CN103185871A - Method for measuring vertical component of ship induced magnetic field in one direction - Google Patents

Abstract

A method for measuring the vertical component of a ship's induced magnetic field in a single direction designed by the present invention, the method surrounds a geomagnetic simulation coil around the ship, energizes the coil to simulate different geomagnetic fields, and utilizes the magnetic field generated by different geomagnetic fields to magnetize the ship Decompose the vertical component of its induced magnetic field. The invention adopts the method of simulating the generation of the geomagnetic field by the geomagnetic simulation coil to realize the unidirectional measurement of the vertical component of the ship's induced magnetic field, which solves the problem of needing to reverse the direction and transfer the position in the existing method of measuring the vertical component of the ship's induced magnetic field, and has high measurement efficiency, The advantages of fast decomposition and saving manpower and material resources.

Description

A kind of folk prescription is to the method for measuring boats and ships induced field vertical component

Technical field

The present invention relates to the demagnetization technical field, refer to that particularly a kind of folk prescription is to the method for measuring boats and ships induced field vertical component.

Technical background

Ferromagnetic objects such as boats and ships are under the effect of magnetic field of the earth, can produce induced magnetism, and then produce induced field around the ferromagnetic object, induced field is a kind of magnetic field that changes with external magnetic field (mainly being the magnetic field of the earth), it is relevant with factors such as the real-time position of ferromagnetic object, direction, attitudes, thereby is a kind of temporal effect magnetic field.The size of ferromagnetic object induced magnetism is relevant with following factors:

1) size of terrestrial magnetic field, ferromagnetic object position;

2) direction of ferromagnetic object, attitude etc.;

The magnetic property of used steel when 3) ferromagnetic object is built;

4) ferromagnetic object shape, size and structure.

If the material that the ferromagnetic object of same type is built is identical, structure is identical, and then its induced magnetism should be identical.

When ferromagnetic object is demagnetized, need accurately to measure the vertical component of its induced field, thus can be to its processing of demagnetizing.

Generally speaking, the vertical component of the horizontal induced field of ferromagnetic object is decomposed with the same point magnetic-field measurement data that Ci Dong, magnetic west or magnetic south, two of magnetic north differ 180 ° of directions; The vertical component of vertical induced field is decomposed in the magnetic-field measurement data of different regions with ferromagnetic object.

This induced field decomposition method is easy to realize for small-sized ferromagnetic object, still, for large-scale ferromagnetic objects such as boats and ships, it is carried out reverses its direction need waste lot of manpower and material resources, and is very inconvenient; And for the measurement of vertical induced field vertical component, need that again measured target is transferred to the another one area to measure, more inconvenient like this.Therefore, realize that folk prescription is extremely important to the vertical component of measuring the ferromagnetic object induced field, have very important realistic meaning.

Summary of the invention

Purpose of the present invention is exactly to provide a kind of folk prescription to the method for measuring boats and ships induced field vertical component, this method has solved the problem that needs to turn tested boats and ships direction in the existing measurement ferromagnetic object induced field vertical component method, can be applicable to the measurement of the vertical induced field vertical component of large-scale ferromagnetic objects such as boats and ships.

For realizing this purpose, the designed folk prescription of the present invention is characterized in that to the method for measuring boats and ships induced field vertical component it comprises the steps:

Step 1): before hull to be measured enters checkout area, measure the vertical component Z of terrestrial magnetic field by Magnetic Sensor _D1

Step 2): according to the design size of hull, coiling can cover bow to the vertical earth magnetism former-wound coil of the multiturn of stern, and the inner ring of described vertical earth magnetism former-wound coil can wrap the horizontal outline of hull; Coiling can cover two horizontal earth magnetism former-wound coils of hull port and starboard; Coiling can cover the vertical earth magnetism former-wound coil of hull bottom;

Step 3): only to vertical earth magnetism former-wound coil energising, make vertical earth magnetism former-wound coil center produce uniformly vertically simulation terrestrial magnetic field, the numerical value of hub of a spool changes of magnetic field is coil 2 times of geomagnetic field horizontal component numerical value when not switching on, measure magnetic field vertical component that vertical earth magnetism former-wound coil center contain terrestrial magnetic field by Magnetic Sensor this moment, is designated as Z _D2

Step 4): only two horizontal earth magnetism former-wound coils that can cover the hull port and starboard of above-mentioned coiling are switched on, make two horizontal earth magnetism former-wound coils produce uniformly laterally simulation terrestrial magnetic field, the numerical value that two horizontal earth magnetism former-wound coil central magnetic fields change is two horizontal earth magnetism former-wound coils 2 times of geomagnetic field horizontal component numerical value when not switching on, measure magnetic field vertical component that two horizontal earth magnetism former-wound coil centers contain terrestrial magnetic field by Magnetic Sensor this moment, is designated as Z _D3

Step 5): only the vertical earth magnetism former-wound coil that can cover hull bottom of above-mentioned coiling is switched on, make vertical earth magnetism former-wound coil produce uniform vertical simulation terrestrial magnetic field, the numerical value that vertical earth magnetism former-wound coil central magnetic field changes is vertical earth magnetism former-wound coil 2 times of geomagnetic field vertical component numerical value when not switching on, measure magnetic field vertical component that vertical earth magnetism former-wound coil center contain terrestrial magnetic field by Magnetic Sensor this moment, is designated as Z _D4

Step 6): the power supply that disconnects above-mentioned vertical earth magnetism former-wound coil, vertical earth magnetism former-wound coil and two horizontal earth magnetism former-wound coils, bring hull into checkout area then, and hull sent in above-mentioned vertical earth magnetism former-wound coil, vertical earth magnetism former-wound coil and two the horizontal earth magnetism former-wound coil region surrounded, measure magnetic field and the geomagnetic field vertical component sum that hull produces by Magnetic Sensor, be designated as Z ₁

Step 7): only to vertical earth magnetism former-wound coil energising and produce 2 times of geomagnetic field horizontal components, measure the magnetic field of tested hull, vertically earth magnetism former-wound coil magnetic field and terrestrial magnetic field vertical component sum by Magnetic Sensor then, be designated as Z ₂

Step 8): the vertical component Z that draws longitudinal induction magnetic field according to following formula _Ix

$Z_{\mathrm{ix}}=\frac{((Z_1-Z_{D1})-(Z_2-Z_{D2}))}{2}---\left(1\right)$

So namely finished the measurement of the longitudinal induction magnetic field vertical component of hull to be measured;

Step 9): only to two horizontal earth magnetism former-wound coils energisings that can cover the hull port and starboard and produce 2 times of geomagnetic field horizontal components, measure the magnetic field of tested hull, two magnetic field and geomagnetic field vertical component sums that horizontal earth magnetism former-wound coil produces by Magnetic Sensor then, be designated as Z ₃

Step 10) draws the vertical component Z in transvercal induction magnetic field according to following formula _Iy

$Z_{\mathrm{iy}}=\frac{((Z_1-Z_{D1})-(Z_3-Z_{D3}3))}{2}---\left(2\right)$

So namely finished the measurement of the transvercal induction magnetic field vertical component of hull to be measured;

Step 11): only to the vertical earth magnetism former-wound coil energising that can cover hull bottom and produce 2 times of geomagnetic field vertical components, measure magnetic field and the geomagnetic field vertical component sum of the magnetic field of tested hull, the generation of vertical earth magnetism former-wound coil then by Magnetic Sensor, be designated as Z ₄

Step 12): the vertical component Z that draws vertical induced field according to following formula _Iz

$Z_{\mathrm{iz}}=\frac{((Z_1-Z_{D1})-(Z_4-Z_{D4}))}{2}---\left(3\right)$

So namely having finished the vertical component of the vertical induced field of hull to be measured measures.

Described vertical earth magnetism former-wound coil is solenoid coil.

The described vertical earth magnetism former-wound coil that can cover hull bottom is rectangle earth magnetism former-wound coil with two horizontal earth magnetism former-wound coils that can cover the hull port and starboard.

The method that the present invention adopts the simulation of earth magnetism former-wound coil to produce the terrestrial magnetic field realizes that folk prescription is to the vertical component of measuring the boats and ships induced field, solved the problem that needs reverses its direction and transfer position in the existing measurement boats and ships induced field vertical component method, had and measure the advantage that efficient height, decomposition rate are fast, use manpower and material resources sparingly.

Description of drawings

Fig. 1 is vertical earth magnetism former-wound coil synoptic diagram among the present invention;

Fig. 2 is horizontal earth magnetism former-wound coil synoptic diagram among the present invention;

Fig. 3 is the horizontal cross-sectional synoptic diagram of earth magnetism former-wound coil among the present invention;

Fig. 4 is vertical earth magnetism former-wound coil synoptic diagram among the present invention;

Fig. 5 is the vertical cross-sectional synoptic diagram of earth magnetism former-wound coil among the present invention;

Embodiment

The present invention is described in further detail below in conjunction with the drawings and specific embodiments:

As everyone knows, the terrestrial magnetic field makes it have the magnetic of three directions to the magnetization of ferromagnetic object: vertical magnetism, vertical magnetic, horizontal magnetic.It is synthetic by fixed magnetic and two parts of induced magnetism that the magnetic of ferromagnetic object can be regarded as, wherein fixed magnetic under certain condition, visually in the certain hour fix constantly, change irrelevant with the terrestrial magnetic field; Induced magnetism changes pro rata with the terrestrial magnetic field.Because the magnetic field of ferromagnetic object is a vector field, for easy analysis, generally every kind of magnetic field is resolved into the component of three directions again, i.e. vertical component, longitudinal component, cross stream component.

Vertical component for the ferromagnetic object induced field, three kinds of the vertical components that the vertical component in vertical component, transvercal induction magnetic field in longitudinal induction magnetic field and vertical induced field are generally arranged, the measurement of the vertical component of the vertical component of utilizing following method can be implemented in to finish boats and ships longitudinal induction magnetic field under the situation of not turning tested boats and ships direction, the vertical component in transvercal induction magnetic field and vertical induced field.

A kind of folk prescription is characterized in that to the method for measuring boats and ships induced field vertical component it comprises the steps:

Step 1): before hull to be measured enters checkout area, measure the vertical component Z of terrestrial magnetic field by Magnetic Sensor _D1

Step 2): according to the design size of hull, coiling can cover bow to the vertical earth magnetism former-wound coil of the multiturn of stern (as shown in Figure 1), and the inner ring of described vertical earth magnetism former-wound coil can wrap the horizontal outline of hull; Coiling can cover two horizontal earth magnetism former-wound coils (as shown in Figures 2 and 3) of hull port and starboard; Coiling can cover the vertical earth magnetism former-wound coil (as shown in Figure 4 and Figure 5) of hull bottom;

Step 3): only to vertical earth magnetism former-wound coil energising, make vertical earth magnetism former-wound coil center produce uniformly vertically simulation terrestrial magnetic field, the numerical value of hub of a spool changes of magnetic field is coil 2 times of geomagnetic field horizontal component numerical value when not switching on, measure magnetic field vertical component that vertical earth magnetism former-wound coil center contain terrestrial magnetic field by Magnetic Sensor this moment, is designated as Z _D2

Step 4): only two horizontal earth magnetism former-wound coils that can cover the hull port and starboard of above-mentioned coiling are switched on, make two horizontal earth magnetism former-wound coils produce uniformly laterally simulation terrestrial magnetic field, the numerical value that two horizontal earth magnetism former-wound coil central magnetic fields change is two horizontal earth magnetism former-wound coils 2 times of geomagnetic field horizontal component numerical value when not switching on, measure magnetic field vertical component that two horizontal earth magnetism former-wound coil centers contain terrestrial magnetic field by Magnetic Sensor this moment, is designated as Z _D3

Step 5): only the vertical earth magnetism former-wound coil that can cover hull bottom of above-mentioned coiling is switched on, make vertical earth magnetism former-wound coil produce uniform vertical simulation terrestrial magnetic field, the numerical value that vertical earth magnetism former-wound coil central magnetic field changes is vertical earth magnetism former-wound coil 2 times of geomagnetic field vertical component numerical value when not switching on, measure magnetic field vertical component that vertical earth magnetism former-wound coil center contain terrestrial magnetic field by Magnetic Sensor this moment, is designated as Z _D4

Step 6): the power supply that disconnects above-mentioned vertical earth magnetism former-wound coil, vertical earth magnetism former-wound coil and two horizontal earth magnetism former-wound coils, bring hull into checkout area then, and hull sent in above-mentioned vertical earth magnetism former-wound coil, vertical earth magnetism former-wound coil and two the horizontal earth magnetism former-wound coil region surrounded, measure magnetic field and the geomagnetic field vertical component sum that hull produces by Magnetic Sensor, be designated as Z ₁

Step 7): only to vertical earth magnetism former-wound coil energising and produce 2 times of geomagnetic field horizontal components, measure the magnetic field of tested hull, vertically earth magnetism former-wound coil magnetic field and terrestrial magnetic field vertical component sum by Magnetic Sensor then, be designated as Z ₂

Step 8): the vertical component Z that draws longitudinal induction magnetic field according to following formula _Ix

$Z_{\mathrm{ix}}=\frac{((Z_1-Z_{D1})-(Z_2-Z_{D2}))}{2}---\left(1\right)$

So namely finished the measurement of the longitudinal induction magnetic field vertical component of hull to be measured;

Step 9): only to two horizontal earth magnetism former-wound coils energisings that can cover the hull port and starboard and produce 2 times of geomagnetic field horizontal components, measure the magnetic field of tested hull, two magnetic field and geomagnetic field vertical component sums that horizontal earth magnetism former-wound coil produces by Magnetic Sensor then, be designated as Z ₃

Step 10) draws the vertical component Z in transvercal induction magnetic field according to following formula _Iy

$Z_{\mathrm{iy}}=\frac{((Z_1-Z_{D1})-(Z_3-Z_{D3}))}{2}---\left(2\right)$

So namely finished the measurement of the transvercal induction magnetic field vertical component of hull to be measured;

Step 11): only to the vertical earth magnetism former-wound coil energising that can cover hull bottom and produce 2 times of geomagnetic field vertical components, measure magnetic field and the geomagnetic field vertical component sum of the magnetic field of tested hull, the generation of vertical earth magnetism former-wound coil then by Magnetic Sensor, be designated as Z ₄

Step 12): the vertical component Z that draws vertical induced field according to following formula _Iz

$Z_{\mathrm{iz}}=\frac{((Z_1-Z_{D1})-(Z_4-Z_{D4}))}{2}---\left(3\right)$

So namely having finished the vertical component of the vertical induced field of hull to be measured measures.

In the technique scheme, described vertical earth magnetism former-wound coil is solenoid coil.

In the technique scheme, the described vertical earth magnetism former-wound coil that can cover hull bottom is rectangle earth magnetism former-wound coil with two horizontal earth magnetism former-wound coils that can cover the hull port and starboard.

In the technique scheme, for Z _IxAsk for, adopt vertical earth magnetism former-wound coil shown in Figure 1, coil is switched on, make hub of a spool produce uniform longitudinal magnetic field, the numerical value that hub of a spool magnetic field longitudinal component changes is coil 2 times of geomagnetic field horizontal component numerical value when not switching on, like this, can directly utilize formula (1) to ask for the induced field vertical component Z of this ferromagnetic object _Ix

In the technique scheme, for Z _IyAsk for, adopt Fig. 2 and horizontal earth magnetism former-wound coil shown in Figure 3, coil is switched on, make hub of a spool produce uniform transverse magnetic field, the numerical value that hub of a spool magnetic field cross stream component changes is coil 2 times of geomagnetic field horizontal component numerical value when not switching on.Like this, can directly utilize formula (2) to ask for the induced field vertical component Z of this ferromagnetic object _Iy

In the above-mentioned technical method, for Z _IzAsk for, can adopt Fig. 4 and vertical earth magnetism former-wound coil shown in Figure 5, coil is switched on, make hub of a spool produce uniform vertical magnetic field, the numerical value that hub of a spool magnetic field vertical component changes is coil 2 times of geomagnetic field vertical component numerical value when not switching on.Like this, can directly utilize formula (3) to ask for the induced field vertical component Z of this ferromagnetic object _Iz

The present invention is by said method coiling earth magnetism former-wound coil around the boats and ships, and simulation produces different terrestrial magnetic field to coil electricity, the vertical component of utilizing the magnetic field that magnetization produces to boats and ships, magnetic field differently to decompose its induced field.

The content that this instructions is not described in detail belongs to this area professional and technical personnel's known prior art.

Claims (3)

1. A method for measuring the vertical component of the ship's induced magnetic field in one direction, characterized in that it comprises the steps: Step 1): Before the hull to be tested enters the test field, measure the vertical component Z _D1 of the geomagnetic field through a magnetic sensor; Step 2): According to the design size of the hull, wind a multi-turn longitudinal geomagnetic simulation coil that can cover the bow to the stern, and the inner ring of the longitudinal geomagnetic simulation coil can wrap the transverse outer contour of the hull; winding can cover the port side of the hull and two transverse geomagnetic simulation coils on the starboard side; a vertical geomagnetic simulation coil that can cover the bottom of the ship is wound; Step 3): Only energize the longitudinal geomagnetic simulation coil, so that the center of the longitudinal geomagnetic simulation coil generates a uniform longitudinal simulated geomagnetic field. The sensor measures the vertical component of the magnetic field containing the geomagnetic field at the center of the longitudinal geomagnetic simulation coil, which is denoted as Z _D2 ; Step 4): Only energize the above-mentioned two transverse geomagnetic simulation coils that can cover the port and starboard sides of the hull, so that the two transverse geomagnetic simulation coils generate a uniform transverse simulated geomagnetic field, and the central magnetic field of the two transverse geomagnetic simulation coils changes The value of is 2 times of the value of the horizontal component of the geomagnetic field when the two transverse geomagnetic simulation coils are not energized. At this time, the vertical component of the magnetic field containing the geomagnetic field at the center of the two transverse geomagnetic simulation coils is measured by the magnetic sensor, which is denoted as Z _D3 ; Step 5): Only energize the above-mentioned vertical geomagnetic simulation coil that can cover the bottom of the ship, so that the vertical geomagnetic simulation coil generates a uniform vertical simulated geomagnetic field, and the value of the central magnetic field change of the vertical geomagnetic simulation coil is vertical When the geomagnetic simulation coil is not energized, it is twice the value of the vertical component of the geomagnetic field. At this time, the vertical component of the magnetic field containing the geomagnetic field at the center of the vertical geomagnetic simulation coil is measured by a magnetic sensor, which is denoted as Z _D4 ; Step 6): Disconnect the power supply of the above-mentioned longitudinal geomagnetic simulation coil, vertical geomagnetic simulation coil and two transverse geomagnetic simulation coils, then bring the hull into the test field, and send the hull into the above-mentioned longitudinal geomagnetic simulation coil, vertical geomagnetic simulation coil In the area surrounded by the coil and two transverse geomagnetic simulation coils, the sum of the magnetic field generated by the hull and the vertical component of the geomagnetic field is measured by the magnetic sensor, which is denoted as Z ₁ ; Step 7): Only energize the longitudinal geomagnetic simulation coil and generate 2 times the horizontal component of the geomagnetic field, and then measure the magnetic field of the measured hull, the sum of the magnetic field of the longitudinal geomagnetic simulation coil and the vertical component of the geomagnetic field through the magnetic sensor, which is recorded as Z ₂ ; Step 8): Obtain the vertical component Z _ix of the longitudinal induced magnetic field according to the following formula; ${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; ix</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ In this way, the measurement of the vertical component of the longitudinal induced magnetic field of the hull to be measured is completed; Step 9): Only energize the two transverse geomagnetic simulation coils that can cover the port and starboard sides of the hull and generate 2 times the horizontal component of the geomagnetic field, and then measure the magnetic field of the measured hull and the magnetic field generated by the two transverse geomagnetic simulation coils through the magnetic sensor and the sum of the vertical component of the geomagnetic field, denoted as Z ₃ ; Step 10) Obtain the vertical component Z _iy of the transverse induced magnetic field according to the following formula; ${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; iy</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 3</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$ This completes the measurement of the vertical component of the transverse induced magnetic field of the hull to be measured; Step 11): Only energize the vertical geomagnetic simulation coil that can cover the bottom of the ship and generate 2 times the vertical component of the geomagnetic field, and then measure the magnetic field of the measured hull, the magnetic field generated by the vertical geomagnetic simulation coil and the vertical component of the geomagnetic field through the magnetic sensor The sum is recorded as Z ₄ ; Step 12): Obtain the vertical component Z _iz of the vertical induced magnetic field according to the following formula; ${\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; iz</span>}}<span\; class="notranslate">\; =</span>\frac{<span\; class="notranslate">\; (</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; Z</span>}}_{\mathrm{<span\; class="notranslate">\; D.</span>}\mathrm{<span\; class="notranslate">\; 4</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; )</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$ In this way, the measurement of the vertical component of the vertical induced magnetic field of the hull to be measured is completed. 2. The method for unidirectionally measuring the vertical component of the ship's induced magnetic field according to claim 1, wherein the longitudinal geomagnetic simulation coil is a solenoid coil. 3. The method for measuring the vertical component of the ship's induced magnetic field in one direction according to claim 1, characterized in that: the vertical geomagnetic simulation coil that can cover the bottom of the ship and the two transverse geomagnetic simulation coils that can cover the port and starboard sides of the hull The coils are all rectangular geomagnetic simulation coils.

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