JPS5845679B2 - magnetic detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a movable magnetic sensing device that is compensated for the effects of agitation.

There is a method of using a magnetic detector to detect magnetic metals.

For example, when moving on the sea surface and detecting magnetic metal sunk on the ocean floor, if you hang a magnetic detector from the ship to an appropriate depth and use an appropriate method to eliminate the influence of the geomagnetic field, the detected magnetic field is a magnetic field generated when magnetic metal is magnetized by the induction effect of the earth's magnetic field, so if you move the ship toward the direction where the magnetic field is stronger, you will be able to land on the metal you are trying to detect.

As such a magnetic detection device, one shown in FIG. 1 has been proposed.

That is, the magnetic detectors 81 to S4 are arranged at each vertex of a regular polygon centered on the magnetic detector So, and these are integrally connected and suspended from the ship into the sea.

These magnetic detectors output signals in response to the magnetic field strength in the vertical direction, and the vertical component of the earth's magnetism is detected by other magnetic detectors placed on board the ship, etc., and the output of each magnetic detector in 5o-84 above is detected. By subtraction, 5o-s3 detects the distorted component of earth's magnetism, that is, the lines of magnetic force emitted by magnetic metal.

In this way, the ship is moved in the direction of the one that outputs the maximum detection output among 81 to S4 until the output of the other magnetic detectors becomes a dog (also performs a sideways movement). As the ship repeats the process, it approaches the metal it is trying to detect while drawing a curved course, and eventually the ship approaches the metal it is trying to detect.
comes to the position where the maximum detection output is produced.

At this time, the object is located directly below the SO at a distance determined by a formula.

As mentioned above, rather than moving the ship closer to the target step by step along a curved route, the gradient of the magnetic field is calculated using vectorial calculations from the outputs of 81 to S4, and the ship is moved continuously in the direction of the maximum gradient. It is more efficient.

However, even if it falls over, with the above-mentioned device, the positional relationship between the ship and the magnetic detector will be different from the positional relationship that is assumed in principle due to the shaking of the ship due to the waves, causing the ship's wake to wander unnecessarily. become.

Figure 2 explains the reason: F is the sea surface, B is a metal exploration ship, and S is a group of magnetic detectors dismounted from ship B.

In order to fix the positional relationship between the ship B and the magnetic detector group S, the arm A that hangs down from S is a rigid body and is fixed to the ship B.

Therefore, if ship B is tilted by an angle θ due to waves, magnetic detector S
will respond to a magnetic field at a location shifted by J = 1 sin θ from its original location.

Note that the vertical component of the magnetic field at that location is Hz. The horizontal component is Hx
Then, the output of the magnetic detector S is not Hz, but HzcoS
θ+Hx sin θ, but since θ is about 5 degrees, COS θ=1. Treated as sin θ20.

In ship B, if the direction of travel of the ship is determined based on the above detection results assuming that the magnetic detector group S is in the normal position, the direction of travel of the ship will be swayed due to the movement of the ship.

It is an object of the present invention to provide a magnetic detection device that eliminates such wandering and allows a user to quickly and accurately approach a target.

The present invention will be explained below with reference to Examples.

FIG. 3 shows the horizontal arrangement of magnetic detectors in an embodiment of the present invention.

SO, 81 to S4 are magnetic detectors, and S□ to S4 are arranged at each vertex of a square centered on SO, and each magnetic detector detects a vertical magnetic field, and the mutual positional relationship is fixed.
It is the same as the conventional example shown in FIGS. 1 and 2 that it is suspended from the ship by a rigid arm.

Magnetic detector group S. ~An inclinometer to detect the inclination of the ship is attached to the upper end of the arm hanging down S4.

There are 1,202 inclinometers, one of which measures the inclination θ in a plane including the X direction and the vertical direction (perpendicular to the plane of the figure) in Figure 3.
The other one detects the inclination φ in a plane including the Y direction and the vertical direction.

From the outputs θ and φ of these inclinometers, the components X and Y in the X and Y directions of the deviation of each magnetic detector from the correct position are
It is determined as = l sin θ Y = l sin φ.

By subtracting the output of the magnetic detector placed on board the ship from the output of each magnetic detector 5o-84, the geomagnetic component is eliminated, and the result becomes an input signal in the calculations described below.

Below, this signal will simply be referred to as the output of 5o-s4, and it will be referred to as the output of HO
Represented by yH1 to H4.

The origin is the position of the central magnetic detector So when the ship is tilted, and the coordinate axes are set as shown in Figure 4 using the distance between So and sl-s4 etc. as the unit of length, and the tilt of the ship is 0. It is assumed that the positions of the magnetic detectors 5o-s4 at this time are So' to 84'.

Since the displacement of the magnetic detectors 80 to S4 is translational, the movement can be expressed by a displacement vector (X, Y) from the origin of So.

Let H(X, y) be the horizontal distribution of the detection output detected by the magnetic detector So-s4 or the like for the vertical component of the magnetic field.

In this process, the data obtained by the device of the present invention are X, Y
and detection outputs H8 to H4 of each magnetic detector at positions shifted due to the inclination of the ship.

The first stage of calculation is to obtain the outputs H8', H,' to H4' of each magnetic detector when the ship's inclination is O from this data.

Putting H(xy) into equations (8) to α above into equations (3) to (7), obtain a1 to C, and inserting these into equation (1), we get (1
) formula is determined specifically.

The direction R in which the ship should proceed is H(x, y) at position (x, y)
y), it is the vector g rad
H direction and the X of this vector.

The components in each y direction are: Hx (XY) = a1+2 a 2 ・X+cY
”=(13)Hy (XY) =bi+z b 2
・Y+ cX −・−・−(t4)0, by inserting the above formulas (3) to α into the a4 formula, the actual value of the 0° set is determined only by the data obtained by the device,
This determines the ship's direction of travel.

In Fig. 3, 3 is the above-mentioned X from the outputs of the inclinometers 1 and 2.

A calculation circuit that calculates Y, 4 a calculation circuit that calculates coefficients a1 to b27c from the output of 5o-s4, 5 these X, Y
, a1-c is a calculation circuit that calculates the direction of the maximum gradient in the horizontal distribution of the vertical component of the magnetic field using the above equations (13) and e14, and 6 displays the calculation result as the direction in which the ship will move. It is a display device that

The magnetic detection device of the present invention has the above-described configuration, and even if the position of the magnetic detector fluctuates irregularly, it detects the amount of displacement, and determines the direction of movement by estimating the output of the magnetic detector when there is no displacement. The indicated direction becomes substantially stable, and it becomes possible to reach the target accurately and quickly without requiring functions such as storing past data.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing the arrangement of magnetic detectors in a device to which the present invention is applied, FIG. 2 is a side view of the entire device, and FIG. 3 is a diagram showing the configuration of a device according to an embodiment of the present invention. The block diagram and FIG. 4 are plan views illustrating the operation of the device of the present invention. 5OjS engineering ~ S4... Magnetic detector, 1, 2...
... Inclinometer, 3, 4, 5 ... Calculation circuit, 6
...Display device.

Claims (1)

[Claims] 1. In a type of magnetic detection device in which other magnetic detectors are arranged at each vertex of a polygon centered on one magnetic detector, and the mutual positional relationship of these magnetic detectors is fixed and hangs down from a moving object, means for detecting the inclination of the moving object; a circuit for calculating the amount of horizontal displacement of the group from the detected inclination angle and the drooping distance of the group of magnetic detectors; and an output from each of the magnetic detectors and the displacement. A circuit that calculates the output of each of the above-mentioned magnetic detectors when the inclination of the moving body is O from the amount, and a direction of maximum magnetic field strength is calculated and displayed from the output of each magnetic detector calculated by this circuit. A magnetic detection device consisting of a device.