Lightning very high frequency interferometric positioning method based on irregular array

Abstract

The application discloses a lightning VHF interference positioning method based on an irregular array, relates to the lightning positioning field, and comprises the following steps: S1, acquiring the antenna positions of N station interferometers and calculating the time difference τ of a radiation source reaching all baselines ij ; S2, judging whether all the antennas are on the same plane, if yes, entering S3, otherwise, entering S4; S3, calculating the positioning direction of the radiation source by using M groups of baselines and entering S6; S4, combining any three stations to form a selection; S5, calculating the direction of the radiation source under each selection and determining the positioning direction of the radiation source; S6, calculating the elevation angle and the azimuth angle of the radiation source according to the positioning direction of the radiation source; when the interference positioning is performed, the non-coplanar characteristics of the antenna array and the increase of the number of antennas can obviously improve the positioning result of the interferometer, and the method can be applied to any irregular array, that is, the antenna array can be randomly arranged, the coplanar of the antenna array is not required, and the baselines formed by the antenna array are not required to be orthogonal to each other, so that the installation difficulty of the antenna is effectively reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of lightning positioning, in particular to a lightning VHF interferometry positioning method based on irregular array. BACKGROUND

[0002] Lightning discharge produces abundant VHF radiation, and the cloud is almost transparent to these radiations. By detecting and positioning these radiations, the dynamic characteristics of lightning channel development and propagation in thunderstorm clouds can be revealed. The most widely used method at present is to erect at least three antennas with a distance (baseline) of several meters to tens of meters between adjacent antennas, which is called VHF short baseline lightning interferometer. These antennas are all distributed on the same horizontal plane, and the array structure is isosceles right triangle or cross type, which can form two mutually orthogonal baselines. Assuming that the radiation source produced by lightning several kilometers away is parallel incident to each station, the direction of arrival of the radiation can be calculated by calculating the time difference of the radiation source reaching each station. The current algorithm is also based on the premise of the same horizontal plane array and orthogonal baseline. For example , Shao et al. (2020) used three antennas to form an isosceles right triangle, Sun et al. (2014) used four antennas to form a square, and seven antennas to form an L-shaped.

[0003] Therefore, the traditional algorithm requires that during the actual site arrangement process, each station must be strictly located on the same horizontal plane and orthogonal to each other, which is very inconvenient. SUMMARY

[0004] The purpose of the present application is to design a lightning VHF interferometry positioning method based on irregular array to solve the above problems.

[0005] The present application realizes the above-mentioned purpose through the following technical solutions:

[0006] The lightning VHF interferometry positioning method based on irregular array comprises:

[0007] S1, obtaining the antenna positions of N station interferometers and calculating the time difference τ of the radiation source reaching all baselines ij , wherein i and j are stations;

[0008] S2, judging whether all antennas are on the same plane, if yes, entering S3, otherwise entering S4;

[0009] S3, using baseline to calculate the direction of the radiation source positioning and entering S6;

[0010] S4, combining any three stations to form selection;

[0011] S5, calculate the direction of the radiation source under each selection, and determine the positioning direction of the radiation source;

[0012] S6, calculate the elevation angle and azimuth angle of the radiation source according to the positioning direction of the radiation source.

[0013] The present application has the beneficial effect that when the interference positioning is performed, the non-coplanar characteristics of the antenna array and the increase of the number of antennas can obviously improve the positioning result of the interferometer, and the method can be applied to any irregular array, that is, the antenna array can be randomly arranged, and the coplanar of the antenna array is not required, and the formed baselines are not required to be orthogonal to each other, and the installation difficulty of the antenna is effectively reduced. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a flowchart of the lightning VHF interference positioning method based on the irregular array of the present application. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical scheme and advantages of the embodiments of the present application more clear, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. The components of the embodiments of the present application described and shown in the drawings can be arranged and designed in various different configurations.

[0016] Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0017] It should be noted that similar reference numerals and letters indicate similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0018] In the description of the present application, it should be understood that the terms "upper", "lower", "inner", "outer", "left", "right", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly placed when the product of the present application is used, or the orientation or positional relationship commonly understood by those skilled in the art, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0019] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0020] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0021] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0022] Establish a coordinate system with the center of the interferometer as the origin, with east and north as the x-axis and y-axis respectively, and upward as the z-axis. Let the unit direction vector of the radiation source be (cosα, cosβ, cosγ), where cosα, cosβ, and cosγ are the angles between the radiation source direction and the positive directions of the x-axis, y-axis, and z-axis, respectively.

[0023] Therefore, there is cos 2 α+cos 2 β+cos 2 γ=1, and: .

[0024] like Figure 1 As shown, the lightning VHF interferometric localization method based on irregular arrays includes:

[0025] S1. Obtain the antenna positions of the interferometers at N sites and calculate the time difference τ between the radiation sources and all baselines. ij , where i and j are the stations.

[0026] S2. Determine if all antennas are on the same plane. If yes, proceed to S3; otherwise, proceed to S4. Specifically:

[0027] The antenna is located at (x i ,y i ,z i ), where i=1,2,…,N, the positions of N antenna stations form a matrix X, and the dimension of X is . Calculate the rank of the position matrix X, which has 3 rows and 3 columns, and express it as follows: When the rank of the position matrix X is greater than 2, all antennas are not on the same plane and enter S4; otherwise, all antennas are on the same plane and enter S3.

[0028] S3, Adopt The group baseline calculates the orientation of the radiation source, and enters S6, and the orientation of the radiation source is represented as , , the number of rows of X is , that is, the number of all baseline combinations of N groups of antennas , wherein each row represents the direction of a baseline participating in calculation (the connection line of station i and station j), τ ij is the time difference of the radiation source reaching the baseline group.

[0029] S4, any three stations are combined to form selections.

[0030] S5, calculate the orientation of the radiation source under each selection, and determine the orientation of the radiation source; specifically comprising:

[0031] S51, calculate the normal vector (m, n, 1) of the plane where the three antennas in the selection are located, and convert it into a unit normal vector (a, b, c), , ;

[0032] S52, rotate the antennas counterclockwise along the y-axis by θ degrees, and rotate the antennas counterclockwise along the x-axis by ψ degrees, until the antennas are parallel to the horizontal plane of the earth, and determine the coordinates of the antennas after rotation, , , the coordinates of the antennas after rotation are ;

[0033] S53, calculate the position of the radiation source under the selection in the rotated coordinate system, and the position of the radiation source is represented as , , ;

[0034] S54, convert the position of the radiation source to the horizontal plane coordinate system of the earth to obtain the orientation of the radiation source, and the orientation of the radiation source is represented as ;

[0035] S55, average the orientations of the radiation source calculated from selections to obtain the orientation of the radiation source.

[0036] S6, calculate the elevation angle and azimuth angle of the radiation source according to the orientation of the radiation source, and the elevation angle EL is represented as , and the azimuth angle AZ is represented as , wherein .

[0037] The detection of the non-coplanar array has more advantages than the traditional coplanar array and orthogonal baseline array. The method proposed in the patent can fully utilize all the information of the antenna array, which is not only beneficial to the early installation of the equipment, but also can effectively improve the detection precision.

[0038] The technical solution of the present application is not limited to the above specific embodiments, and any technical variation made according to the technical solution of the present application falls within the protection scope of the present application.

Claims

1. A lightning VHF interferometric localization method based on irregular arrays, characterized in that, include: S1. Obtain the antenna positions of the interferometers at N sites and calculate the time difference τ between the radiation sources and all baselines. ij Where i and j are stations; S2. Determine if all antennas are on the same plane. If yes, proceed to S3; otherwise, proceed to S4. S3, Adopt The baseline calculation determines the location and direction of the radiation source, and then proceeds to S6; S4, combine any 3 stations to form a choice; S5. Calculate the direction of arrival of the radiation source for each option, and determine the location of the radiation source; specifically including: S51. Calculate the normal vector (m,n,1) of the plane containing the three selected antennas, and convert it into a unit normal vector (a,b,c). S52. Rotate the antenna until it is parallel to the horizontal plane of the ground, and determine the coordinates of the antenna after rotation; when rotating the antenna, rotate it counterclockwise by an angle θ along the y-axis and counterclockwise by an angle ψ along the x-axis. , The coordinates of the antenna after rotation are ; S53. Calculate the position of the radiation source under this selection from the perspective of the rotated coordinate system; the position of the radiation source after rotation is... , , ; S54. The direction of radiation source can be obtained by transforming its location to the horizontal coordinate system of the Earth; the direction of radiation source is represented as... ; S55, according to The direction of radiation source is calculated using a selection method to determine its location; specifically: ... The location of the radiation source can be obtained by averaging the calculated directions of the radiation source. S6. Calculate the elevation and azimuth angles of the radiation source based on its location; the elevation angle EL and azimuth angle AZ of the radiation source are respectively expressed as... , ,in .

2. The lightning VHF interferometric localization method based on an irregular array according to claim 1, characterized in that, In S2, the antenna is located at (x i ,y i ,z i ), where i=1,2,…,N, the positions of N antenna stations form a matrix X, and the dimension of X is . Calculate the rank of the position matrix X, which has 3 rows and 3 columns, and express it as follows: When the rank of the position matrix X is greater than 2, all antennas are not on the same plane and enter S4; otherwise, all antennas are on the same plane and enter S3.

3. The lightning VHF interferometric localization method based on an irregular array according to claim 1, characterized in that, In S3, the location of the radiation source is represented as follows: , The number of rows for X is That is, the total number of baseline combinations formed by N antennas. Each row represents a baseline direction involved in the calculation, τ ij It is the time difference between the arrival of the radiation source at this set of baselines.

Images