A method for measuring the electric dipole moment of a ship

Abstract

The application provides a warship electric dipole moment measuring method, the bow and stern direction of the warship and the axial direction of the simulated electric dipole are distributed along the same line, the electric field measuring system is arranged at the center point of the warship and the simulated electric dipole connection line, the output current of the simulated electric dipole or the length of the simulated electric dipole is adjusted to further adjust the electric dipole moment size of the simulated electric dipole, so that the electric field size generated by the simulated electric dipole and the warship at the electric field measuring system arrangement point is equal and the direction is opposite, at this time, the electric dipole moment of the simulated electric dipole is equal to the electric dipole moment of the warship; it can be seen from the above that the electric dipole moment of the unshaped or shaped warship, submarine and underwater navigation body can be directly measured, and the measurement error caused by the noise level of the electric field measuring system or the conversion error of the electric dipole moment after inversion caused by the inconsistency between the electromagnetic parameter setting of the measurement site layered medium and the actual situation is overcome.

Description

Technical Field

[0001] This invention belongs to the field of ship electric field measurement technology, and particularly relates to a method for measuring the electric dipole moment of ships. Background Technology

[0002] In the calculation of the electric field characteristics of ship targets, the ship's electric dipole moment, to a certain extent, reflects the magnitude of the target source intensity and is a raw input parameter that needs to be obtained in advance. Currently, methods for obtaining the ship's electric dipole moment involve measuring the electric field generated by the ship at one or several specific points, and then inverting the measured electric field using the expression for the electric field generated by the electric dipole moment to obtain the ship's electric dipole moment. This is an indirect measurement of the ship's electric dipole moment itself. After obtaining the ship's electric dipole moment, the target electric field characteristics of the ship in different sea areas can be calculated using the electric field expression of the electric dipole in a layered medium model, thereby assessing its electric field stealth performance and the likelihood of detection.

[0003] The process of retrieving the ship's electric dipole moment from measured electric field data needs to consider the following three factors: 1) the relative position and distance between the ship target and the electric field measurement system; 2) the error level of the electric field value obtained by the electric field measurement system; and 3) the layered structure of the measurement site and the electromagnetic parameters (permeability μ, permittivity ε, conductivity σ) of each layer. With current technology: 1) the relative position and distance between the ship target and the electric field measurement system can be obtained through precise measurement; 2) the error level of the electric field value obtained by the electric field measurement system is related to the sensitivity and noise level of the system itself. Currently, the electric field measurement system with the best reported sensitivity and noise level is the one developed by Ludwig Systemtechnik in Germany using a carbon fiber electric field sensor, with a sensitivity of 2nV / m@1Hz and a noise level of... EU countries have a policy of limiting noise levels to below 100%. Electric field sensors are strictly prohibited from being exported to China; domestically developed electric field sensors have a self-noise level of... Due to the noise level and measurement error of the electric field measurement system, the conversion error of the electric dipole moment of a ship will occur when using the measured electric field data of the ship to obtain the electric dipole moment; 3) There is currently no fixed standard for how many layers the medium of the measurement site is divided into, the depth of each layer, and how to determine the electromagnetic parameters of each layer. In the process of obtaining the electric dipole moment of a ship from the measured electric field data of the ship, the following two methods are usually used: a) Relying on the experience of the testers, the number of layers the medium of the measurement site is divided into, the depth of each layer, and how to determine the electromagnetic parameters of each layer are entirely up to the testers. Experience dictates that, at the same measurement site, different personnel will have different numbers of layers, depths of each layer, and electrical parameter values. This leads to inconsistencies in the ship's electric dipole moment obtained by different operators from the ship's measured electric field data for the same target; b) Considering only a single medium model without considering layered medium models, while the actual measurement site must be a multi-layered medium model, will result in a large error in the obtained ship's electric dipole moment, which will not match the actual value. Summary of the Invention

[0004] To address the issue of large errors in calculating the electric dipole moment of ships by measuring the electric field generated by the ship during the target electric field characteristics calculation process, this invention provides a method for measuring the electric dipole moment of ships, submarines, and underwater vehicles that can directly measure the electric dipole moment of undetermined or determined ships, submarines, and underwater vehicles.

[0005] A method for measuring the electric dipole moment of a ship includes the following steps:

[0006] Ships were moored and simulated electric dipoles were deployed in the test area, with the bow and stern of the ships aligned with the axial direction of the simulated electric dipoles.

[0007] The electric field measurement system is positioned at the center point of the line connecting the ship and the simulated electric dipole, with the simulated electric dipole and the ship's propeller rotation axis at the same depth.

[0008] Adjust the length of the electrode cable of the simulated electric dipole so that the length of the simulated electric dipole is the same as the length of the ship;

[0009] Adjust the output current of the simulated electric dipole until the output voltage of the electric field measurement system is zero, and take the product of the output current value I and the length L of the electrode cable as the electric dipole moment of the ship.

[0010] Furthermore, the electric field measurement system is deployed along the bow-stern extension line of the ship, and the electric field measurement system includes two measurement channels. One measurement channel is parallel to the bow-stern direction of the ship and is used to obtain the voltage value in the bow-stern direction. The other measurement channel is parallel to the lateral direction of the ship and is used to obtain the voltage value in the lateral direction.

[0011] When the voltage values ​​of both measurement channels are 0, the output voltage value of the electric field measurement system is zero. At this time, the electric dipole moment of the simulated electric dipole is equal to the electric dipole moment of the ship.

[0012] Furthermore, there are at least two electric field measurement systems, and each electric field measurement system includes two measurement channels. At the same time, the bow and stern directions of the ship are taken as the X-axis direction.

[0013] The positions of each electric field measurement system are arranged in a straight line along the Y direction, and one electric field measurement system is located on the extension line of the bow and stern of the ship; one measurement channel of each electric field measurement system is parallel to the bow and stern of the ship and is used to obtain the voltage value at different points parallel to the bow and stern, and the other measurement channel is parallel to the lateral direction of the ship and is used to obtain the voltage value at different points parallel to the lateral direction.

[0014] When the output voltage values ​​of the two measurement channels of each electric field measurement system are both 0, the overall output voltage value of each electric field measurement system is zero. At this time, the electric dipole moment of the simulated electric dipole is equal to the electric dipole moment of the ship, which can reduce the measurement error of the ship's electric dipole moment caused by the measurement error of the electric field measurement system.

[0015] Furthermore, the simulated electric dipole consists of a power supply, an electrode cable, and a emitting electrode, and has adjustable electrode cable length and water immersion depth. The output current of the power supply of the simulated electric dipole has positive and negative and magnitude adjustment functions. By adjusting the magnitude and direction of its output current, the output voltage value of each measurement channel of the electric field measurement system is zero. The emitting electrode is used to discharge to the outside according to the set output current.

[0016] Furthermore, the test sea area is used as a layered medium model, which is divided into an air layer, a seawater layer, and a bottom layer from top to bottom. The air layer and the bottom layer are further divided into multiple sub-layers according to a set step size. Ships, simulated electric dipoles, and electric field measurement systems are placed in the seawater layer.

[0017] Beneficial effects:

[0018] 1. This invention provides a method for measuring the electric dipole moment of a ship. The bow and stern directions of the ship and the axial direction of the simulated electric dipole are aligned along the same straight line. The electric field measurement system is positioned at the center point of the line connecting the ship and the simulated electric dipole. By adjusting the output current or length of the simulated electric dipole, the magnitude of its electric dipole moment is adjusted, ensuring that the electric fields generated by the simulated electric dipole and the ship at the point where the electric field measurement system is deployed are equal in magnitude and opposite in direction. At this point, the electric dipole moment of the simulated electric dipole is equal to that of the ship. Therefore, this invention can directly measure the electric dipole moment of undetermined or finalized ships, submarines, and underwater vehicles. It overcomes the measurement errors caused by the noise level of the electric field measurement system or the inconsistency between the electromagnetic parameters of the layered medium at the measurement site and the actual measurement process, which leads to errors in the conversion of the inverted electric dipole moment during the indirect measurement process of obtaining the ship's electric dipole moment through electric field inversion. Furthermore, it features simple operation and high measurement accuracy.

[0019] 2. This invention provides a method for measuring the electric dipole moment of a ship. To increase the measurement accuracy, multiple electric field measurement systems can be set up on the central axis of the line connecting the bow and stern directions of the ship and the axial direction of the simulated electric dipole to determine the output current or the length of the simulated electric dipole that makes the output voltage value zero, thereby increasing the measurement accuracy of the electric dipole moment of the ship.

[0020] 3. This invention provides a method for measuring the electric dipole moment of a ship. Since the ship, the simulated electric dipole, and the electric field measurement system are all located in the same dielectric layer, the layered dielectric model of the measurement site has no effect on the measurement results regardless of the dielectric layer. This effectively avoids the conversion error of electric dipole moment caused by factors such as the number of dielectric layers, the depth of each layer, and the electromagnetic parameter values ​​of each dielectric layer during the inversion process. In addition, this invention essentially considers the layered dielectric structure rather than the measurement results under a single dielectric in the process of measuring the electric dipole moment of a ship, and has the characteristics of simple operation and high measurement accuracy.

[0021] 4. This invention provides a method for measuring the electric dipole moment of a ship. In the measurement process, it not only considers the layered medium model of the measurement site but also ignores the error brought by the model to the electric dipole moment measurement process. It belongs to the direct measurement method of the electric dipole moment of a ship and is particularly suitable for measuring the electric dipole moment of ships, submarines and underwater vehicles that are either undetermined or have been determined. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the shipboard electric dipole moment measurement position according to the present invention;

[0023] Figure 2 This is a schematic diagram of the layered medium during the measurement of the electric dipole moment of a ship according to the present invention. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings.

[0025] A method for measuring the electric dipole moment of a ship includes the following steps:

[0026] S1: As Figure 1 As shown, ships were moored and simulated electric dipoles were deployed in the test sea area, with the bow and stern directions of the ships and the axial direction of the simulated electric dipoles distributed along the same straight line.

[0027] S2: The electric field measurement system is placed at the center point of the line connecting the ship and the simulated electric dipole, and the simulated electric dipole and the ship's propeller rotation axis are at the same depth; that is, the distance s1 between the center point of the ship and the electric field measurement system is equal to the distance s2 between the center point of the simulated electric dipole and the electric field measurement system.

[0028] The electric field measurement system can be deployed in one or more sets. When one set of electric field measurement system is deployed, the system is positioned along the bow-stern extension of the ship, and includes two measurement channels, one of which is parallel to the bow-stern axis of the ship. Figure 1 The thick black solid line in the horizontal direction of the electric field measurement system shown is used to obtain the voltage value from bow to stern. The other measurement channel is parallel to the lateral direction of the ship, as shown... Figure 1 The thick black solid line in the vertical direction of the electric field measurement system shown is used to obtain the voltage value in the horizontal direction; when the voltage values ​​of both measurement channels are 0, the electric dipole moment of the simulated electric dipole is equal to that of the ship.

[0029] When two or more electric field measurement systems are deployed, each electric field measurement system includes two measurement channels. The bow and stern of the ship is taken as the X-axis direction. The positions of each electric field measurement system are arranged in a straight line along the Y-axis, and one electric field measurement system is located on the extension line of the bow and stern of the ship. One measurement channel of each electric field measurement system is parallel to the bow and stern of the ship and is used to obtain the voltage values ​​at different points parallel to the bow and stern. The other measurement channel is parallel to the lateral direction of the ship and is used to obtain the voltage values ​​at different points parallel to the lateral direction.

[0030] When the output voltage values ​​of the two measurement channels of each electric field measurement system are both 0, the electric dipole moment of the simulated electric dipole is equal to that of the ship, which can reduce the measurement error of the ship's electric dipole moment caused by the measurement error of the electric field measurement system.

[0031] S3: Adjust the length of the electrode cable of the simulated electric dipole so that the length of the simulated electric dipole is the same as the length of the ship;

[0032] It should be noted that the simulated electric dipole consists of a power supply, an electrode cable, and a transmitting electrode, and has the function of adjustable electrode cable length and water immersion depth; wherein, the output current of the power supply of the simulated electric dipole has the function of adjusting positive and negative and magnitude, adjusting the magnitude and direction of its output current so that the output voltage value of each measurement channel of the electric field measurement system is zero; the transmitting electrode is used to discharge to the outside according to the set output current.

[0033] S4: Adjust the output current of the simulated electric dipole until the output voltage of the electric field measurement system is zero, record the output current value I of the power supply, and take the product of the output current value I at this time and the length L of the electrode cable as the electric dipole moment of the ship.

[0034] It should be noted that the simulated electric dipole discharges to the outside through the emitting electrode according to the set output current, thereby affecting the electric field at the electric field measurement system. Due to the different metal materials used in the components of the ship, such as the propeller and the hull, electrochemical reactions such as galvanic cell discharge will occur in the conductive seawater, which will also affect the electric field at the electric field measurement system. Therefore, by adjusting the output current of the simulated electric dipole until the output voltage of the electric field measurement system is zero, the electric dipole moment of the ship can be equivalently obtained.

[0035] This completes the measurement of the ship's electric dipole moment.

[0036] like Figure 2 As shown, the test sea area is a layered medium model, which is divided into an air layer, a seawater layer, and a seabed layer from top to bottom. The air layer and the seabed layer are further divided into multiple sub-layers according to a set step size. Ships, simulated electric dipoles, and electric field measurement systems are placed in the seawater layer.

[0037] Therefore, this invention relates to the direct measurement of the electric dipole moment of undetermined or determined ships, submarines, and underwater vehicles. Furthermore, since the ship, the simulated electric dipole, and the electric field measurement system are all located in the same dielectric layer, the layered dielectric model of the measurement site has no impact on the measurement results, regardless of the dielectric layer. This effectively avoids the electric dipole moment conversion errors caused by factors such as the number of dielectric layers, the depth of each layer, and the electromagnetic parameter values ​​of each layer during the inversion process.

[0038] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A method for measuring the electric dipole moment of a ship, characterized in that, Includes the following steps: Ships were moored and simulated electric dipoles were deployed in the test area, with the bow and stern of the ships aligned with the axial direction of the simulated electric dipoles. The electric field measurement system is positioned at the center point of the line connecting the ship and the simulated electric dipole, with the simulated electric dipole and the ship's propeller rotation axis at the same depth. Adjust the length of the electrode cable of the simulated electric dipole so that the length of the simulated electric dipole is the same as the length of the ship; Adjust the output current of the simulated electric dipole until the output voltage of the electric field measurement system is zero, and take the product of the output current value I at this time and the length L of the electrode cable as the electric dipole moment of the ship. The electric field measurement system is deployed along the bow-stern extension of the ship and includes two measurement channels. One measurement channel is parallel to the bow-stern direction of the ship and is used to obtain the voltage value in the bow-stern direction. The other measurement channel is parallel to the lateral direction of the ship and is used to obtain the voltage value in the lateral direction. When the voltage values ​​of both measurement channels are 0, the output voltage value of the electric field measurement system is zero. At this time, the electric dipole moment of the simulated electric dipole is equal to the electric dipole moment of the ship.

2. A method for measuring the electric dipole moment of a ship, characterized in that, Includes the following steps: Ships were moored and simulated electric dipoles were deployed in the test area, with the bow and stern of the ships aligned with the axial direction of the simulated electric dipoles. The electric field measurement system is positioned at the center point of the line connecting the ship and the simulated electric dipole, with the simulated electric dipole and the ship's propeller rotation axis at the same depth. Adjust the length of the electrode cable of the simulated electric dipole so that the length of the simulated electric dipole is the same as the length of the ship; Adjust the output current of the simulated electric dipole until the output voltage of the electric field measurement system is zero, and take the product of the output current value I at this time and the length L of the electrode cable as the electric dipole moment of the ship. There are at least two electric field measurement systems, and each electric field measurement system includes two measurement channels. At the same time, the bow and stern directions of the ship are used as the X-axis direction. The positions of each electric field measurement system are arranged in a straight line along the Y direction, and one electric field measurement system is located on the extension line of the bow and stern of the ship; one measurement channel of each electric field measurement system is parallel to the bow and stern of the ship and is used to obtain the voltage value at different points parallel to the bow and stern, and the other measurement channel is parallel to the lateral direction of the ship and is used to obtain the voltage value at different points parallel to the lateral direction. When the output voltage values ​​of the two measurement channels of each electric field measurement system are both 0, the overall output voltage value of each electric field measurement system is zero. At this time, the electric dipole moment of the simulated electric dipole is equal to the electric dipole moment of the ship, which can reduce the measurement error of the ship's electric dipole moment caused by the measurement error of the electric field measurement system.

3. The method for measuring the electric dipole moment of a ship as described in claim 1, characterized in that, The simulated electric dipole consists of a power supply, an electrode cable, and a transmitting electrode, and has adjustable electrode cable length and water immersion depth. The power supply of the simulated electric dipole has adjustable output current in terms of positive and negative values ​​and magnitude. Adjusting the magnitude and direction of its output current ensures that the output voltage values ​​of each measurement channel of the electric field measurement system are all zero. The transmitting electrode is used to discharge to the outside according to the set output current.

4. A method for measuring the electric dipole moment of a ship as described in any one of claims 1 to 3, characterized in that, The test sea area is used as a layered medium model, which is divided into an air layer, a seawater layer, and a seabed layer from top to bottom. The air layer and the seabed layer are further divided into multiple sub-layers according to a set step size. Ships, simulated electric dipoles, and electric field measurement systems are placed in the seawater layer.

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