Calibration device and method for a magnetic compass

Abstract

The application discloses a kind of magnetic compass's calibration device and method, the device includes cylindrical rotating table, azimuth circle and azimuth marker post assembly, the cylindrical rotating table is used to fix the compass bowl of magnetic compass at its rotation center, the azimuth circle is coaxially fixed on the upper surface of the compass bowl, and the azimuth marker post assembly is axially arranged on the peripheral circumference concentric with the cylindrical rotating table;The cylindrical rotating table is suitable for rotating to drive the compass bowl and the azimuth circle to rotate synchronously, and the pointing accuracy of the magnetic compass is calibrated by aligning the azimuth circle to the azimuth marker post assembly.The application adopts multi-azimuth calibration method, which can greatly improve the installation accuracy of the scale disc and the pointing magnet, thereby improving the pointing accuracy of the magnetic compass.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of ship navigation instruments, and particularly relates to a calibration device and method for a magnetic compass. BACKGROUND

[0002] A magnetic compass is a kind of navigation instrument for indicating geographical direction and ship heading by using geomagnetic force. The magnetic compass is composed of a bowl and a compass cabinet, and the scale disc in the bowl is a disc with 0°-359° azimuth angle marked thereon. A pointing magnet is installed below the scale disc. Under the action of geomagnetic force, the pointing magnet can drive the scale disc to indicate the geographical direction.

[0003] When the magnetic compass is installed, the center of the scale disc and the center of the pointing magnet should be very accurately corresponding, so that the south and north poles of the pointing magnet correspond to 180° and 0° on the scale disc respectively, and the magnetic field center of the pointing magnet should be on the line connecting 90° and 270° on the scale disc. If there is a deviation between the center of the scale disc and the center of the pointing magnet during installation, it will inevitably affect the pointing accuracy of the magnetic compass. Therefore, the installation accuracy of the scale disc and the pointing magnet determines the pointing accuracy of the magnetic compass.

[0004] At present, the south and north directions of the pointing magnet are generally determined by suspension method or geometric method. Due to the influence of reverse torsional force in the suspension method and the non-uniformity of the magnetic field of the pointing magnet in the geometric method, uncertain errors may be caused. SUMMARY

[0005] The present application aims to overcome the deficiencies in the prior art, and uses an eight-azimuth calibration method to greatly improve the installation accuracy of the scale disc and the pointing magnet, thereby improving the pointing accuracy of the magnetic compass.

[0006] To achieve the above-mentioned purpose, in a first aspect, the present application provides a calibration device for a magnetic compass, comprising a cylindrical rotating table, an azimuth circle and an azimuth staff assembly. The cylindrical rotating table is used to fix the bowl of the magnetic compass at its rotating center. The azimuth circle is coaxially fixed to the upper surface of the bowl. The azimuth staff assembly is axially arranged on the peripheral circle concentric with the cylindrical rotating table. The cylindrical rotating table is adapted to rotate to drive the bowl and the azimuth circle to rotate synchronously, and the pointing accuracy of the magnetic compass is calibrated by aligning the azimuth circle with the azimuth staff assembly.

[0007] Further, the azimuth staff assembly comprises at least four azimuth staffs arranged at intervals, wherein the first azimuth staff is arranged at the north of the cylindrical rotating table and marked as 0°.

[0008] Further, the azimuth staff assembly comprises four azimuth staffs, and the interval between two adjacent azimuth staffs is 90°.

[0009] Further, the azimuth marker assembly comprises eight azimuth markers, and adjacent two are spaced 45°.

[0010] Further, the azimuth circle comprises a body circle, and a sighting hole and a sighting line are axially arranged on the body circle, the sighting hole and the sighting line are spaced 180°, and both sides of the sighting line are hollowed.

[0011] In the second aspect, the application provides a calibration method of a magnetic compass, comprising the following steps: (1) installing a pointing magnet on a float chamber; (2) making the 0° direction of a scale disc consistent with the north pole of the pointing magnet; (3) installing the scale disc on the float chamber and putting it into compass liquid to make good counterweight; (4) filling the compass liquid in a compass basin, putting the installed scale disc into the compass basin, and supporting an axis needle at the center of the compass basin; (5) setting a cylindrical rotating table in an open flat field, and axially arranging an azimuth marker assembly on a peripheral circle concentric with the cylindrical rotating table, the azimuth marker assembly comprising at least four azimuth markers spaced apart, wherein a first azimuth marker is arranged at the north of the cylindrical rotating table and marked as 0°; (6) setting the compass basin at the rotating center of the cylindrical rotating table, making the 0° of the azimuth circle consistent with the 0° of the outer circle of the compass basin, coaxially placing an azimuth circle on the compass basin, axially arranging a sighting hole and a sighting line on the azimuth circle, the sighting hole and the sighting line being spaced 180°, and both sides of the sighting line being hollowed; (7) rotating the cylindrical rotating table to rotate the compass basin thereon until the sighting hole of the azimuth circle looks at the sighting line and is just aligned with the first azimuth marker, recording the reading of the scale disc after the scale disc is stabilized in the compass liquid, and recording the readings of the scale disc corresponding to other azimuth markers in the same way; (8) after determining the adjustment direction by analyzing the scale disc readings of the above-mentioned multiple azimuths, finely adjusting the installation position of the scale disc on the float chamber, recalibrating the scale disc readings of each azimuth, and stopping until the scale disc readings of each azimuth are within a preset accuracy range.

[0012] Further, the azimuth marker assembly in step (5) comprises four azimuth markers, and adjacent two are spaced 90°.

[0013] Further, the azimuth marker assembly in step (5) comprises eight azimuth markers, and adjacent two are spaced 45°.

[0014] Further, the flat field in step (5) is free of external magnetic field interference.

[0015] Compared with the prior art, the application has the following beneficial effects:

[0016] The calibration method of eight azimuths can greatly improve the installation accuracy of the scale disc and the pointing magnet, thereby improving the pointing accuracy of the magnetic compass. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 This is a schematic diagram of one embodiment of the present invention. Figure 1 ;

[0018] Figure 2 This is a schematic diagram of one embodiment of the present invention. Figure 2 ;

[0019] Figure 3 This is a schematic diagram of an orientation ring placed on a compass in one embodiment of the present invention;

[0020] Figure 4 This is a schematic diagram of a floating chamber assembly in one embodiment of the present invention;

[0021] Figure 5 This is a schematic diagram of the dial in one embodiment of the present invention.

[0022] In the diagram, 1 is a compass; 2 is a float assembly; 21 is a dial; 22 is a float; 23 is a pointing magnet; 24 is a fastener screw and nut; 25 is the center of the float; 3 is a azimuth ring; 31 is a aiming hole; 32 is an aiming line; 4 is a azimuth marker assembly; 41 is a first azimuth marker; 42 is a second azimuth marker; 43 is a third azimuth marker; 44 is a fourth azimuth marker; 45 is a fifth azimuth marker; 46 is a sixth azimuth marker; 47 is a seventh azimuth marker; 48 is an eighth azimuth marker; and 5 is a cylindrical rotating platform. Detailed Implementation

[0023] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0024] like Figures 1-5 As shown, one embodiment of the magnetic compass calibration device of the present invention includes a cylindrical rotating platform 5, an azimuth ring 3, and an azimuth pointer assembly 4. The cylindrical rotating platform 5 is used to fix the compass bowl 1 of the magnetic compass at its rotation center. The azimuth ring 3 is coaxially fixed to the upper surface of the compass bowl 1. The azimuth pointer assembly 4 is axially arranged on the outer circumference concentric with the cylindrical rotating platform 5. The cylindrical rotating platform 5 is adapted to rotate to drive the compass bowl 1 and the azimuth ring 3 to rotate synchronously. The pointing accuracy of the magnetic compass is calibrated by aligning the azimuth ring 3 with the azimuth pointer assembly 4.

[0025] In one embodiment, the orientation marker assembly 4 includes at least four orientation markers spaced apart, wherein the first orientation marker 41 is located due north of the cylindrical rotating platform and marked as 0°.

[0026] In one embodiment, the orientation marker assembly 4 includes four orientation markers, with adjacent markers spaced 90° apart.

[0027] In one embodiment, such as Figure 2As shown, the azimuth marker assembly 4 includes eight azimuth markers, namely a first azimuth marker 41, a second azimuth marker 42, a third azimuth marker 43, a fourth azimuth marker 44, a fifth azimuth marker 45, a sixth azimuth marker 46, a seventh azimuth marker 47, and an eighth azimuth marker 48, and the adjacent two are spaced 45° apart.

[0028] In one embodiment, the azimuth circle 3 includes a body circle and an aiming hole 31 and an aiming line 32 axially arranged thereon, the aiming hole 31 and the aiming line 32 are spaced 180° apart, and the two sides of the aiming line 32 are hollow. In this embodiment, the aiming hole 31 is a vertical long and thin hole, and the aiming line 32 is a vertical thin straight line, and the two sides are hollow for left and right aiming of the peripheral azimuth markers. Looking through the aiming hole 31 to the aiming line 32, rotating the cylindrical rotating table 5, the bowl 1 and the azimuth circle 3 are rotated, the peripheral azimuth marker assembly 4 is not moved, and each azimuth marker in the azimuth marker assembly 4 is aligned with the aiming hole 31 and the aiming line 32 in turn, and the degrees of the dial 21 of the magnetic compass are recorded at the time of alignment. If the readings corresponding to each azimuth marker are within the accuracy range, it indicates that the installation of the dial 21 meets the requirements; if there is a reading below the accuracy, the adjustment direction is determined by analyzing the dial reading, the installation position of the dial 21 on the float chamber 22 is fine-tuned, and then the above calibration steps are repeated until the readings corresponding to each azimuth marker are within the accuracy range.

[0029] One embodiment of the calibration method of the magnetic compass of the present application includes the following steps:

[0030] A. Install the pointing magnet 23 at the geometric center of the float chamber, and the float chamber 22 has four evenly distributed mounting holes, as shown in Figure 4 and Figure 5 ;

[0031] B. Determine that the 0° direction of the magnetic compass dial 21 is consistent with the north pole of the pointing magnet 23;

[0032] C. Install the magnetic compass dial 21 on the float chamber 22 through the fastener 24, and put it into the compass liquid to make good counterweight;

[0033] D. Fill the bowl 1 with compass liquid, put the installed float chamber assembly 2 into the bowl 1, and determine that the shaft needle at the center of the bowl supports the center 25 of the float chamber;

[0034] E. Set a rotating center 5 at the center of a place with an open and flat field and no external magnetic field interference, and set an azimuth marker 4 at the true north of the center, marked as 0°, and then set other seven azimuth markers at 45°, 90°, 135°, 180°, 225°, 270°, and 315°, respectively, a total of eight azimuth markers 41-48, as shown in Figure 2 ; and

[0035] F, place the bowl 1 at the rotation center 5 of the eight azimuth markers, place the magnetic compass azimuth circle 3 on the bowl 1, and make the 0° of the azimuth circle 3 coincide with the 0° of the outer circle of the bowl 1;

[0036] G, rotate the bowl 1 to align with the 0° azimuth marker by rotating the rotation center 5 through the sighting hole 31 and the sighting line 32 on the azimuth circle 3, as shown in Figure 1 and Figure 3 Wait for the dial 21 of the bowl 1 to stabilize in the compass liquid, record the reading of the current magnetic compass dial 21, and record it down; in the same way, rotate the bowl 1 to align with the 45° azimuth marker through the sighting hole 31 and the sighting line 32 on the azimuth circle 3, and record the reading of the dial 21 corresponding to the 45° azimuth marker;

[0037] H, if the readings of the eight azimuths are all within the accuracy range, it indicates that the installation of the dial meets the requirements;

[0038] I, if the readings of the eight azimuths exceed the accuracy, after determining the adjustment direction by analyzing the dial readings of the eight azimuths, slightly adjust the installation position of the dial 21 on the float chamber 22, redo steps D and G until the requirements of step H are met.

[0039] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application and not to limit it, although the present application has been described in detail with reference to the above examples, those skilled in the art should understand that: the specific embodiments of the present application can still be modified or replaced by the equivalent, without departing from the spirit and scope of the present application, any modification or equivalent replacement, which should be covered within the protection scope of the claims of the present application.

Claims

1. A calibration device for a magnetic compass, characterized in that The application relates to a magnetic compass calibration device, which comprises a cylindrical rotating table, a bearing circle and a bearing marker assembly, the cylindrical rotating table is used for fixing a compass bowl of the magnetic compass at the rotating center of the cylindrical rotating table, the bearing circle is coaxially fixed to the upper surface of the compass bowl, and the bearing marker assembly is axially arranged on the peripheral circumference concentric with the cylindrical rotating table; the cylindrical rotating table is suitable for rotating to drive the compass bowl and the bearing circle to rotate synchronously, the pointing precision of the magnetic compass is calibrated by aligning the bearing circle with the bearing marker assembly; wherein, The bearing circle comprises a body circle, a sighting hole and a sighting line axially arranged on the body circle, the sighting hole and the sighting line are spaced by 180 degrees, and the two sides of the sighting line are hollowed.

2. A calibration device for a magnetic compass according to claim 1, characterized in that The bearing marker assembly comprises at least four bearing markers, and the first bearing marker is arranged at the north of the cylindrical rotating table and marked as 0 degree.

3. A calibration device for a magnetic compass according to claim 2, characterized in that The bearing marker assembly comprises four bearing markers, and the interval between two adjacent bearing markers is 90 degrees.

4. The calibration device for a magnetic compass according to claim 2, characterized in that The bearing marker assembly comprises eight bearing markers, and the interval between two adjacent bearing markers is 45 degrees.

5. A method of calibrating a magnetic compass, characterized by, The application further discloses a magnetic compass calibration method comprising the following steps: (1) installing a pointing magnet on a floating chamber; (2) aligning the 0 degree direction of a scale disc with the north pole of the pointing magnet; (3) installing the scale disc on the floating chamber and placing the scale disc in compass liquid to add counterweight; (4) filling the compass bowl with compass liquid, placing the installed scale disc in the compass bowl, and supporting the shaft needle at the center of the compass bowl; (5) arranging a cylindrical rotating table on a flat and open site, and axially arranging a bearing marker assembly on the peripheral circumference concentric with the cylindrical rotating table, the bearing marker assembly comprises at least four bearing markers, and the first bearing marker is arranged at the north of the cylindrical rotating table and marked as 0 degree; (6) arranging the compass bowl at the rotating center of the cylindrical rotating table, aligning the 0 degree of the bearing circle with the 0 degree of the outer circle of the compass bowl, coaxially arranging the bearing circle on the compass bowl, axially arranging a sighting hole and a sighting line on the bearing circle, spacing the sighting hole and the sighting line by 180 degrees, and hollowing the two sides of the sighting line; (7) rotating the cylindrical rotating table to rotate the compass bowl thereon until the first bearing marker is aligned with the sighting line when the sighting hole of the bearing circle is aligned with the sighting line, recording the reading of the scale disc after the scale disc is stabilized in the compass liquid, and recording the readings of the scale disc corresponding to other bearing markers in the same way; (8) adjusting the installation position of the scale disc on the floating chamber according to the readings of the scale disc in the above steps, recalibrating the readings of the scale disc in each direction, and stopping until the readings of the scale disc in each direction are within a preset precision range.

6. The method of calibrating a magnetic compass of claim 5, wherein, The bearing marker assembly in step (5) comprises four bearing markers, and the interval between two adjacent bearing markers is 90 degrees.

7. The method of calibrating a magnetic compass of claim 5, wherein, The bearing marker assembly in step (5) comprises eight bearing markers, and the interval between two adjacent bearing markers is 45 degrees.

8. The method of calibrating a magnetic compass of claim 5, wherein, The flat site in step (5) is free from external magnetic field interference.

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