A Method for Evaluating the Detection Efficiency of Sonar Regions Based on Marine Environmental Data

Abstract

The present invention relates to a method for evaluating the sonar regional detection efficiency based on marine environmental data. Based on the marine environmental data including sound velocity gradient, seabed sediment, and sea depth, and on the basis of a grid-based marine environmental database, a suitable sound field calculation model is adaptively selected according to the sea depth and the working frequency of the active / passive sonar, and three-dimensional sound field calculation is carried out in units of subdomains to obtain the calculation result data of the three-dimensional sound propagation loss in the subdomains, so as to support the evaluation of the regional detection efficiency. This method uses statistical methods to quantitatively evaluate the overall detection efficiency of sonar in a certain sea area at a specified depth, and can provide auxiliary decision-making information support for the mission planning of users before going to sea.

Description

Technical Field

[0001] The present invention relates to the technical field of sonar detection, and particularly relates to a method for evaluating the detection efficiency of a sonar area based on marine environmental data. Background Art

[0002] When a sonar receiver processes target echo or target noise signals, it is necessary to determine whether there is a target. The simplest detection decision mechanism is related to the concept of a threshold or a limit. As long as the amplitude of the signal plus noise exceeds this threshold, it is considered that there is a target. Traditional sonar detection efficiency evaluation mainly relies on the sonar equation to calculate the probability of detecting a target by different types of sonars.

[0003] Traditional sonar detection efficiency evaluation only evaluates for a single sound source emission point. When performing a detection task in a large-scale mission sea area, during the planning stage before the mission starts, both the position of the detection sonar and the position of the target are uncertain. At this time, the traditional sonar detection efficiency evaluation cannot achieve the expected effect. At the same time, at the present stage, when evaluating the sonar detection efficiency, the importance of marine environmental data and underwater acoustic field propagation is often ignored, and only simple calculations are carried out using empirical formulas. The obtained evaluation results have a large gap with the actual situation, and it is difficult to provide support for the deployment and parameter optimization of sonar equipment. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for evaluating the detection efficiency of a sonar area based on marine environmental data to solve the problems encountered in the above background art.

[0005] To achieve the above purpose, the technical solution of the present invention is as follows:

[0006] A method for evaluating the detection efficiency of a sonar area based on marine environmental data includes the following steps:

[0007] S1. Integrate and process multi-source environmental data to form a grid-based marine environmental database;

[0008] S2. Determine the mission sea area, evenly divide it into multiple sub-areas, and read the marine environmental data within the sea area;

[0009] S3. Adaptively select a suitable acoustic field calculation model according to the sea depth and the working frequency of the active / passive sonar, perform three-dimensional acoustic field calculation for each sub-area, and obtain the three-dimensional acoustic propagation loss calculation result data for the sub-area;

[0010] S4. Based on the three-dimensional acoustic propagation loss data of the sub-area, combine with the active / passive sonar equation, calculate the signal margin of the sub-area, and map the signal margin to the conditional detection probability of each sub-area;

[0011] S5. Model the target distribution in the mission sea area based on the marine environmental data to obtain the target prior probability.

[0012] S6. Obtain the joint detection probability of each sub-domain based on the conditional detection probability and the target prior probability of each sub-domain, that is, the evaluation result of the regional detection efficiency of the active / passive sonar at different depths in the mission sea area.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The main application scenario of the present invention is the planning stage before the detection task. Based on the constructed grid-shaped marine environmental database, the statistical idea is adopted to quantitatively evaluate the overall detection performance of a certain sea area at a specified depth, and the comprehensive detection performance of each node in the mission sea area is analyzed and characterized from multiple perspectives of environmental data, active / passive sonar working parameters, and target information, providing information support for the user platform deployment and route planning. Description of the Drawings

[0014] The disclosure of the present invention will be described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes and are not intended to limit the protection scope of the present invention. In the drawings, the same reference numerals are used to refer to the same components. Among them:

[0015] Figure 1 is a schematic diagram of the working process of the present invention; Detailed Embodiments

[0016] In order to make the technical means, creative features, achieved purposes, and functions of the present invention easy to understand, the present invention will be further described in detail below with reference to the accompanying drawings. These drawings are all simplified schematic diagrams, only illustrating the basic structure of the present invention in a schematic manner, so they only show the components related to the present invention.

[0017] According to the technical solution of the present invention, without changing the essence of the present invention, those of ordinary skill in the art can propose various structural ways and implementation ways that can be mutually replaced. Therefore, the following detailed embodiments and the accompanying drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction on the technical solution of the present invention.

[0018] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0019] As Figure 1 shown, a method for evaluating the sonar regional detection efficiency based on marine environmental data includes the following steps:

[0020] S1. Integrate and process the multi-source environmental data to form a grid-shaped marine environmental database, providing basic environmental data support for the regional detection efficiency evaluation.

[0021] Environmental data includes sound speed gradient data, seabed sediment data, and seabed topography data. Sound speed gradient data affects underwater acoustic propagation. For example, sound rays always bend towards areas with lower sound speeds. Therefore, sound speed gradient data must be considered when calculating propagation. Seabed sediment data includes seabed sediment types and sediment acoustic parameters. In shallow sea environments, seabed sediment attenuation has a greater impact on underwater acoustic propagation. Therefore, seabed sediment data must be considered when calculating propagation loss. The undulation of the seabed topography affects underwater acoustic propagation. Therefore, seabed topography data must be considered when calculating propagation loss.

[0022] S2. Determine the mission sea area, evenly divide it into multiple sub-areas, and read the marine environmental data within the sea area. After the user sets the calculation parameters, the software automatically divides the area using the algorithms set in the software.

[0023] S3. Adaptively select a suitable acoustic field calculation model based on the sea depth and the working frequency of the active / passive sonar, and perform three-dimensional acoustic field calculations for each sub-area to obtain the three-dimensional acoustic propagation loss calculation result data for the sub-area. The acoustic field calculation model can be any one of the parabolic equation model, the ray model, and the normal mode model.

[0024] When selecting the acoustic field calculation model, the parabolic equation and normal mode models are suitable for low-frequency shallow sea environments, but their calculation speeds are relatively slow in high-frequency deep sea environments. The ray model is more suitable for high-frequency deep sea environments. Based on the sea depth and frequency parameters, while comprehensively considering the calculation speed and calculation accuracy, an adaptive selection of the acoustic field model is made. The specific steps are as follows:

[0025] 1. First, read the seabed topography data to determine whether it is a shallow sea environment or a deep sea environment;

[0026] 2. Secondly, read the sonar working frequency data to determine whether it is low frequency or high frequency;

[0027] 3. Make a comprehensive discrimination of the sea depth and frequency, comprehensively consider the calculation speed and calculation accuracy, and give a suitable acoustic field model.

[0028] In this solution, three-dimensional acoustic field calculations are performed for each sub-area to obtain the three-dimensional acoustic propagation loss calculation result data for the sub-area. Among them, the three-dimensional propagation loss data is the basis for calculating the detection efficiency of the calculation area. Using the propagation loss, the signal margin can be calculated, and then the detection probability can be calculated. The three-dimensional propagation loss calculation here is based on actual environmental data and acoustic field models, rather than simply calculating using empirical formulas, which is closer to the actual situation and can better achieve the purpose of evaluating the regional detection efficiency.

[0029] S4. Based on the three-dimensional sound propagation loss data of sub-domains, combined with the active / passive sonar equations, calculate the signal margin of each sub-domain, and map the signal margin to the conditional detection probability of each sub-domain. The propagation loss is converted into the signal margin through the sonar equation, and then the signal margin is converted into the detection probability through the calculation formula. The evaluation result of the detection efficiency in this area is ultimately characterized by the area detection probability. Therefore, this step is a key step in result conversion, expanding from single-point efficiency evaluation to area efficiency evaluation.

[0030] The calculation methods of the active / passive sonar equations are as follows:

[0031] First, calculate the isotropic noise background:

[0032] SL - 2TL + TS - (NL - DI) = DT (1)

[0033] Where: SL is the source radiation source level of the active sonar; TL is the propagation loss; TS is the target strength; NL is the environmental noise level within the working bandwidth; DI is the receiving directivity index of the receiving array; DT is the detection threshold;

[0034] Then, calculate the reverberation interference background:

[0035] SL - 2TL + TS - RL = DT (2)

[0036] Where: RL is the equivalent plane wave reverberation level;

[0037] The passive sonar equation is:

[0038] SL 1 - TL - (NL - DI) = DT (3)

[0039] Where: SL 1 is the source radiation source level.

[0040] The signal margin of the active sonar is:

[0041] Isotropic noise background:

[0042] SE = SL - 2TL + TS - (NL - DI) - DT (4)

[0043] Reverberation interference main background:

[0044] SE = SL - 2TL + TS - RL - DT (5)

[0045] The signal margin of the passive sonar is:

[0046] SE = SL 1 - TL - (NL - DI) - DT (6)

[0047] The idea of evaluating the detection efficiency of active / passive sonar in a region is different from the traditional evaluation of the detection efficiency of single-point sonar. Based on the conditional detection probability and the target prior probability of each sub-region in the mission sea area, the comparison of the detection efficiency of active / passive sonar at different position points in the entire mission sea area is obtained.

[0048] S5. Model the target distribution in the mission sea area based on the ocean environmental data and the target prior information, so as to obtain the target prior probability.

[0049] The target distribution modeling method is any one of the Monte Carlo method, the quasi-Monte Carlo method, and the Las Vegas method.

[0050] S6. Obtain the joint detection probability of the sub-region based on the conditional detection probability and the target prior probability of each sub-region, that is, the evaluation result of the regional detection efficiency of active / passive sonar at different depths in the mission sea area.

[0051] This solution is based on the ocean environmental data including the sound speed gradient, the seabed sediment, and the sea depth. Based on the grid-based ocean environmental database, the appropriate sound field calculation model is adaptively selected according to the sea depth and the working frequency of active / passive sonar. The three-dimensional sound field calculation is carried out in units of sub-regions to obtain the calculation result data of the three-dimensional sound propagation loss of the sub-region, so as to support the evaluation of the regional detection efficiency. This method of quantitatively evaluating the overall detection efficiency of sonar in a certain sea area at a specified depth by using statistical methods can provide auxiliary decision-making information support for the mission planning before the personnel go to sea.

[0052] The main application scenario of the present invention is the planning stage before performing the detection task. Based on the constructed grid-based ocean environmental database, the statistical idea is used to quantitatively evaluate the overall detection performance of a certain sea area at a specified depth. The comprehensive detection performance of each node in the mission sea area is analyzed and characterized from the perspectives of the ocean environment and the working parameters of active / passive sonar, so as to provide information support for the platform deployment and route planning of the personnel.

[0053] The specific embodiments described above further elaborate the purpose, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for evaluating the detection efficiency of sonar in a region based on marine environmental data, characterized in that, it includes the following steps: S1. Integrate and process multi-source environmental data to form a grid-based marine environmental database; S2. Determine the mission sea area, evenly divide it into multiple sub-areas, and read the marine environmental data within the sea area; S3. Adaptively select an appropriate acoustic field calculation model according to the sea depth and the working frequency of the active / passive sonar, perform three-dimensional acoustic field calculations for each sub-area, and obtain the three-dimensional acoustic propagation loss calculation result data for the sub-area; S4. Based on the three-dimensional acoustic propagation loss data of the sub-area, combined with the active / passive sonar equation, calculate the signal margin of the sub-area, and map the signal margin to the conditional detection probability of each sub-area; Among them, the calculation method of the active / passive sonar equation is as follows: First, calculate the isotropic noise background: SL - 2TL + TS - (NL - DI) = DT (1) In the formula: SL is the source radiation sound level of the active sonar; TL is the propagation loss; TS is the target strength; NL is the environmental noise level within the working bandwidth; DI is the receiving directivity index of the receiving array; DT is the detection threshold; Then, calculate the reverberation interference background: SL - 2TL + TS - RL = DT (2) In the formula: RL is the equivalent plane wave reverberation level; The passive sonar equation is: SL 1 -TL-(NL-DI) = DT (3) where: SL 1 is the sound source radiation sound source level; Among them, the signal margin of the active sonar is: Isotropic noise background: SE = SL - 2TL + TS - (NL - DI) - DT (4) Main reverberation interference background: SE = SL - 2TL + TS - RL - DT (5) The signal margin of the passive sonar is: SE = SL 1 -TL-(NL-DI)-DT (6); S5. Based on the marine environmental data, model the target distribution within the mission sea area to obtain the target prior probability; S6. Based on the conditional detection probability and the target prior probability of each sub-area, obtain the joint detection probability of the sub-area, that is, the evaluation result of the regional detection efficiency of the active / passive sonar at different depths in the mission sea area.

2. A method for evaluating the detection efficiency of sonar in a region based on marine environmental data according to claim 1, characterized in that: In step S1, the environmental data includes sound speed gradient data, seabed sediment data, and seabed topography data.

3. A method for evaluating the detection efficiency of sonar in a region based on marine environmental data according to claim 1, characterized in that: In step S3, the acoustic field calculation model is any one of the parabolic equation model, ray model, and normal mode model.

4. A method for evaluating the detection efficiency of sonar in a region based on marine environmental data according to claim 1, characterized in that: In step S5, the target distribution modeling method is any one of the Monte Carlo method, quasi-Monte Carlo method, and Las Vegas method.

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