Method and system for calculating millimeter wave radar air-ground demarcation line

Abstract

The present application relates to radar data processing technical field, disclose a kind of millimeter wave radar air-ground demarcation line calculation method and system, to obtain echo variation characteristics by the data analysis of a period of echo, calculate the boundary of ground object and air, to improve radar detection data quality, provide support for accurate early warning icing.Method includes the following steps: radar reflectivity measurement data collection;Reflectivity difference calculation;Reflectivity stability calculation;From bottom to top variation gradient calculation and ground object profile construction.The present application finds the maximum change by calculating the change of reflectivity under different visibility, judges the demarcation line of air and ground, can be used for the identification analysis of ground object and air interface of different regional terrain, and improves and makes up radar icing detection inversion performance.

Description

Technical Field

[0001] This invention relates to the field of radar data processing technology, and in particular to a method and system for calculating the air-to-ground boundary line of millimeter-wave radar. Background Technology

[0002] Radar, as an important means of wide-area ground monitoring, can be used for precise monitoring of the distribution of water particles during icing, providing a reliable means for power grids to carry out short-term early warning of line icing.

[0003] However, because icing power lines are often located in high-altitude micro-topographical areas with significant terrain undulations, radar detection is highly susceptible to interference from ground features, causing ground reflection signals to become mixed with freezing rain and fog detection signals, making them difficult to distinguish. Currently, meteorological and aviation departments are eliminating ground influences by deploying radar at high points, but detection of power lines often falls short of this requirement. Therefore, eliminating ground influences and improving data accuracy requires distinguishing the boundaries between ground features and the air. Summary of the Invention

[0004] The purpose of this invention is to disclose a method and system for calculating the air-to-ground boundary of millimeter-wave radar. By analyzing the echo data over a period of time, the method can obtain the echo change characteristics and calculate the boundary between ground objects and air, thereby providing support for improving the quality of radar detection data and accurately predicting icing.

[0005] To achieve the above objectives, the millimeter-wave radar air-to-ground boundary calculation method of the present invention includes:

[0006] (1) Collection of radar reflectivity measurement data

[0007] Select the transmission line towers prone to icing that need monitoring and install millimeter-wave radar detection devices at the corresponding locations. Set the radar detection scanning mode and begin a horizontal scan to obtain reflectivity data R in a fixed direction. Simultaneously, use a visibility meter to measure the horizontal visibility value in the surrounding area for a detection duration of T.

[0008] (2) Calculation of reflectivity difference

[0009] The visibility values ​​from step (1) are divided according to interval V, resulting in n categories of reflectance values. For each category, the average reflectance value is calculated, yielding n reflectance values ​​corresponding to different visibility levels. These n reflectance values ​​are then sorted from lowest to highest visibility level. The difference between adjacent reflectance values ​​is calculated to obtain a new difference sequence dRi, i = 1…n-1. For each dRi, its internal grid is recorded as dRi. sq The position of the grid is represented by s = 1…M, q = 1…N.

[0010] (3) Calculation of reflectivity stability

[0011] For the reflectance difference calculated in step (2), calculate the variance matrix for different visibility at the same location on the grid. For each grid point value SR in the matrix... sq The calculation formula is as follows:

[0012]

[0013]

[0014] (4) Calculation of bottom-up gradient

[0015] For the matrix SR calculated in step (3) sq Starting from each column, calculate the difference between adjacent grid points from bottom to top as the gradient change value, and obtain the gradient change matrix.

[0016] (5) Constructing the outline of ground features

[0017] Based on the gradient change matrix established in step (4), the point where the gradient change value is the largest in each column is selected as the boundary between the ground feature and the air. By connecting the positions of the maximum values ​​in each column in sequence, the outline of the ground feature boundary is obtained.

[0018] To achieve the above objectives, the present invention also discloses a millimeter-wave radar air-to-ground boundary calculation system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the above-described method when executing the computer program.

[0019] The present invention has the following beneficial effects:

[0020] 1. This invention calculates the change in reflectivity under different visibility conditions, finds the point of maximum change, and determines the boundary between air and ground.

[0021] 2. This invention has good versatility and can be used for the identification and analysis of ground features and air interfaces in different regions.

[0022] 3. By using the technology of this invention, ground feature boundaries can be quickly identified. In the detection process, ground feature boundaries are used to eliminate inaccurate parts in the measurement, thereby improving data quality and enhancing the performance of radar icing detection inversion.

[0023] The present invention will now be described in further detail with reference to the accompanying drawings. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0025] Figure 1 This is a schematic flowchart of the millimeter-wave radar air-to-ground boundary calculation method disclosed in an embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram illustrating the calculation of the same position of the grid in an embodiment of the present invention.

[0027] Figure 3 This is a schematic diagram of gradient change matrix calculation and maximum gradient connection according to an embodiment of the present invention. Detailed Implementation

[0028] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, but the present invention can be implemented in many different ways as defined and covered by the claims.

[0029] Example 1

[0030] This embodiment takes a 500kV line in Hunan Province as an example. Figure 1 As shown, the method for calculating the air-to-ground boundary line using millimeter-wave radar includes the following steps:

[0031] (1) Collection of radar reflectivity measurement data

[0032] Tower #1 of a 500kV power line in Hunan Province was selected as the detection point. A millimeter-wave radar detection device was set up. The radar detection scan was set to horizontal directional scanning to obtain reflectivity data R in a fixed direction. At the same time, a visibility meter was used to measure the horizontal visibility value in the surrounding area. The detection period was 5 days, and one set of data was obtained every hour, for a total of 120 sets of data.

[0033] (2) Calculation of reflectivity difference

[0034] The visibility values ​​from step (1) are divided into 20 categories at 50-meter intervals, corresponding to 20 different reflectance values. For each category, the average reflectance value is calculated, resulting in 20 reflectance values ​​corresponding to different visibility levels. These 20 reflectance values ​​are then sorted from lowest to highest visibility level. The difference between adjacent reflectance values ​​is calculated to obtain a new difference sequence dRi, i = 1…n-1. For each dRi, its internal grid is recorded as dRi. sq The position of the grid is represented by s = 1…20, q = 1…30.

[0035] (3) Calculation of reflectivity stability

[0036] For the reflectivity difference calculated in step (2), such as Figure 2 As shown, the variance matrix for the same location on the grid under different visibility conditions is calculated. For each grid point value SR in the matrix... sq The calculation formula is as follows:

[0037]

[0038]

[0039] (4) Calculation of bottom-up gradient

[0040] like Figure 3 As shown, for the matrix SR calculated in step (3) sq Starting from each column, calculate the difference between adjacent grid points from bottom to top as the gradient change value, and obtain the gradient change matrix.

[0041] (5) Constructing the outline of ground features

[0042] Based on the gradient change matrix established in step (4), the point where the gradient change value is the largest in each column is selected as the boundary between the ground feature and the air. By connecting the positions of the maximum values ​​in each column in sequence, the outline of the ground feature boundary is obtained.

[0043] Example 2

[0044] Corresponding to the above embodiments, this embodiment discloses a millimeter-wave radar air-to-ground boundary calculation system, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the following method:

[0045] (1) Collection of radar reflectivity measurement data

[0046] Select the transmission line towers prone to icing that need to be monitored, and set up millimeter-wave radar detection devices at the corresponding locations; set up the radar detection scanning mode to obtain reflectivity data R in a fixed direction through horizontal scanning; at the same time, use a visibility meter to measure the horizontal visibility value in the surrounding area, and the detection duration is T.

[0047] (2) Calculation of reflectivity difference

[0048] The visibility values ​​in step (1) are divided according to the interval V, and the corresponding reflectance values ​​are divided into n categories. For each category, the average reflectance value is calculated to obtain n reflectance values, corresponding to different visibility levels. The n reflectance values ​​are sorted according to the visibility from smallest to largest, and the difference between the corresponding reflectance values ​​of adjacent visibility levels is calculated to obtain a new difference sequence dRi, i = 1…n-1. For each dRi, the internal grid records it as dRi. sq The position of the grid is represented by s = 1…M, q = 1…N.

[0049] (3) Calculation of reflectivity stability

[0050] For the reflectance difference calculated in step (2), calculate the variance matrix for different visibility at the same location on the grid. For each grid point value SR in the matrix...sq The calculation formula is as follows:

[0051]

[0052]

[0053] (4) Calculation of bottom-up gradient

[0054] For the matrix SR calculated in step (3) sq Starting from each column, from bottom to top, calculate the difference between adjacent grid points as the gradient change value, and obtain the gradient change matrix.

[0055] (5) Constructing the outline of ground features

[0056] Based on the gradient change matrix established in step (4), select the maximum gradient change value in each column as the boundary between the ground feature and the air; then connect the positions of the maximum values ​​in each column in sequence to obtain the outline of the ground feature boundary.

[0057] Through the methods and systems disclosed in the above embodiments, the present invention has at least the following beneficial effects:

[0058] 1. This invention calculates the change in reflectivity under different visibility conditions, finds the point of maximum change, and determines the boundary between air and ground.

[0059] 2. This invention has good versatility and can be used for the identification and analysis of ground features and air interfaces in different regions.

[0060] 3. By using the technology of this invention, ground feature boundaries can be quickly identified. In the detection process, ground feature boundaries are used to eliminate inaccurate parts in the measurement, thereby improving data quality and enhancing the performance of radar icing detection inversion.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calculating the air-to-ground boundary line of millimeter-wave radar, characterized in that, include: (1) Collection of radar reflectivity measurement data Select the transmission line towers that are prone to icing that need to be monitored, and install millimeter-wave radar detection devices at the corresponding locations; The radar detection scanning mode is set up to obtain reflectivity data R in a fixed direction through horizontal scanning; at the same time, a visibility meter is used to measure the visibility value in the surrounding horizontal direction, and the detection duration is T. (2) Calculation of reflectivity difference The visibility values ​​in step (1) are divided according to the interval V. The corresponding reflectance values ​​are divided into n categories. For each category, the average reflectance value is calculated to obtain n reflectance values, which correspond to different visibility levels. Sort the n reflectance values ​​according to visibility from smallest to largest, calculate the difference between corresponding reflectance values ​​of adjacent visibility values, and obtain a new difference sequence dRi, i=1…n-1. For each dRi, the internal grid records it as dRi. sq sq represents the position of the grid, s=1…M, q=1…N; (3) Calculation of reflectivity stability For the reflectivity difference calculated in step (2), calculate the variance matrix for the same location on the grid with different visibility levels, and calculate the value of each grid point in the variance matrix. The calculation formula is as follows: (4) Calculation of the gradient from bottom to top For the variance matrix calculated in step (3), starting from each column, calculate the difference between adjacent grid points from bottom to top as the gradient change value, and obtain the gradient change matrix. (5) Constructing the outline of ground features Based on the gradient change matrix established in step (4), select the maximum gradient change value in each column as the boundary between the ground feature and the air; then connect the positions of the maximum values ​​in each column in sequence to obtain the outline of the ground feature boundary.

2. A millimeter-wave radar air-to-ground boundary calculation system, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method described in claim 1.

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