Visibility inversion method based on cooperation of radar reflectivity and laser extinction

Abstract

The invention relates to the technical field of radar detection, in particular to a visibility inversion method based on cooperation of radar reflectivity and laser extinction, which fully combines the advantages of high near-field extinction measurement precision of a laser ceilometer and long-distance wide-area coverage of a millimeter-wave radar, realizes full-range continuous monitoring from a near field to a far field, and improves the visibility inversion accuracy. And the monitoring blind area of the traditional scheme is eliminated. A drop spectrum state dynamic correction mechanism is established, and the industrial pain points of poor adaptability of a fixed coefficient and large inversion error are solved from the source. By adopting the three-dimensional Gaussian weighted space matching and Sigmoid easement curve smooth splicing technology, the time-space accurate alignment of the two types of data is realized, the boundary data jump is eliminated, and the continuity of the global extinction field is ensured. The method does not need complex scene prior calibration, is high in generalization capability, can stably adapt to various meteorological conditions, and can provide high-precision and high-reliability wide-area visibility data for highway meteorological early warning.

Description

Technical Field

[0001] This invention relates to the field of radar detection technology, and in particular to a visibility inversion method based on the synergy of radar reflectivity and laser extinction. Background Technology

[0002] Low visibility weather conditions (such as fog and rainfall) are a core contributing factor to major traffic accidents on highways. Wide-area, high-precision, and real-time visibility monitoring is the core foundation for highway traffic weather early warning. Currently, mainstream transmission and scattering visibility meters can only achieve single-point monitoring, failing to cover continuous spatial areas along highways and resulting in numerous monitoring blind spots. While single millimeter-wave weather radars can achieve long-distance, wide-area detection, their extinction coefficient inversion is significantly affected by atmospheric particle droplet distribution, leading to insufficient accuracy and stability. Although single laser cloud meters can achieve high-precision near-field extinction coefficient measurement, their effective detection distance in foggy weather is severely limited by atmospheric attenuation, failing to meet the needs of long-distance continuous monitoring. Therefore, developing a method that combines the advantages of both types of sensors and achieves high-precision visibility inversion across the entire range has become an urgent need in the field of traffic meteorological monitoring.

[0003] Existing visibility inversion technologies suffer from several unavoidable drawbacks. Single-sensor solutions have inherent limitations. Single laser monitoring devices experience severe signal attenuation in high-extinction scenarios such as fog and haze, with an effective detection range typically not exceeding 5km, and far-field data becoming completely ineffective, making long-distance continuous monitoring impossible. Single millimeter-wave radars employ a fixed power-law coefficient radar reflectivity-extinction coefficient conversion relationship; when atmospheric particle droplet distribution changes with meteorological conditions, this fixed coefficient introduces significant inversion errors, making them unsuitable for complex scenarios such as fog, rain, and mixed phases. Existing multi-sensor fusion solutions have significant technical limitations. Most solutions simply stitch together two types of data, lacking a dynamic correction mechanism for the far-field radar conversion coefficient from near-field high-precision laser data, thus failing to eliminate systematic errors caused by droplet spectrum variations. Some solutions rely on extensive prior data from specific scenarios for calibration, exhibiting weak generalization capabilities and severe data jumps at boundaries, making it difficult to meet the complex and variable meteorological monitoring needs along highways. Summary of the Invention

[0004] The main objective of this invention is to provide a visibility inversion method based on the synergy of radar reflectivity and laser extinction. A collaborative inversion architecture combining millimeter-wave radar and laser cloud meter is constructed, fully leveraging the advantages of high near-field extinction measurement accuracy of the laser cloud meter and the long-range, wide-area coverage of the millimeter-wave radar. This achieves continuous monitoring across the entire range from near-field to far-field, eliminating the monitoring blind spots of traditional methods. A dynamic correction mechanism for droplet spectrum state is established. By extracting global state variables characterizing the distribution of atmospheric particle droplets from near-field synchronous data, the conversion coefficient of far-field radar reflectivity to extinction coefficient is adaptively adjusted, fundamentally solving the industry pain points of poor adaptability of fixed coefficients and large inversion errors. Three-dimensional Gaussian weighted spatial matching and Sigmoid smoothing curve stitching techniques are employed to achieve precise spatiotemporal alignment of the two types of data, eliminating boundary data jumps and ensuring the continuity of the global extinction field. No complex scenario-based prior calibration is required, exhibiting strong generalization ability and stable adaptation to various meteorological conditions. This provides high-precision, high-reliability wide-area visibility data for highway weather warnings.

[0005] The technical solution of the present invention is as follows: Firstly, a visibility inversion method based on the synergy of radar reflectivity and laser extinction is proposed, which includes the following steps: S1. Real-time acquisition of radar equivalent reflectivity factor through millimeter-wave radar, synchronous acquisition of laser echo reception power through laser cloud meter, and division of near-field overlap area and far-field single detection area according to detection distance. S2. Perform a three-dimensional Gaussian weighted average transformation on the radar equivalent reflectivity factor collected by the millimeter-wave radar to obtain the spatially matched radar reflectivity factor that is aligned with the laser cloud measuring instrument beam space. S3. Based on the laser echo received power collected by the laser cloud meter, the lidar equation is solved by the Klett inversion algorithm to obtain the measured extinction coefficient of the laser in the near-field overlapping region. S4. Extract the spatial matching radar reflectivity factor and the measured laser extinction coefficient in the near-field overlap region to obtain the global state variables characterizing the current distribution state of the gas cloud droplet spectrum. S5. The dynamic conversion coefficient of radar reflectivity-extinction coefficient is adaptively adjusted based on global state variables, and the radar equivalent reflectivity factor in the far-field single detection area is combined to calculate the far-field corrected extinction coefficient. S6. The measured extinction coefficient of the laser in the near-field overlapping area and the far-field corrected extinction coefficient in the far-field single detection area are smoothly spliced ​​together to obtain the global visibility distribution covering the entire detection range.

[0006] A further improvement of the present invention is that the specific content of S1 is: real-time acquisition of radar equivalent reflectivity factor through millimeter-wave radar. And the laser echo receiving power synchronously collected by the laser cloud measuring instrument The near-field overlap region and the far-field single detection region are divided according to the detection distance r, and the near-field boundary distance of the laser cloud meter is determined as follows: The range of the near-field overlap region is The range of the far-field single detection zone is defined by the radar's equivalent reflectivity factor. The effective range covers the entire area. The laser echo receiving power The effective range is the near-field overlap region. Indexed by time nodes.

[0007] A further improvement of this invention is that S2 includes the following specific content: constructing a three-dimensional Gaussian weighted weighting function based on the laser sampling volume of the laser cloud meter, and applying it to the radar equivalent reflectivity factor. A three-dimensional Gaussian weighted average transformation is performed on adjacent detection range, azimuth, and elevation angle dimensions. The expression for the three-dimensional Gaussian weighting function is as follows: ;in, These are the detection distance, azimuth angle, and elevation angle at the center of the laser sampling volume, respectively. The Gaussian kernel standard deviations for detection range, azimuth, and elevation are respectively used. Based on the three-dimensional Gaussian weighted average transformation, a spatially matched radar reflectivity factor aligned with the laser beam space is output. .

[0008] A further improvement of the present invention is that step S3 includes the following specific steps: S31. Extract the laser echo received power within the near-field overlap region. Construct the lidar equation: ;in, Where is the laser emission power, and C is the lidar system constant. The laser backscattering coefficient is... Let be the measured extinction coefficient of the laser light to be solved; S32. Solve the lidar equations using the Klett inversion algorithm, setting the power-law relationship between the measured laser extinction coefficient and the laser backscattering coefficient as follows: Where n is the power-law exponent and k is the proportionality coefficient, the measured extinction coefficient of the laser within the near-field overlap region is obtained by solving. .

[0009] A further improvement of the present invention is that step S4 includes the following specific steps: S41. Extract the spatially matched radar reflectivity factor within the near-field overlap region. Extinction coefficient measured by laser After performing dimensionless processing, the radar reflectivity term is obtained. and extinction coefficient term ;in, This is a reference value for the radar reflectivity factor. This is a reference value for the measured extinction coefficient of the laser. S42. Along the detection distance r, calculate the logarithmic spatial gradients of the radar reflectivity term and the extinction coefficient term respectively, to obtain the radar reflectivity gradient sequence. With extinction coefficient gradient sequence The radar reflectivity gradient sequence and the extinction coefficient gradient sequence are combined by ratio to obtain a gradient ratio sequence. Median filtering is then applied to this gradient ratio sequence to obtain the global state variable characterizing the current distribution of air mass droplets within the near-field overlap region. ;in, This indicates a median filtering operation.

[0010] A further improvement of the present invention is that step S5 includes the following specific steps: S51, Based on global state variables Establish a dynamic transformation function and calculate the first dynamic transformation coefficient at the current time. Second dynamic conversion coefficient ; ;in, These are the preset fitting coefficients; S52. Extract the radar equivalent reflectivity factor within the far-field single detection area. Combined with the first dynamic conversion coefficient Second dynamic conversion coefficient The far-field corrected extinction coefficient within the far-field single-detection region was calculated by constructing a far-field extinction mapping formula. The expression for the far-field extinction mapping formula is: .

[0011] A further improvement of the present invention is that step S6 includes the following specific steps: S61. Measured extinction coefficient of laser light within the near-field overlap region. Far-field corrected extinction coefficient within the far-field single detection area A weight gradient function based on the Sigmoid transition curve is constructed, and the expression of the weight gradient function is as follows: Where k is the smoothing coefficient, This represents the weight value at a detection distance r. S62. Based on the weighted gradient function, calculate the measured extinction coefficient of the laser within the near-field overlap region. Far-field corrected extinction coefficient within the far-field single detection area By performing a smooth stitching with gradually varying weights, a global continuous extinction coefficient covering the entire detection range is obtained. The expression for the global continuous extinction coefficient is: ; S63, the global continuous extinction coefficient Substituting Koschmieder's law, the global visibility distribution covering the entire detection range is obtained by inversion. .

[0012] Secondly, a computer-readable storage medium is proposed, on which a computer program is stored. When the computer program is executed by a processor, it implements the above-mentioned visibility inversion method based on the synergy of radar reflectivity and laser extinction.

[0013] Thirdly, an electronic device is proposed, including a memory for storing instructions and a processor for executing the instructions, causing the device to perform the aforementioned visibility inversion method based on the synergy of radar reflectivity and laser extinction.

[0014] The technical effects of this invention are as follows: A visibility inversion method based on the synergy of radar reflectivity and laser extinction was constructed, and a collaborative inversion architecture of millimeter-wave radar and laser cloud instrument was built. This fully leverages the advantages of high near-field extinction measurement accuracy of the laser cloud instrument and the long-range, wide-area coverage of the millimeter-wave radar, achieving continuous monitoring across the entire range from near-field to far-field, eliminating the monitoring blind spots of traditional methods. A dynamic correction mechanism for droplet spectrum state was established. By extracting global state variables characterizing the distribution of atmospheric particle droplets from near-field synchronous data, the conversion coefficient of far-field radar reflectivity to extinction coefficient is adaptively adjusted, fundamentally solving the industry pain points of poor adaptability of fixed coefficients and large inversion errors. Three-dimensional Gaussian weighted spatial matching and Sigmoid smoothing curve stitching techniques were employed to achieve precise spatiotemporal alignment of the two types of data, eliminating boundary data jumps and ensuring the continuity of the global extinction field. No complex scenario-based prior calibration is required, and the method has strong generalization ability, stably adapting to various meteorological conditions, providing high-precision, high-reliability wide-area visibility data for highway weather warnings. Attached Figure Description

[0015] Other features, objects, and advantages of the invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flowchart illustrating the visibility inversion method based on the synergy of radar reflectivity and laser extinction in Embodiment 1 of the present invention. Detailed Implementation

[0016] Example 1: This example proposes a visibility inversion method based on the synergy of radar reflectivity and laser extinction. It constructs a collaborative inversion architecture combining millimeter-wave radar and a laser cloud meter, fully leveraging the advantages of the laser cloud meter's high near-field extinction measurement accuracy and the millimeter-wave radar's long-range, wide-area coverage. This achieves continuous monitoring across the entire range from near-field to far-field, eliminating the monitoring blind spots of traditional methods. A dynamic correction mechanism for the droplet spectrum state is established. By extracting global state variables characterizing the atmospheric particle droplet spectrum distribution from near-field synchronous data, the conversion coefficient of far-field radar reflectivity to extinction coefficient is adaptively adjusted, fundamentally solving the industry pain points of poor adaptability of fixed coefficients and large inversion errors. Three-dimensional Gaussian weighted spatial matching and Sigmoid smoothing curve stitching techniques are employed to achieve precise spatiotemporal alignment of the two types of data, eliminating boundary data jumps and ensuring the continuity of the global extinction field. It requires no complex scenario-based prior calibration, has strong generalization ability, and can stably adapt to various meteorological conditions, providing high-precision, high-reliability wide-area visibility data for highway weather warnings. Specifically, such as... Figure 1 As shown, the visibility inversion method based on the synergy of radar reflectivity and laser extinction proposed in this embodiment includes the following specific steps: S1. Real-time acquisition of radar equivalent reflectivity factor through millimeter-wave radar, synchronous acquisition of laser echo reception power through laser cloud meter, and division of near-field overlap area and far-field single detection area according to detection distance. S2. Perform a three-dimensional Gaussian weighted average transformation on the radar equivalent reflectivity factor collected by the millimeter-wave radar to obtain the spatially matched radar reflectivity factor that is aligned with the laser cloud measuring instrument beam space. S3. Based on the laser echo received power collected by the laser cloud meter, the lidar equation is solved by the Klett inversion algorithm to obtain the measured extinction coefficient of the laser in the near-field overlapping region. S4. Extract the spatial matching radar reflectivity factor and the measured laser extinction coefficient in the near-field overlap region to obtain the global state variables characterizing the current distribution state of the gas cloud droplet spectrum. S5. The dynamic conversion coefficient of radar reflectivity-extinction coefficient is adaptively adjusted based on global state variables, and the radar equivalent reflectivity factor in the far-field single detection area is combined to calculate the far-field corrected extinction coefficient. S6. The measured extinction coefficient of the laser in the near-field overlapping area and the far-field corrected extinction coefficient in the far-field single detection area are smoothly spliced ​​together to obtain the global visibility distribution covering the entire detection range.

[0017] In this embodiment, the specific content of S1 is: real-time acquisition of radar equivalent reflectivity factor through millimeter-wave radar. And the laser echo receiving power synchronously collected by the laser cloud measuring instrument The near-field overlap region and the far-field single detection region are divided according to the detection distance r, and the near-field boundary distance of the laser cloud meter is determined as follows: The range of the near-field overlap region is The range of the far-field single detection area is The radar equivalent reflectivity factor The effective range covers the entire area. The laser echo receiving power The effective range is the near-field overlap region. Indexed by time nodes.

[0018] In this embodiment, the radar equivalent reflectivity factor is acquired in real time using millimeter-wave radar. Where r represents the detection distance and t represents the time. This represents the total backscattering cross section of water particles at time t and distance r, with dimensions of . Effective coverage of the entire area Simultaneously, the laser echo reception power is collected by a laser cloud measuring instrument. The dimension is mW, representing the instantaneous backscattered light power received, and its effective range is limited by the near-field boundary distance. ,Right now The near-field boundary distance is set to 5km, a value determined in conjunction with the effective detection distance of the laser cloud measuring instrument under typical foggy conditions.

[0019] In this embodiment, S2 includes the following specific content: Based on the laser sampling volume of the laser cloud meter, a three-dimensional Gaussian weighted weight function is constructed to adjust the radar equivalent reflectivity factor. A three-dimensional Gaussian weighted average transformation is performed on adjacent detection range, azimuth, and elevation angle dimensions. The expression for the three-dimensional Gaussian weighting function is as follows: ;in, These are the detection distance, azimuth angle, and elevation angle at the center of the laser sampling volume, respectively. The Gaussian kernel standard deviations for detection range, azimuth, and elevation are respectively used. Based on the three-dimensional Gaussian weighted average transformation, a spatially matched radar reflectivity factor aligned with the laser beam space is output. .

[0020] In this embodiment, the laser sampling volume of the laser cloud measuring instrument is used as the benchmark. The laser sampling volume is determined by the laser beamwidth. and distance resolution It is determined that the laser sampling volume at a distance r is approximately cylindrical, with a base radius of r. The height is A three-dimensional Gaussian weighted weighting function is constructed to evaluate the radar equivalent reflectivity factor. A three-dimensional Gaussian weighted average transformation is performed on adjacent detection range, azimuth, and elevation dimensions. The expression for the three-dimensional Gaussian weighting function is as follows: This represents the i-th sampling distance in the radar range library. This represents the radar's j-th azimuth angle sample value. This represents the radar's k-th elevation angle sample value. These are the detection distance, azimuth angle, and elevation angle at the center of the laser sampling volume, respectively. These are the Gaussian kernel standard deviations for detection range, azimuth angle, and elevation angle, respectively. Set it to twice the resolution of the radar range database. and Set to twice the radar beamwidth, and based on the three-dimensional Gaussian weighted average transformation result, output a spatially matched radar reflectivity factor aligned with the laser beam space. Dimensions are .

[0021] In this embodiment, step S3 includes the following specific steps: S31. Extract the laser echo received power within the near-field overlap region. Construct the lidar equation: ;in, Where is the laser emission power, and C is the lidar system constant. The laser backscattering coefficient is... Let be the measured extinction coefficient of the laser light to be solved; S32. Solve the lidar equations using the Klett inversion algorithm, setting the power-law relationship between the measured laser extinction coefficient and the laser backscattering coefficient as follows: Where n is the power-law exponent and k is the proportionality coefficient, the measured extinction coefficient of the laser within the near-field overlap region is obtained by solving. .

[0022] In this embodiment, Let be the laser emission power, in mW, and C be the lidar system constant, determined by system parameters such as the effective receiving area of ​​the telescope, pulse space length, optical efficiency, and detector gain, in units of . Let be the laser backscattering coefficient, with dimensions . sr represents steradian, a dimensionless derived unit that is not used in dimension calculations. Let be the measured extinction coefficient of the laser to be solved, with dimensions . For the distance variable in the integration process, the Klett inversion algorithm is used to solve the lidar equation, and the power-law relationship between the measured laser extinction coefficient and the laser backscattering coefficient is set as follows: Where n is the power-law exponent, which is 1 for water-phase particles, and k is the proportionality constant, which is 1 for water-phase particles. During the inversion process at the near-field boundary Set boundary conditions at the location, with the boundary extinction coefficient set to a value of [value to be filled in]. The initial inversion value after moving average is used to obtain the measured laser extinction coefficient within the near-field overlap region through iterative solution. Dimensions are .

[0023] In this embodiment, step S4 includes the following specific steps: S41. Extract the spatially matched radar reflectivity factor within the near-field overlap region. Extinction coefficient measured by laser After performing dimensionless processing, the radar reflectivity term is obtained. and extinction coefficient term ;in, This is a reference value for the radar reflectivity factor. This is a reference value for the measured extinction coefficient of the laser. S42. Along the detection distance r, calculate the logarithmic spatial gradients of the radar reflectivity term and the extinction coefficient term respectively, to obtain the radar reflectivity gradient sequence. With extinction coefficient gradient sequence The radar reflectivity gradient sequence and the extinction coefficient gradient sequence are combined by ratio to obtain a gradient ratio sequence. Median filtering is then applied to this gradient ratio sequence to obtain the global state variable characterizing the current distribution of air mass droplets within the near-field overlap region. ;in, This indicates a median filtering operation.

[0024] In this embodiment, the radar reflectivity gradient sequence With extinction coefficient gradient sequence All dimensions are During the calculation process, Let be the i-th sampling point in the distance sequence. The interval between adjacent sampling points is the laser's distance resolution. For the first and last boundary points of the distance sequence, i.e., at r=0, forward differencing is used. Backward difference is used at the midpoint, and central difference is used at the intermediate point. A minimum threshold is set for the gradient value of the denominator. When the absolute value of the denominator is less than To avoid outliers in the calculation, the ratio data at that distance point is discarded. The radar reflectivity gradient sequence and the extinction coefficient gradient sequence are combined by ratio to obtain the gradient ratio sequence. The ratio of two physical quantities with the same dimension is calculated, and the result is a dimensionless value. The gradient ratio sequence is then subjected to median filtering transformation. The median filtering window size is set to 5 consecutive distance sampling points. Median filtering does not change the dimensions of the input data, thus obtaining the global state variable characterizing the current distribution state of the air mass droplet spectrum within the near-field overlap region. , is a dimensionless number.

[0025] The design concept of this embodiment is as follows: Millimeter-wave weather radar has a long detection range, but its extinction inversion of fog droplets is greatly affected by the droplet spectrum distribution. Different phases of droplets have different spectra, which will lead to an increase in the deviation of the fixed conversion relationship. While the measurement results of fog droplet extinction by laser cloud meter are stable, the detection range is short and limited by the signal-to-noise ratio. Therefore, synchronous data from the near-field overlap region is used to extract parameters that can reflect the evolution of the droplet spectrum, dynamically correct the far-field conversion relationship, and combine the advantages of the two devices to improve the inversion effect. In the derivation process, radar reflectivity is more sensitive to large raindrops, while laser extinction is more sensitive to small raindrops. The spatial gradient changes of the two can reflect the changes in the droplet spectrum. When the air mass is dominated by fog droplets, the gradient change trends of the two are similar and the ratio is stable. When large raindrops are mixed in, the gradient change of radar reflectivity will be significantly greater than that of laser extinction, and the ratio will change. The stable value of this ratio is extracted by median filtering and used as a global state variable to dynamically adjust the far-field conversion coefficient, thereby correcting the deviation caused by the droplet spectrum change.

[0026] In this embodiment, step S5 includes the following specific steps: S51, Based on global state variables Establish a dynamic transformation function and calculate the first dynamic transformation coefficient at the current time. Second dynamic conversion coefficient ; ;in, These are the preset fitting coefficients; S52. Extract the radar equivalent reflectivity factor within the far-field single detection area. Combined with the first dynamic conversion coefficient Second dynamic conversion coefficient The far-field corrected extinction coefficient within the far-field single-detection region was calculated by constructing a far-field extinction mapping formula. The expression for the far-field extinction mapping formula is: .

[0027] In this embodiment, The preset fitting coefficients were obtained by performing least-squares fitting on a large amount of synchronous observation data of foggy, rainy, and mixed-phase weather conditions. The specific values ​​were [values ​​to be filled in]. Polynomial operations take dimensionless numerical values ​​as input and output the first dynamic transformation coefficient. Second dynamic conversion coefficient All are dimensionless numbers, representing the far-field corrected extinction coefficients within the far-field single-detection region. Dimensions are .

[0028] In this embodiment, step S6 includes the following specific steps: S61. Measured extinction coefficient of laser light within the near-field overlap region. Far-field corrected extinction coefficient within the far-field single detection area A weight gradient function based on the Sigmoid transition curve is constructed, and the expression of the weight gradient function is as follows: Where k is the smoothing coefficient, This represents the weight value at a detection distance r. S62. Based on the weighted gradient function, calculate the measured extinction coefficient of the laser within the near-field overlap region. Far-field corrected extinction coefficient within the far-field single detection area By performing a smooth stitching with gradually varying weights, a global continuous extinction coefficient covering the entire detection range is obtained. The expression for the global continuous extinction coefficient is: ; S63, the global continuous extinction coefficient Substituting Koschmieder's law, the global visibility distribution covering the entire detection range is obtained by inversion. .

[0029] In this embodiment, in the expression of the weight gradient function, k is a smoothing coefficient, denoted as . Global continuous extinction coefficient The dimensions are Visibility distribution across the entire region In the expression, 3.912 is a constant corresponding to the human eye contrast threshold of 0.02, and its effective range covers the entire field. .

[0030] The threshold can be set using the default settings according to the present invention, or it can be set by the operator.

[0031] Example 2: This example provides an electronic device, including a processor and a memory, wherein the memory stores a computer program that can be called by the processor; the processor executes the above-mentioned visibility inversion method based on the synergy of radar reflectivity and laser extinction by calling the computer program stored in the memory.

[0032] The electronic device can vary considerably depending on its configuration or performance. It may include one or more Central Processing Units (CPUs) and one or more memories, wherein the memory stores at least one computer program, which is loaded and executed by the processor to implement the visibility inversion method based on the synergy of radar reflectivity and laser extinction provided in the above-described embodiment. The electronic device may also include other components for implementing its functions; for example, it may have wired or wireless network interfaces and input / output interfaces for data input and output. Details will not be elaborated upon in this embodiment.

[0033] Those skilled in the art will recognize that this invention can be implemented as a system, method, or computer program product. Therefore, this invention can be implemented in the following forms: it can be entirely hardware, entirely software (including firmware, resident software, microcode, etc.), or a combination of hardware and software, generally referred to herein as a "circuit," "module," or "system." Furthermore, in some embodiments, this invention can also be implemented as a computer program product contained in one or more computer-readable media, which includes computer-readable program code.

[0034] Any combination of one or more computer-readable media may be used. A computer-readable medium can be a computer-readable signal medium or a computer-readable storage medium. A computer-readable storage medium can be, for example, but not limited to, an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples (a non-exhaustive list) of computer-readable storage media include: an electrical connection having one or more wires, a portable computer disk, a hard disk, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage device, magnetic storage device, or any suitable combination thereof. In this document, a computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0035] This invention is described with reference to flowchart illustrations and block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and block diagrams, as well as combinations of blocks in the flowchart illustrations and block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart. Figure 1 One or more processes and boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0036] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and boxes Figure 1 The steps of the function specified in one or more boxes.

[0037] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A visibility inversion method based on the synergy of radar reflectivity and laser extinction, characterized in that: The specific steps include the following: S1. Real-time acquisition of radar equivalent reflectivity factor through millimeter-wave radar, synchronous acquisition of laser echo reception power through laser cloud meter, and division of near-field overlap area and far-field single detection area according to detection distance. S2. Perform a three-dimensional Gaussian weighted average transformation on the radar equivalent reflectivity factor collected by the millimeter-wave radar to obtain the spatially matched radar reflectivity factor that is aligned with the laser cloud measuring instrument beam space. S3. Based on the laser echo received power collected by the laser cloud meter, the lidar equation is solved by the Klett inversion algorithm to obtain the measured extinction coefficient of the laser in the near-field overlapping region. S4. Extract the spatial matching radar reflectivity factor and the measured laser extinction coefficient in the near-field overlap region to obtain the global state variables characterizing the current distribution state of the gas cloud droplet spectrum. S5. The dynamic conversion coefficient of radar reflectivity-extinction coefficient is adaptively adjusted based on global state variables, and the radar equivalent reflectivity factor in the far-field single detection area is combined to calculate the far-field corrected extinction coefficient. S6. The measured extinction coefficient of the laser in the near-field overlapping area and the far-field corrected extinction coefficient in the far-field single detection area are smoothly spliced ​​together to obtain the global visibility distribution covering the entire detection range.

2. The visibility inversion method based on the synergy of radar reflectivity and laser extinction as described in claim 1, characterized in that: The specific content of S1 is: real-time acquisition of radar equivalent reflectivity factor through millimeter-wave radar. And the laser echo receiving power synchronously collected by the laser cloud measuring instrument The near-field overlap region and the far-field single detection region are divided according to the detection distance r, and the near-field boundary distance of the laser cloud meter is determined as follows: The range of the near-field overlap region is The range of the far-field single detection area is The radar equivalent reflectivity factor The effective range covers the entire area. The laser echo receiving power The effective range is the near-field overlap region. Indexed by time nodes.

3. The visibility inversion method based on the synergy of radar reflectivity and laser extinction as described in claim 2, characterized in that: S2 includes the following specific content: Based on the laser sampling volume of the laser cloud measuring instrument, a three-dimensional Gaussian weighted weight function is constructed to adjust the radar equivalent reflectivity factor. A three-dimensional Gaussian weighted average transformation is performed on adjacent detection range, azimuth, and elevation angle dimensions. The expression for the three-dimensional Gaussian weighting function is as follows: ;in, These are the detection distance, azimuth angle, and elevation angle at the center of the laser sampling volume, respectively. The Gaussian kernel standard deviations for detection range, azimuth, and elevation are respectively used. Based on the three-dimensional Gaussian weighted average transformation, a spatially matched radar reflectivity factor aligned with the laser beam space is output. .

4. The visibility inversion method based on the synergy of radar reflectivity and laser extinction as described in claim 3, characterized in that: S3 includes the following specific steps: S31. Extract the laser echo received power within the near-field overlap region. Construct the lidar equation: ;in, Where is the laser emission power, and C is the lidar system constant. The laser backscattering coefficient is... Let be the measured extinction coefficient of the laser light to be solved; S32. Solve the lidar equations using the Klett inversion algorithm, setting the power-law relationship between the measured laser extinction coefficient and the laser backscattering coefficient as follows: Where n is the power-law exponent and k is the proportionality coefficient, the measured extinction coefficient of the laser within the near-field overlap region is obtained by solving. .

5. The visibility inversion method based on the synergy of radar reflectivity and laser extinction as described in claim 4, characterized in that: S4 includes the following specific steps: S41. Extract the spatially matched radar reflectivity factor within the near-field overlap region. Extinction coefficient measured by laser After performing dimensionless processing, the radar reflectivity term is obtained. and extinction coefficient term ;in, This is a reference value for the radar reflectivity factor. This is a reference value for the measured extinction coefficient of the laser. S42. Along the detection distance r, calculate the logarithmic spatial gradients of the radar reflectivity term and the extinction coefficient term respectively, to obtain the radar reflectivity gradient sequence. With extinction coefficient gradient sequence The radar reflectivity gradient sequence and the extinction coefficient gradient sequence are combined by ratio to obtain a gradient ratio sequence. Median filtering is then applied to this gradient ratio sequence to obtain the global state variable characterizing the current distribution of air mass droplets within the near-field overlap region. ;in, This indicates a median filtering operation.

6. The visibility inversion method based on the synergy of radar reflectivity and laser extinction as described in claim 5, characterized in that: S5 includes the following specific steps: S51, Based on global state variables Establish a dynamic transformation function and calculate the first dynamic transformation coefficient at the current time. Second dynamic conversion coefficient ; ;in, These are the preset fitting coefficients; S52. Extract the radar equivalent reflectivity factor within the far-field single detection area. Combined with the first dynamic conversion coefficient Second dynamic conversion coefficient The far-field corrected extinction coefficient within the far-field single-detection region was calculated by constructing a far-field extinction mapping formula. The expression for the far-field extinction mapping formula is: .

7. The visibility inversion method based on the synergy of radar reflectivity and laser extinction as described in claim 6, characterized in that: S6 includes the following specific steps: S61. Measured extinction coefficient of laser light within the near-field overlap region. Far-field corrected extinction coefficient within the far-field single detection area A weight gradient function based on the Sigmoid transition curve is constructed, and the expression of the weight gradient function is as follows: Where k is the smoothing coefficient, This represents the weight value at a detection distance r. S62. Based on the weighted gradient function, calculate the measured extinction coefficient of the laser within the near-field overlap region. Far-field corrected extinction coefficient within the far-field single detection area By performing a smooth stitching with gradually varying weights, a global continuous extinction coefficient covering the entire detection range is obtained. The expression for the global continuous extinction coefficient is: ; S63, the global continuous extinction coefficient Substituting Koschmieder's law, the global visibility distribution covering the entire detection range is obtained by inversion. .

8. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the visibility inversion method based on the synergy of radar reflectivity and laser extinction as described in any one of claims 1-7.

9. An electronic device, characterized in that, Includes a memory for storing instructions; and a processor for executing the instructions, causing the device to perform the visibility inversion method based on the synergy of radar reflectivity and laser extinction as described in any one of claims 1 to 7.

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