A helical space array for underwater acoustic testing

Abstract

This invention discloses a helical spatial array for underwater acoustic testing, relating to the field of underwater acoustic testing. It includes a helical spatial array, surface buoys, a float, an underwater positioning beacon, and a gravity anchor. The helical spatial array is obtained by spatially twisting a single linear array to form a single helical array, with array elements arranged at equal intervals in the vertical direction; multiple single helical arrays are combined in the circumferential direction to form the helical spatial array. An underwater positioning beacon is connected to the top and bottom of the helical spatial array, respectively. The top is kept fixed in attitude by the float and surface buoy, and the bottom is kept fixed in attitude by the float and gravity anchor. Compared to conventional volumetric arrays, this invention has a lower sidelobe level, further improving the capabilities of underwater acoustic testing.

Description

Technical Field

[0001] This invention relates to the field of underwater acoustic testing, and in particular to a spiral spatial array for underwater acoustic testing. Background Technology

[0002] Compared to one-dimensional and two-dimensional arrays, cylindrical arrays have better spatial symmetry and a constant beamwidth in the circumferential direction, providing the same detection capability across a 360° horizontal range. Therefore, they are widely used in various shipborne sonar systems. However, the directivity function of a cylindrical array in the circumferential direction is a Bessel function, resulting in a high sidelobe level and insufficient anti-jamming capability. Summary of the Invention

[0003] To address the aforementioned problems and technical requirements, the inventors have proposed a helical spatial array for underwater acoustic testing. The technical solution of this invention is as follows:

[0004] A helical spatial array for underwater acoustic testing includes a helical spatial array and underwater positioning acoustic beacons connected to both sides of the spatial array, as well as a float and a surface buoy sequentially connected to one underwater positioning acoustic beacon, and a float and a gravity anchor sequentially connected to the other underwater positioning acoustic beacon, so that the helical spatial array is fixed in a vertical attitude underwater; the helical spatial array is a double cone array formed by combining N single helical arrays in the circumferential direction, and the two cones are centrally symmetrically distributed along the axis.

[0005] The further technical solution is that the single helical array is obtained by spatially twisting the single linear array around the axis and is centrally symmetrically distributed along the axis in the vertical direction. The single helical array has K circles, each circle is 2π, and the radius of the circle gradually shrinks to zero from the two ends of the helical array to the axis. Each helical array contains M array elements, which are arranged at equal intervals d in the vertical direction. The height of the single helical array is H=(M-1)·d.

[0006] A further technical solution involves using the height of a single helical array to obtain the coordinates of each element in the vertical direction within the helical spatial array as follows:

[0007] z i,j = (i-1)·dH / 2;

[0008] Where i represents the i-th planar circle in layer M, j represents the j-th spiral array in column N, and z i,j The range is between -H / 2 and H / 2.

[0009] A further technical solution involves using the radius and circumferential angle of the plane circle where each element of the single helical array is located to obtain the horizontal coordinates of each element of the single helical array; for each circle, obtaining the angle at which N equally spaced array elements uniformly divide the circle; rotating each element of any column of the single helical array around the axis at equal intervals with this angle, and combining the horizontal coordinates of the column of the single helical array to obtain the horizontal coordinates of each element of each column of the single helical array.

[0010] A further technical solution is that the radius of the plane circle containing each element of the single helical array is:

[0011] r i,1 =2Rz i,1 / H;

[0012] Where R represents the maximum radius of the circle;

[0013] The circumferential angles of each element in a single helical array are:

[0014]

[0015] A further technical solution is that the coordinates of each element of the single helical array in the horizontal direction are represented as follows:

[0016] x i,1 =r i,1 ·cosα i,1 ;

[0017] y i,1 =r i,1 ·sinα i,1 ;

[0018] Where, r i,1 Let α represent the planar circular radius of the i-th element in a single helical array. i,1 This represents the circumferential angle of the i-th element in a single helical array.

[0019] A further technical solution is that, for each circle, N equally spaced array elements uniformly divide the circle by an angle of:

[0020]

[0021] A further technical solution is that the coordinates of each element in each column of the single-spiral array in the horizontal direction are represented as follows:

[0022] x i,j =x i,1 ·cosβ j -y i,1 sinβ j ;

[0023] y i,j =xi,1 ·sinβ j +y i,1 cosβ j ;

[0024] Where, x i,1 y i,1 Let β represent the horizontal and vertical coordinates of the i-th element in the single-spiral array, respectively. j This indicates the angle at which an array element rotates around its axis to the next array element.

[0025] A further technical solution is that the beam response of the helical spatial array is expressed as:

[0026]

[0027] in, The observation directions are represented by the horizontal angle θ0 and the pitch angle. The array manifold vector at time, w H This represents the array weighting vector under different scanning angles;

[0028] Let θ0 = 0, The beam response is normalized and then logarithmically represented to indicate the spatial directivity of the array. A horizontal directivity slice is taken to observe the height of the horizontal array directivity sidelobes. The spatial directivity expression is:

[0029]

[0030] A further technical solution is that each array element represents a hydrophone.

[0031] The beneficial technical effects of this invention are:

[0032] This application obtains a helical array by spatially twisting a linear array, and then further combines them to form a helical spatial array. It makes full use of the sparse characteristics of the spatial distribution of this array, and each array element is set according to regulations to avoid repeated spatial sampling, which can effectively suppress the aliasing effect and significantly reduce the height of the array's directional sidelobes. Compared with cylindrical arrays and biconical arrays, it has a lower sidelobe level, stronger anti-interference ability, and can further improve the underwater acoustic testing capabilities. Attached Figure Description

[0033] Figure 1 The spiral space array model provided in this application.

[0034] Figure 2 A schematic diagram of a single spiral array after spatial twisting, provided for this application.

[0035] Figure 3 (a) is a three-dimensional diagram of the spatial scale and element distribution of the spiral spatial array provided in this application.

[0036] Figure 3 (b) is a left view of the spatial scale and element distribution of the spiral spatial array provided in this application.

[0037] Figure 3 (c) is a top view of the spatial scale and element distribution of the spiral spatial array provided in this application.

[0038] Figure 4 (a) is a three-dimensional diagram of the spatial scale and element distribution of the cylindrical array.

[0039] Figure 4 (b) is a three-dimensional diagram of the spatial scale and element distribution of the biconical array.

[0040] Figure 5 (a) Spatial directivity diagram of the spiral space array provided in this application at a frequency of 1000 Hz.

[0041] Figure 5 (b) is the spatial directivity diagram of the cylindrical array at a frequency of 1000 Hz.

[0042] Figure 5 (c) is the spatial directivity diagram of the biconical array at a frequency of 1000 Hz.

[0043] Figure 6 The horizontal directional slices of the spiral space array, cylindrical array, and biconical array at a frequency of 1000 Hz are provided.

[0044] Among them: 1-Surface buoy; 2-Floating body; 3-Underwater positioning acoustic beacon; 4-Helical spatial array; 5-Underwater positioning acoustic beacon; 6-Floating body; 7-Gravity anchor. Detailed Implementation

[0045] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0046] like Figure 1 As shown, this application provides a helical spatial array for underwater acoustic testing, including a helical spatial array 4 and underwater positioning acoustic beacons 3 and 5 connected to both sides of the spatial array, as well as a float 2 and a surface buoy 1 sequentially connected to one underwater positioning acoustic beacon 3, and a float 6 and a gravity anchor 7 sequentially connected to the other underwater positioning acoustic beacon 5, so that the helical spatial array 4 is fixed in a vertical attitude underwater. The helical spatial array 4 is a biconical array formed by N single helical arrays arranged at equal intervals in the circumferential direction, and the two cones are centrally symmetrically distributed along the axis O.

[0047] like Figure 2As shown, a single helical array is obtained by spatially twisting a single linear array (i.e., a linear array) around an axis O, and is centrally symmetrically distributed along the axis O in the vertical direction (i.e., the z-direction). The example in the figure shows a single helical array with 4 circles, each circle being 2π, and the radius of the circles gradually shrinks from the ends of the helical array to zero from the axis O. Each helical array contains M array elements (i.e., black dots in the figure represent one array element), arranged at equal intervals d in the vertical direction. The height of a single helical array is H = (M-1)·d, and the helical spatial array has M layers and N columns. Optionally, each array element represents a hydrophone.

[0048] To construct an array with a spatially sparse structure, this application provides design requirements for the coordinate positions of each array element:

[0049] The coordinates of each element of a single helical array in the vertical direction can be obtained using the height of the helical array as follows:

[0050] z i,1 = (i-1)·dH / 2 (1)

[0051] Where i represents the i-th planar circle in layer M, 1 represents the first spiral array in column N, and z i,1 The range is between -H / 2 and H / 2.

[0052] After the linear array is twisted, the radius of the plane circle containing each element of the single spiral linear array is:

[0053] r i,1 =2Rz i,1 / H (2)

[0054] The circumferential angles of each element in a single helical array are:

[0055]

[0056] Using the circumference radius and circumferential angle of the plane containing each element of the single helix array, the coordinates of each element in the horizontal direction can be obtained as follows:

[0057] x i,1 =r i,1 ·cosα i,1 (4)

[0058] y i,1 =r i,1 ·sinα i,1 (5)

[0059] Where, r i,1 Let α represent the planar circular radius of the i-th element in a single helical array. i,1 This represents the circumferential angle of the i-th element in a single helical array.

[0060] For ease of explanation, a helical space array can also be understood as rotating a single helical array in a circular direction to obtain a helical space array composed of N single helical arrays, that is, the helical space array has M layers and N columns.

[0061] For each circle of the spiral space array, the angle at which N equally spaced array elements uniformly divide the circle is:

[0062]

[0063] Where j represents the j-th spiral array in N columns.

[0064] In this example, the first column (strip) of the single spiral array is selected, and its elements are arranged around the axis at an angle β. j By performing equal-interval rotations and combining the horizontal coordinates of the single-spiral array, the horizontal coordinates of each element in each column of the single-spiral array are represented as follows:

[0065] x i,j =x i,1 ·cosβ j -y i,1 sinβ j (7)

[0066] y i,j =x i,1 ·sinβ j +y i,1 cosβ j (8)

[0067] Where, x i,1 y i,1 Let β represent the horizontal and vertical coordinates of the i-th element in the single-spiral array, respectively. j This indicates the angle at which an array element rotates around its axis to the next array element.

[0068] Since the z-coordinates of each element in the spiral space array are the same, the z-coordinates of each element in the spiral space array are:

[0069] z i,j = (i-1)·dH / 2 (9)

[0070] In this embodiment, the sparse characteristics of the spatial distribution of the spiral space array are fully utilized, and each array element is set according to regulations to avoid repeated spatial sampling, which can effectively suppress the aliasing effect and significantly reduce the height of the array's directional sidelobes.

[0071] To demonstrate that the sidelobe level of the spiral spatial array designed in this application is lower than that of existing spatial arrays, the beam response of the spiral spatial array is expressed as follows:

[0072]

[0073] in, The observation directions are represented by the horizontal angle θ0 and the pitch angle. The array manifold vector at time, w H This represents the array weighting vector under different scanning angles.

[0074] Let θ0 = 0, The beam response is normalized and then logarithmically represented to indicate the spatial directivity of the array. A horizontal directivity slice is taken to observe the height of the horizontal array directivity sidelobes. The spatial directivity expression is:

[0075]

[0076] The effectiveness of the present invention will be analyzed below with reference to simulation examples.

[0077] According to the specific implementation method described above, a spiral spatial array with radius R = 2.5m, number of layers M = 21, number of columns N = 16, number of torsion circles K = 2, vertical spacing d = 0.5m, and height H = 10m is constructed. The three-view diagram of its scale and element distribution is shown below. Figure 3 (a) Figure 3 (b) Figure 3 As shown in (c), the element distribution and spatial scale of cylindrical and biconical arrays with the same spatial scale and number of elements are illustrated in the figure. Figure 4 (a) and Figure 4 As shown in (b). At the analysis frequency of 1000Hz, the spatial directivity diagram of the spiral spatial array is as follows. Figure 5 As shown in (a), the spatial orientation diagram of the cylindrical array is as follows: Figure 5 As shown in (b), the spatial orientation diagram of the biconical array is as follows: Figure 5 As shown in (c), horizontal directional slices at a frequency of 1000Hz are selected from their respective spatial directional maps, as follows. Figure 6 As shown, compared to cylindrical arrays and biconical arrays, the spiral space array has the lowest and flattest side lobes in the horizontal direction, possessing stronger anti-interference capabilities and further improving the ability to conduct underwater acoustic tests.

[0078] The above descriptions are merely preferred embodiments of this application, and the present invention is not limited to the above embodiments. It is understood that other improvements and variations directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included within the protection scope of the present invention.

Claims

1. A spiral spatial array for underwater acoustic testing, characterized in that, The application relates to a spiral space array, underwater positioning acoustic beacons connected to both sides of the space array, a floating body and a water surface buoy connected to one underwater positioning acoustic beacon in sequence, a floating body and a gravity anchor connected to another underwater positioning acoustic beacon in sequence, and a vertical posture of the spiral space array is fixed underwater; the spiral space array is composed of N The spiral space array is composed of a plurality of spiral arrays which are arranged in a circumferential direction to form a double-cone array, and the two cones are centrally symmetrically distributed along the axis. The single helical array is obtained by spatially twisting a single linear array around an axis, and is centrally symmetrically distributed along the axis in the vertical direction. The single helical array has... K Each helix has a radius of 2π, and the radius of each helix gradually shrinks to zero from both ends of the helix to the axis; each helix contains M Each array element is spaced at intervals in the vertical direction. d Arranged at equal intervals; Using the radius and circumferential angle of the circular plane containing each element of the single helix array, the horizontal coordinates of each element are obtained; for each circle, the coordinates of each element in the single helix array are obtained. N The circle is evenly divided by an angle by an equally spaced array element; each element of any column of single spiral array is rotated around the axis at equal intervals at this angle, and the coordinates of each element of each column of single spiral array in the horizontal direction are obtained by combining the coordinates of the column of single spiral array in the horizontal direction.

2. The helical spatial array for underwater acoustic testing according to claim 1, characterized in that, The coordinates of each element in the vertical direction of the spiral space array are obtained using the height of a single spiral array as follows: ； in, i express M The first in the layer i Circumference of the layer plane j express N The first in the column j A spiral array, z i,j The range is in - H / 2~ H Between / 2, The height of the single helical array is given.

3. The helical spatial array for underwater acoustic testing according to claim 1, characterized in that, The radius of the circular circumference of the plane containing each element of the single spiral array is: ； in, R Indicates the maximum radius of the circle; The circumferential angle of each element of the single spiral array is: 。 4. The helical spatial array for underwater acoustic testing according to claim 1, characterized in that, The coordinates of each element of the single helical array in the horizontal direction are represented as follows: ； ； in, r i,1 In a single spiral array, the first... i The planar circular radius of the layer array element, α i,1 In a single spiral array, the first... i The circumferential angle of the layer array element.

5. The helical spatial array for underwater acoustic testing according to claim 1, characterized in that, For each circumference N The angle by which the equally spaced array elements uniformly divide the circumference is: 。 6. The helical spatial array for underwater acoustic testing according to claim 1, characterized in that, The coordinates of each element in the single-spiral array in the horizontal direction are represented as follows: ； ； in, x i,1 , y i,1 They represent the first and second helical arrays respectively. i The horizontal and vertical coordinates of the layer array elements. β j This indicates the angle at which an array element rotates around its axis to the next array element.

7. The helical spatial array for underwater acoustic testing according to any one of claims 1-6, characterized in that, The beam response of a helical spatial array is expressed as: ； in, Indicates the observation direction as a horizontal angle. and pitch angle The array manifold vector at that time, This represents the array weighting vector under different scanning angles; make The beam response is normalized and then logarithmically represented to indicate the spatial directivity of the array. A horizontal directivity slice is taken to observe the height of the horizontal array directivity sidelobes. The spatial directivity expression is: 。 8. The helical spatial array for underwater acoustic testing according to any one of claims 1-6, characterized in that, Each array element represents a hydrophone.

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