CN109960266A - A comb-shaped path design method for underwater acoustic beacon search and detection of submersible platforms - Google Patents

Abstract

The invention proposes a comb-shaped path design method applied to underwater acoustic beacon search and detection of a submersible platform. The method includes sonar action distance prediction, comb-shaped path interval calculation and comb-shaped path implementation. In the prediction of the sonar operating distance, the figure of merit and the distribution of sound propagation loss are calculated, and an accurate estimate of the sonar operating distance is obtained; the comb path interval calculation considers the search and detection efficiency and detection probability. A calculation formula is established with the distance margin and the predicted sonar action distance into the formula to obtain the optimized comb path interval; the comb path implementation is based on the calculated comb path interval and the submersible voyage to reasonably plan the submarine. According to the comb-shaped path of the submersible platform, the search path of the underwater acoustic beacon of the submersible platform is designed. The invention can be applied to the scene of searching for black boxes of planes and ships, and rescue of wrecked submarines and submersibles. The comb-shaped search and detection path designed by the invention can effectively improve the search and detection efficiency and detection probability of the search and detection system.

Description

A comb-shaped path design method for underwater acoustic beacon search and detection of submersible platforms

technical field

The invention belongs to the technical field of acoustic beacon search and detection, in particular to a comb-shaped path design method applied to underwater acoustic beacon search and detection of submersible platforms.

Background technique

The black box acoustic beacon search and detection technology is widely used in the search of wrecked ships and aircraft, submarine rescue and other occasions. The traditional underwater acoustic beacon search and exploration is mainly realized by the surface ship platform, which cannot be completed in the deep sea area due to the limitation of the underwater acoustic distance. This limitation can be effectively avoided by using an autonomous underwater vehicle (Autonomous Underwater Vehicle) platform. The submersible can dive to deeper sea areas, which improves the depth of underwater acoustic beacon search and exploration, and can be used for deep-sea search and exploration; and the submersible can travel along the predetermined route autonomously, saving labor costs and having important economic significance.

One of the key issues in the underwater acoustic beacon search and detection of the submersible platform is to plan the route, that is, to design the driving trajectory of the submersible vehicle to optimize the acoustic beacon search and detection efficiency and detection probability. The most commonly used planning routes are comb paths. A key parameter of the comb-shaped path is the comb-shaped path interval. In the existing route planning, the comb-shaped path interval is often set based on experience. In this way, on the one hand, when the sonar action distance is relatively long, it is easy to form a large impact on the search area. Repeated coverage reduces the search and detection efficiency; on the other hand, when the sonar action distance is relatively short, an uncovered area is generated, which reduces the detection probability.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problems in the prior art, and propose a comb-shaped path design method applied to the search and detection of underwater acoustic beacons of submersible platforms. The method of the invention can effectively ensure the search and detection quality of the underwater acoustic beacon, and avoid the decline of the search and detection efficiency and the detection probability.

The present invention is achieved through the following technical solutions. The present invention proposes a comb-shaped path design method applied to underwater acoustic beacon search and detection of a submersible platform. The method includes three steps: sonar action distance prediction, comb-shaped path design Path interval calculation and comb path implementation;

Step 1: Sonar action distance prediction, in the sonar action distance prediction, first calculate the figure of merit based on the sonar equation, then calculate the distribution of sound propagation loss according to the knowledge of ray acoustics, and finally obtain the figure of merit and the distribution of sound propagation loss by combining Accurate estimation of sonar range;

Step 2: Calculate the interval of the comb-shaped path. The calculation of the interval of the comb-shaped path introduces the seafloor heave margin and the action distance margin, and establishes the optimization calculation formula; the sonar action distance estimated in the previous step is used as the design input and substituted into the optimization calculation formula The optimal calculation results of the comb-shaped path interval are obtained;

Step 3: Comb-shaped path implementation, comb-shaped path implementation According to the optimized calculation result of the comb-shaped path interval, combined with the voyage information of the submersible vehicle, the submersible comb-shaped path planning is carried out, and the underwater acoustic beacon search and exploration of the submersible platform is designed. path.

Further, according to the sonar equation, within the operating distance of the sonar, there are:

(SL-NL+DI-DT)≥TL (1)

In the formula: SL is the sound source level of the acoustic beacon; NL is the noise sound source level; DI is the signal processing gain, which includes the time processing gain and the spatial processing gain; DT is the detection threshold; TL is the propagation loss; ( SL-NL+DI-DT) are collectively referred to as the figure of merit.

Further, based on the figure of merit and sound propagation loss, the specific steps for estimating the sonar action distance are as follows:

Step 1: Determine the figure of merit (SL-NL+DI-DT) according to the sound source level of the acoustic beacon, the noise sound source level, the signal processing gain and the detection threshold;

Step 2: Determine the distribution of acoustic transmission loss according to the on-site hydrological conditions and acoustic beacon frequency information;

The third step: select the maximum distance that makes the sound propagation loss less than or equal to the quality factor as the estimated value of the sonar action distance.

Further, in step 2, the sea floor fluctuation margin d _S and the action distance margin R _S are introduced; assuming that the sea floor fluctuation changes within the range of d ± d _S , and d is the depth of the sea floor, then the maximum value of the depth difference of the submersible vehicle relative to the acoustic beacon for:

h _S =max(hd _S ,h+d _S ) (3)

In the formula, h is the voyage depth of the submersible;

Then, the optimal calculation formula of comb path interval S after introducing two margins is:

where R is the estimated sonar range.

Further, the comb-shaped path interval refers to the interval between two adjacent comb teeth.

Further, in step 2, the optimization calculation result of the comb-shaped path interval has been obtained through the optimization calculation. Combined with the comb-shaped path width L and the voyage K of the submersible vehicle, the comb-shaped path width L satisfies L >> S, then The area of the search area that a single submersible can cover during the voyage is:

It can be seen from the formula that the search area that each submersible can cover during the voyage is only related to the submersible voyage and the interval of the comb-shaped path, but has nothing to do with the width of the comb-shaped path.

Beneficial effects of the present invention: when the submersible uses the comb-shaped path designed by the present invention to search and detect the acoustic beacon, the search and detection efficiency and the detection probability can be effectively improved.

Description of drawings

Figure 1 shows the distribution of sound propagation loss at different depths and distances;

Fig. 2 is a graph showing the variation of scanning efficiency and detection probability with comb path interval;

Fig. 3 is a schematic diagram of comb path interval optimization;

Fig. 4 is a comb path interval diagram under different margin requirements;

FIG. 5 is a schematic diagram of the result of comb path design and its corresponding coverage search area.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

The present invention provides a comb-shaped path design method applied to underwater acoustic beacon search and detection of a submersible platform. The method includes three steps: sonar action distance prediction, comb-shaped path interval calculation, and comb-shaped path implementation;

Step 1: Sonar action distance prediction, in the sonar action distance prediction, first calculate the figure of merit based on the sonar equation, then calculate the distribution of sound propagation loss according to the knowledge of ray acoustics, and finally obtain the figure of merit and the distribution of sound propagation loss by combining Accurate estimation of sonar range;

Step 2: Calculate the interval of the comb-shaped path. The calculation of the interval of the comb-shaped path introduces the seafloor heave margin and the action distance margin, and establishes the optimization calculation formula; the sonar action distance estimated in the previous step is used as the design input and substituted into the optimization calculation formula The optimal calculation result of comb path spacing is obtained; the result is the optimization of detection efficiency under the guarantee of 100% detection probability.

Step 3: Comb-shaped path implementation, comb-shaped path implementation According to the optimized calculation result of the comb-shaped path interval, combined with the voyage information of the submersible vehicle, the submersible comb-shaped path planning is carried out, and the underwater acoustic beacon search and exploration of the submersible platform is designed. path.

Concrete step 1: Sonar action distance prediction.

Sonar range prediction is a prerequisite for acoustic beacon route planning. Only after the sonar operating distance is known, the comb-shaped path interval can be determined according to the sonar operating distance, so as to avoid the missed scanning of the acoustic beacon.

According to the sonar equation, within the range of the sonar, there are:

(SL-NL+DI-DT)≥TL (1)

In the formula: SL is the sound source level of the acoustic beacon; NL is the noise sound source level; DI is the signal processing gain, including the time processing gain and the spatial processing gain; DT is the detection threshold; TL is the propagation loss. (SL-NL+DI-DT) are collectively referred to as the quality factor. Only when the quality factor is greater than the sound propagation loss, the sonar mounted on the submersible can detect the acoustic signal emitted by the acoustic beacon.

Figure 1 shows the propagation loss distribution diagram of the submersible at different depths and distances when the acoustic beacon is located on the seabed. Among them, Figure 1(a) shows the distribution in shallow seas, and Figure 1(b) shows the distribution in deep seas. It can be seen that in the shallow sea, at the same depth, the TL changes basically monotonically with the distance; while in the deep sea, due to the existence of the main sound ray (the sinusoidal curve in the figure), the TL oscillates to a certain extent with the distance.

In practical application, based on the figure of merit and sound propagation loss, the specific steps for predicting the sonar operating distance are as follows:

Step 1: Determine the figure of merit (SL-NL+DI-DT) according to the sound source level of the acoustic beacon, the noise sound source level, the signal processing gain and the detection threshold;

Step 2: Determine the propagation loss distribution according to the on-site hydrological conditions, acoustic beacon frequency and other information;

Step 3: Select the maximum distance that makes the propagation loss less than or equal to the quality factor as the estimated value of the sonar operating distance.

The second step is to calculate the interval of the comb path.

The comb path spacing refers to the spacing between two adjacent comb teeth. Comb path spacing is a main parameter in comb path design, which directly affects two key indicators, search efficiency and detection probability. Figure 2 shows the effect of comb path spacing on search efficiency and detection probability. It can be seen that with the increase of the comb path interval, the search efficiency increases, but the detection probability decreases significantly. Therefore, the requirements of detection probability and search efficiency for comb path spacing are contradictory. It is more necessary to optimize the comb path interval to improve the search efficiency as much as possible while ensuring the detection probability.

Figure 3 shows a schematic diagram of comb path spacing optimization. In the figure: h is the navigation depth of the submersible; d is the seabed depth (assuming the acoustic beacon is located on the seabed plane); S is the comb-shaped path interval, and R is the estimated sonar action distance. As shown in Figure 3, in an ideal case, the optimal formula for comb path spacing is:

In actual situations, affected by random underwater acoustic channels, the sonar operating distance usually changes around the estimated sonar operating distance R; the seabed terrain often has certain fluctuations, and the depth of the acoustic beacon is not a fixed value. d. In this case, using an ideal comb-shaped path interval optimization formula will cause a drop in the detection probability and a missed scan of the acoustic beacon.

In view of the random changes of R and d, the present invention introduces a seafloor relief margin d _S and an action distance margin R _S . Assuming that the seafloor fluctuation varies within the range of d± _dS , the maximum depth difference of the submersible relative to the acoustic beacon is:

h _S =max(hd _S ,h+d _S ) (3)

Furthermore, the optimal calculation formula of the comb-shaped path interval after considering the action distance margin R _S is:

Under different seafloor heave margins and action distance margins, the comb-shaped path interval calculated by the above formula is shown in Fig. 4. It can be seen that when the required margin is larger, the corresponding comb-shaped path interval is smaller, and the search efficiency is lower. Therefore, in practical application, it is not possible to enlarge the seafloor relief margin and the action distance margin indefinitely; instead, the action distance margin should be pre-set according to the hydrological conditions of the sea area, and the terrain should be set according to the terrain complexity of the sea area chart. The fluctuation margin is substituted into the comb path calculation formula according to the two margin requirements to calculate the comb path interval with the margin requirements. For example: in Figure 4, assuming that the action distance margin is 100m and the terrain relief margin is 100m, the comb-shaped path interval is 6693m.

Concrete step 3: Comb path implementation.

Due to the limited amount of electricity or oil, the submersible cannot search along the comb path indefinitely. Therefore, it is necessary to design the comb-shaped search area of the submersible vehicle. In this way, on the one hand, it can ensure that the submersibles can safely surface after completing the search of the predetermined sea area, waiting for charging or refueling; No duplicate scans or missed scans occur between the devices.

In step 2, the optimized calculation result of the comb-shaped path interval has been obtained through the optimization calculation, combined with the comb-shaped path width L (as shown in Figure 3, it is usually determined by the actual situation of the search operation in the sea area, and satisfies L >> S ) and the voyage K of the submersible, then the area of the search area that a single submersible can cover during the voyage is:

It can be seen from the formula that the search area that each submersible can cover during the voyage is only related to the submersible voyage and the interval of the comb-shaped path, but has nothing to do with the width of the comb-shaped path. Therefore, the importance of the spacing design of the comb-shaped path is further confirmed.

Implementation example:

The simulation environment is a shallow sea environment, the sea depth is 500m, and the seabed topography is undulating by 100m. The submersible conducts comb-shaped acoustic beacon search at a sea depth of 300m. The submersible travel speed is 2m/s, and the submersible range is 200km.

Step 1: Sonar action distance prediction.

The input parameters for sonar action distance prediction are: acoustic beacon sound source level SL=136dB; noise sound source level NL=64dB; signal processing gain DI=10dB; detection threshold DT=0dB. Then the figure of merit calculated by formula (1) is 82dB.

The sound source level of the acoustic beacon is 30kHz, and its sound propagation loss is shown in Figure 1(a). As can be seen from the figure, the maximum distance that makes the propagation loss less than the good factor is 3680m. Therefore, the estimated sonar range is 3680m.

Step 2: Calculate the interval of the comb path.

Assuming that the action distance margin is 50m, combined with the sonar action distance of 3680m, and substituting into formula (4), the comb-shaped path interval can be obtained as 3618m.

Step 3: Comb path implementation.

According to formula (5), the area of the search area covered by a single submersible vehicle is 724km ² . Assuming that a total of four submersibles are used to conduct acoustic beacon search in a wide range of sea areas, the results of the comb-shaped path design using the present invention and the corresponding coverage search area are shown in FIG. 5 .

A comb-shaped path design method for underwater acoustic beacon search and detection of a submersible platform provided by the present invention has been described above in detail. In this paper, specific examples are used to illustrate the principles and implementations of the present invention. The description of the above embodiment is only used to help understand the method of the present invention and its core idea; meanwhile, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in specific embodiments and application scope, In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (6)

1. a kind of comb shape route designing method for searching spy applied to the latent underwater acoustic marker of device platform, it is characterised in that: the method Including three steps: sonar operating range prediction, comb shape route interval calculate and comb shape path is implemented；

Step 1: sonar operating range prediction, sonar operating range prediction in, be primarily based on sonar equation calculate it is high-quality because Then number calculates the distribution situation of Acoustic Wave Propagation according to geometrical acoustics relevant knowledge, finally integrate figure of merit and acoustic propagation The accurate estimation of loss distribution acquisition sonar operating range；

Step 2: comb shape route interval calculates, and comb shape route interval, which calculates, introduces submarine relief surplus and operating distance surplus, builds Optimization calculation formula is found；It is inputted sonar operating range estimated by previous step as design, substitutes into optimization calculation formula Obtain the optimization calculated result of comb shape route interval；

Step 3: comb shape path is implemented, and the optimization calculated result according to the comb shape route interval is implemented in comb shape path, in conjunction with latent The voyage information of device carries out latent device comb shape path planning, designs the latent underwater acoustic marker of device platform and searches diameter of exploring the way.

2. according to the method described in claim 1, it is characterized by: in the operating distance of sonar, being had according to sonar equation:

(SL-NL+DI-DT)≥TL (1)

In formula: SL is acoustic marker sound source level；NL is sound source level；DI is signal processing gain, the signal processing gain packet Include time-triggered protocol gain and spatial processing gain；DT is detection threshold；TL is propagation loss；(SL-NL+DI-DT) it is referred to as high-quality Factor.

3. according to the method described in claim 2, it is characterized by: carrying out sonar work based on figure of merit and Acoustic Wave Propagation With distance estimations, specific step is as follows:

Step 1: determining figure of merit (SL-NL according to acoustic marker sound source level, sound source level, signal processing gain and detection threshold +DI-DT)；

Step 2: determining that Acoustic Wave Propagation is distributed according to live hydrologic regime harmony beacon frequency information；

Step 3: choosing estimation of the maximum distance for making Acoustic Wave Propagation be less than or equal to figure of merit as sonar operating range Value.

4. according to the method described in claim 1, it is characterized by: introducing submarine relief surplus d in step 2_SAnd operating distance Surplus R_S；Assuming that submarine relief is in d ± d_SVariation in range, d is seabed depth, then dive device relative to acoustic marker depth difference most Big value are as follows:

h_S=max (h-d_S,h+d_S) (3)

In formula, h is latent device keel depth；

Then, the optimization calculation formula of the comb shape route interval S after introducing two surpluses are as follows:

In formula, R is the sonar operating range of estimation.

5. according to the method described in claim 1, it is characterized by: the comb shape route interval refers between two adjacent fingers Interval.

6. according to the method described in claim 1, it is characterized by: having passed through optimization in step 2 and having calculated, obtained comb shape The optimization calculated result of route interval meets L in conjunction with the voyage K, the comb shape path width L of comb shape path width L and latent device > > S, then device covered spy region area of searching of institute in voyage of individually diving are as follows:

By formula as it can be seen that each latent device can cover that search exploratory area domain only related with latent device voyage and comb shape route interval in voyage, And it is unrelated with comb shape path width.