Satellite-borne photon counting laser ranging forward scattering correction method and device

Abstract

The invention provides a satellite-borne photon counting laser ranging forward scattering correction method and device, relates to the technical field of laser radar ranging, and is used for solving the technical problems that the requirement of a high-frequency observation task for real-time processing cannot be met and high-precision correction of forward scattering errors is difficult to realize in the prior art. The method comprises the following steps: acquiring load parameters of a satellite-borne laser radar system and atmospheric optical physical parameters under different conditions; generating an initial parameter set according to the load parameters and the atmospheric optical physical parameters; utilizing a Monte Carlo method to simulate a first change characteristic of the photon path under the cloud layer condition compared with the photon path under the clear sky condition, and simulating a second change characteristic of the photon path under the aerosol condition compared with the photon path under the clear sky condition; fusing the first change feature and the second change feature to obtain forward scattering correction data; and querying a corresponding forward scattering correction value in the forward scattering correction data according to the current atmospheric optical physical parameter, and correcting the distance measurement error.

Description

Technical Field

[0001] The present invention relates to the field of laser radar ranging technology, and more specifically, to a satellite-borne photon counting laser ranging forward scattering correction method and device. Background Art

[0002] Spaceborne photon counting lidar (such as ICESat-2) is widely used in global topography, glacier monitoring, forest measurement, and ocean exploration due to its high spatial resolution and sensitivity. The system uses single-photon detection technology and has the advantages of high sensitivity and high spatial resolution. However, when the laser beam passes through the atmosphere, especially the cloud layer, the photons will be affected by the forward scattering of cloud particles and aerosols, causing some photons to shift their paths and arrive at the detector with delay, resulting in ranging accuracy deviations. Atmospheric scattering also includes multiple scattering and single scattering, among which multiple scattering is particularly significant in media such as thick clouds and fog. This complex scattering phenomenon not only reduces the reliability of laser altimetry data, but also, if there is a lack of effective correction methods, some effective observation data will be directly discarded, thereby limiting the commercial application potential of spaceborne photon counting lidar.

[0003] At present, the forward scattering correction of spaceborne photon counting lidar mainly relies on complex Monte Carlo simulation of the optical and physical properties of atmospheric clouds and aerosols to obtain the correction value. Monte Carlo simulation is used to statistically simulate the random scattering path of photons in the medium, and the propagation and scattering characteristics of photons can be accurately restored under ideal conditions. However, due to the extremely high computing resources and time costs, the Monte Carlo simulation method cannot meet the real-time processing requirements of high-frequency observation tasks. In addition, due to the complexity of the atmospheric multipath scattering effect, it is difficult to achieve high-precision correction of forward scattering errors. Summary of the invention

[0004] In view of this, the present invention provides a satellite-borne photon counting laser ranging forward scattering correction method and device to solve the technical problems that the existing technology cannot meet the real-time processing requirements of high-frequency observation tasks and is difficult to achieve high-precision correction of forward scattering errors.

[0005] One aspect of the present invention provides a forward scattering correction method for satellite-borne photon counting laser ranging, comprising: obtaining payload parameters of a satellite-borne laser radar system and atmospheric optical and physical parameters under different conditions, wherein the atmospheric optical and physical parameters under different conditions include atmospheric optical and physical parameters under cloud conditions and atmospheric optical and physical parameters under aerosol conditions; generating an initial parameter set according to the payload parameters and the atmospheric optical and physical parameters under different conditions; simulating, according to the initial parameter set, a first change feature of a photon path under cloud conditions compared to a photon path under clear sky conditions using a Monte Carlo method, and simulating a second change feature of a photon path under aerosol conditions compared to a photon path under clear sky conditions; fusing the first change feature and the second change feature to obtain forward scattering correction data; in response to receiving a ranging task, querying a forward scattering correction value corresponding to the current atmospheric optical and physical parameters in the forward scattering correction data according to the current atmospheric optical and physical parameters to correct the ranging error.

[0006] According to an embodiment of the present invention, based on the initial parameter set, before using the Monte Carlo method to simulate the first change characteristic of the photon path under cloudy conditions compared to the photon path under clear sky conditions, and simulating the second change characteristic of the photon path under aerosol conditions compared to the photon path under clear sky conditions, it also includes: determining a first initial photon number based on the standard deviation and target error of the photon scattering path, wherein the first initial photon number is used to characterize the correction accuracy; determining a second initial photon number based on the total computing resource consumption required for a given photon and the average computing cost constant required for a single photon, wherein the second initial photon number is used to characterize the correction cost; determining a target initial photon number based on the first initial photon number and the second initial photon number.

[0007] According to an embodiment of the present invention, based on an initial parameter set, using the Monte Carlo method to simulate the first change characteristics of the photon path under cloudy conditions compared to the photon path under clear sky conditions includes: based on the initial parameter set and the target initial number of photons, using the Monte Carlo method to randomly generate a first initial photon position that obeys a uniform distribution, wherein the atmospheric optical physical parameters under cloudy conditions in the initial parameter set are set to a non-uniform distribution state; based on the first initial photon position, calculating the first free path of the photon in the cloud medium; based on the first free path, updating the photon position to obtain the first path change characteristics of the photon in the cloud medium; based on the first path change characteristics, calculating a first photon counting lidar forward scattering correction amount, wherein the first photon counting lidar forward scattering correction amount characterizes the first change characteristics of the photon path under cloudy conditions compared to the photon path under clear sky conditions.

[0008] According to an embodiment of the present invention, based on an initial parameter set, using the Monte Carlo method to simulate the second change characteristics of the photon path under aerosol conditions compared to the photon path under clear sky conditions includes: based on the initial parameter set and the target initial photon number, using the Monte Carlo method to randomly generate a second initial photon position that obeys a uniform distribution, wherein the atmospheric optical physical parameters under aerosol conditions in the initial parameter set are set to a non-uniform distribution state; based on the second initial photon position, calculating the second free path of the photon in the aerosol medium; based on the second free path, updating the photon position to obtain the second path change characteristics of the photon in the aerosol medium; based on the second path change characteristics, calculating a second photon counting lidar forward scattering correction amount, wherein the second photon counting lidar forward scattering correction amount characterizes the second change characteristics of the photon path under aerosol conditions compared to the photon path under clear sky conditions.

[0009] According to an embodiment of the present invention, the atmospheric optical physical parameters under cloud conditions include: optical thickness of the cloud layer, effective radius of cloud particles, asymmetry factor of cloud particles, cloud layer thickness and cloud bottom height.

[0010] According to an embodiment of the present invention, the atmospheric optical physical parameters under aerosol conditions include: optical thickness of aerosol, effective radius of aerosol particles, asymmetry factor of aerosol particles, thickness of aerosol layer and height of bottom of aerosol layer.

[0011] According to an embodiment of the present invention, fusing the first change feature and the second change feature to obtain forward scatter correction data includes: generating a first 5-dimensional lookup table with non-uniform distribution according to the first change feature; generating a second 5-dimensional lookup table with non-uniform distribution according to the second change feature; fusing the first 5-dimensional lookup table and the second 5-dimensional lookup table to obtain a target 5-dimensional lookup table, wherein the target 5-dimensional lookup table represents the forward scatter correction data generated based on 5 dimensions.

[0012] According to an embodiment of the present invention, the method also includes: in response to not completely finding the forward scattering correction value corresponding to the current atmospheric optical and physical parameters in the forward scattering correction data, calculating the forward scattering correction intermediate value corresponding to the current atmospheric optical and physical parameters using a multidimensional interpolation algorithm; and correcting the ranging error based on the forward scattering correction intermediate value.

[0013] According to an embodiment of the present invention, the method also includes: in response to the range of the current atmospheric optical and physical parameters exceeding the range of the forward scattering correction data, using a boundary extrapolation mechanism to extrapolate a forward scattering correction estimated value corresponding to the current atmospheric optical and physical parameters; or using a neighboring value replacement mechanism to query a forward scattering correction replacement value corresponding to the current atmospheric optical and physical parameters; and correcting the ranging error according to the forward scattering correction estimated value or the forward scattering correction replacement value.

[0014] Another aspect of the present invention provides a forward scattering correction device for satellite-borne photon counting laser ranging, comprising: an acquisition module, used to acquire the load parameters of the satellite-borne laser radar system, and the atmospheric optical and physical parameters under different conditions, wherein the atmospheric optical and physical parameters under different conditions include the atmospheric optical and physical parameters under cloud conditions and the atmospheric optical and physical parameters under aerosol conditions; a generation module, used to generate an initial parameter set according to the load parameters and the atmospheric optical and physical parameters under different conditions; a simulation module, used to simulate, according to the initial parameter set, a first change feature of a photon path under cloud conditions compared to that under clear sky conditions, and to simulate a second change feature of a photon path under aerosol conditions compared to that under clear sky conditions using the Monte Carlo method; a fusion module, used to fuse the first change feature and the second change feature to obtain forward scattering correction data; and a correction module, used to query a forward scattering correction value corresponding to the current atmospheric optical and physical parameters in the forward scattering correction data in response to receiving a ranging task, and correct the ranging error according to the current atmospheric optical and physical parameters.

[0015] Another aspect of the present invention provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the above method.

[0016] Another aspect of the present invention provides a computer-readable storage medium storing computer-executable instructions, which are used to implement the above method when executed.

[0017] Another aspect of the present invention provides a computer program product, the computer program product comprising computer executable instructions, and the instructions are used to implement the above method when being executed.

[0018] Compared with the prior art, the satellite-borne photon counting laser ranging forward scattering correction method and device provided by the present invention have at least the following beneficial effects:

[0019] (1) The forward scatter correction method and device for spaceborne photon counting laser ranging provided by the embodiment of the present invention, by combining the optical and physical properties of atmospheric clouds and aerosols, generates forward scatter correction data (which can be configured as a lookup table structure) in advance using refined Monte Carlo simulation. In practical applications, only a small number of input parameters such as atmospheric optical thickness and aerosol pattern need to be quickly queried in the forward scatter correction data to obtain the correction value to correct the forward scatter error. This method is particularly suitable for achieving high-precision laser ranging correction in complex atmospheric environments and under cloudy and multi-aerosol conditions. Since the fast query mechanism significantly shortens the correction time, it can meet the real-time processing requirements of high-frequency observation tasks of spaceborne photon counting laser radars.

[0020] (2) The satellite-borne photon counting laser ranging forward scattering correction method and device provided in the embodiment of the present invention combines the optical and physical properties of clouds and aerosols in five dimensions (optical thickness, particle size, asymmetry factor, physical thickness and height, etc.) to construct a high-resolution non-uniform five-dimensional lookup table. The introduction of the non-uniform lookup table resolution method ensures a balance between correction accuracy and computational efficiency within the key parameter range, further broadening the scope of application of the technology.

[0021] (3) The satellite-borne photon counting laser ranging forward scattering correction method and device provided in the embodiments of the present invention are optimized by adopting a multi-dimensional interpolation algorithm, thereby ensuring that an accurate correction value can be obtained under any input conditions.

[0022] (4) The forward scatter correction method and device for spaceborne photon counting laser ranging provided by the embodiments of the present invention can be flexibly adjusted according to different laser radar payload parameters (operating wavelength, field of view angle, and orbital altitude) to adapt to different spaceborne laser radar systems. In addition, it can be further combined with real-time observation data for dynamic update, and has good expansion capabilities. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0024] Figure 1 A flow chart of a forward scatter correction method for spaceborne photon counting laser ranging according to an embodiment of the present invention is schematically shown;

[0025] Figure 2 A schematic diagram showing a variation trend of the forward scattering correction value under cloud conditions with the cloud layer height and the effective radius of cloud particles according to an embodiment of the present invention;

[0026] Figure 3 A schematic diagram showing a variation trend of the forward scattering correction value with the cloud height and the effective radius of cloud particles under aerosol conditions according to an embodiment of the present invention;

[0027] Figure 4 A diagram schematically showing a linear regression analysis result between a corrected lookup table estimate and a Monte Carlo calculated value under cloud conditions according to an embodiment of the present invention;

[0028] Figure 5 A diagram schematically showing a linear regression analysis result between a corrected lookup table estimate and a Monte Carlo calculated value under aerosol conditions according to an embodiment of the present invention;

[0029] Figure 6 A schematic diagram of a forward scattering correction method for spaceborne photon counting laser ranging according to an embodiment of the present invention is shown;

[0030] Figure 7 A structural block diagram of a satellite-borne photon counting laser ranging forward scattering correction device according to an embodiment of the present invention is schematically shown;

[0031] Figure 8 The structural block diagram of an electronic device suitable for implementing a forward scattering correction method for spaceborne photon counting laser ranging according to an embodiment of the present invention is schematically shown. DETAILED DESCRIPTION

[0032] Below, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of concepts of the present invention.

[0033] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0034] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0035] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0036] In the embodiments of the present invention, the collection, updating, analysis, processing, use, transmission, provision, disclosure, storage and other aspects of the data involved (for example, including but not limited to user personal information) are in compliance with the provisions of relevant laws and regulations, are used for legitimate purposes, and do not violate public order and good morals. In particular, necessary measures are taken for user personal information to prevent illegal access to user personal information data and maintain the security of user personal information and network security.

[0037] Spaceborne photon counting lidar (such as ICESat-2) is widely used in global topography, glacier monitoring, forest measurement, and ocean exploration due to its high spatial resolution and sensitivity. The system uses single-photon detection technology and has the advantages of high sensitivity and high spatial resolution. However, when the laser beam passes through the atmosphere, especially the cloud layer, the photons will be affected by the forward scattering of cloud particles and aerosols, causing some photons to shift their paths and arrive at the detector with delay, resulting in ranging accuracy deviations. Atmospheric scattering also includes multiple scattering and single scattering, among which multiple scattering is particularly significant in media such as thick clouds and fog. This complex scattering phenomenon not only reduces the reliability of laser altimetry data, but also, if there is a lack of effective correction methods, some effective observation data will be directly discarded, thereby limiting the commercial application potential of spaceborne photon counting lidar.

[0038] At present, the forward scattering correction of spaceborne photon counting lidar mainly relies on complex Monte Carlo simulation of the optical and physical properties of atmospheric clouds and aerosols to obtain the correction value. Monte Carlo simulation statistically simulates the random scattering path of photons in the medium, and can accurately restore the propagation and scattering characteristics of photons under ideal conditions.

[0039] However, Monte Carlo simulations are extremely demanding in terms of computing resources and time, and require a large number of photon trajectory samples to obtain statistically significant results, making it difficult to meet the real-time processing requirements of high-frequency observation tasks. As a result, mature operational scattering correction methods have not yet been formed, resulting in the atmospheric scattering effect still being a key bottleneck in improving the utilization and reliability of laser altimetry data. In addition, Monte Carlo simulations require comprehensive and accurate input data, including cloud and aerosol distribution, optical thickness, particle size and other parameters, which are usually obtained by other observation methods, increasing the possibility of error propagation.

[0040] It can be seen that the existing technology has the technical problem of being unable to meet the real-time processing requirements of high-frequency observation tasks and having difficulty in achieving high-precision correction of forward scattering errors.

[0041] Based on this, an embodiment of the present invention provides a satellite-borne photon counting laser ranging forward scattering correction method to solve the technical problems that the existing technology cannot meet the real-time processing requirements of high-frequency observation tasks and is difficult to achieve high-precision correction of forward scattering errors.

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0043] Figure 1 The flowchart of the forward scattering correction method of space-borne photon counting laser ranging according to an embodiment of the present invention is schematically shown.

[0044] like Figure 1 As shown, the satellite-borne photon counting laser ranging forward scattering correction method of this embodiment may include operations S1 to S5.

[0045] In operation S1, payload parameters of a satellite-borne lidar system and atmospheric optical and physical parameters under different conditions are obtained, wherein the atmospheric optical and physical parameters under different conditions include atmospheric optical and physical parameters under cloud conditions and atmospheric optical and physical parameters under aerosol conditions.

[0046] In operation S2, an initial parameter set is generated according to the load parameters and atmospheric optical and physical parameters under different conditions.

[0047] In operation S3, based on the initial parameter set, the Monte Carlo method is used to simulate the first change characteristics of the photon path under cloud conditions compared to the photon path under clear sky conditions, and the second change characteristics of the photon path under aerosol conditions compared to the photon path under clear sky conditions.

[0048] In operation S4, the first variation feature and the second variation feature are fused to obtain forward scatter correction data.

[0049] In operation S5, in response to receiving the ranging task, according to the current atmospheric optical and physical parameters, a forward scattering correction value corresponding to the current atmospheric optical and physical parameters is searched in the forward scattering correction data to correct the ranging error.

[0050] The forward scattering correction method for spaceborne photon counting laser ranging provided by the embodiment of the present invention combines the optical and physical properties of clouds and aerosols, and generates forward scattering correction data (which can be configured as a lookup table structure) in advance using refined Monte Carlo simulation. In practical applications, only a small number of input parameters such as atmospheric optical thickness and aerosol mode need to be quickly queried in the forward scattering correction data to obtain correction values ​​to correct forward scattering errors. This method is particularly suitable for achieving high-precision laser ranging correction in complex atmospheric environments and under cloudy and multi-aerosol conditions. Since the fast query mechanism significantly shortens the correction time, it can meet the real-time processing requirements of high-frequency observation tasks of spaceborne photon counting laser radars.

[0051] In this embodiment, operation S1 obtains the payload parameters of the satellite-borne laser radar system and the atmospheric optical physical parameters under different conditions. Specifically, the following parameters can be obtained:

[0052] The payload parameters of the spaceborne laser radar system include, for example:

[0053] λ: operating wavelength of the LiDAR (unit: nanometers)

[0054] FOV: LiDAR field of view (unit: microradians)

[0055] Zorb : The orbital altitude of the lidar (unit: kilometers)

[0056] Atmospheric optical physical parameters under cloud conditions, such as:

[0057] τ c : Optical thickness of the cloud layer

[0058] r c : Effective radius of cloud particles (unit: micrometer)

[0059] g c : Cloud particle asymmetry factor

[0060] D c : Cloud thickness (unit: km)

[0061] H c : Cloud base height (unit: km)

[0062] Atmospheric optical physical parameters under aerosol conditions, for example:

[0063] τ a : Optical thickness of aerosol

[0064] r a : Effective radius of aerosol particles (unit: micrometer)

[0065] g a : Aerosol particle asymmetry factor

[0066] D a : Aerosol layer thickness (unit: km)

[0067] H a : Height of the bottom of the aerosol layer (unit: km)

[0068] In this embodiment, operation S2 generates an initial parameter set according to the load parameters and the atmospheric optical physical parameters under different conditions. For example, the above parameters can be integrated to form a complete initial parameter set. .

[0069]

[0070] After generating the initial parameter set, in order to improve the correction accuracy and reduce computing resources, it is necessary to determine the optimal initial number of photons, that is, before performing operation S3 based on the initial parameter set, using the Monte Carlo method to simulate the first change characteristics of the photon path under cloudy conditions compared to the photon path under clear sky conditions, and simulating the second change characteristics of the photon path under aerosol conditions compared to the photon path under clear sky conditions, the initial number of photons needs to be determined first.

[0071] According to an embodiment of the present invention, determining the initial number of photons may include, for example:

[0072] Determine a first initial photon number according to a standard deviation of a photon scattering path and a target error, wherein the first initial photon number is used to characterize a correction accuracy;

[0073] Determine a second initial photon number according to the total computing resource consumption required for a given photon and an average computing cost constant required for a single photon, wherein the second initial photon number is used to characterize the correction cost;

[0074] A target initial photon number is determined according to the first initial photon number and the second initial photon number.

[0075] Since the initial photon number N will directly affect the accuracy and calculation cost of the correction, in this embodiment, the calculation accuracy and calculation resources are fully considered when determining the initial photon number N.

[0076] For calculation accuracy considerations, the initial photon number N1 (first initial photon number) can be determined according to the following formula:

[0077]

[0078] where σ represents the standard deviation of the photon scattering path, Represents the target error.

[0079] Considering computing resources, the initial photon number N2 (second initial photon number) can be determined according to the following formula:

[0080]

[0081] Where c represents the average computational cost constant required for a single photon, and the function R(N) is used to estimate the resource consumption required for a given photon N.

[0082] Taking the above two aspects into consideration, the model for determining the initial number of photons N can be optimized as follows:

[0083]

[0084] The first term is used to minimize statistical errors, and the second term considers computing resource consumption. is a regularization parameter that weighs the importance of both.

[0085] The optimization model helps to optimize the use of computing resources while ensuring simulation accuracy. Therefore, based on the optimization model, the target initial photon number N can be ultimately determined.

[0086] After determining the target initial photon number N, the next step is to use the initial parameter set And the target initial photon number N, using the Monte Carlo method to simulate respectively:

[0087] (1) The change of the photon path under cloudy conditions compared with the photon path under clear sky conditions ΔL c (The first change feature).

[0088] (2) The change of the photon path under aerosol conditions compared with the photon path under clear sky conditions ΔL a (Second change feature).

[0089] According to an embodiment of the present invention, in operation S3, according to the initial parameter set, using the Monte Carlo method to simulate the first change characteristics of the photon path under the condition of cloud layer compared with the photon path under the condition of clear sky includes:

[0090] According to the initial parameter set and the target initial photon number, the first initial photon position that obeys uniform distribution is randomly generated by using the Monte Carlo method, wherein the atmospheric optical physical parameters under cloud conditions in the initial parameter set are set to a non-uniform distribution state;

[0091] Calculating a first free path of the photon in the cloud medium based on the first initial photon position;

[0092] According to the first free path, the photon position is updated to obtain the first path change characteristics of the photon in the cloud medium;

[0093] According to the first path change characteristic, a first photon counting lidar forward scattering correction amount is calculated, wherein the first photon counting lidar forward scattering correction amount represents a first change characteristic of the photon path under cloudy conditions compared to that under clear sky conditions.

[0094] In this embodiment, the Monte Carlo method is used to track the paths of multiple scattering of photons in the cloud medium, and the state of photons propagating in the cloud medium is recorded to analyze the scattering characteristics and path distribution thereof.

[0095] For example, first according to the initial parameter set And the target initial photon number N, generate a series of random numbers (first initial photon position) R∈[0,1] that obey the uniform distribution, and calculate the photon free path of the photon and the new photon position.

[0096] It should be noted that, in this embodiment, the initial parameter set The atmospheric optical physical parameters under mid-cloud conditions are set to a non-uniform distribution state, for example:

[0097] τ c =[0.01:0.02:0.1 0.2:0.1:0.9 1.0:0.2:2.0]

[0098] r c =[1:1:80 82:100]

[0099] g c =[-0.9:0.1:0 0.1:0.1:0.5 0.6:0.05:0.9]

[0100] D c =[0.3:0.2:3]

[0101] H c =[0.5:0.2:6]

[0102] Then calculate the photon free path L (first free path). The photon free path L in the cloud medium can be calculated by the following formula:

[0103]

[0104] Where: δ represents the extinction coefficient, R∈[0,1].

[0105] The photon position is further updated. The photon moves in the current direction Propagate, the position is updated as:

[0106]

[0107] in, represents the current position of the photon, Represents the position of the photon after the update.

[0108] According to the updated data of the photon position, the path change characteristics of the photon in the cloud medium (the first path change characteristics) can be obtained.

[0109] Finally, the first photon counting lidar forward scattering correction is calculated, that is, the change of the photon path under cloud conditions compared with the photon path under clear sky conditions ΔL c (The first change feature).

[0110] Figure 2 The diagram schematically shows the variation trend of the forward scattering correction value (unit: centimeter) under cloud conditions according to an embodiment of the present invention with the cloud height (unit: kilometer) and the effective radius of cloud particles (unit: micrometer).

[0111] like Figure 2As shown in the figure, when the effective radius of cloud particles is small (such as 0.1 to 1 micron), the forward scattering effect is significantly enhanced, resulting in a larger correction value; when the effective radius of cloud particles increases to a certain extent (such as above 10 microns), the correction value gradually decreases. At the same time, the cloud height also has a significant impact on the forward scattering correction value: low cloud heights (such as below 1 km) correspond to larger correction values, while higher cloud heights (such as 4 to 6 km) have a more gradual change in correction values. According to the analysis results of this figure, the distribution range of the lookup table parameters can be optimized, especially increasing the resolution in the small particle size range and low cloud height, so as to more accurately reflect the changing characteristics of the forward scattering correction value, thereby improving the accuracy and efficiency of the correction.

[0112] According to an embodiment of the present invention, in operation S3, according to the initial parameter set, using the Monte Carlo method to simulate the second change characteristic of the photon path under the aerosol condition compared with the photon path under the clear sky condition includes:

[0113] According to the initial parameter set and the target initial photon number, the second initial photon position that obeys the uniform distribution is randomly generated by using the Monte Carlo method, wherein the atmospheric optical physical parameters under the aerosol condition in the initial parameter set are set to a non-uniform distribution state;

[0114] According to the second initial photon position, a second free path of the photon in the aerosol medium is calculated; according to the second free path, the photon position is updated to obtain a second path change characteristic of the photon in the aerosol medium;

[0115] According to the second path change characteristic, a second photon counting lidar forward scattering correction amount is calculated, wherein the second photon counting lidar forward scattering correction amount characterizes the second change characteristic of the photon path under aerosol conditions compared to that under clear sky conditions.

[0116] In this embodiment, the Monte Carlo method is also used to track the paths of multiple scattering of photons in the aerosol medium, and the state of photon propagation in the cloud medium is recorded to analyze its scattering characteristics and path distribution.

[0117] Since the principle of tracing the multiple scattering paths of photons in an aerosol medium by using the Monte Carlo method is the same as the principle of the multiple scattering paths in a cloud medium, the process of tracing the multiple scattering paths of photons in an aerosol medium by using the Monte Carlo method is not repeated in this embodiment. For details, please refer to the above process of tracing the multiple scattering paths of photons in a cloud medium by using the Monte Carlo method.

[0118] It should be noted that, in this embodiment, the initial parameter set The atmospheric optical physical parameters under mesoaerosol conditions are also set to a non-uniform distribution state, for example:

[0119] τ a=[0.01:0.02:0.1 0.2:0.1:1]

[0120] r a =[0.1:0.2:5 6:1:50]

[0121] g a =[0.6:0.05:0.9]

[0122] D a =[0.3:0.2:3]

[0123] H a =[0.5:0.2:6]

[0124] Based on the same process as for cloud media, the second photon counting lidar forward scattering correction is finally calculated, that is, the change of the photon path under aerosol conditions compared to the photon path under clear sky conditions ΔL a (Second change feature).

[0125] Figure 3 The diagram schematically shows the variation trend of the forward scattering correction value (unit: centimeter) under aerosol conditions according to an embodiment of the present invention with the cloud height (unit: kilometer) and the effective radius of cloud particles (unit: micrometer).

[0126] like Figure 3 As shown, based on the relationship between forward scattering, aerosol layer height and effective particle radius, it can be seen that the parameter step size can be set smaller in areas with more rapid changes.

[0127] The first change characteristic ΔL is calculated c and the second variation characteristic ΔL a After that, the non-uniform 5-dimensional lookup table 5DLUT can be constructed c and 5DLUT a .

[0128] According to an embodiment of the present invention, operation S4 of fusing the first variation feature and the second variation feature to obtain forward scatter correction data includes:

[0129] Generate a first 5-dimensional lookup table with non-uniform distribution according to the first change characteristic;

[0130] Generating a second 5-dimensional lookup table with non-uniform distribution according to the second change characteristic;

[0131] The first 5-dimensional lookup table and the second 5-dimensional lookup table are merged to obtain a target 5-dimensional lookup table, wherein the target 5-dimensional lookup table represents forward scatter correction data generated based on 5 dimensions.

[0132] In this embodiment, according to the first variation characteristic ΔL cand the second variation characteristic ΔL a Generate non-uniform 5-dimensional lookup table 5DLUT c and 5DLUT a Then, the non-uniform 5-dimensional lookup table 5DLUT c and 5DLUT a After fusion, the final target 5-dimensional lookup table can be obtained.

[0133] The satellite-borne photon counting laser ranging forward scattering correction method and device provided in the embodiments of the present invention construct a high-resolution non-uniform five-dimensional lookup table by combining the optical and physical properties of clouds and aerosols in five dimensions (optical thickness, particle size, asymmetry factor, physical thickness and height, etc.). Due to the introduction of the method of non-uniform lookup table resolution, it is ensured that the correction accuracy and computational efficiency are balanced within the key parameter range, further broadening the scope of application of the technology.

[0134] After the 5-dimensional lookup table is generated, in order to improve the correction accuracy, the lookup table can also be calibrated. Specifically, the prediction value P generated by the lookup table can be LUT and the Monte Carlo calculated value P MC Linear regression is used to recalibrate the forecast data to bring it closer to the ideal Monte Carlo calculated value.

[0135] For example, first predict the value P LUT and the Monte Carlo calculated value P MC The regression analysis was then performed for calibration verification.

[0136] About the predicted value P LUT and the Monte Carlo calculated value P MC Regression Analysis:

[0137] Assume that the initial fitted regression line is: , where a represents the original slope and b represents the intercept. Ideally, we want the relationship between the output value of the lookup table and the actual value to be one-to-one, that is, the slope a should be 1, and the intercept b should be close to 0. By calculating the deviation between the actual regression line and the ideal regression line (slope 1), we can determine the amount of correction that needs to be made. The adjustment formula is:

[0138]

[0139] Through this formula, all the predicted values ​​P in the lookup table are LUT Convert to corrected predicted value , making the new fitting line closer, that is: .

[0140] About calibration verification:

[0141] Perform linear regression analysis on the corrected data again to verify the correction effect. The accuracy of the corrected data can be evaluated by calculating the new root mean square error RMSE and mean absolute error MAE. Perform statistical tests and use the determination coefficient R 2 The value is used to evaluate the goodness of fit and the effectiveness of data correction. 2 The closer the value is to 1, the higher the model explanatory power and the better the data fit.

[0142] Figure 4 A linear regression analysis result diagram between the corrected lookup table estimate and the Monte Carlo calculated value under cloud conditions according to an embodiment of the present invention is schematically shown.

[0143] Figure 5 A linear regression analysis result diagram between the corrected lookup table estimate and the Monte Carlo calculated value under aerosol conditions according to an embodiment of the present invention is schematically shown.

[0144] like Figure 4 and Figure 5 As shown, the fit between the two is very high, and the correlation coefficient R 2 Both reached 0.99, indicating that the predicted values ​​of the lookup table can well reflect the actual Monte Carlo calculation values. At the same time, the root mean square error (RMSE) and mean absolute error (MAE) are both less than 0.22 cm, further proving the high accuracy of the lookup table. The regression slopes all reached 0.97, which is very close to the ideal slope of 1, indicating that the correction effect is very ideal.

[0145] In this embodiment, in response to receiving the ranging task, operation S5 queries the forward scattering correction data for a forward scattering correction value corresponding to the current atmospheric optical and physical parameters according to the current atmospheric optical and physical parameters, and corrects the ranging error, which may be specifically:

[0146] When the lidar system performs ranging, it collects the current atmospheric optical and physical parameters (because the lookup table has been refined, only a small number of parameters need to be collected), and then searches the lookup table for the corresponding forward scattering correction value based on the current atmospheric optical and physical parameters. The forward scattering correction value is then used to correct the ranging error. The specific formula is as follows:

[0147]

[0148] Among them, L corr Indicates the corrected distance measurement value, L obs represents the uncorrected ranging value of the lidar ranging, and ΔL represents the forward scattering correction value retrieved from the lookup table.

[0149] The satellite-borne photon counting laser ranging forward scattering correction method and device provided in the embodiments of the present invention can achieve efficient correction with only a small number of input parameters, thereby avoiding the error propagation caused by the high requirements on the comprehensiveness and accuracy of input data in the prior art, significantly reducing the amount of calculation and the difficulty of real-time processing, and improving the feasibility and accuracy of laser altimetry data in business applications.

[0150] According to an embodiment of the present invention, the satellite-borne photon counting laser ranging forward scattering correction method further includes:

[0151] In response to not completely finding the forward scatter correction value corresponding to the current atmospheric optical physical parameter in the forward scatter correction data, calculating the forward scatter correction intermediate value corresponding to the current atmospheric optical physical parameter using a multi-dimensional interpolation algorithm;

[0152] The intermediate value is corrected according to the forward scattering to correct the ranging error.

[0153] In this embodiment, since the intervals between parameter points in the lookup table are limited and the actual observation conditions may fall between the grid points of the lookup table, this embodiment uses a multi-dimensional interpolation algorithm to smooth the lookup table to ensure that it can provide accurate correction factors under any input conditions.

[0154] When the input parameters do not exactly match the lookup table grid points, a multidimensional interpolation algorithm is used to calculate the correction factors.

[0155] The satellite-borne photon counting laser ranging forward scattering correction method and device provided in the embodiment of the present invention are optimized by adopting a multi-dimensional interpolation algorithm, thereby ensuring that an accurate correction value can be obtained under any input condition.

[0156] According to an embodiment of the present invention, the satellite-borne photon counting laser ranging forward scattering correction method further includes:

[0157] In response to the range of the current atmospheric optical and physical parameters exceeding the range of the forward scatter correction data, using a boundary extrapolation mechanism to extrapolate a forward scatter correction extrapolated value corresponding to the current atmospheric optical and physical parameters;

[0158] Or use the neighboring value replacement mechanism to query the forward scatter correction replacement value corresponding to the current atmospheric optical and physical parameters; correct the ranging error according to the forward scatter correction estimated value or the forward scatter correction replacement value.

[0159] In this embodiment, if the input parameter exceeds the range of the lookup table, the robustness of the algorithm is ensured by boundary extrapolation or using adjacent values ​​instead.

[0160] Boundary extrapolation: Boundary extrapolation means that when the input parameter exceeds the range of the lookup table, the boundary value (i.e., minimum or maximum value) of the lookup table is used for estimation, or the value outside the range is calculated according to a certain rule. Specifically:

[0161] If the input parameter is greater than the maximum value of the lookup table, the maximum value in the lookup table is used for processing. If the input parameter is less than the minimum value in the lookup table, the minimum value in the lookup table is used for processing.

[0162] In another case, the out-of-range results can be predicted through a certain mathematical model (such as linear extrapolation) based on the relationship between the input parameters and the boundary values ​​of the lookup table.

[0163] This method can ensure that even if the input data exceeds the range of the lookup table, the system can still output a reasonable result.

[0164] Neighboring value replacement: When the input parameter exceeds the range of the lookup table, the closest value in the lookup table can be used to replace it to ensure that the system can continue to run. Specifically:

[0165] If the input value is less than the minimum value in the lookup table, or greater than the maximum value, the nearest known value can be selected to replace the out-of-range value. For example, if the minimum value of the lookup table is X and the maximum value is Y, when the input value is less than X, X is used; when the input value is greater than Y, Y is used.

[0166] This approach does not perform extrapolation or deduction, but instead uses the existing values ​​in the lookup table directly. It is usually more conservative and avoids the inaccuracies that may be introduced by extrapolation.

[0167] It should be noted that the forward scattering correction method for spaceborne photon counting laser ranging provided by the embodiment of the present invention can be flexibly adjusted according to different laser radar payload parameters (operating wavelength, field of view angle and orbital altitude) to adapt to different spaceborne laser radar systems. In addition, it can be further combined with real-time observation data for dynamic update, and has good expansion capabilities.

[0168] Figure 6 The principle diagram of the forward scattering correction method for spaceborne photon counting laser ranging according to an embodiment of the present invention is schematically shown.

[0169] like Figure 6 As shown, the principle of the forward scattering correction method for spaceborne photon counting laser ranging in the embodiment of the present invention is as follows:

[0170] Obtain the payload parameters (working wavelength, field of view angle and orbital altitude) of the satellite-borne lidar system, as well as the atmospheric optical and physical parameters under different conditions.

[0171] Among them, the atmospheric optical physical parameters under different conditions include:

[0172] Atmospheric optical physical parameters under cloud conditions (optical thickness of cloud layer, effective radius of cloud particles, asymmetry factor of cloud particles, cloud thickness and cloud base height);

[0173] Atmospheric optical physical parameters under aerosol conditions (aerosol optical thickness, effective radius of aerosol particles, aerosol particle asymmetry factor, aerosol layer thickness and aerosol layer bottom height).

[0174] The initial parameter set is generated according to the payload parameters and atmospheric optical and physical parameters under different conditions.

[0175] According to the initial parameter set, the Monte Carlo method is used to simulate the first change characteristics of the photon path under cloud conditions compared to the photon path under clear sky conditions, and the second change characteristics of the photon path under aerosol conditions compared to the photon path under clear sky conditions.

[0176] The first variation feature and the second variation feature are fused to obtain forward scatter correction data (non-uniform lookup table).

[0177] In response to receiving the ranging task, according to the current atmospheric optical and physical parameters, a forward scattering correction value corresponding to the current atmospheric optical and physical parameters is queried in the forward scattering correction data to correct the ranging error.

[0178] It should be noted that the principle of the satellite-borne photon counting laser ranging forward scattering correction method of the embodiment of the present invention corresponds to the operation flow of the foregoing satellite-borne photon counting laser ranging forward scattering correction method, so its specific details are not repeated here.

[0179] Figure 7 The structure block diagram of the satellite-borne photon counting laser ranging forward scattering correction device according to an embodiment of the present invention is schematically shown.

[0180] like Figure 7 As shown, the satellite-borne photon counting laser ranging forward scattering correction device 700 of the embodiment of the present invention includes: an acquisition module 710, a generation module 720, a simulation module 730, a fusion module 740 and a correction module 750.

[0181] Among them, the acquisition module 710 is used to obtain the payload parameters of the satellite-borne lidar system and the atmospheric optical and physical parameters under different conditions, wherein the atmospheric optical and physical parameters under different conditions include the atmospheric optical and physical parameters under cloud conditions and the atmospheric optical and physical parameters under aerosol conditions.

[0182] The generation module 720 is used to generate an initial parameter set according to the load parameters and atmospheric optical physical parameters under different conditions.

[0183] The simulation module 730 is used to simulate the first change characteristics of the photon path under cloud conditions compared to the photon path under clear sky conditions using the Monte Carlo method according to the initial parameter set, and to simulate the second change characteristics of the photon path under aerosol conditions compared to the photon path under clear sky conditions.

[0184] The fusion module 740 is used to fuse the first change feature and the second change feature to obtain forward scatter correction data.

[0185] The correction module 750 is used to respond to receiving the ranging task and, according to the current atmospheric optical and physical parameters, query the forward scattering correction data for a forward scattering correction value corresponding to the current atmospheric optical and physical parameters to correct the ranging error.

[0186] According to the embodiments of the present invention, any one or more of the modules, submodules, units, and subunits, or at least part of the functions of any one of them can be implemented in one module. According to the embodiments of the present invention, any one or more of the modules, submodules, units, and subunits can be split into multiple modules for implementation. According to the embodiments of the present invention, any one or more of the modules, submodules, units, and subunits can be at least partially implemented as hardware circuits, such as field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), systems on chips, systems on substrates, systems on packages, application specific integrated circuits (ASICs), or can be implemented by hardware or firmware in any other reasonable way of integrating or packaging the circuit, or by any one of the three implementation methods of software, hardware, and firmware, or by a proper combination of any of them. Alternatively, according to the embodiments of the present invention, one or more of the modules, submodules, units, and subunits can be at least partially implemented as computer program modules, and when the computer program modules are run, the corresponding functions can be executed.

[0187] For example, any multiple of the acquisition module 710, the generation device 720, the simulation module 730, the fusion module 740 and the correction module 750 can be combined in one module / unit / sub-unit for implementation, or any one of the modules / units / sub-units can be split into multiple modules / units / sub-units. Alternatively, at least part of the functions of one or more of these modules / units / sub-units can be combined with at least part of the functions of other modules / units / sub-units and implemented in one module / unit / sub-unit. According to an embodiment of the present invention, at least one of the acquisition module 710, the generation device 720, the simulation module 730, the fusion module 740 and the correction module 750 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented by hardware or firmware such as any other reasonable way of integrating or packaging the circuit, or by any one of the three implementation methods of software, hardware and firmware or by a suitable combination of any of them. Alternatively, at least one of the acquisition module 710, the generation device 720, the simulation module 730, the fusion module 740 and the correction module 750 may be at least partially implemented as a computer program module, and when the computer program module is executed, the corresponding function may be performed.

[0188] It should be noted that the part of the track association device based on parameter space conversion in the embodiment of the present invention corresponds to the part of the track association method based on parameter space conversion in the embodiment of the present invention. The description of the part of the track association device based on parameter space conversion specifically refers to the part of the track association method based on parameter space conversion, which will not be repeated here.

[0189] Figure 8 The structural block diagram of an electronic device suitable for implementing a forward scattering correction method for spaceborne photon counting laser ranging according to an embodiment of the present invention is schematically shown. Figure 8 The electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present invention.

[0190] like Figure 8As shown, the electronic device 800 according to an embodiment of the present invention includes a processor 801, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 802 or a program loaded from a storage part 808 to a random access memory (RAM) 803. The processor 801 may include, for example, a general-purpose microprocessor (e.g., a CPU), an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (e.g., an application-specific integrated circuit (ASIC)), etc. The processor 801 may also include an onboard memory for caching purposes. The processor 801 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present invention.

[0191] In the storage part 808, various programs and data required for the operation of the electronic device 800 are stored. The processor 801, the ROM 802 and the storage part 808 are connected to each other through the bus 804. The processor 801 performs various operations of the method flow according to the embodiment of the present invention by executing the program in the ROM 802 and / or the storage part 808. It should be noted that the program can also be stored in one or more memories other than the ROM 802 and the storage part 808. The processor 801 can also perform various operations of the method flow according to the embodiment of the present invention by executing the program stored in the one or more memories.

[0192] According to an embodiment of the present invention, the electronic device 800 may further include an input / output (I / O) interface 805, which is also connected to the bus 804. The electronic device 800 may further include one or more of the following components connected to the input / output (I / O) interface 805: an input portion 806 including a keyboard, a mouse, etc.; an output portion 807 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage portion 808 including a hard disk, etc.; and a communication portion 809 including a network interface card such as a LAN card, a modem, etc. The communication portion 809 performs communication processing via a network such as the Internet. A drive 810 is also connected to the input / output (I / O) interface 805 as needed. A removable medium 811, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 810 as needed, so that the computer program read therefrom is installed into the storage portion 808 as needed.

[0193] According to an embodiment of the present invention, the method flow according to an embodiment of the present invention can be implemented as a computer software program. For example, an embodiment of the present invention includes a computer program product, which includes a computer program carried on a computer-readable storage medium, and the computer program includes a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 809, and / or installed from the removable medium 811. When the computer program is executed by the processor 801, the above-mentioned functions defined in the system of the embodiment of the present invention are executed. According to an embodiment of the present invention, the system, equipment, device, module, unit, etc. described above can be implemented by a computer program module.

[0194] The present invention also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiment; or may exist independently without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiment of the present invention is implemented.

[0195] According to an embodiment of the present invention, the computer-readable storage medium may be a non-volatile computer-readable storage medium. For example, it may include but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present invention, the computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, an apparatus or a device.

[0196] For example, according to an embodiment of the present invention, the computer-readable storage medium may include the ROM 802 and / or the storage portion 808 described above and / or one or more memories other than the ROM 802 and the storage portion 808 .

[0197] An embodiment of the present invention also includes a computer program product, which includes a computer program, and the computer program contains program code for executing the method provided by the embodiment of the present invention. When the computer program product runs on an electronic device, the program code is used to enable the electronic device to implement the method provided by the embodiment of the present invention.

[0198] When the computer program is executed by the processor 801, the above functions defined in the system / device of the embodiment of the present invention are executed. According to the embodiment of the present invention, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0199] In one embodiment, the computer program may rely on tangible storage media such as optical storage devices, magnetic storage devices, etc. In another embodiment, the computer program may also be transmitted and distributed in the form of signals on a network medium, and downloaded and installed through the communication part 809, and / or installed from a removable medium 811. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0200] According to an embodiment of the present invention, the program code for executing the computer program provided by the embodiment of the present invention can be written in any combination of one or more programming languages. Specifically, these computing programs can be implemented using high-level process and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, Java, C++, python, "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on the remote computing device, or entirely on the remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (e.g., using an Internet service provider to connect through the Internet).

[0201] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present invention. In this regard, each box in the flowchart or block diagram may represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box may also occur in an order different from the order marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions. It can be understood by those skilled in the art that the features recorded in the various embodiments of the present invention can be combined and / or combined in various ways, even if such a combination or combination is not explicitly recorded in the present invention. In particular, without departing from the spirit and teachings of the present invention, the features recorded in the various embodiments of the present invention can be combined and / or combined in various ways. All these combinations and / or combinations fall within the scope of the present invention.

[0202] The embodiments of the present invention are described above. However, these embodiments are only for the purpose of illustration, and are not intended to limit the scope of the present invention. Although each embodiment is described above, it does not mean that the measures in each embodiment cannot be used in combination advantageously. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A forward scatter correction method for spaceborne photon counting laser ranging, characterized in that: The method comprises: Obtaining payload parameters of a spaceborne laser radar system and atmospheric optical and physical parameters under different conditions, wherein the atmospheric optical and physical parameters under different conditions include atmospheric optical and physical parameters under cloud conditions and atmospheric optical and physical parameters under aerosol conditions; generating an initial parameter set according to the load parameters and the atmospheric optical physical parameters under the different conditions; According to the initial parameter set, using the Monte Carlo method to simulate a first change characteristic of the photon path under cloud conditions compared to the photon path under clear sky conditions, and to simulate a second change characteristic of the photon path under aerosol conditions compared to the photon path under clear sky conditions; fusing the first variation feature and the second variation feature to obtain forward scatter correction data; In response to receiving the ranging task, according to the current atmospheric optical and physical parameters, the forward scattering correction value corresponding to the current atmospheric optical and physical parameters is searched in the forward scattering correction data to correct the ranging error.

2. The method according to claim 1, characterized in that Before simulating the first change characteristic of the photon path under cloud conditions compared to the photon path under clear sky conditions by using the Monte Carlo method according to the initial parameter set, and simulating the second change characteristic of the photon path under aerosol conditions compared to the photon path under clear sky conditions, the method further includes: Determining a first initial photon number according to a standard deviation of a photon scattering path and a target error, wherein the first initial photon number is used to characterize a correction accuracy; Determine a second initial photon number according to the total computing resource consumption required for a given photon and an average computing cost constant required for a single photon, wherein the second initial photon number is used to characterize the correction cost; A target initial photon number is determined according to the first initial photon number and the second initial photon number.

3. The method according to claim 2, characterized in that The method of simulating the first change characteristics of the photon path under cloudy conditions compared with the photon path under clear sky conditions using the Monte Carlo method according to the initial parameter set includes: According to the initial parameter set and the target initial photon number, a first initial photon position that obeys a uniform distribution is randomly generated using a Monte Carlo method, wherein the atmospheric optical physical parameters under cloud conditions in the initial parameter set are set to a non-uniform distribution state; Calculating a first free path of the photon in the cloud medium according to the first initial photon position; According to the first free path, the photon position is updated to obtain a first path change characteristic of the photon in the cloud medium; According to the first path change characteristic, a first photon counting lidar forward scattering correction amount is calculated, wherein the first photon counting lidar forward scattering correction amount represents a first change characteristic of the photon path under cloudy conditions compared to that under clear sky conditions.

4. The method according to claim 2, characterized in that: According to the initial parameter set, the second change characteristics of the photon path under aerosol conditions compared with the photon path under clear sky conditions are simulated using the Monte Carlo method, including: According to the initial parameter set and the target initial photon number, a second initial photon position that obeys a uniform distribution is randomly generated using a Monte Carlo method, wherein the atmospheric optical physical parameters under aerosol conditions in the initial parameter set are set to a non-uniform distribution state; Calculating a second free path of the photon in the aerosol medium according to the second initial photon position; According to the second free path, updating the photon position, and obtaining the second path change characteristics of the photon in the aerosol medium; According to the second path change characteristic, a second photon counting lidar forward scattering correction amount is calculated, wherein the second photon counting lidar forward scattering correction amount characterizes the second change characteristic of the photon path under aerosol conditions compared to the photon path under clear sky conditions.

5. The method according to claim 1, characterized in that The atmospheric optical physical parameters under the cloud conditions include: Optical thickness of clouds, effective radius of cloud particles, asymmetry factor of cloud particles, cloud thickness and cloud base height.

6. The method according to claim 5, characterized in that The atmospheric optical physical parameters under the aerosol conditions include: Optical thickness of aerosol, effective radius of aerosol particles, asymmetry factor of aerosol particles, thickness of aerosol layer and height of aerosol layer bottom.

7. The method according to claim 6, characterized in that The fusing the first change feature and the second change feature to obtain forward scatter correction data includes: Generate a first 5-dimensional lookup table with non-uniform distribution according to the first change characteristic; generating a second 5-dimensional lookup table with non-uniform distribution according to the second variation characteristic; The first 5-dimensional lookup table and the second 5-dimensional lookup table are merged to obtain a target 5-dimensional lookup table, wherein the target 5-dimensional lookup table represents forward scatter correction data generated based on 5 dimensions.

8. The method according to claim 7, characterized in that The method further comprises: In response to not completely finding the forward scatter correction value corresponding to the current atmospheric optical physical parameter in the forward scatter correction data, calculating the forward scatter correction intermediate value corresponding to the current atmospheric optical physical parameter by using a multidimensional interpolation algorithm; The ranging error is corrected according to the forward scatter correction intermediate value.

9. The method according to claim 7, characterized in that: The method further comprises: In response to the range of the current atmospheric optical and physical parameters exceeding the range of the forward scattering correction data, using a boundary extrapolation mechanism to extrapolate a forward scattering correction extrapolated value corresponding to the current atmospheric optical and physical parameters; Or use the neighbor value substitution mechanism to query the forward scatter correction substitution value corresponding to the current atmospheric optical physical parameters; The ranging error is corrected according to the forward scatter correction estimated value or the forward scatter correction substitute value.

10. A satellite-borne photon counting laser ranging forward scattering correction device, characterized in that: The device comprises: An acquisition module, used to acquire the payload parameters of the spaceborne laser radar system and the atmospheric optical and physical parameters under different conditions, wherein the atmospheric optical and physical parameters under different conditions include the atmospheric optical and physical parameters under cloud conditions and the atmospheric optical and physical parameters under aerosol conditions; A generating module, used for generating an initial parameter set according to the load parameters and the atmospheric optical physical parameters under the different conditions; A simulation module, configured to simulate, based on the initial parameter set, a first change characteristic of a photon path under a cloud condition compared to a photon path under a clear sky condition, and a second change characteristic of a photon path under an aerosol condition compared to a photon path under a clear sky condition by using a Monte Carlo method; A fusion module, used for fusing the first change feature and the second change feature to obtain forward scatter correction data; The correction module is used to respond to receiving the ranging task and query the forward scattering correction value corresponding to the current atmospheric optical and physical parameters in the forward scattering correction data according to the current atmospheric optical and physical parameters to correct the ranging error.

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