JPH11110114A - Magnetic three-dimensional tracker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make eliminable a measuring error caused by an eddy current, which occurs on a metal object around a movable body as an object for measurement of position/attitude angle, by finding the position and attitude angle of the movable body based on a corrected magnetic field signal, for which a detected magnetic field caused by the eddy current is subtracted from a magnetic field detecting signal. SOLUTION: The AC magnetic fields of different frequencies are radiated from a radiation antenna 1 fixed at a constant position by an excitation driving part 4, the AC magnetic fields of respective frequencies are received by a reception antenna 2 integrally attached to the movable body, and the magnetic field detecting signals are respectively provided. Afterwards, based on these magnetic field detecting signals, the detected magnetic field component caused by the eddy current, which occurs around the movable body, is obtained by an eddy current magnetic field finding part 10. Then, the corrected magnetic field signal obtained by subtracting the detected magnetic field component caused by the eddy current from the magnetic field detecting signal obtained by the reception antenna 2 is obtained by an eddy current magnetic field removing part 11 and this signal is sent to a position/attitude angle finding part 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic three-dimensional tracker for measuring the instantaneous three-dimensional position and posture angle (direction or posture) of a movable body in real time.
The present invention relates to a technique for improving measurement accuracy of a position and a posture angle of a movable body.

[0002]

2. Description of the Related Art A magnetic three-dimensional tracker is used, for example, to constantly capture the movement of a pilot's head while maneuvering. A fighter pilot equipped with an HMD (head-mounted display) controls the aircraft while simultaneously checking external information visible through the translucent visor and various information projected on the translucent visor. A receiving antenna (magnetic sensor) of a three-dimensional tracker is attached to the helmet worn by the pilot, and the movement of the pilot's head is constantly captured based on a magnetic field detection signal output from the receiving antenna. Automatic control for directing the missile toward the enemy aircraft is performed based on the results captured by the three-dimensional tracker.

[0003] In the case of a magnetic three-dimensional tracker, it is fixed at a fixed position away from the pilot and 10 k
A radiating antenna that radiates an alternating magnetic field at a frequency of about Hz,
A receiving antenna attached to the pilot's helmet and receiving an alternating magnetic field from the radiating antenna is provided. By analyzing the magnetic field detection signal output from the receiving antenna, the position and attitude angle of the pilot's head are sometimes determined. It is configured to find every moment.

[0004]

However, the conventional magnetic three-dimensional tracker has a problem that the measurement accuracy of the position / posture angle is not sufficient. This is because an eddy current generated in a surrounding metal object causes a measurement error. When there is a metallic object around, an eddy current of the same frequency as the alternating magnetic field of the radiating antenna is generated in the metallic object by an alternating magnetic field of about 10 kHz radiated from the radiating antenna, and a secondary alternating magnetic field due to the eddy current is generated by the metallic object. Released from objects. On the other hand, in the receiving antenna, since the secondary AC magnetic field is detected simultaneously with the AC magnetic field of the radiation antenna, the magnetic field detection signal of the reception antenna has the secondary AC magnetic field at the same frequency as the AC magnetic field component of the radiation antenna. The components will overlap. In other words, the magnetic field detection signal of the receiving antenna includes a secondary AC magnetic field component due to the eddy current of the metal object that is unrelated to the movement of the pilot's head.
This causes an error in the measurement result of the position / orientation angle and lowers the measurement accuracy.

The present invention has been made in view of the above circumstances, and provides a magnetic three-dimensional tracker that can eliminate a measurement error caused by an eddy current generated in a metal object around a movable body whose position and attitude are to be measured. The task is to

[0006]

In order to achieve the above object, a magnetic three-dimensional tracker according to the present invention is a tracker for measuring a three-dimensional position and posture angle (direction) of a movable body in real time. An AC magnetic field radiating means fixed at a fixed position away from the movable body to be measured and emitting an AC magnetic field, and an AC magnetic field integrally attached to the movable body and receiving the AC magnetic field A magnetic type including a receiving unit and a position / posture angle calculating unit that calculates a position / posture angle of a movable body to be measured by analyzing a magnetic field detection signal output from the AC magnetic field receiving unit. In a three-dimensional tracker, an excitation driving means for causing an AC magnetic field radiating means to emit AC magnetic fields having different frequencies, and an AC magnetic field having a different frequency radiated from the AC magnetic field radiating means An eddy current magnetic field obtaining means for obtaining a detection magnetic field component based on an eddy current magnetic field generated around the movable body based on magnetic field detection signals of different frequencies detected by the stray magnetic field receiving means; And an eddy current magnetic field removing means for obtaining a corrected magnetic field signal by subtracting the detected magnetic field due to the eddy current from the detected magnetic field detection signal and outputting the corrected magnetic field signal to the position / posture angle calculating means.

[Operation] Next, in the magnetic three-dimensional tracker of the present invention, a measurement error caused by an eddy current generated in a metal object around a movable body whose three-dimensional position and attitude angle is to be measured is eliminated. The operation at that time will be described. In the magnetic type three-dimensional tracker according to the present invention, the excitation driving means radiates AC magnetic fields having different frequencies from the AC magnetic field radiating means fixed at a fixed position,
After receiving the alternating magnetic field of each frequency by the alternating magnetic field receiving means integrally attached to the movable body and obtaining the respective magnetic field detection signals, based on these magnetic field detection signals, by the eddy current magnetic field determining means, The detection magnetic field component due to the eddy current generated around the movable body is obtained. Then, the eddy current magnetic field removing means obtains a corrected magnetic field signal obtained by subtracting the detected magnetic field due to the eddy current from the magnetic field detection signal obtained by the AC magnetic field receiving means, and sends this to the position / posture angle calculating means. position·
In the attitude angle calculating means, an analysis process based on the corrected magnetic field signal is performed, and the position and the attitude angle of the movable body to be measured are calculated.

For easier understanding of the above-described eddy current magnetic field determination and eddy current magnetic field removal, more specific explanations will be repeated. When the metal object is, for example, a metal plate having a radius a, a thickness b, and an electric resistivity ρ, an eddy current magnetic field emitted from the metal plate has a magnetic moment represented by 2π ² μ ₀ Ba ⁴ bf / (8ρ). Is proportional to μ ₀ is the magnetic permeability, B is the amplitude of the AC magnetic field, and f is the frequency of the AC magnetic field. Therefore, the eddy current magnetic field is proportional to the frequency f. The situation is the same even if the shape of the metal object changes. The magnetic field detection signal S of the AC magnetic field receiving means at the frequency f1 of the AC magnetic field
1, and the magnetic field detection signal S2 of the AC magnetic field receiving means at the frequency f2 of the AC magnetic field (f1> f2). or,
ΔS = S2-S1, and Δf = f2-f1. And
The magnetic field detection signal S1 is set so that the magnetic field detection signal S2 becomes equal to the magnetic field detection signal S2 in the absence of a metal object.

In this way, when there is a metal object around the movable body to be measured, a difference proportional to the frequency difference occurs between the magnetic field detection signals S1 and S2 due to the eddy current magnetic field.
The magnetic field detection signals S1 and S2 include a detection magnetic field component due to an eddy current of ΔS / Δf per Hz. Therefore, with respect to the magnetic field detection signal S1, the eddy current magnetic field determining means determines the detected magnetic field component due to the eddy current of (ΔS / Δf) · f1, and the eddy current magnetic field removing means determines [S
1− (ΔS / Δf) · f1], a corrected magnetic field signal from which the detected magnetic field component due to the eddy current is removed is obtained. Based on the corrected magnetic field signal, the position / posture angle calculation means calculates the position / posture angle. The corrected magnetic field signal that was the source of the position / posture angle calculation excludes the detected magnetic field component due to the eddy current, so the obtained position / posture angle calculation result shows the error due to the eddy current. Not included, accuracy is sufficient.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a magnetic type 3 according to the embodiment.
FIG. 2 is a block diagram showing the entire configuration of the dimension tracker, and is an explanatory diagram of one cycle of a frequency change of an AC magnetic field emitted from a radiation antenna.

The magnetic three-dimensional tracker of the embodiment is shown in FIG.
As shown in the figure, a loop-shaped radiating antenna (AC magnetic field radiating means) that is fixed at a fixed position away from the head HD of the pilot whose position and attitude angle (direction) is to be measured and radiates an AC magnetic field 1 and pilot's head H
And a loop-shaped receiving antenna (AC magnetic field receiving means) 2 which is integrally attached to the helmet HM over D and receives an AC magnetic field. The radiating antenna 1 is composed of three coils 1a to 1c orthogonal to each other, and the receiving antenna (magnetic sensor) 2 is also composed of three coils 2a to 2c orthogonal to each other. By calculating six parameters of the position (α, β, γ) and attitude angle (Ψ, θ, φ) of the receiving antenna 2, the momentary movement of the head HD can be grasped. In the case of the embodiment, the position (α, β, γ) is represented by spherical coordinates, and the posture angle (Ψ, β)
θ, φ) are Euler angles.

An excitation driving section (excitation driving means) 4 is connected to the radiation antenna 1 via a multiplexer 3. Multiplexer 3 is provided for each coil 1a of radiation antenna 1.
1c to the excitation drive unit 4 in order. The excitation driving unit 4 includes a high-frequency transmitting unit 5 and an AC amplifying unit 6, and outputs a frequency f1 or a frequency f1 output from the high-frequency transmitting unit 5 based on a command signal from the controller 7.
After the high-frequency signal of the second is amplified by the AC amplifying section 6, it is supplied to one of the coils 1a to 1c selected by the multiplexer 3 as AC power for excitation. Of course, AC magnetic fields are radiated one after another from the coils 1a to 1c which receive AC power in order.

As shown in FIG. 2 (a), the high-frequency transmitting section 5 transmits the high-frequency signal so that the alternating magnetic field of the frequency f1 is sequentially emitted from each of the coils 1a to 1c and then the alternating magnetic field of the frequency f2 is emitted. Change the frequency, or
As shown in FIG. 2 (b), the frequency f
After one AC magnetic field is radiated, the coil immediately radiates an AC magnetic field of frequency f2, and then is switched to the next coil to change the frequency of the high-frequency signal so that the AC magnetic field is radiated similarly. Any of the above configurations. Specific values of the frequencies f1 and f2 of the AC magnetic field include a frequency f1 = 10 kHz and a frequency f2 = 20 kHz.
z is exemplified, but if the receiving antenna 2 uses ferrite, the sensitivity is in a good range of 10 kHz to 10 kHz.
It is preferable to select the frequencies f1 and f2 from between 100 kHz. In addition, the radiation period of the AC magnetic field is changed every moment.
In order to capture the movement of, it is sufficient to measure around 100 mSEC. For example, as shown in FIG.
2, the emission period TU of each AC magnetic field is about 10 mSEC, and one emission cycle TS is 60 mSEC.

On the other hand, a detection amplifier 9 is connected to the receiving antenna 2 via a multiplexer 8. The multiplexer 8 controls the coils 2a to 2c of the receiving antenna 2 for each radiation period TU of the AC magnetic field in accordance with a command from the controller 7.
2c is sequentially switched and connected to the detection amplification unit 9. Therefore, the AC magnetic field radiated from the coil 1a of the radiation antenna 1 is received by all the coils 2a to 2c of the receiving antenna 2, and the operation of the multiplexer 8 detects and amplifies the magnetic detection signal of each coil 2a to 2c. It is sequentially sent to the unit 9.

In the case of the embodiment, when the amplitude of the AC power supplied from the excitation driver 4 is such that there is no metal object around the receiving antenna 2, the magnetic field detection signal by the AC magnetic field of the frequency f1 and the frequency f2 Are adjusted so that the magnetic field detection signals due to the AC magnetic field are equal.

Further, in the magnetic three-dimensional tracker of the embodiment, as shown in FIG. 1, the frequency transmitted from the detection amplification unit 9 via the AD conversion unit (not shown) after the detection amplification unit 9 is used. An eddy current magnetic field determination unit 10 for determining a detection magnetic field component based on an eddy current magnetic field based on the magnetic field detection signals of f1 and frequency f2, and a eddy current detection based on the magnetic field detection signal at a stage subsequent to the eddy current magnetic field determination unit 10. An eddy current magnetic field removing unit 11 for obtaining a correction magnetic field signal by subtracting a magnetic field component is connected in order. After the eddy current magnetic field removing unit 11, a position / posture angle calculating unit 12 for calculating the position / posture angle of the head HD by analyzing the correction magnetic field signal from the eddy current magnetic field removing unit 11 is provided. ing. The eddy current magnetic field calculating unit 10, the eddy current magnetic field removing unit 11, and the position / posture angle calculating unit 12
It is provided with a function of executing a calculation necessary for obtaining a detected magnetic field component and a position / posture angle based on an eddy current magnetic field, and is mainly configured by a computer (CPU) and a control program thereof. .

Next, the operation for finding the instantaneous position and posture angle of the head HD by the tracker of the embodiment having the above-described configuration will be specifically described. Determining the position / posture angle of the head HD substantially means finding the instantaneous position and posture angle of the receiving antenna 2 with the radiation antenna 1 as the origin. Hereinafter, assuming an X, Y, Z orthogonal coordinate system with the radiation antenna 1 as the origin, the position of the receiving antenna 2 is obtained by spherical coordinates (α, β, γ), and the attitude angle is Euler angles (Ψ, θ, φ).

First, how to detect the detected magnetic field by the eddy current will be described. As shown in FIG. 2B, the AC magnetic field is generated by radiating an AC magnetic field having a frequency f1 (= 10 kHz) from one coil of the radiating antenna 1 and immediately following the frequency f2 (= 20 kHz) from the coil.
After the AC magnetic field is radiated, the next coil is switched and the AC magnetic field is similarly radiated. As the AC magnetic field is radiated from the radiating antenna 1, the signal received by the receiving antenna 2 passes through a detection / amplification unit 9 and is converted into an A / D signal by an AD conversion unit (not shown).
After being D-converted, it is sent to the eddy current magnetic field determination unit 10.

A magnetic field detection signal obtained by radiating an AC magnetic field from the radiation antenna 1 is a magnetic field detection signal S1 = (S _1X , S _1Y , S _1Z ) due to radiation at a frequency f1 (= 10 kHz).
And the magnetic field detection signal S2 = ( _S2X , _S2Y , _S2Z ) due to radiation at the frequency f2 (= 20 kHz). Here, S _1X is three signals obtained from each of the coils 2a to 2c when an AC magnetic field of frequency f1 is emitted from the X-axis coil 1a, and S _1Y is an AC magnetic field of frequency f1 from the Y-axis coil 1b. Three signals are obtained from each of the coils 2a to 2c when radiated, and S _1Z is a signal when an AC magnetic field having a frequency f1 is radiated from the Z-axis coil 1c.
2c, respectively, three signals each obtained from
_{S 1X = (S 1XX, S} 1XY, S 1XZ) ... (1), S 1Y = (S 1YX, S
_{1YY, S 1YZ) ... (2} ), S 1Z = (S 1ZX, S 1ZY, S 1ZZ) ...
(3) is indicated. S _2X is the frequency f from the coil 1a.
A three signals obtained from each coil 2a~2c when emit second alternating magnetic field, the coils 2a~ when S _2Y is radiated alternating magnetic field of a frequency f2 from the coil 1b
2c is a three signals respectively obtained from, S _2Z is a three signals obtained from each coil 2a~2c when emitting the AC magnetic field of frequency f2 from the coil _{1c, S 2X = (S 2XX} , S _2XY, S _2XZ )… (4), S _2Y =
(S _2YX , S _2YY, S _2YZ ) ... (5), S _2Z = (S _2ZX , S
_2ZY, S _2ZZ )... (6).

Then, the eddy current magnetic field calculating unit 10 obtains the detected magnetic field Hn by the eddy current by using H
The operation of n = (ΔS / Δf) · f1 (7) is executed. In the above equation (7), ΔS is the magnetic field detection signal S1,
The difference of S2 (= S2-S1), as shown in the matrix of the following equation (8), and Δf is the frequency f1, f
2 (= f2−f1). The detected magnetic field component Hn is sent to the next eddy current magnetic field removing unit 11. When there is no metal object around the radiation antenna 1, S2 = S1
And ΔS = 0, so that Hn = 0.

[0021]

(Equation 1)

Then, the eddy current magnetic field elimination unit 11 obtains H = S1−Hn = S1− (ΔS / Δf) · f1 (9) in order to obtain the correction magnetic field signal H. The correction magnetic field signal H in Expression (9) is represented by a matrix represented by Expression (10) below. Thus, the detection magnetic field component due to the eddy current generated in the metal object around the measurement target has been removed, and the correction magnetic field signal H is sent to the next-stage position / posture angle calculation unit 12.

[0023]

(Equation 2)

The eddy current magnetic field determination unit 1 of the tracker of the embodiment
Specifically, in the case of 0 and the eddy current magnetic field removing unit 11, the processing proceeds as follows. The radiation of the AC magnetic field of frequency f1 from the X-axis coil 1a causes S _1X =
_{(S 1XX, S 1X Y,} S 1XZ) with obtaining, X-axis coil 1a
S _2X =
After _obtaining (S _2XX , S _2XY, S _2XZ ), the eddy current magnetic field calculation unit 10 calculates Hn _XX = [(S _2XX −S _1XX ) / Δf] · f1 Hn _XY = [( In S _2XY -S _1XY) / Δf] · f1 Hn _XZ = [(S _2XZ -S _1XZ) / Δf] · f1 is determined, then the eddy current magnetic field removal section 11, (9)
According to the equation, it is _{H XX = S 1XX -Hn XX H} XY = S 1XY -Hn XY H XZ = S 1YZ -Hn XY obtained.

Next, the frequency f1 from the Y-axis coil 1b
And an AC magnetic field of frequency f2 are radiated,
S_1Y= (S_1YX, S_1YY,S_1YZ) And S_2Y= (S_2YX, S_2YY,S
_2YZ) Is obtained and, as above, H_YX,H_YY,H_YZSought
After that, the frequency f1 from the Z-axis coil 1c is further reduced.
An AC magnetic field and an AC magnetic field of frequency f2 are radiated, and S
_1Z= (S_1ZX, S_1ZY,S_1ZZ) And S_2Z= (S_2ZX, S
_2ZY,S_2ZZ) Is obtained and, as above, H_ZX,H_ZY,H_ZZSought
Can be Now that the corrected magnetic field signal H has been determined
It becomes. The figure shows the flow of the process of finding the correction magnetic field signal above
3 are shown together.

Next, the calculation of the position / posture angle based on the correction magnetic field signal H will be described. In principle, the position / posture angle is calculated according to the following procedure. In general, a transfer vector H1 generated by the radiation antenna 1 and a detection vector H2 obtained by the reception antenna 2 are linked via a transfer function T as shown in the following equation (11). H2 = T · H1 (11) When the position and orientation of the receiving antenna 2 are accurately known, the data is substituted for the transfer function, and the inverse transfer function T ⁻¹ obtained by inversely transforming the transfer function is obtained. obtain. The product of the inverse transfer function T ^-1 and the detection vector H2 is, as shown in the following equation (12),
It matches the transfer vector H1. H1 = T ^-1 · H2 (12) If the position and the attitude angle of the receiving antenna 2 are not known accurately, an error signal is generated, and the value substituted into the transfer function is improved. The data at the time of showing a good match that repeats repeatedly is taken as the exact position and attitude angle,
Hereinafter, the transfer function T will be specifically described.

The transfer function T is, as shown in the following equation (13), an attitude transfer function T _A relating to the attitude angle of the receiving antenna 2.
And the magnetic field transfer function T _B relating to the position of the receiving antenna 2. T = T _A · T _B (13) Further, as shown in the following equation (14), the attitude transfer function T _A is a matrix of the azimuth angle Ψ, the pitching angle θ, and the rolling angle φ of the receiving antenna 2. The product of T _A = T _A1 · T _A2 · T _A3 (14) The matrix T _A3 of the azimuth angle Ψ is as shown in the following equation (15), and the matrix T _A2 of the pitching angle θ is given by the following equation (16). The lower T _A1 of the matrix of the rolling angle φ is as shown in the following equation (17).

[0028]

(Equation 3)

[0029] Further, the magnetic field transfer function T _B is below formula (18)
Shown with T _B = (C / γ ³ ) T _p ^-1 · J · T _p (18) C is a constant determined by the coil characteristics of the radiation antenna 1,
γ is, of course, the distance between the radiating antenna 1 and the receiving antenna 2 (γ in spherical coordinates), and T _p is a matrix expressed by the following equation (19), where α and β are α, β in spherical coordinates. β. J is a matrix represented by the following equation (20).

[0030]

(Equation 4)

Then, the position / posture angle calculating section 12 proceeds with the analysis processing as described below to calculate the position / posture angle. First, based on the corrected magnetic field signal H of the equation (9), H2 _X = (H _XX , H _XY , H _XZ ), H 2 _Y = (H _YX ,
H _YY, obtaining _{H YZ), H2 Z = (} H ZX, H ZY, the H _ZZ).
Next, appropriate temporary data of the position (α, β, γ) and attitude angle (Ψ, θ, φ) of the receiving sensor 2 are selected.

Subsequently, the tentative data of the attitude angles (θ, θ, φ) are substituted into the equations (15) to (17), and the equation (1)
It performs an operation of 4), to obtain a posture transfer function T _A. Further, the tentative data of the position (α, β, γ) is substituted into Expression (19), and the operation of Expression (18) is executed to obtain the magnetic field transfer function T
_{Get B.} Next, the transfer function T and the inverse transfer function T ^-1 are calculated.

Further, according to equation (12), H1 _{calc, X}
= T ^-1 · H2 _X , H1 _{calc, Y} = T ^-1 · H2 _Y , H1
_{Calc, Z} = T ⁻¹ · H2 _Z is calculated.

Then, the calculated H1 _{calc, X} , H
1 _{Calc, Y} , H1 _{calc, Z} is compared with the actual H1 _X , H2 _Y , H2 _Z transmitted from the radiating coil 1, and if they match (the same or the difference is within a certain range), the temporary data is obtained. The position and posture angle are recognized, and if they do not match, the temporary data is changed and the above process is repeated. The flow of the above-described position / posture angle calculation process is summarized in the flowchart of FIG.

As described above, in the magnetic type three-dimensional tracker of the embodiment, the position and the posture angle are obtained based on the correction magnetic field signal H from which the magnetic field detected by the eddy current is removed. Since the error caused by the measurement is not included, the measurement accuracy is sufficient.

The present invention is not limited to the above embodiment, but can be modified as follows. (1) In the above-described embodiment, the AC magnetic fields of different frequencies output from the radiation antenna 1 are two of the frequencies f1 and f2. However, the AC magnetic fields of different frequencies may be three or more.

(2) Although the tracker of the embodiment captures the movement of the pilot's head, the magnetic three-dimensional tracker of the present invention is not limited to a specific use.

(3) Although the embodiment is an analysis method for substituting tentative data and examining the coincidence of the operation results, the analysis method for solving nine equations in the corrected magnetic field signal H may be modified. It is listed as.

(4) In the embodiment, the calculation of H = S1− (ΔS / Δf) · f1 was performed by the eddy current magnetic field removing unit, but the calculation of H = S2− (ΔS / Δf) · f2 is performed. You may do so.

[0040]

According to the magnetic three-dimensional tracker of the present invention, even if there is a disturbing metal object that generates an eddy current that causes a measurement error around the movable object to be measured,
Based on an appropriate correction magnetic field signal obtained by subtracting the detection magnetic field component due to the eddy current from the magnetic field detection signal by the eddy current magnetic field removal device while the eddy current magnetic field determination unit determines the detection magnetic field component by the eddy current magnetic field determination unit. Since the position and the posture angle are obtained, the obtained position and posture angle do not include an error caused by the eddy current, and the accuracy of the measurement result is sufficient.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an overall configuration of a magnetic three-dimensional tracker according to an embodiment.

FIG. 2 is an explanatory diagram for one cycle of a frequency change of an AC magnetic field emitted from a radiation antenna.

FIG. 3 is a flowchart showing a flow of a process of obtaining a correction magnetic field signal.

FIG. 4 is a flowchart showing a flow of a position / posture angle finding process.

[Description of Signs] 1 ... Emission antenna 2 ... Reception antenna 4 ... Excitation drive unit 10 ... Eddy current magnetic field calculation unit 11 ... Eddy current magnetic field removal unit 12 ... Position / posture angle calculation unit

Claims (1)

[Claims] 1. A tracker for measuring a three-dimensional position and a posture angle (direction) of a movable body in real time, wherein the tracker is fixed at a fixed position away from the movable body to be measured. AC magnetic field radiating means for radiating an AC magnetic field, AC magnetic field receiving means integrally attached to a movable body and receiving an AC magnetic field, and analyzing and processing a magnetic field detection signal output from the AC magnetic field receiving means. Excitation driving means for radiating AC magnetic fields having different frequencies to AC magnetic field radiating means in a magnetic type three-dimensional tracker comprising: a position / posture angle calculating means for calculating a position / posture angle of a movable body to be measured. And, based on a magnetic field detection signal of a different frequency detected by the AC magnetic field receiving means with an AC magnetic field of a different frequency radiated from the AC magnetic field radiating means, An eddy current magnetic field deriving means for deriving a detected magnetic field component due to an eddy current magnetic field generated around the device, and a corrected magnetic field signal obtained by subtracting the detected magnetic field component due to the eddy current from the magnetic field detection signal output from the alternating magnetic field receiving means A magnetic three-dimensional tracker comprising: an eddy current magnetic field removing unit that outputs to a position / posture angle calculating unit.