio is set to be no less than 250 db.

[0014] Furthermore, it also includes a satellite platform, and the payload body is carried on the satellite platform.

[0015] Furthermore, the acquisition of detection data of the methane source identification sensor, identification of the suspected methane emission source by the ratio threshold method, and determination of the coordinate information of the suspected methane emission source include:

[0016] The detection data of the dual detection channels of the methane source identification sensor are obtained, and the ratio between the dual detection channels is calculated. If the strong absorption band / weak absorption band is greater than the threshold 1, the point is considered to be a suspected methane emission source. Accordingly, the detection data is traversed pixel by pixel to find the high-value distribution area, and the center position of the high-value distribution is recorded as the coordinate information of the suspected methane emission source.

[0017] Furthermore, before acquiring the detection data of the methane source identification sensor, a cloud discrimination algorithm is also included. In areas and times with high cloud cover, the methane source identification sensor does not collect data.

[0018] Furthermore, when suspected methane emission sources appear more densely, the methane source identification sensor identifies multiple suspected methane emission sources, sorts them from large to small according to the threshold, starts the distance clustering calculation using the sorted sequence, and then judges whether the methane concentration detection sensor can complete the conversion of two adjacent detection areas in sequence according to the order of satellite transit. If it can, it will detect according to the order of satellite transit. If not, the detection area with relatively small threshold will be abandoned.

[0019] Furthermore, when the methane source identification sensor identifies multiple suspected methane emission sources, it specifically includes:

[0020] 1) Using the information of the suspected methane emission source identified by the methane source identification sensor, a data sequence similar to [Lon1, lat1, thre1] is formed, including the longitude l on, latitude l at and calculated threshold thre of the suspected methane emission source, and the threshold is used for sorting. The threshold is sorted from large to small to generate an ordered sequence Xarry1 with the structure of [ID1, Lon1, l at1, thre1];

[0021] 2) Using the sorting sequence to start distance clustering calculation, calculate the nearby point potential of ID1 and ID1 to form a point group Set1, which is included in the minimum bounding rectangle corresponding to the detection range of the methane concentration detection sensor. The minimum bounding rectangle of this point group, rectang l e1, includes the coordinates of the four corner points and one center point of the rectangle;

[0022] 3) In the ordered sequence Xarry2 excluding the point data in Set1, select the point with the largest threshold, repeat the calculation in 2) to obtain Set2 and another minimum enclosing rectangle rectang l e2, until all suspected methane emission sources are classified into a Set sequence and a minimum enclosing rectangle;

[0023] 4) Taking the minimum bounding rectangle as the unit, sort the rectangles according to the satellite transit order based on the information of the rectangle center point, and calculate the distance d and maneuvering time t between the first bounding rectangle and its nearest adjacent bounding rectangle. If t is less than the distance d / satellite running speed v, it means that the conversion of the two detection areas cannot be completed within this time, and the one with a relatively small threshold thre in the Set sequence needs to be discarded. If it can be completed, it means that both areas can be detected;

[0024] 5) Repeat the operation in 4) until a set of determined target detection rectangular sequences is obtained, and the center point information of the rectangular sequence is used to subsequently generate posture adjustment instructions for the swing arm structure.

[0025] Furthermore, the attitude adjustment instruction of the swing arm structure includes a target pointing mode and a reset mode. The target pointing mode is to calculate the swing angle and attitude adjustment time of the swing arm structure according to the satellite running speed v, the target coordinate loc, the satellite running heading angle ρ, and the satellite orbit height h information after receiving the coordinate information; the formula is expressed as (t, β1, β2) = f(v, loc, ρ, h), t is the time for the attitude to be adjusted to β1, β1 is the front swing angle information, β2 is the rear swing angle information, and the swing arm structure adjusts the lens of the methane concentration detection sensor from the original state perpendicular to the satellite to the target pointing state according to the calculation result; the reset mode is that the swing arm structure adjusts the lens of the methane concentration detection sensor to β2, at which time, the acquisition is completed and reset is performed, waiting for the next adjustment instruction.

[0026] Furthermore, according to the detection instruction, starting the target detection mode includes: when the swing arm structure adjusts the lens of the methane concentration detection sensor to β1, the methane concentration detection sensor lens is turned on and data collection begins; when the swing arm structure adjusts the lens of the methane concentration detection sensor to β2, the methane concentration detection sensor lens is turned off and waits for the next turn-on.

[0027] By adopting the above technical solution, the present invention has at least the following beneficial effects:

[0028] 1. The present invention proposes a dual-sensor payload design, including a methane source identification sensor and a methane concentration detection sensor, wherein the methane source identification sensor has a coarse spectral resolution and includes two methane sensitive bands, and can quickly screen out suspected methane emission sources through a ratio threshold method; the methane concentration detection sensor is a methane hyperspectral sensor, which can meet the requirements of high-precision inversion of methane; at the same time, the forward tilt angle setting of the methane source identification sensor and the swing arm structure setting of the methane concentration detection sensor can meet the time requirements when the satellite transits and switches the target mode, can successfully complete the detection mission, and can improve the satellite's ability to detect and invert the methane source strength with high precision.

[0029] 2. The present invention is based on autonomous target detection with coordinated multi-means of a single satellite, which can effectively improve the utilization rate of satellite resources, increase the number of methane emission sources detected, intelligently identify unknown sources, and enrich the existing list of methane emission sources.

[0030] 3. Aiming at the situation where suspected methane emission sources appear densely, the present invention proposes an optimized algorithm that takes multiple factors into consideration, which can ensure that the information of suspected methane emission sources is obtained to the greatest extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The above is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0032] Figure 1 A schematic diagram of the structure of a dual-payload device for autonomous identification and detection of methane point sources on a satellite provided by an embodiment of the present invention;

[0033] Figure 2 A schematic diagram of the structure of a dual-payload device for autonomous identification and detection of methane point sources on a satellite provided by an embodiment of the present invention (including changes in the front and rear swing angles);

[0034] Figure 3 A simulated curve diagram of signal-to-noise ratio and methane detection accuracy provided by an embodiment of the present invention;

[0035] Figure 4 An absorption characteristic curve diagram of a CH4 strong absorption spectrum band with a wavelength of 1.64 μm provided by an embodiment of the present invention;

[0036] Figure 5 A schematic diagram of multi-point source detection provided by an embodiment of the present invention;

[0037] Figure 6 This is a diagram of point group clustering results during multi-point source detection provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0038] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0039] The following describes the embodiments of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0040] At present, for methane monitoring, traditional satellite detection mission planning mainly relies on ground control. The detection area is determined on the ground, and the methane characteristic detection band is set. After mission planning, the detection mission instructions are generated and injected into the satellite. There is only a methane concentration detection sensor with a lens facing downward on the satellite. It collects data according to the detection instructions on the ground. After collecting the data, it is transmitted to the satellite for processing to invert the methane concentration and quantify the source strength. However, the present invention breaks through the conventional methane satellite monitoring method and proposes a payload device with on-board autonomous identification capabilities. At the same time, by improving the structure and method, it solves the problem that it is difficult to meet the requirements of "detection-target identification-target detection instructions-target detection mode conversion" in time when using a single payload or a payload of the same type to identify the source strength emission source on the satellite and then detect the target.

[0041] like Figure 1 As shown, this embodiment provides a dual-payload device for autonomous identification and detection of methane point sources on satellites. It includes a payload body 1, which can be carried on a satellite platform; along the flight direction of the satellite, a methane source identification sensor 2 and a methane concentration detection sensor 3 are respectively installed at the front and rear positions of the bottom of the payload body 1, and the methane source identification sensor 2 has a forward tilt angle θ. The methane concentration detection sensor 3 is connected to the payload body 1 through a swing arm structure 4 with extension and angle conversion, and the swing arm structure 4 can drive the lens of the methane concentration detection sensor 3 to rotate 360 ​​degrees.

[0042] In the above structural design, the methane source identification sensor 2 is mainly used for autonomous identification of methane source targets, and has dual detection channels, which are two spectral channels of the strong absorption band and the weak absorption band of methane; the payload body 1 includes a satellite computer module, which is used to obtain the detection data of the methane source identification sensor 2, and identify the suspected methane emission source and determine the coordinate information of the suspected methane emission source through the ratio threshold method, and then generate the attitude adjustment instruction of the swing arm structure 4 according to the coordinate information of the suspected methane emission source, and generate the detection instruction to the methane concentration detection sensor 3 after the adjustment is completed. The methane concentration detection sensor 3 is a hyperspectral sensor, which is used to start the target detection mode according to the detection instruction, continuously image the suspected methane emission source, and detect high-precision methane column concentration products.

[0043] The following is a detailed description:

[0044] 1. Methane source identification sensor performance

[0045] In order to meet the needs of methane source identification, it is necessary to first determine the performance of the methane source identification sensor, mainly including the detection channel, as well as the sub-satellite point resolution and width.

[0046] In the effective identification of methane sources, the design of the detection channel is the most important. This embodiment designs dual detection channels, namely two spectral channels for strong and weak absorption of methane. Based on this dual-channel sensor, strong identification of methane sources can be achieved based on the ratio threshold method. The characteristic absorption bands of methane include 1.65μm, 3.31μm, 3.41μm, 6.53μm, and 7.66μm, of which 1.65μm is a weak absorption band of methane, and the spectral band is less affected by other gases and can be selected as a weak absorption band. Relatively speaking, the absorption intensity of methane at a wavelength of 3.31μm is more than 160 times that of 1.65μm, and mid-infrared and near-infrared are widely used in satellite payload design. Therefore, this embodiment preferably selects 1.65μm as the weak absorption band of methane, and selects 3.31μm as the strong absorption band of methane. That is, the central wavelength of the dual channels for methane source identification in this embodiment is:

[0047]

[0048] Perform spectral testing according to the central wavelength designed above, determine the spectral resolution and modulate it to a suitable level so that the signal-to-noise ratio meets the detection requirements.

[0049] The sub-satellite point resolution is affected by the field of view. To meet the needs of point source monitoring, the sub-satellite point resolution of the sensor needs to be as high as possible. In this embodiment, it is set that at least 1km resolution is required to distinguish methane point sources, and the sub-satellite point resolution of the payload can be designed to be 1km. Of course, it is understandable that those skilled in the art can also make adaptive adjustments according to the actual point source monitoring needs.

[0050] The width is the coverage range. There is a trade-off between the coverage range and the sub-satellite point resolution. Under the condition of meeting the sub-satellite point resolution, the width of the methane source identification sensor should be as wide as possible to increase the coverage area and the detectable range. On the other hand, the angle adjustment and range that the methane concentration detection sensor can achieve must also be considered to avoid the methane concentration detection sensor being unable to perform high-precision detection and source strength inversion due to exceeding the range after source identification. In this embodiment, combined with the satellite parameters such as Sentinel-2, the width is designed to be 200*200km, which is highly feasible. At the same time, this indicator is a relatively advanced indicator among existing methane detection satellites.

[0051] 2. Methane concentration detection sensor performance

[0052] Methane concentration detection sensors are mainly used to detect high-precision methane column concentration products, so their performance mainly includes spectral range (including effective central wavelength), spectral resolution, sub-satellite point resolution, bandwidth, high sensitivity and relatively high signal-to-noise ratio.

[0053] The spectral range must include the absorption band of methane, and the spectral resolution must be as high as possible to achieve high-precision methane concentration inversion. The sub-satellite point resolution must meet the requirements of methane emission point source detection (better than 1km, that is, less than 1km can meet the point source monitoring capability), and the width should cover the point source and its vicinity as much as possible, not less than 10*10km, so that the data volume can meet the strong inversion of methane sources.

[0054] Figure 3 This is a simulated curve diagram of signal-to-noise ratio and methane detection accuracy; Figure 4 The absorption characteristic curve of the strong absorption spectrum band of CH4 with a wavelength of 1.64 μm. According to the analysis of the above curve, in this embodiment, it is preferred to select 1.64 μm as the central wavelength, the bandwidth is 35 nm, the spectral resolution is 0.125 nm, the signal-to-noise ratio is set to no less than 250 db, the width is set to 50*50 km, and the sub-satellite point resolution is set to 500 m.

[0055] Under this setting, the methane concentration detection sensor will obtain satellite hyperspectral products of more than 280 bands with a resolution of 500m at the sub-satellite point within a range of 50*50km near the methane emission source. It can realize the inversion of high-precision methane column concentration remote sensing products and conduct quantitative estimation of source strength in combination with meteorological, topographic and other data.

[0056] 3. Dual sensor structure design

[0057] In order to meet the requirements of "target recognition-target detection", the dual sensors in this embodiment are designed to detect in sequence, and can better meet the time requirements when the satellite switches target modes during transit.

[0058] Along the satellite's flight direction, the methane source identification sensor and the methane concentration detection sensor are on the same center line. The methane source identification sensor is in front and has a certain forward inclination angle, and the methane concentration detection sensor is in the back with a swing arm structure to achieve target mode detection.

[0059] Specifically, with Figure 1As shown, the present embodiment provides a dual-payload device for autonomous identification and detection of methane point sources on board, including: 1) a payload body 1, which includes, in addition to a satellite service computer module, conventional modules such as a power module and a storage module connected to the satellite service computer module, and can meet conventional satellite processing functions; 2) a methane source identification sensor 2 (front sensor), i.e., a sensor responsible for rapid identification of methane emission sources on board, a lens of which is provided with a certain forward tilt angle θ in a direction perpendicular to the sub-satellite point, and the payload is a dual-channel sensor, including a methane strong absorption band and a methane weak absorption band, which in the present embodiment are 3.31 μm and 1.65 μm center wavelengths respectively; 3) a methane concentration detection sensor 3 (rear sensor), i.e., a sensor responsible for high-precision detection of methane concentration, which in the present embodiment is set as a high-spectral high-resolution sensor with more than 280 channels, and is provided with a swing arm structure 4 with extension and angle conversion, to provide mobile support for precise locking and detection of the source.

[0060] Based on the above design, when the satellite moves along the flight direction, the methane source identification sensor located in front with a forward tilt angle performs advance detection and quickly identifies the suspected methane emission source. The coordinate information of the suspected emission source can be generated as a target locking instruction for the methane concentration detection sensor located in the rear. The swing arm structure adjusts the lens of the methane concentration detection sensor to point to the emission source position, turns on the methane concentration detection sensor, and collects data to realize the autonomous identification and detection plan of methane on the satellite. Due to the angle setting of the methane source identification sensor, the working time is cleverly reserved for the swing arm structure to drive the lens adjustment of the methane concentration detection sensor, ensuring that the satellite has enough time to respond.

[0061] 4. Based on the above payload structure design, this embodiment develops an onboard autonomous source identification and detection command algorithm, which mainly runs on the onboard computer module.

[0062] Based on the above payload design, the autonomous source identification and detection on the satellite mainly includes three modules: 1) methane source identification algorithm; 2) generating arm attitude adjustment instructions; 3) after the adjustment is completed, generating detection instructions for the methane concentration detection sensor.

[0063] 1) Methane source identification algorithm

[0064] Get the detection data of the methane source identification sensor and set the spectrum data of the methane strong absorption channel to R 强 , if the absorption channel spectrum data of methane is R 弱 , then the source identification algorithm is as follows:

[0065] Step 1: Read dual-channel detection data from the methane source identification sensor, R 强 , R 弱 .

[0066] Step 2 defines the source identification rules. In this embodiment, the ratio threshold method is used. If the ratio of the strong and weak absorption channels is greater than 1, the point is considered to be a suspected methane emission source. In the specific implementation, the threshold can be dynamically adjusted to optimize the identification result. When a suspicious emission source is identified, the detection data is traversed pixel by pixel to find the high-value distribution area, and the center position of the high-value distribution is recorded as the coordinate information of the suspected methane emission source, and the ground coordinate information corresponding to the data is output.

[0067] Further preferably, before acquiring the detection data of the methane source identification sensor, a cloud discrimination algorithm may be added. In areas and times with high cloud cover, the methane source identification sensor does not collect data, thereby saving power, storage and other resources.

[0068] In addition, the ratio threshold method can also be performed using multiple thresholds. This is mainly aimed at situations where methane sources appear more densely. By setting multiple thresholds, the strength of the source emission is preliminarily marked. Generally speaking, the larger the strength ratio, the stronger the source. When the suspected methane emission sources appear more densely, the methane source identification sensor identifies multiple suspected methane emission sources, sorts them from large to small according to the threshold, and uses the sorting sequence to start the distance clustering calculation. Then, the methane concentration detection sensor is judged according to the order of satellite transit to determine whether it can complete the conversion of two adjacent detection areas in sequence. If it can, it will be detected in the order of satellite transit. If not, the detection area with a relatively small threshold will be abandoned to avoid the rear sensor from having no time to adjust multiple times in a short time.

[0069] For example, if the satellite passes by a dense methane emission point source on the ground, the methane source identification sensor (front sensor) detects n thresholds greater than 1, that is, more than 1 suspected methane emission source is detected. At this time, it is necessary to comprehensively consider the number of point source detections, point source detection intensity and other goals to calculate the automatic command for the methane concentration detection sensor (rear sensor) and start shooting.

[0070] Figure 5 The following is a possible example. Within the 200*200km detection range of the front sensor, n suspected methane emission sources are identified, and their geographic coordinates and threshold sequence data are obtained. For this situation, an optimization instruction calculation method that comprehensively considers the importance and number of emission sources is designed. The specific logic includes:

[0071] 1) Using the methane emission source information identified by the methane source identification sensor (front sensor), a data sequence similar to [Lon1, l at1, thre1] is formed, including the longitude l on, latitude l at and calculated threshold thre of the suspected methane emission source, and the threshold is used for sorting. The threshold is sorted from large to small to generate an ordered sequence Xarry1 with the structure of [ID1, Lon1, l at1, thre1];

[0072] 2) Use the sorted sequence to start distance clustering calculation, combined with Figure 6 As shown, the nearby points of ID1 can form a point group Set1 with ID1, which is included in the minimum bounding rectangle with a maximum length and width of 50*50km (that is, it is included in the minimum bounding rectangle corresponding to the detection range of the methane concentration detection sensor). The point group is a collection of n points and is also a subset of the above ordered sequence. The minimum bounding rectangle rectang l e1 information of this point group includes the coordinates of the four corner points and one center point of the rectangle;

[0073] 3) In the ordered sequence Xarry2 excluding the point data in Set1, select the point IDn with the largest threshold, repeat the calculation in 2) to obtain Set2 and the minimum enclosing rectangle rectang l e2, until all suspected methane emission sources are classified into a Set sequence and a minimum enclosing rectangle rectang le;

[0074] 4) Taking the smallest enclosing rectangle as the unit, sort by the information of the rectangle center point (i.e. the order of satellite transit), calculate the distance d and maneuvering time t between the first enclosing rectangle and its nearest adjacent enclosing rectangle. If t is less than the distance d / satellite speed v, it means that the conversion of the two detection areas cannot be completed within this time, and the one with the relatively smaller maximum threshold thre in the Set sequence needs to be discarded. If it can be completed, it means that both areas can be detected;

[0075] 5) Repeat the operation of 4) until a set of determined target detection rectangular sequences is obtained, and the center point information of the rectangular sequence is used to subsequently generate the posture adjustment instructions of the swing arm structure. Based on the above method, it can be achieved.

[0076] 2) Generate arm swing posture adjustment instructions

[0077] The most core basic information of the attitude adjustment instruction of the swing arm structure is the coordinate information of the source. In the present embodiment, the attitude adjustment instruction of the swing arm structure is set to at least two types of instruction working modes: one is the target pointing mode; the other is the reset mode. In the target pointing mode, after receiving the coordinate information, the swing angle and attitude adjustment time of the swing arm structure are calculated according to the satellite running speed v, the target coordinates l oc(x, y), the satellite running heading angle ρ, the satellite orbit height h and other information. The formula can be expressed as (t, β1, β2) = f(v, loc, ρ, h), t is the time for the attitude adjustment to β1, β1 is the front swing angle information, and β2 is the rear swing angle information (see for details). Figure 2 ), the swing arm structure adjusts the lens of the methane concentration detection sensor from the original state perpendicular to the satellite to the target pointing state according to the calculation results. The reset mode is to reset after the acquisition of the suspected target source is completed (when the swing arm structure adjusts the lens of the methane concentration detection sensor to β2), and wait for the next adjustment instruction.

[0078] Through the above settings, the lens of the methane concentration detection sensor can switch the field of view angle to the target source area according to the swing arm posture adjustment instruction.

[0079] 3) Adjustment is completed and detection instructions are generated for the methane concentration detection sensor

[0080] After the swing arm structure is adjusted, a high-precision methane detection instruction is generated. When the swing arm structure adjusts the lens of the methane concentration detection sensor to β1, the lens of the methane concentration detection sensor is turned on, which can ensure that the data is stable and reliable. The detection instruction essentially contains two commands, namely, turn on and turn off. Among them, the turn-on instruction is to open the lens at the set time t (that is, the time when the swing arm structure drives the lens of the methane concentration detection sensor to adjust to β1) after receiving the adjustment of the swing arm structure, and start data collection. The turn-off instruction is to receive the turn-off instruction of the star service computer module after reaching the farthest collection point (the swing arm structure drives the lens of the methane concentration detection sensor to adjust to β2), and the lens is turned off and waits for the next turn-on. In this embodiment, the swing arm structure has extension and angle conversion, and can realize 360-degree angle conversion. Therefore, the adjustment of the swing angle mainly involves the switching of the field of view angles such as front, back, left, and right.

[0081] In summary, the dual-payload device for autonomous on-board identification and detection of methane point sources of the present invention can realize autonomous on-board methane source identification and plan data collection tasks through the methane source identification sensor of the dual detection channels, and form autonomous, fast, and continuous imaging capabilities for methane targets. At the same time, based on the detection data of the methane concentration detection sensor, it can also accurately quantify the methane emission source strength, estimate greenhouse gas emissions and climate change impacts, and improve the satellite's ability to detect and invert methane source strength with high precision. In addition, the autonomous target detection based on the single-satellite multi-means collaboration of the present invention can effectively improve the utilization rate of satellite resources, increase the number of methane emission source detections, intelligently identify unknown sources, and enrich the existing methane emission source list.

[0082] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A dual-payload device for autonomous onboard identification and detection of methane point sources, characterized in that: It comprises a payload body for being carried on a satellite platform; along the flight direction of the satellite, a methane source identification sensor and a methane concentration detection sensor are respectively installed at the front and rear positions of the bottom of the payload body, the methane source identification sensor has a forward tilt angle, and the methane concentration detection sensor is connected to the payload body through a swing arm structure with extension and angle conversion; The methane source identification sensor has dual detection channels, which are two spectral channels of a methane strong absorption band and a methane weak absorption band; The payload body includes a satellite computer module, which is used to obtain detection data of a methane source identification sensor, identify a suspected methane emission source through a ratio threshold method, and determine coordinate information of the suspected methane emission source, and then generate an attitude adjustment instruction of the swing arm structure according to the coordinate information of the suspected methane emission source, and generate a detection instruction to the methane concentration detection sensor after the adjustment is completed; The methane concentration detection sensor is a hyperspectral sensor, which is used to start the target detection mode according to the detection instruction, continuously image the suspected methane emission source, and detect high-precision methane column concentration products.

2. The dual-payload device for autonomous onboard identification and detection of methane point sources according to claim 1 is characterized in that: The central wavelengths of the two spectral channels of the methane strong absorption band and the weak absorption band are 3.31 μm and 1.65 μm respectively.

3. The dual-payload device for autonomous onboard identification and detection of methane point sources according to claim 1 is characterized in that: The methane concentration detection sensor has a central wavelength of 1.64 μm, a bandwidth of 35 nm, a spectral resolution of 0.125 nm, and a signal-to-noise ratio set to be no less than 250 db.

4. The dual-payload device for autonomous onboard identification and detection of methane point sources according to claim 1 is characterized in that: It also includes a satellite platform, and the payload body is carried on the satellite platform.

5. The dual-payload device for autonomous onboard identification and detection of methane point sources according to any one of claims 1 to 4, characterized in that: The method of acquiring detection data of a methane source identification sensor, identifying a suspected methane emission source by a ratio threshold method, and determining coordinate information of the suspected methane emission source includes: The detection data of the dual detection channels of the methane source identification sensor are obtained, and the ratio between the dual detection channels is calculated. If the strong absorption band / weak absorption band is greater than the threshold 1, the point is considered to be a suspected methane emission source. Accordingly, the detection data is traversed pixel by pixel to find the high-value distribution area, and the center position of the high-value distribution is recorded as the coordinate information of the suspected methane emission source.

6. The dual-payload device for autonomous onboard identification and detection of methane point sources according to claim 5 is characterized in that: Before obtaining the detection data of the methane source identification sensor, a cloud discrimination algorithm is also included. In areas and times with high cloud cover, the methane source identification sensor does not collect data.

7. The dual-payload device for autonomous onboard identification and detection of methane point sources according to claim 5 is characterized in that: When suspected methane emission sources appear densely, the methane source identification sensor identifies multiple suspected methane emission sources, sorts them from large to small according to the threshold, starts the distance clustering calculation using the sorted sequence, and then judges whether the methane concentration detection sensor can complete the conversion of two adjacent detection areas in sequence according to the order of satellite transit. If it can, it will detect according to the order of satellite transit. If not, the detection area with relatively small threshold will be abandoned.

8. The dual-payload device for autonomous onboard identification and detection of methane point sources according to claim 7 is characterized in that: When the methane source identification sensor identifies multiple suspected methane emission sources, they include: 1) Using the information of the suspected methane emission source identified by the methane source identification sensor, a data sequence is formed, including the longitude lon, latitude lat and calculated threshold thre of the suspected methane emission source, and the threshold is used for sorting, and the threshold is sorted from large to small to generate an ordered sequence Xarry1 with a structure of [ID1, Lon1, lat1, thre1]; the threshold thre is calculated by the ratio of the detection data between the dual detection channels of the methane source identification sensor; 2) Using the sorting sequence to start distance clustering calculation, calculate the nearby point potential of ID1 and ID1 to form a point group Set1, which is included in the minimum bounding rectangle corresponding to the detection range of the methane concentration detection sensor. The minimum bounding rectangle rectangle1 information of this point group includes the coordinates of the four corner points and one center point of the rectangle; 3) In the ordered sequence Xarry2 excluding the point data in Set1, select the point with the largest threshold, repeat the calculation in 2) to obtain Set2 and another minimum enclosing rectangle rectangle2, until all suspected methane emission sources are classified into a Set sequence and a minimum enclosing rectangle; 4) Taking the minimum bounding rectangle as the unit, sort the rectangles according to the satellite transit order based on the information of the rectangle center point, and calculate the distance d and maneuvering time t between the first bounding rectangle and its nearest adjacent bounding rectangle. If t is less than the distance d / satellite running speed v, it means that the conversion of the two detection areas cannot be completed within this time, and the one with a relatively small threshold thre in the Set sequence needs to be discarded. If it can be completed, it means that both areas can be detected; 5) Repeat the operation in 4) until a set of determined target detection rectangular sequences is obtained, and the center point information of the rectangular sequence is used to subsequently generate posture adjustment instructions for the swing arm structure.

9. The dual-payload device for autonomous onboard identification and detection of methane point sources according to any one of claims 1 to 4, characterized in that: The attitude adjustment instruction of the swing arm structure includes a target pointing mode and a reset mode. The target pointing mode is to calculate the swing angle and attitude adjustment time of the swing arm structure according to the satellite running speed v, the target coordinate loc, the satellite running heading angle ρ, and the satellite orbit height h information after receiving the coordinate information; the formula is expressed as (t, β1, β2) = f(v, loc, ρ, h), t is the time for the attitude adjustment to β1, β1 is the front swing angle information, β2 is the rear swing angle information, and the swing arm structure adjusts the lens of the methane concentration detection sensor from the original state perpendicular to the satellite to the target pointing state according to the calculation result; the reset mode is that the swing arm structure adjusts the lens of the methane concentration detection sensor to β2, at this time, the acquisition is completed and reset is performed, waiting for the next adjustment instruction.

10. The dual-payload device for autonomous onboard identification and detection of methane point sources according to claim 9, characterized in that: The step of starting the target detection mode according to the detection instruction includes: When the swing arm structure adjusts the lens of the methane concentration detection sensor to β1, the lens of the methane concentration detection sensor is turned on and data collection begins. When the swing arm structure adjusts the lens of the methane concentration detection sensor to β2, the lens of the methane concentration detection sensor is closed and waits to be turned on next time.

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