Airborne meteorological radar thunderstorm rapid identification method

Abstract

The invention provides an airborne meteorological radar thunderstorm rapid identification method, and belongs to the technical field of airborne meteorological radars, and the method specifically comprises the steps: carrying out the ground clutter suppression of the obtained airborne meteorological radar three-dimensional echo data; carrying out reflectivity factor calculation on each piece of wave position data in the stereoscopic scanning process to obtain three-dimensional echo reflectivity factor data of the airborne meteorological radar after ground clutter suppression; processing the three-dimensional echo reflectivity factor data after the ground clutter suppression to obtain reflectivity factor data of a two-dimensional plane; extracting a potential thunderstorm region from the reflectivity factor data of the two-dimensional plane; the data of each potential thunderstorm area are traced back to the three-dimensional reflectivity factor data, and the features of a thunderstorm body are counted; and judging the potential thunderstorm area and the counted thunderstorm body features according to the thunderstorm identification feature threshold. Through the processing scheme provided by the invention, the speed and accuracy of thunderstorm identification are improved, and the perception ability of a pilot to a dangerous meteorological area on a flight route is improved.

Description

Technical Field

[0001] The present application relates to the field of airborne weather radars, and in particular to a method for quickly identifying thunderstorms using airborne weather radars. Background Art

[0002] Aircraft are subject to a variety of weather threats during flight, among which thunderstorms are currently recognized by the world's aviation industry and meteorological departments as a serious threat to aviation flight safety, and are called "air killers" in the aviation industry. Thunderstorms can generate severe meteorological phenomena such as turbulence, wind shear, lightning, hail, etc. that threaten aviation safety, and they will go through different development stages over time, and the impact and threat level on aircraft flight will also vary. When an aircraft mistakenly enters a thunderstorm activity area, it may encounter dangers such as turbulence, ice accumulation, lightning strikes, hail strikes, etc., which may cause damage to people and aircraft at the least.

[0003] Early airborne weather radar products could only detect rainfall, reflectivity factor, turbulence and wind shear. The identification of dangerous weather such as thunderstorms required pilots to combine visual judgment with weather radar detection results, which was affected by human factors such as pilot experience.

[0004] There are several main methods for judging dangerous weather such as thunderstorms by using airborne meteorological radar: 1) Thunderstorms are identified from the perspective of image recognition based on the meteorological characteristics of thunderstorms, such as target intensity, distribution range and specific shape, based on the detection results of airborne meteorological radar; 2) Thunderstorms are identified based on echoes. The principle of thunderstorm identification is to regard "thunderstorms" as three-dimensional continuous areas with a certain volume whose reflectivity factor exceeds a certain threshold, such as classic thunderstorm identification algorithms such as TITAN, SCIT, and DBSCAN. The first method is simple to implement, but due to the limited image information detected by airborne meteorological radar, its thunderstorm identification accuracy is not as good as that based on data processing. The second method uses radar echoes to identify thunderstorms. Considering that the thunderstorm body is a three-dimensional continuous target that meets certain volume requirements, the identification algorithm is complex and the amount of calculation is large, which will be difficult to implement in engineering. Moreover, when identifying thunderstorms, the algorithm may cause inaccurate thunderstorm identification due to phenomena such as thunderstorm splitting and tilting. For example, one thunderstorm may be identified as multiple thunderstorm cells. When the thunderstorm has a large inclination, the thunderstorm may be considered as multiple thunderstorms or may not meet the volume requirements and be "missed", etc., which cannot meet the needs of airborne platforms for thunderstorm detection and identification. Summary of the invention

[0005] In view of this, the present application provides a method for rapid identification of thunderstorms by airborne weather radar, which solves the problems in the prior art, improves the speed and accuracy of thunderstorm identification, and enhances the pilot's ability to perceive dangerous weather areas on the flight route.

[0006] The present application provides a method for rapid identification of thunderstorms by airborne weather radar using the following technical solutions:

[0007] A method for rapid thunderstorm identification using airborne weather radar comprises the following steps:

[0008] Acquire three-dimensional echo data of airborne weather radar;

[0009] Perform ground clutter suppression on the three-dimensional echo data of airborne weather radar;

[0010] The reflectivity factor is calculated for each wave position data in the stereoscopic scanning process to obtain the three-dimensional echo reflectivity factor data of the airborne meteorological radar after ground clutter suppression;

[0011] Processing the three-dimensional echo reflectivity factor data after ground clutter suppression to obtain the reflectivity factor data of the two-dimensional plane;

[0012] Extract potential thunderstorm areas from reflectivity factor data on a two-dimensional plane;

[0013] The data of each potential thunderstorm area is traced back to the three-dimensional reflectivity factor data to statistically analyze the characteristics of the thunderstorm body;

[0014] The potential thunderstorm area and the statistical thunderstorm body characteristics are judged according to the thunderstorm identification characteristic threshold, the target that meets the thunderstorm identification characteristic threshold conditions is judged as a thunderstorm, and the judged thunderstorm area is warned.

[0015] Optionally, the method for processing the three-dimensional echo reflectivity factor data after ground clutter suppression includes:

[0016] Calculate the range gate position after the slant range is projected to the ground range based on the radar echo parameters;

[0017] Align the three-dimensional meteorological reflectivity factor data;

[0018] The different pitch scanning data at the same projection distance are fused to obtain the reflectivity data after the plane projection of the multi-layer meteorological data.

[0019] Optionally, methods for extracting potential thunderstorm areas from reflectivity factor data of a two-dimensional plane include:

[0020] Set the reflectivity threshold DBZ that reflects the characteristics of thunderstorm echoes threshold , the reflectivity factor data of the two-dimensional plane that is greater than or equal to the reflectivity threshold is set to 1, and the reflectivity factor data of the two-dimensional plane that is less than the reflectivity threshold is set to 0, to obtain the binary data distribution of the reflectivity factor data of the two-dimensional plane;

[0021] According to the distribution of binary data, the boundary of binary data is searched and the boundary of potential thunderstorm area is extracted, and then the extracted thunderstorm area is marked.

[0022] Optionally, the extracted potential thunderstorm areas are merged and deleted. If the correlation among several potential thunderstorm areas is higher than a first preset value, the corresponding potential thunderstorm areas are merged into one thunderstorm area. Otherwise, they are not merged. If the area of ​​the merged thunderstorm area is smaller than a second preset value, the corresponding thunderstorm area is deleted.

[0023] Optionally, the method for obtaining three-dimensional echo data of an airborne weather radar includes:

[0024] The airborne weather radar obtains three-dimensional echo data in the specified airspace in front of the carrier aircraft through stereo scanning. The obtained three-dimensional echo data includes meteorological data and ground clutter data;

[0025] The stereo scanning method is:

[0026] First fix the pitch angle to complete one azimuth scan line and then switch to the next pitch angle until the azimuth scan of all pitch angles is completed; or;

[0027] First fix the azimuth angle to complete one elevation scan line and then switch to the next azimuth angle until the elevation scan in all azimuth directions is completed; or;

[0028] Perform stereoscopic scanning of the specified airspace in a scanning and tracking manner.

[0029] Optionally, the thunderstorm body characteristics include thunderstorm volume, echo top height, bottom height, and cloud height.

[0030] In summary, this application includes the following beneficial technical effects:

[0031] The method of the present application is based on the target characteristics and distribution characteristics of thunderstorms. It uses stereo scanning to obtain three-dimensional echo data of meteorological targets such as thunderstorms, extracts the combined reflectivity factor of the three-dimensional echo data and performs binarization, identifies possible thunderstorm target areas and extracts relevant information, extracts features for each associated area, and considers those that exceed the threshold requirements as thunderstorms. This method does not require processing steps such as one-dimensional thunderstorm segment search, two-dimensional thunderstorm component synthesis, and three-dimensional thunderstorm body synthesis, and directly realizes the extraction and identification of thunderstorm areas based on three-dimensional echoes. This method is easy to implement, with a significantly lower amount of calculation, and can ensure better thunderstorm identification performance. It can greatly improve the pilot's perception of dangerous meteorological areas such as thunderstorms, help pilots assess the threat level of meteorological targets, improve flight safety, and improve flight efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 This is a flow chart of the method for rapid thunderstorm identification using airborne weather radar in this application. DETAILED DESCRIPTION

[0034] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0035] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0036] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0037] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0038] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0039] An embodiment of the present application provides a method for quickly identifying thunderstorms with an airborne weather radar.

[0040] like Figure 1 As shown, a method for rapid thunderstorm identification by airborne weather radar comprises the following steps:

[0041] Acquire three-dimensional echo data from airborne weather radar.

[0042] The three-dimensional echo data of the airborne weather radar is subjected to ground clutter suppression processing. In order to prevent the influence of ground clutter on thunderstorm identification, the data should be subjected to ground clutter suppression processing before thunderstorm identification, so that there is no ground clutter influence in the area where the thunderstorm identification is located. The selected ground clutter processing method is not limited in the process of the present invention, but the prerequisite is that the ground clutter suppression processing does not affect the weather echo.

[0043] The reflectivity factor is calculated for each wave position data in the stereo scanning process to obtain the three-dimensional echo reflectivity factor data S(n az ,n el ,n r ), where n az ,n el ,n r They represent azimuth scan count, elevation scan count, and range gate count respectively.

[0044] The three-dimensional echo reflectivity factor data after ground clutter suppression is processed to obtain the reflectivity factor data of the two-dimensional plane.

[0045] Extract potential thunderstorm areas from reflectivity factor data on a two-dimensional plane.

[0046] For the extracted potential thunderstorm areas, the data of each potential thunderstorm area are traced back to the three-dimensional reflectivity factor data to statistically analyze the characteristics of the thunderstorm body.

[0047] The potential thunderstorm area and the statistical thunderstorm body characteristics are judged according to the thunderstorm identification characteristic threshold, the target that meets the thunderstorm identification characteristic threshold conditions is judged as a thunderstorm, and the judged thunderstorm area is warned.

[0048] This application uses a planar projection method for three-dimensional volume scanning data to quickly and effectively extract the boundaries of potential thunderstorm areas, and on this basis extracts the characteristics of potential thunderstorm bodies to achieve identification of thunderstorm bodies. Compared with other thunderstorm identification algorithms, this algorithm does not need to perform one-dimensional thunderstorm component search, two-dimensional component synthesis, storm body synthesis, and consider the correlation between components caused by target characteristics, effectively simplifying the algorithm process and reducing the amount of calculation; at the same time, it can effectively improve the problem of target splitting and merging during thunderstorm identification, making thunderstorm identification results and dangerous areas more accurate and more in line with the use requirements of airborne platforms for thunderstorm identification functions.

[0049] Methods for obtaining three-dimensional echo data of airborne weather radar include:

[0050] The airborne weather radar obtains three-dimensional echo data in the specified airspace in front of the aircraft through stereo scanning. The acquired three-dimensional echo data includes meteorological data and ground clutter data. The stereo scanning should be able to cover the altitude range where most meteorological targets exist.

[0051] The stereo scanning method is: first fix the pitch angle to achieve one azimuth scanning line and then switch to the next pitch angle until the azimuth scanning of all pitch angles is completed.

[0052] The stereoscopic scanning method may be: firstly fix the azimuth angle to realize one elevation scanning line and then switch to the next azimuth angle until the elevation scanning in all azimuth directions is completed.

[0053] The stereoscopic scanning method may also be: stereoscopic scanning of a designated range of airspace is performed in a scanning and tracking manner.

[0054] The method for processing the three-dimensional echo reflectivity factor data after ground clutter suppression includes:

[0055] The range gate position after the slant range is projected to the ground is calculated based on the radar echo parameters; the range gate position after the slant range is projected to the ground is calculated based on the echo slant range and pitch angle. The range gate position R after the slant range is projected to the ground is calculated based on the radar echo slant range and pitch angle. groud =ceil(R(n r )×cos(El) / ΔR); where ceil(·) means rounding up, R(n r ) indicates the nth r The slant range corresponding to a range gate, El is the radar stability elevation angle, and ΔR is the range gate resolution unit.

[0056] Align the three-dimensional meteorological reflectivity factor data: S(n az ,n el ,R groud )=S(n az ,n el ,n r ).

[0057] The different pitch scanning data at the same projection distance are fused to obtain the reflectivity data of the plane projection of the multi-layer meteorological data. The fusion process adopts the large selection process, that is, the point with the strongest reflectivity of the different pitch layer data at the same projection distance is extracted as the processing result, S 1 (n az ,R groud )=max(S(n az ,:,R groud )), the distance projection calculation can also use other calculation methods and is not limited to the above calculation formula.

[0058] Fusion processing can also use other processing methods and is not limited to selecting the largest processing method.

[0059] Methods for extracting potential thunderstorm areas from reflectivity factor data of a two-dimensional plane include:

[0060] Set the reflectivity threshold DBZ that reflects the characteristics of thunderstorm echoes threshold , the reflectivity factor data of the two-dimensional plane greater than or equal to the reflectivity threshold is set to 1, and the reflectivity factor data of the two-dimensional plane less than the reflectivity threshold is set to 0, that is:

[0061]

[0062] The binary data distribution of the reflectivity factor data of the two-dimensional plane is obtained; in the thunderstorm processing process, a reflectivity threshold reflecting the characteristics of the thunderstorm echo is set, and only the echoes above the reflectivity threshold are processed and analyzed; at the same time, in the thunderstorm search stage, the size of the specific reflectivity value is not concerned.

[0063] According to the distribution of binary data, the boundary of binary data is searched and the boundary of potential thunderstorm area is extracted. Then the extracted thunderstorm area is marked and numbered, which is recorded as Info Storm {n cell}, indicating the nth cell Boundary information of potential thunderstorm areas, n cell is the number of the extracted potential thunderstorm area, Info Storm {n cell}.Az、Info Storm {n cell}.Edge represents the nth cell The azimuth and distance boundaries of each potential thunderstorm area are recorded. The boundary information of each potential thunderstorm area is recorded. The data of each potential thunderstorm area searched out belongs to the closed-loop state, and the subsequent data processing is also carried out on the basis of the closed-loop state; the subsequent thunderstorm identification will process the data of each thunderstorm body separately.

[0064] The extracted potential thunderstorm areas are merged and deleted. In the process of searching for potential thunderstorm areas, there may be some special cases that lead to incomplete data extraction. In this case, the intervals with strong correlation are merged after extraction. This process avoids the splitting of body targets during thunderstorm identification and can merge and display the same target as much as possible. Potential thunderstorm areas with smaller associated areas are deleted, and it is considered that the area of ​​the interval is small and not a thunderstorm body. This process can effectively avoid false alarms in small meteorological areas. The specific process of merging and deleting is that if the correlation of several potential thunderstorm areas is higher than the first preset value, the corresponding potential thunderstorm areas are merged into one thunderstorm area, otherwise they are not merged. If the area of ​​the merged thunderstorm area is smaller than the second preset value, the thunderstorm area is deleted.

[0065] The final thunderstorm area after merging and deletion is recorded as Info Storm_New {m cell}, where m cell is the number of potential thunderstorm areas in the current stereoscopic scanning line, satisfying m cell ≤n cell Info Storm_New {m cell}.Az、Info Storm_New {m cell}.Edge represents the mth cell Updated azimuth and range boundaries for potential thunderstorm areas.

[0066] The specific methods of feature extraction and thunderstorm identification are as follows:

[0067] For the extracted potential thunderstorm areas, the data of each potential thunderstorm area is traced back to the three-dimensional reflectivity data, and the characteristics of the thunderstorm body are counted. The characteristics of the thunderstorm body include thunderstorm volume, echo top height, bottom height and cloud height, which are used as thunderstorm identification features. cell potential thunderstorm area, extract the boundary area, and search vertically in the boundary area to obtain the characteristics of the thunderstorm area, such as the integrated volume, echo top height, bottom height, and cloud height;

[0068] The specific methods for thunderstorm identification and warning display are as follows:

[0069] According to the meteorological characteristics of thunderstorms, thunderstorm feature thresholds are set, such as thunderstorm volume threshold Vmax, echo top height threshold Htop, cloud height threshold Hmax, etc., as the basis for thunderstorm identification. This feature judgment can select one or multiple features at the same time; the potential thunderstorm area and its corresponding features are judged according to the thunderstorm identification feature threshold. If the thunderstorm identification feature threshold conditions are met, the target is considered to be a thunderstorm, and the area where the thunderstorm is identified is displayed with a specific icon for warning.

[0070] In view of the problems that the thunderstorm identification algorithm of existing airborne meteorological radar is complex and computationally intensive, and the thunderstorm identification performance is reduced due to phenomena such as thunderstorm target splitting and cloud body tilting during the identification process, this application proposes a method for rapid thunderstorm identification, which uses the three-dimensional scanning data of airborne meteorological radar, fully considers the spatial distribution characteristics of thunderstorms, and uses a combined reflectivity method to determine the strong echo area. On this basis, the three-dimensional data of the strong echo is associated and features are extracted to realize the identification of thunderstorms and the division of thunderstorm-affected areas. The method of the invention can improve the speed and accuracy of thunderstorm identification and improve the pilot's perception of dangerous meteorological areas on the flight route.

[0071] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for rapid thunderstorm identification using airborne weather radar, characterized in that: The steps include: Acquire three-dimensional echo data of airborne weather radar; Perform ground clutter suppression on the three-dimensional echo data of airborne weather radar; The reflectivity factor is calculated for each wave position data in the stereoscopic scanning process to obtain the three-dimensional echo reflectivity factor data of the airborne meteorological radar after ground clutter suppression; Processing the three-dimensional echo reflectivity factor data after ground clutter suppression to obtain the reflectivity factor data of the two-dimensional plane; Extract potential thunderstorm areas from reflectivity factor data on a two-dimensional plane; The data of each potential thunderstorm area is traced back to the three-dimensional reflectivity factor data to statistically analyze the characteristics of the thunderstorm body; The potential thunderstorm area and the statistical thunderstorm body characteristics are judged according to the thunderstorm identification characteristic threshold, the target that meets the thunderstorm identification characteristic threshold conditions is judged as a thunderstorm, and the judged thunderstorm area is warned.

2. The method for rapid thunderstorm identification by airborne weather radar according to claim 1, characterized in that: The method for processing the three-dimensional echo reflectivity factor data after ground clutter suppression includes: Calculate the range gate position after the slant range is projected to the ground range based on the radar echo parameters; Align the three-dimensional meteorological reflectivity factor data; The different pitch scanning data at the same projection distance are fused to obtain the reflectivity data after the plane projection of the multi-layer meteorological data.

3. The method for rapid thunderstorm identification by airborne weather radar according to claim 1, characterized in that: Methods for extracting potential thunderstorm areas from reflectivity factor data of a two-dimensional plane include: Set the reflectivity threshold DBZ that reflects the characteristics of thunderstorm echoes threshold , the reflectivity factor data of the two-dimensional plane that is greater than or equal to the reflectivity threshold is set to 1, and the reflectivity factor data of the two-dimensional plane that is less than the reflectivity threshold is set to 0, to obtain the binary data distribution of the reflectivity factor data of the two-dimensional plane; According to the distribution of binary data, the boundary of binary data is searched and the boundary of potential thunderstorm area is extracted, and then the extracted thunderstorm area is marked.

4. The method for rapid identification of thunderstorms by airborne weather radar according to claim 3, characterized in that: The extracted potential thunderstorm areas are merged and deleted. If the correlation of several potential thunderstorm areas is higher than a first preset value, the corresponding potential thunderstorm areas are merged into one thunderstorm area, otherwise they are not merged. If the area of ​​the merged thunderstorm area is smaller than a second preset value, the corresponding thunderstorm area is deleted.

5. The method for rapid thunderstorm identification by airborne weather radar according to claim 1, characterized in that: Methods for obtaining three-dimensional echo data of airborne weather radar include: The airborne weather radar obtains three-dimensional echo data in the specified airspace in front of the carrier aircraft through stereo scanning. The obtained three-dimensional echo data includes meteorological data and ground clutter data; The stereo scanning method is: First fix the pitch angle to complete one azimuth scan line and then switch to the next pitch angle until the azimuth scan of all pitch angles is completed; or; First fix the azimuth angle to complete one elevation scan line and then switch to the next azimuth angle until the elevation scan in all azimuth directions is completed; or; Perform stereoscopic scanning of the specified airspace in a scanning and tracking manner.

6. The method for rapid thunderstorm identification by airborne weather radar according to claim 1, characterized in that: The characteristics of a thunderstorm include thunderstorm volume, echo top height, echo bottom height, and cloud height.

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