JPS6216362B2 - - Google Patents

Description

[Detailed Description of the Invention] Conventional magnetic compasses have mechanically movable parts such as magnetic needles, so they require a complicated and large mechanism to hold them, and errors may occur depending on the structure of the ship etc. in which it is installed. . In addition, special additional equipment is required to separate the indicator from the main body and place it in another location, or to transmit the indicator value to a remote location. Therefore, there are drawbacks such as the need to install the main body in a location with small errors based on the structure of the ship, etc., and to conduct observations at that location. The present invention provides a magnetic compass that has no mechanically moving parts, can eliminate the above-mentioned drawbacks, and can detect orientation steplessly with a simple configuration.

The drawings show one embodiment of the present invention, in which FIG. 1 is a plan view of a geomagnetic field detection section, and FIG. 2 is a sectional view taken along line A-A. That is, two of eight sector-shaped magnetic plates 1 are arranged in parallel in the vertical direction, and are connected by a magnetic core 2, with a coil 3 wound around each magnetic core. Four such sets are arranged in an annular shape in a horizontal plane at 90 degree intervals, and the opposing latch portions of each sector-shaped magnetic plate are connected by a thin saturable magnetic path 4. Therefore, four narrow magnetic paths 4 are formed at the center of the detection section, and a common output coil 5 is wound around these four magnetic paths, both ends of which are connected to the terminal T0, and the relative Coils wound around magnetic cores 2 facing each other are connected in series with polarity so as to apply magnetic fluxes in opposite directions to the two magnetic paths, and are connected to terminals T1 and T2.

In the above-mentioned earth magnetic field detection section, for example, the terminal T
When an alternating current excitation current is applied to 1, a magnetic flux as shown by the arrow p in FIG. 2 is generated. This magnetic flux is the magnetic path 4
If the amplitude of the excitation current is selected so that the excitation current is sufficiently saturated, a saturation magnetic flux is generated in the magnetic path regardless of the strength of the earth's magnetic field at the time of saturation, and this magnetic flux flows inside the output coil 5. Since the current flows in the opposite direction, no output is generated in the coil 5. However, at the time when the excitation current disappears, only the magnetic flux based on the earth's magnetic field flows in the two magnetic paths in the same direction, for example, as shown by arrow q. In other words, at the point in time when the excitation current disappears when the phase angle is 0 degrees and 180 degrees,
Since the magnetic flux due to the earth's magnetic field is considered to be generated in the same direction in the magnetic path as indicated by the arrow q, a pulse output is generated at the terminal T0 at the above phase angle. Since the amplitude of this pulse output corresponds to the amount of magnetic flux indicated by the arrow q, and therefore to the azimuth at which the magnetic plate 1 is arranged, this azimuth can be determined from the amplitude of the pulse output. and B- as shown in Figure 4.
When a magnetic material with H magnetization characteristics is magnetized by a low-frequency current with an angular frequency of ω and a sufficiently large amplitude, the magnetic permittivity μ changes with time t as shown in Figure 5a, so if the average value is taken as μ ₀ . μ is μ ₀ (cos2ω
t+1), and the output pulse current i
is represented by b in the same figure. In this way, the magnetic permittivity μ changes with twice the frequency of the magnetizing current, but if we look at the fundamental wave component of this change, as shown in Figure 6, it changes at an angle θ with respect to the magnetic north N with a magnetic field strength H ₀ . In the coil 5 of the arranged magnetic plate 1, a current of _if =Kμ ₀ H ₀ cosθsin2ωt is generated, where K is the proportionality constant. Similarly, if a magnetic plate is provided perpendicularly to the magnetic plate, the coil current is given by i ₂ =Kμ ₀ H ₀ sinθcos2ωt. Therefore, a current shown as I=i ₁ +i ₂ =Kμ ₀ H ₀ sin(2ωt+θ) is generated in the coil 5 of FIG. In this way, terminal T1,
When magnetic paths 4, 4...... are excited by adding an alternating current with the same frequency and a phase difference of 45 degrees to T2, the output terminal T0 has a frequency twice that of the above alternating current,
An alternating current output whose phase angle corresponds to the direction of the earth's magnetic field is generated. The present invention detects the direction of the earth's magnetic field based on the phase angle of this AC output.

FIG. 3 is a diagram showing the configuration of a circuit for digitally measuring the phase angle.
When the frequency of the excitation current applied to is f, the clock pulse generator 0 sends out pulses with a period of 1/720f. This pulse is repeatedly counted by a reference counter _Ns with a full scale of 360, and the pulses generated every time the count value reaches 0 and 270 drive flip-flops F1 and F2, amplify their output, and form a waveform. After shaping, the terminals T1 and T2 in Fig.
In addition to. Therefore, an alternating current of frequency f having a phase difference of 45 degrees is applied to the terminal. Also the first
The output obtained from the terminal T0 in the figure is added to the narrowband amplifier G, the transfer circuit P, and the waveform shaping circuit S to form a pulse with a frequency of 2f and a phase angle corresponding to the direction of the earth's magnetic field as described above. This pulse is applied to a phase comparator M. Furthermore, by applying the output pulse of the clock pulse generator 0 to the tracking counter Np with a full scale of 360 via the controller K,
It is repeatedly counted and its significant pulse is applied to the phase comparator M and flip-flop F3. The tracking counter Np described above sends out a carry pulse with a period of 1/2f, and the phase comparator M detects the sequential relationship between this pulse and the pulse of the same period applied from the shaping circuit S, and performs reversible counting. Set the device Nr to addition or subtraction state. The counter Nr is used to remove the influence of drift in the output of the comparator M, and has a full scale of, for example, several tens.
The output pulses of clock pulse generator 0 are added or subtracted and the carry or carry-down pulses thereof are applied to the controller K. When a carry pulse is added, the controller K interrupts the input pulse of the counter Np for a small fixed period of time, for example, and when a carry down pulse is added, an additional pulse is inserted between the input pulses to start the counter.
Add to Np. Therefore, the tracking counter Np is automatically controlled so that its carry pulse is sent out simultaneously with the output pulse of the shaping circuit S, and the flip-flop F3 is driven by this carry pulse to send out an output. The counter Nv can adjust its full scale arbitrarily, and when the above output is applied, it starts counting the output pulses of the clock pulse generator 0, with a time delay corresponding to the set full scale. A carry pulse is sent. The flip-flop F3 is reset by the carry pulse, and at the same time the latch circuit L1 is driven. Since the count value of the reference counter _Ns is added to the latch circuit L1, when the latch circuit is driven, the count value at that time is stored and displayed on the display D1. Since the counter N _s performs a repetitive operation with a frequency of 2f, the counter changes the phase angle of the pulse applied to the terminal T0 according to the above-mentioned display value.
It is possible to know the phase angle with a correction corresponding to the full scale setting of Nv, and therefore the direction of the earth's magnetic field.

When installing the above-mentioned magnetic compass on a ship, etc., by appropriately adjusting the counter Nv or phase shifter P, it is possible to directly display the ship's heading direction and to correct for the declination of the earth's magnetic field. etc. Further, errors due to the structure of the ship, etc. can be easily corrected by storing them in advance in a fixed storage device for each angle. Furthermore, if necessary, it is also possible to perform analog display by arranging, for example, 360 light emitting elements in a circle and causing the elements corresponding to the measured orientation to emit light.

In addition, in the embodiment shown in FIG. 3, a setting device B is provided to set the azimuth angle at which the ship is to proceed, and when the counted value of the reference counter N _s matches the set angle, the matching circuit C Output pulses are arranged to be sent out. That is, this pulse drives the flip-flop F4, and its output activates the counter Na with a full scale of 360 to start counting the output pulses of the clock pulse generator 0. Further, the flip-flop is reset by the carry pulse of the counter Nv to stop and reset the operation of the counter Na, and at the same time, the latch circuit L2 is driven to store the count value at that time. This counted value is displayed on the display D2 and simultaneously converted into an analog voltage by the digital-to-analog converter A. Therefore, the angle of deviation between the direction in which the ship is intended to proceed and the actual direction of the ship is displayed on the display D2. Furthermore, by controlling the automatic steering system of the ship with the above-mentioned voltage, the ship can be automatically steered.

As explained above, the magnetic compass of the present invention has
Since there is no mechanically moving part such as a magnetic needle, the device can be configured to be simple, small and lightweight. In addition, the display section can be separated from the main body and installed at any number of locations, and it is also easy to correct errors or send automatic steering signals, and the resolution can be improved arbitrarily by changing the configuration of the device that processes the detection signal. It is possible.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; Fig. 1 is a plan view of the detection unit, Fig. 2 is a sectional view taken along line A-A in Fig. 1, Fig. 3 is an electric circuit, and Fig. 4 is a diagram showing the principle of the present invention. FIG. 5 is a waveform diagram for explaining characteristic curves, and FIG. 6 is a diagram showing the arrangement of magnetic plates. In the figure, 1 is a magnetic plate, 2 is a magnetic core, 3 is a coil, 4 is a saturable magnetic path, 5 is an output coil, F1, F
2, F3, F4 are flip-flops, N _s ,
Np, Nr, Nv, Na are counters, L1, L2 are latch circuits, K is a controller, M is a phase comparator, G is a band amplifier, P is a phase shift circuit, S is a shaping circuit, D1, D2
is the display, A is the digital-to-analog converter, C
is a matching circuit, and B is a setter.

Claims (1)

[Claims] 1. Two saturable magnetic paths arranged perpendicularly to each other in a horizontal plane are excited with an alternating current having a phase difference of 45 degrees and an amplitude sufficient to saturate the magnetic paths. A coil is provided and a single output coil common to the two magnetic paths is wound to generate a coil having a frequency twice that of the alternating current and a phase angle corresponding to the angle between the earth's magnetic field and the direction of the magnetic path. A magnetic compass characterized in that the phase angle of the output alternating current is detected by generating the output alternating current in the output coil. 2. The magnetic compass according to claim 1, wherein a desired error correction is applied to the phase angle of the output alternating current. 3. The magnetic compass according to claim 1, which displays the deviation angle between the phase angle of the output alternating current and an arbitrarily set phase angle. 4. The magnetic compass according to claim 3, which sends out an analog control output corresponding to a deviation angle.