Passive Sonar Target Resolution Parameter-Level Simulation Method

Abstract

The present invention provides a method for passive sonar target resolution parameter-level simulation, which includes the following steps: selecting a first target and a second target from a target group; when the passive sonar can resolve the first target and the second target, dividing the target group into two new target groups; when the passive sonar cannot resolve the first target and the second target, merging the first target and the second target into one target to obtain a new target group; repeating the above steps for the new target group until the number of targets in the new target group is one. According to the principle of passive sonar target resolution, the present invention determines the target resolution result of the passive sonar based on the target azimuth and the intensity of the target beam output, and can effectively improve the credibility of the passive sonar target resolution parameter-level simulation.

Description

Technical Field

[0001] The present invention relates to the technical field of underwater detection, and particularly to a parametric simulation method for passive sonar target resolution. Background Art

[0002] Underwater detection usually uses sonar as the main detection means. In the simulation of parametric underwater passive detection, parameters such as target azimuth and target noise intensity are usually used as input information, and relevant information of the detected target is output. When there are multiple targets, it is necessary to simulate the passive sonar target resolution ability to judge the number and azimuth information of the detected targets.

[0003] Currently, the commonly used parametric simulation method for passive sonar target resolution is based on the target resolution ability index of the passive sonar. When the azimuth difference between two targets is greater than this index, it is considered that the two targets can be resolved; when the azimuth difference between two targets is less than this index, it is considered that the two targets cannot be resolved. This simulation method fails to reflect the principle of passive sonar target resolution and has low simulation credibility. Summary of the Invention

[0004] To solve the above problems, the present invention provides a parametric simulation method for passive sonar target resolution, including the following steps:

[0005] Select a first target and a second target from the target group;

[0006] When the passive sonar can resolve the first target and the second target, divide the target group into two new target groups;

[0007] When the passive sonar cannot resolve the first target and the second target, merge the first target and the second target into one target to obtain a new target group;

[0008] Repeat the above steps for the new target group until the number of targets in the new target group is one.

[0009] Further, the first target is the one with the strongest beam output in the target group, and the second target is the one with the strongest beam output among the targets adjacent to the target with the strongest beam output.

[0010] Further, judging whether the passive sonar can resolve the first target and the second target includes the following steps:

[0011] When the azimuth difference between the first target and the second target is less than the resolution ability of the passive sonar, it is determined that the first target and the second target cannot be resolved;

[0012] When the azimuth difference between the first target and the second target is greater than or equal to the resolution ability of the passive sonar, it is determined that the first target and the second target can be resolved.

[0013] Further, determining whether the passive sonar can distinguish the first target and the second target further includes the following steps:

[0014] When the azimuth difference between the first target and the second target is greater than or equal to the resolution ability of the passive sonar, perform a second-order fitting on the beam outputs of the first target and the second target, and calculate the intersection coordinates of the beam outputs of the first target and the second target;

[0015] When the azimuth difference between the second target and the intersection coordinates is less than half of the target resolution ability of the passive sonar, it is determined that the first target and the second target cannot be distinguished;

[0016] When the azimuth difference between the second target and the intersection coordinates is greater than or equal to half of the target resolution ability of the passive sonar, it is determined that the first target and the second target can be distinguished.

[0017] Further, the calculation method of the intersection coordinate X of the beam outputs of the first target and the second target is as follows:

[0018]

[0019] where α i is the azimuth of the first target, and A i is the beam output of the first target; α i±1 is the azimuth of the second target, and A i±1 is the beam output of the second target; where θ and D are constants of the passive sonar (specifically related to the detection ability of the passive sonar).

[0020] Further, it further includes the following steps:

[0021] Arrange all the targets in the target group in ascending order of target azimuth to obtain digital numbers.

[0022] Further, divide the target group into two new target groups - the first new target group and the second new target group. The first new target group includes i targets, and the second target group includes (N - i) targets;

[0023] where N is the total number of targets in the target group, and i is the digital number corresponding to the first target.

[0024] Further, the azimuth and beam output of the merged target m of the first target and the second target are respectively:

[0025]

[0026]

[0027] The beneficial effects of the present invention are as follows: The passive sonar target resolution parameter-level simulation method provided by the present invention determines the passive sonar target resolution result based on the target azimuth and the intensity of the target beam output according to the principle of passive sonar target resolution, which can effectively improve the credibility of the passive sonar target resolution parameter-level simulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 . Schematic diagram of passive sonar target resolution ability

[0029] Figure 2 . Schematic flow diagram of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] The present invention will be further described below with reference to the drawings and embodiments. The following embodiments are only used to explain the content of the present invention and are not used to limit the protection scope of the present invention.

[0031] The principle of passive sonar target resolution is to detect the output formed by two target beams. When the difference between the peak value and the valley value reaches a certain value, the passive sonar can distinguish two targets.

[0032] Refer to Figure 1 , define the resolution ability of a passive sonar for two targets with equal intensity as θ, and its meaning is: when the azimuth difference between two targets with equal intensity is θ, the intersection value of their beam outputs differs from the highest value by D (the value of D is related to the detection ability of this sonar, usually taking the value of 3), and at this time the passive sonar can just distinguish two targets. Based on this, θ and D can be obtained, which is convenient for the following calculations.

[0033] Combined with Figure 2 , the present invention proposes a passive sonar target resolution parameter-level simulation method, and the specific resolution process is as follows:

[0034] (1) Assume that there is a target group containing N targets, and the target azimuth and beam output are respectively (α1, A1), (α2, A2),..., (α N , A N ), and satisfy α1 < α2 <... < α N ;

[0035] (2) Select the maximum value A N of A1, A2,..., A i (i ∈ [1, N]), that is, obtain the first target i;

[0036] (3) Compare A i-1 with A i+1 , if A i-1 < A i+1, then distinguish between target i and target i + 1, that is, obtain the second target i + 1; if A i-1 > A i+1 , then distinguish between target i - 1 and target i, that is, obtain the second target i - 1;

[0037] The following takes the case when A i-1 < A i+1 as an example (that is, the second target is i + 1),

[0038] (4) If α i+1 - α i < θ, it is considered that the two targets cannot be distinguished, and go to step (8);

[0039] (5) If α i+1 - α i ≥ θ, by performing a quadratic fit on the beam output, the intersection coordinates of the two target beam outputs are calculated as:

[0040]

[0041] (6) Calculate the difference between the smaller target (i.e., target i + 1) in the two target beam outputs and the intersection coordinates:

[0042] F = |α i+1 - X|

[0043] (7) If it is considered that the two targets cannot be distinguished, and go to step (8); if it is considered that the two targets can be distinguished, and go to step (9);

[0044] (8) If the two targets cannot be distinguished, then merge target i and target i + 1 into 1 target m. The azimuth and beam output of target m are respectively:

[0045]

[0046]

[0047] The original target group reduces by 1 target and becomes N - 1 targets. The target azimuths and beam outputs are respectively (α1, A1), (α2, A2), ……, (α i-1 , A i-1 ), (α m , A m ), (α i+2 , A i+2 ), ……, (α N , A N );

[0048] (9) If two targets can be distinguished, the original target group is divided into two target groups, namely Target Group 1 (including i targets, namely (α1, A1), (α2, A2), ……, (α i , A i )) and Target Group 2 (including N - i targets, namely (α i+1 , A i+1 ), (α i+2 , A i+2 ), ……, (α N , A N ));

[0049] (10) Repeat steps (1) to (9) for each target group until there is only one target in each target group.

[0050] At this time, all target groups are the results of passive sonar target discrimination.

[0051] For the target discrimination of multiple targets, the present invention preferentially starts target discrimination from the target with the largest beam output, accurately describes the principle of passive sonar azimuth discrimination; in addition, the present invention performs quadratic fitting on the beam output, improving the credibility of passive sonar target discrimination parameter - level simulation.

[0052] In summary, this is only a preferred embodiment of the present invention, and does not limit the protection scope of the present invention. All equivalent changes and modifications made according to the scope of the present invention patent and the content of the specification are within the scope covered by the present invention patent.

Claims

1. A passive sonar target resolution parameter-level simulation method, characterized in that It includes the following steps: Select a first target and a second target from the target group; When the passive sonar can distinguish the first target and the second target, divide the target group into two new target groups; When the passive sonar cannot distinguish the first target and the second target, merge the first target and the second target into one target, and then obtain a new target group; Repeat the above steps for the new target group until the number of targets in the new target group is one; The first target is the one with the strongest beam output in the target group, and the second target is the one with the strongest beam output among the targets adjacent to the target with the strongest beam output; Judging whether the passive sonar can distinguish the first target and the second target includes the following steps: When the azimuth difference between the first target and the second target is less than the resolution ability of the passive sonar, it is determined that the first target and the second target cannot be distinguished; When the azimuth difference between the first target and the second target is greater than or equal to the resolution ability of the passive sonar, it is determined that the first target and the second target can be distinguished; Judging whether the passive sonar can distinguish the first target and the second target also includes the following steps: When the azimuth difference between the first target and the second target is greater than or equal to the resolution ability of the passive sonar, perform a secondary fitting on the beam outputs of the first target and the second target, and calculate the intersection coordinates of the beam outputs of the first target and the second target; When the azimuth difference between the second target and the intersection coordinates is less than half of the target resolution ability of the passive sonar, it is determined that the first target and the second target cannot be distinguished; When the azimuth difference between the second target and the intersection coordinates is greater than or equal to half of the target resolution ability of the passive sonar, it is determined that the first target and the second target can be distinguished; The first target The calculation method of the intersection coordinate X of the beam outputs of the target and the second target is as follows: where α i is the azimuth of the first target, and A i is the beam output of the first target; α i is ±1 the azimuth of the second target, and A i±1 is the beam output of the second target; where θ and D are constants of the passive sonar.

2. The passive sonar target resolution parameter-level simulation method according to claim 1, wherein It also includes the following steps: Arrange all the targets in the target group in ascending order of target azimuth to obtain digital numbers.

3. The passive sonar target resolution parameter-level simulation method according to claim 2, wherein: Divide the target group into two new target groups - the first new target group and the second new target group. The first new target group includes i targets, and the second target group includes (N - i) targets; Where N is the total number of targets in the target group, and i is the digital number corresponding to the first target.

4. The passive sonar target resolution parameter-level simulation method according to claim 1, wherein The azimuth and beam output of the target m after the merger of the first target and the second target are respectively:

Images