Real-time three-dimensional positioning method for distributed noise measurement system

Abstract

The application discloses a real-time three-dimensional positioning method of a distributed noise measuring system, and comprises the following steps: Step 1, preparation, two depth sensors are additionally arranged at each branch of the distributed radiation noise measuring system, and one active ranging sound source is additionally arranged at the submarine target to be measured; Step 2, after the system starts to work, the measuring value and the intermediate calculation value of each hydrophone are obtained; Step 3, the depth (An) and the horizontal position (Xn, Yn) of each hydrophone are calculated through N times of mutual cross verification of adjacent hydrophones, wherein the value of N is not less than the value of the number of hydrophones. The three-dimensional space positioning of the distributed measuring system can be obtained in real time, the noise measuring accuracy is improved, the underwater flow distribution is obtained at the same time, and information support is provided for the fine analysis of the radiation noise.

Description

Technical fields:

[0001] This invention belongs to the field of underwater acoustic engineering technology, specifically relating to a real-time three-dimensional positioning method for a distributed noise measurement system. Background technology:

[0002] As a naval combat platform, submarine radiated noise measurement is essential for evaluating its tactical advantages and weaknesses. Various systems can be used to measure submarine radiated noise, such as hydrophones, hydrophone clusters, horizontal arrays, and vertical arrays. Typical deployment methods include: fixed on the seabed, floating at sea, and towed behind a measurement vessel. With the improvement of submarine acoustic stealth capabilities, radiated noise is decreasing. To obtain higher measurement "gain" and acquire three-dimensional noise radiation information, measurement systems incorporating multiple hydrophones, i.e., distributed noise measurement systems, are often used, such as… Figure 1 As shown, the main features of its underwater wet-end section are: several hydrophones are arranged on the horizontal plane around the submarine. Each hydrophone is connected in series with a buoy, cable, tow rope, and counterweight (submerged on the seabed) to form a branch. Each branch is connected in parallel to a cable and then to the main equipment. The depth of each hydrophone suspended in the water is adjustable. It receives and uploads radiated noise signals in real time. Based on the actual radiated noise measurement requirements, the system's array configuration and spacing on the horizontal plane, as well as the depth of each hydrophone, are determined to complete the radiated noise measurement task. Under the complex sea conditions—waves, currents, wind, and other loads—the three-dimensional position (depth position and horizontal plane position) of each hydrophone in the distributed noise measurement system changes continuously and in real time with the external load. Taking an initial hydrophone depth of 50 meters (the branch is in the vertical direction with an inclination angle of 0°) and a branch inclination angle of 20° after being subjected to an external load as an example, the hydrophone's offset on the horizontal plane is approximately 17 meters, and the depth change is 3.1 meters. As the hydrophones move continuously in the water, their relative positions around the target (submarine) change in real time, reducing the accuracy and precision of the measurement. Therefore, obtaining the real-time three-dimensional position of the hydrophones in the water quickly, easily, accurately, and reliably is crucial for improving radiated noise measurement. Summary of the Invention:

[0003] The technical problem to be solved by the present invention is to provide a real-time three-dimensional positioning method for a distributed noise measurement system. This method can calculate and obtain the three-dimensional spatial positioning of the distributed measurement system in real time, which improves the accuracy of noise measurement. At the same time, it indirectly obtains the underwater water flow distribution, providing information support for the refined analysis of radiated noise. It is also applicable to other marine systems or devices composed of several vertical branches.

[0004] The technical solution of this invention is to provide a real-time three-dimensional positioning method for a distributed noise measurement system, comprising the following steps:

[0005] Step 1, Preparation: Add two depth sensors (built into the depth sensor compartment) to each branch of the distributed radiated noise measurement system where the hydrophone is located, and add one active ranging sound source at the target submarine. The depth sensor is used to measure the depth value in real time and upload it to the trunk equipment, and the active ranging sound source is used to intermittently transmit active high-frequency signals for the hydrophone to receive and measure the distance in real time.

[0006] Step 2: After the system starts working, acquire the measurement values ​​and intermediate calculation values ​​of each hydrophone;

[0007] Step 3: Through N cross-verifications of adjacent hydrophones, continuous corrections are made to calculate the depth (An) and horizontal position (Xn, Yn) of each hydrophone, where the value of N is not less than the number of hydrophones.

[0008] Step 4: Repeat the above calculation process every M seconds (determined according to actual accuracy requirements, M generally does not exceed 2 seconds) to obtain the real-time three-dimensional spatial position of each hydrophone.

[0009] Preferably, one of the two depth sensors located on the same branch is installed at the corresponding hydrophone, and the other is installed at the junction of the branch where the corresponding hydrophone is located and the main cable.

[0010] As a preferred method, based on the branch where each hydrophone is located, the hydrophones in each branch are sequentially coded. Assuming the hydrophone code for the branch is n, the length between the two depth sensors above and below the branch is denoted as D, and the initial position is set when the branch does not tilt. At this time, the depth values ​​of the two depth sensors are denoted as Hn-1 and Hn-2, respectively, the ranging value of the ranging sound source is denoted as Ln, and the sound source depth is S. When the current flows in real time, the branch tilts. The tilt direction of the branch is consistent with the direction of the current, and the tilt angle is larger as the flow velocity increases. The tilt angle is denoted as θn, the depth values ​​of the two depth sensors are denoted as Hn-1' and Hn-2', respectively, and the ranging value of the ranging sound source is denoted as Ln'. The tilt angle is calculated by geometric relationship (inverse cosine function) as θn=arccos((Hn-2')-(Hn-1') / D).

[0011] Furthermore, in step 4, assuming that after the hydrophone coded as n deviates from its initial position, the distance between its real-time position and the ranging sound source is Ln', and the tilt angle is θn, and the adjacent hydrophone coded as n+1 and its branch are synchronously analyzed, the real-time tilt angle of the hydrophone coded as n+1 is calculated and recorded as θn+1, and the distance between the real-time position of the hydrophone coded as n+1 and the ranging sound source is calculated and recorded as L(n+1)';

[0012] By using Ln' and tilt angle θn, the three-dimensional spatial position of the hydrophone coded as n can be determined to be one of Pn-1 and Pn-2. Similarly, by using L(n+1)' and θn+1, the three-dimensional spatial position of the hydrophone coded as n++1 can be determined to be one of P(n+1)-1 and (n+1)-2.

[0013] Based on the distance between adjacent hydrophones and the degree of change in the direction of the incoming flow, it is approximately assumed that the hydrophone coded as n and the hydrophone coded as n+1 have the same direction of water flow. Based on the two inclination angles θn+1 of the two directions of the hydrophone coded as n+1, two possible positions of the hydrophone coded as n+1 are determined, and the distance between the two possible positions and the sound source is calculated respectively. Based on the matching of the calculated distance with the real-time distance L(n+1)', the position of the hydrophone coded as n+1 is determined. And by reverse calculation, the position of the hydrophone coded as n is determined.

[0014] Compared with the prior art, the present invention has the following advantages after adopting the above solution:

[0015] 1. The several depth sensors and ranging sound sources added to the existing radiated noise measurement system are mature devices, simple and convenient, easy to implement in engineering, and do not affect the functionality, performance and reliability of the original system; 2. By adding depth measurement and horizontal plane ranging functions, the three-dimensional spatial positioning of the measurement system can be calculated in real time, improving the accuracy of noise measurement, and indirectly obtaining the underwater water flow distribution, providing information support for the refined analysis of radiated noise; 3. It is also applicable to other marine systems or devices composed of several vertical branches. Attached image description:

[0016] Figure 1 This is a schematic diagram of a prior art distributed radiated noise measurement system;

[0017] Figure 2 This is a schematic diagram of the distributed radiated noise measurement system of the present invention;

[0018] Figure 3 This is a schematic diagram of a vertical cross-section of a three-dimensional positioning calculation method.

[0019] Figure 4 This is a horizontal plane schematic diagram of the three-dimensional positioning calculation method;

[0020] Figure 5 For the calculation flowchart;

[0021] Figure 6 This is a schematic diagram of the system's operating mode. Detailed implementation method:

[0022] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0023] A real-time three-dimensional localization method for a distributed noise measurement system includes the following steps.

[0024] Step 1, Preparation: Add two depth sensors (built into the depth sensor compartment) to each branch of the distributed radiated noise measurement system where the hydrophone is located, and add one active ranging sound source at the target submarine. The depth sensor is used to measure the depth value in real time and upload it to the trunk equipment, and the active ranging sound source is used to intermittently transmit active high-frequency signals for the hydrophone to receive and measure the distance in real time.

[0025] Step 2: After the system starts working, acquire the measurement values ​​and intermediate calculation values ​​of each hydrophone;

[0026] Step 3: Through N cross-verifications of adjacent hydrophones, continuous corrections are made to calculate the depth (An) and horizontal position (Xn, Yn) of each hydrophone, where the value of N is not less than the number of hydrophones.

[0027] Step 4: Repeat the above calculation process every M seconds (determined according to actual accuracy requirements, M generally does not exceed 2 seconds) to obtain the real-time three-dimensional spatial position of each hydrophone.

[0028] During preparation, two depth sensors are added to each branch where the hydrophone is located: one at the hydrophone and one at the junction of the branch and the main cable. These depth sensors measure depth values ​​in real time and upload the data to the trunk equipment. A small ranging sound source can be installed at the target (submarine) to intermittently transmit active high-frequency signals for the hydrophone to receive and measure distances in real time. (See...) Figure 2 Through hardware design and implementation, the system can comprehensively calculate and process real-time sensor depth and ranging information to achieve real-time three-dimensional positioning of the radiated noise measurement system.

[0029] In this embodiment, the original system provides power and signal transmission for the depth sensor. A small ranging sound source (fixed position and depth) is added to the target submarine. The original system's trunk equipment powers, transmits, and controls the ranging sound source via a single cable. The depth sensor is an off-the-shelf product with a measurement accuracy of no less than 0.02m. Other parameters are selected and determined based on the original system. The depth sensor housing is made of stainless steel or titanium alloy to prevent seawater corrosion. If a metal structure housing already exists at the original system's installation location, it can be integrated and added separately. The active ranging sound source can transmit single-frequency and high-frequency signals, with a frequency range of 15kHz-25kHz, a sound source level of no less than 120dB, a transmission period of 1s, and a miniaturized design in terms of size and weight (no specific requirements). The timing synchronization, transmission control, and processing of the active ranging signal received by the hydrophone are achieved by adding corresponding software function modules to the original system's trunk equipment.

[0030] Specifically, such as Figure 3 The diagram shown is a vertical cross-sectional schematic of the three-dimensional positioning calculation method (taking hydrophone 1 with code 1 as an example). The length between the two depth sensors on the branch is denoted as D. When the branch does not tilt, it is the initial position. At this time, the depth values ​​of the two depth sensors are denoted as H1-1 and H1-2, respectively. The distance measured by the ranging sound source is denoted as L1, and the sound source depth is S. When the current flows in real time, the branch tilts. The tilt direction of the branch is consistent with the direction of the current, and the tilt angle is larger when the flow velocity is greater. The tilt angle is denoted as θ1. The depth values ​​of the two depth sensors are denoted as H1-1' and H1-2', respectively. The distance measured by the ranging sound source is denoted as L1'. The tilt angle can be calculated by geometric relationship (inverse cosine function) as θ1=arccos((H1-2')-(H1-1') / D).

[0031] like Figure 4 The diagram shows a horizontal plane schematic of the three-dimensional positioning calculation method (taking hydrophone 1 and hydrophone 2 as examples). After hydrophone 1 deviates from its initial position, the distance between its real-time position and the ranging sound source is L1', and its tilt angle is θ1. Since L1' and θ1 are two definite measurement values, the three-dimensional spatial position of hydrophone 1 cannot be determined. It may have two positions, denoted as "P1-1" and "P1-2", symmetrically distributed on both sides of the line connecting hydrophone 1 and the ranging sound source. Because the offset direction of hydrophone 1 is consistent with the flow direction, there are also two possible incoming flow directions, denoted as "O1-1" and "O1-2". By synchronously analyzing the nearby hydrophone 2 and its branch, the real-time tilt angle of hydrophone 2 can be calculated and denoted as θ2, and the distance between the real-time position of hydrophone 2 and the ranging sound source can be calculated and denoted as L2'. Since the distance between adjacent hydrophones is small and the change in the direction of the incoming flow is minimal, it is assumed that the flow directions of hydrophone 2 and hydrophone 1 are basically the same, and there are also two possible incoming flow directions, namely "O1-1" and "O1-2". For ease of description, hydrophone 2 is denoted as "O2-1" and "O2-2", and "O2-1" is equivalent to "O1-1" and "O2-2" is equivalent to "O1-2". When hydrophone 2 is tilted by an angle θ2 along the two flow directions "O2-1" and "O2-2", the possible positions of hydrophone 2 "P2-1" and "P2-2" can be found. The distances between "P2-1" and "P2-2" and the sound source are calculated respectively. The position that is equal to the real-time distance L2' is the actual position of hydrophone 2. By working backward, the flow direction of hydrophone 2 ("O2-1" or "O2-2"), the flow direction of hydrophone 1 ("O1-1" or "O1-2"), and the actual position of hydrophone 1 ("P1-1" or "P1-2") can be determined.

[0032] like Figure 5This is a flowchart of the entire system calculation process. In the initial state, the horizontal coordinates (Xn, Yn) and depth (Hn-1) of each hydrophone n (where n is the hydrophone number) are measured. After the system starts working, the measured values ​​and intermediate calculated values ​​of each hydrophone can be obtained. Through cross-verification of adjacent hydrophones (no less than the number of hydrophones), the system is continuously corrected and the depth (An) and horizontal position (Xn, Yn) of each hydrophone can be accurately calculated. At the same time, the above calculation process is repeated every few seconds (determined according to the actual accuracy requirements, generally not exceeding 2 seconds) to obtain the real-time three-dimensional spatial position of each hydrophone.

[0033] like Figure 6 This is a schematic diagram of actual usage modes. Mode 1 is that each hydrophone can be arranged along the direction away from the submarine, which can measure the submarine's radiated noise at different distances. Mode 2 is that each hydrophone is arranged in a circle centered on the submarine, which can measure the submarine's radiated noise in different directions.

[0034] This invention can comprehensively calculate and process real-time sensor depth and ranging information to achieve real-time three-dimensional positioning of the radiated noise measurement system. By obtaining the three-dimensional spatial positioning of the distributed measurement system through real-time calculation, the accuracy of noise measurement is improved, and underwater current distribution is indirectly obtained, providing information support for refined analysis of radiated noise. It is also applicable to other marine systems or devices composed of several vertical branches.

[0035] The above description only illustrates preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. Any equivalent structural or procedural modifications made using this specification are included within the patent protection scope of the present invention.

Claims

1. A real-time three-dimensional positioning method for a distributed noise measurement system, characterized in that: Includes the following steps, Step 1, Preparation: Add two depth sensors to each branch of the distributed radiated noise measurement system where the hydrophones are located, and add one active ranging sound source at the target submarine. The depth sensors are used to measure the depth value in real time and upload it to the trunk equipment, while the active ranging sound source is used to intermittently transmit active high-frequency signals for the hydrophones to receive and measure the distance in real time. Step 2: Obtain the measured value and intermediate calculated value for each hydrophone. The intermediate calculated value is the hydrophone tilt angle. Step 3: Based on the fact that the water flow direction of adjacent hydrophones is the same, perform N cross-verifications and make continuous corrections to calculate the depth (An) and horizontal position (Xn, Yn) of each hydrophone. The value of N is not less than the number of hydrophones. Step 4: Repeat the above calculation process every M seconds to obtain the real-time three-dimensional spatial position of each hydrophone, where M is no greater than 2 seconds.

2. The real-time three-dimensional positioning method for a distributed noise measurement system according to claim 1, characterized in that: The depth sensor is built into the depth sensor compartment.

3. The real-time three-dimensional positioning method for the distributed noise measurement system according to claim 1, characterized in that: One of the two depth sensors located on the same branch is installed at the corresponding hydrophone, and the other is installed at the junction of the branch where the corresponding hydrophone is located and the main cable.

4. The real-time three-dimensional positioning method for the distributed noise measurement system according to claim 1, characterized in that: In step 2, based on the branch where each hydrophone is located, the hydrophones in each branch are sequentially coded. Assuming the hydrophone code for the branch is n, the length between the two depth sensors above and below the branch is denoted as D. The initial position is set when the branch does not tilt. At this time, the depth values ​​of the two depth sensors are denoted as Hn-1 and Hn-2, respectively, the ranging value of the ranging sound source is denoted as Ln, and the sound source depth is S. When the current comes in, the branch tilts, and the tilt angle is denoted as θn. The depth values ​​of the two depth sensors are denoted as Hn-1' and Hn-2', respectively, and the ranging value of the ranging sound source is denoted as Ln'. The tilt angle is calculated through geometric relationships as θn = arccos((Hn-2') - (Hn-1') / D).

5. The real-time three-dimensional positioning method for a distributed noise measurement system according to claim 4, characterized in that: The tilt angle is obtained by calculating the inverse cosine function as θn = arccos((Hn-2')-(Hn-1') / D).

6. The real-time three-dimensional positioning method of the distributed noise measurement system according to claim 4, characterized in that: In step 4, assuming that after the hydrophone coded as n deviates from its initial position, the distance between its real-time position and the ranging sound source is Ln', and the tilt angle is θn, and the adjacent hydrophone coded as n+1 and its branch are synchronously analyzed, the real-time tilt angle of the hydrophone coded as n+1 is calculated and recorded as θn+1, and the distance between the real-time position of the hydrophone coded as n+1 and the ranging sound source is calculated and recorded as L(n+1)'; By using Ln' and tilt angle θn, the three-dimensional spatial position of the hydrophone coded as n can be determined to be one of Pn-1 and Pn-2. Similarly, by using L(n+1)' and θn+1, the three-dimensional spatial position of the hydrophone coded as n++1 can be determined to be one of P(n+1)-1 and (n+1)-2. Based on the distance between adjacent hydrophones and the degree of change in the direction of the incoming flow, it is approximately determined that the hydrophone coded as n and the hydrophone coded as n+1 have the same direction of water flow. Based on the two inclination angles θn+1 of the two directions of the hydrophone coded as n+1, two possible positions of the hydrophone coded as n+1 are determined. The distance between the two possible positions and the sound source is calculated respectively. Based on the matching of the calculated distance with the real-time distance L(n+1)', the exact position of the hydrophone coded as n+1 is determined. And by reverse engineering, the exact location of the hydrophone coded as n is determined.

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