JPH0235269B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a system for continuously detecting the position of a moving object using guided radio.

[Background of the Invention] For example, in the automatic operation of a linear motor car, the position of the car body is constantly detected on the ground within the distance between motor poles (propulsion coils) placed at regular intervals along the running route. , it is considered essential for the smooth operation of this vehicle to rationally adjust the frequency, amplitude, and phase of the field current accordingly.

The most typical method among those currently proposed as means to meet this demand will be explained based on FIGS. 1 and 2.

In Figure 1, 1, 2, and 3 are conductors, respectively.
4 is an inductive radio line formed by conductors 1, 2, and 3, and 5 is a mobile tower-mounted antenna.

Each of the conductors 1, 2, and 3 is bent into a waveform shape on a plane with a period P (twice the distance between motor poles), and is laid with a shift of P/3, so the line 4 as a whole has a period P. It has a repeating structure. A frame-shaped loop coil is used as the antenna 5, and when this is excited with a high frequency current of 50 to 200 KHz, the magnetic field formed by the antenna 5 interlinks with the line 4 and is distributed between each conductor 1, 2, and 3. A voltage is induced.

If the distance from the starting point of the track 4 to the antenna 5 (vehicle body) is z, the dimensions of the antenna 5, the antenna 5
By appropriately selecting the separation distance between the conductors 1, 2, and 3, the induced voltage between each conductor 1, 2, and 3 can be made sinusoidal in z.

Now, the voltages between conductors 1 and 2, 2 and 3, and 3 and 1 at the terminals of line 4 are V12 (z) and V23, respectively.
(z), V31(z), then V12(z)=k cos2πz/P・e ^- 〓 ^z V23(z)=k cos2π(z+P/3)/P・e ^- 〓 ^z V31(z)= k cos2π(z+2P/3)/P・e ^- 〓 ^z
It can be expressed as ……(1).

Here, k: constant, γ: line propagation constant, γ=
α+jβ (α: attenuation constant of the line, β: phase constant of the line).

Here, it is assumed that the following signal processing is performed on V12 (z), V23 (z), and V31 (z) to obtain a positive sequence voltage Vp (z) and a negative sequence voltage Vn (z).

Vp (z) = V12 (z) + e ^-j2 〓 ^/3 V23 (z) +e ^j2 〓 ^/3 V31 (z) Vn (z) = V12 (z) + e ^j2 〓 ^/3 V23 (z) + e ^-j2 〓 ^/3 V31(z) ......(2) Substituting equation (1) into equation (2) and rearranging, Vp(z) = (3/2)ke ^(-j2 〓 ^z/P)- 〓 ^z Vn (z) = (3/2) ke ^(j2 〓 ^z/P)- 〓 ^z ………(3) If the phase difference between Vp (z) and Vn (z) is Φ, then Φ = ∠Vp ( z)−∠Vn(z)=4πz/P (4) Here, ∠: is a symbol meaning an argument.

That is, Φ is z as shown in Fig. 2.
Each time it increases, it shows a linear increase of 2π, and by measuring Φ, the antenna (vehicle body) position can be measured continuously at a period of P/2.

Also, V12(z), V23(z), V31 as follows:
Detection can also be performed using only the absolute value of (z). If we linearly detect the induced voltage between each conductor at the starting end of the line, find the absolute value of its envelope, and find its square value, we get |V12(z)| ² = k ² cos ² 2πz/P = k ² (1 + cos4πz /
P) |V23(z)| ² = k ² [1+cos4π(z+P/3)/p]
=k ² [1+cos {(4πz/P)-2π/3}] |V31(z)| ² =k ² [1+cos4π(z+2p/3)/P]
=k ² [1+cos {(4πz/P)+2π/3}]......(5) Now, the carrier wave of angular frequency ωo is modulated with each value of equation (5), and these values are respectively expressed as Vu(z ), Vv
(z) and Vw(z), then Vu(z)=k ² (1+cos4πz/P)・e ^j 〓 ^ot Vv(z)=k ² [1+cos{(4πz/P)−2π/3}]・
e ^j 〓 ^ot Vw (z) = k ² [1 + cos {(4πz/P) + 2π/3}]・
e ^j 〓 ^ot ………(6).

Now, signal processing is applied to each voltage in equation (6) to obtain a positive sequence voltage Vp'(z) and a negative sequence voltage Vn'(z).

Vp′ (z) = Vu (z) + e ^-j2 〓 ^/3 Vv (z) +e ^j2 〓 ^/3 Vw (z) Vn′ (z) = Vu (z) + e ^j2 〓 ^/3 Vv (z) +e ^{- j2} 〓 ^/3 Vw (z) ......(7) The following equation is obtained from equations (6) and (7).

Vp′(z)=(2/3)k ² e ^(-j4 〓 ^z/P)+j 〓 ^ot Vn′(z)=(2/3)k ² e ^(j4 〓 ^z/P)+j 〓 ^ot ......(8) By comparing the phases of Vp'(z), Vn'(z) and the reference signal derived from the carrier wave power source, the following equation is obtained.

Φ′=∠Vn′(z)−∠e ^j 〓 ^ot =−(∠Vp′(z)−∠e ^j 〓 ^ot ) =4πz／P……(9) In other words, exactly the same as equation (4) The results are obtained, and the vehicle body position can be measured continuously at a period of P/2.

The relationship in equation (9) can be obtained not only by the analog method as described above, but also by the digital method as follows.

Directly from equations (5), (6), and (7), Vp′ = [{|V12 (z) | ² − (1/2) | V23 (z) | ²
−(1/2)｜V31(z)｜ ² ｝ −j(√3/2)・{｜V23(z)｜ ² −｜V31(z)｜
² }]・e ^j 〓 ^ot Vn′=[{|V12(z)| ² −(1/2)|V23(z)| ²
−(1/2)｜V31(z)｜ ² } +j(√3/2)・{｜V23(z)｜ ² −｜V31(z)｜
² }]・e ^j 〓 ^ot ...(10) From equations (9) and (10), the following equation is obtained.

(4π/p)z=∠Vn′(z)−∠e ^j 〓 ^ot =tan ^-1 [(√
3/2) {｜V23(z)｜ ² −｜V31(z)｜ ² }/{｜V12(z)｜ ² (1/2)(｜V
23(z) | ² + | V31(z) | ² )}]......(11) In other words, |V12(z)|, |V23(z ) |, |
By converting V31(z) into a digital quantity using an AD converter and digitally processing this using a computer based on equation (11), the moving body position z can be calculated.
can be known.

However, the above method has the following drawbacks.

In other words, the period P of each conductor 1, 2, and 3 must be equal to twice the distance between the poles of a linear motor car, but in a practical linear motor car, the distance between the motor poles is expected to be approximately 6 m. Therefore, the conductor period P must be approximately 12 m.

Therefore, manufacturing the line 4 may be difficult and expensive.

In addition, in order to realize this method, it is necessary that the induced voltage between each conductor has a pure sine wave shape with respect to z, as shown in equation (1), and therefore the length L of the antenna 5 is P /7 to P/5 (1.7 to 2.4 m when P=12 m), which is extremely large. When attaching an antenna to a car body, it is necessary to provide a notch in the car body to avoid the effects of eddy currents flowing through the car body, but it is not desirable from the viewpoint of the mechanical strength of the car body that this becomes large.

In order to solve the above problems, the present inventor devised a position detection method in which a straight conductor was provided in parallel to an inductive radio line consisting of three conductors as shown in Figure 1. The method will be explained with reference to FIG.

In FIG. 3, conductors 1, 2, and 3 are bent into a waveform shape with a period P (twice the distance between the motor poles) and are arranged offset by P/3. A guided radio line 4' is formed by being arranged on a straight line in parallel with the guide line 4'. Note that 7, 8, 9, and 10 are terminating resistors for matching the characteristic impedance of each line. By exciting the antenna 5 with a high frequency current, a voltage is induced between each conductor 1, 2, 3, and 6. Assuming that the voltages appearing between conductors 1 and 6, 2 and 6, and 3 and 6 at the starting end of line 4' are V10 (z), V20 (z), and V30 (z), respectively, V10 (z) = k1 (1 + k2 cos2 πz/P
)e ^- 〓 ^z V20(z)=k1[+k2cos2 π(z+P
/3)/P]e〓 ^z V30(z)=k1[1+k2cos π(z+2
P/3)/P]e ^- 〓 ^z ......(12) Here, k1, k2: constants.

It is clear from Figure 3 that K1>k2,
The value in parentheses or [ ] on the right side of equation (12) is always positive for any value of z.

Now, if the above voltage is linearly detected at the starting end of the line 15 and its envelope is determined, the following equation is obtained.

｜V10(z)｜=k1(1+k2cos2 πz/P)e
〓 ^z ｜V20(z)｜=k1[1+k2cos2 π(z+P
/3)/P]・e ^- 〓 ^z |V30(z)|=k1[1+k2cos2 π(z+2P
/3)/P]・e ^- 〓 ^z ……(13) Here, the new carrier wave of angular frequency ωo is (13)
Modulate each voltage of the equation and make each Vu″(z),
Assuming Vv″(z) and Vw″(z), the following equation is obtained.

Vu″(z)=｜V10(z)｜e ^j 〓 ^ot =k1(1+k2cos2
πz/P)・e ^- 〓 ^z+j 〓 ^ot Vv″(z)=｜V20(z)｜e ^j 〓 ^ot =k1[1+k2cos2
π(z+P/3)/P]・e ^- 〓 ^z+j 〓 ^ot Vw″(z)=｜V30(z)｜e ^j 〓 ^ot =k1[+k2cos2 π
(z+2P/3)/P]・e ^- 〓 ^z+j 〓 ^ot ......(14) Perform the following signal processing on these voltages to obtain the positive sequence voltage.
Vp″(z) and negative sequence voltage Vn″(z) are derived.

Vp″ (z) = Vu″ (z) + e ^-j2 〓 ^/3 Vv″ (z) +e ^j2 〓 ^/3 Vw″ (z) Vn″ (z) = Vu″ (z) + e ^j2 〓 ^/3 Vv″ (z) +e ^-j2 〓 ^/3 Vw″(z) ......(15) The following equation can be obtained immediately from equations (14) and (15).

Vp″(z)=(3/2)k1・k2・e ^- 〓 ^z+(j2 〓 ^z/P)+j 〓 ^ot Vn″(z)=(3/2)k1・k2・e ^- 〓 ^{z- (j2} 〓 ^z/P)+j 〓 ^ot ………(16) Find Φ″ in the following equation by comparing Vp″ (z) or Vn″ (z) with the reference phase signal derived from the carrier wave power source. Can be done.

Φ″＝∠Vp″(z)−∠e ^j 〓 ^ot =−(∠Vn″(z)−∠e ^j 〓 ^ot )=2πz/P
......(17) That is, by measuring Φ'', the moving body position z can be continuously known at a period of P.

Further, Φ'' can be determined by the following digital method.

The following equation is immediately obtained from equations (14) to (17).

(2π/P)z=Φ″=tan ^-1 [(√3/2){−|V20(z
)｜＋｜V30(z)｜}/{｜V10(z)｜ −(1/2)(｜V20(z)｜+｜V30(z)｜)}]...
...(18) That is, by envelope detection of V10(z), V20(z), and V30(z), |V10(z)|, |V20
(z) |, |V30(z)|, convert these quantities into digital quantities using an AD converter, digitally process the calculation on the right side of equation (18) to find Φ″, and from this Therefore, the moving body position z can be continuously known at a period of P.

As described above, according to the method shown in FIG. 3, the position detection period of the moving body can be made equal to the period P of the conductor shape of the guided radio line, which is extremely advantageous compared to the method shown in FIG.

However, according to studies conducted by the present inventors, it has been newly pointed out that although this method is effective when the guided radio line is relatively short, there are problems when the guided radio line becomes long.

That is, the voltage V10 at the beginning of line 4'
(z), V20(z), and V30(z) in equation (12), assuming that the propagation constant of the positive-phase (negative-phase) line is equal to that of the zero-phase line, but if line 4' is long As the distance z from the starting end of the line to the mobile object increases, the influence of the difference in propagation constants of these lines cannot be ignored.

The reason for this can be explained as follows.

Now, γ: Propagation constant of positive-sequence and negative-phase lines γo: Propagation constant of zero-sequence line Δγ=γ−γo, then voltages V10(z), V20(z), and V30(z) can be written as follows. be able to.

V10(z)=k1{e ^- 〓 ^oz +k2cos(2πz/P)・e ^- 〓 ^z
}=k1e ^- 〓 ^oz {1+k2cos(2πz/P)・e ^- 〓〓 ^z } V20(z)=k1e ^- 〓 ^oz {1+k2cos2 π(z+P/3)
/P・e ^- 〓〓 ^z } V30(z)=k1e ^- 〓 ^oz {1+k2cos2 π(z+2P/3)
/P・e ^- 〓〓 ^z }...(19) Here, γ=α+jβ, γo=αo+jβo, Δγ=Δα
Set +jΔβ and substitute this into equation (19) to get |V10
When (z)| is found, it becomes as follows.

｜V10(z)｜=k1e ^- 〓 ^oz {1+2k2e ^- 〓〓 ^z・cosΔβzc
os (2 πz/P) + k2 ² e ^-2 〓〓 ^z・cos ² 2πz/P} ^1/2 = k1e ^- 〓 ^oz {(1+k2e ^- 〓〓 ^z・
cos2πz/P) ² −2k2e ^- 〓〓 ^z (1−cosΔβz)・cos2πz/P} ^1/2 …
...(20) It can be seen that the radical on the right side of equation (20) does not take the form of a perfect square unless Δβ = O, and |V10(z)| contains even-order harmonics. . ｜V20
The same applies to (z)| and |V30(z)|. By including even-order harmonics in this way,
This results in a decrease in position detection accuracy.

[Object of the invention] The present invention can make the position detection period of a moving body equal to the conductor period of the track, and when this is applied to automatic operation of a linear motor car, the conductor period P
A mobile object that can make the distance equal to the distance between motor poles, miniaturize on-board antennas, facilitate track manufacturing, and prevent a decline in position detection accuracy even when the track becomes long. The purpose is to provide a position detection method.

[Summary of the Invention] The main point of the present invention is to
, and each conductor has a periodic structure of P/
An inductive radio line consisting of three conductors arranged at a distance of 3 and a straight conductor parallel to these three conductors was laid, and two antennas were installed on the moving body at an interval of P/2. The inductive radio line is excited by the alternating magnetic field generated by passing alternating currents of different frequencies f1 and f2 through the two antennas, and the connection between each of the three conductors and the linear conductor is Each voltage for frequency f1 induced between (these are V110 (z) and V120
(z), V130(z)) and each voltage for frequency f2 (these are V210(z) and V220, respectively)
(z), V230(z)) is linearly detected to find its envelope. )
｜, ｜V210(z)｜, ｜V220(z)｜, ｜V230(z)｜
), and convert these quantities into digital quantities, V1e(z) = |V110(z) | − | V210(z) | V2e(z) = |V120(z) | − | V220(z ) | V3e (z) = | V130 (z) | − | V230 (z) |, then z = (P/2π) tan ^-1 [(√3/2) {−V2e (z) + V3e
(z)} /{V1e(z)−(1/2)(V2e(z)+V3e(z))}
] The purpose is to continuously detect the position of a moving object at a period P by performing the calculation.

(V110(z) and V210(z) are the voltages induced between the same lines, and V120(z), V220(z), and V130
The same applies to (z) and V230(z). ) The principle of the present invention will be explained based on FIG. Fourth
In the figure, 11, 12, 13, and 14 are conductors, respectively. The conductors 11, 12, and 13 are bent into a waveform shape with a period P and are arranged shifted by P/3, and the conductor 14 is the conductor 11, 12,
A guided radio line 15 is formed by being arranged linearly in parallel with the guide line 13 .

16-1 and 16-2 are antennas, respectively, which are fixed on the moving body at an interval of P/2.

17, 18, 19, and 20 are terminating resistors for matching the characteristic impedance of each line.

When high frequency currents of frequencies f1 and f2 are applied to antennas 16-1 and 16-2, respectively, voltages are induced between conductors 11, 12, 13, and 14, respectively.

Conductors 11, 14, 12 at the starting end of line 15
and 14, and the voltages induced between 13 and 14 are selectively received at frequencies f1 and f2, respectively.
V110(z), V210(z), V120(z), V220(z),
Obtain V130 (z) and V230 (z), perform linear detection to find their absolute values, and derive V1e (z), V2e (z), and V3e (z) by calculating the following equations.

V1e (z) = | V110 (z) | − | V210 (z) | V2e (z) = | V120 (z) | − | V220 (z) | V3e (z) = | V130 (z) | − | V230 (z)｜
......(21) The calculation on the right side of equation (21) is to shift the same waveform by half a cycle (P/2) and find the difference,
Even-order harmonics completely disappear, and the right side of equation (21) becomes an almost perfect sine wave, so V1e(z), V2e
(z) and V3e(z) can be expressed as shown below.

V1e(z)=k3cos2πz/P V2e(z)=k3cos2π(z+P/3)/P V3e(z)=k3cos2π(z+2P/3)/P
......(22) k3: Constant.

Next, a new carrier wave with an angular frequency ωo is modulated with each voltage in equation (22) to obtain Vu1(z) and Vv1, respectively.
(z) and Vw1(z), the following equation is obtained.

Vu1(z)=k3cos2πz/P・e ^j 〓 ^ot Vv1(z)=k3cos2π(z+2π/3)/P・e ^j 〓 ^ot Vw1(z)=k3cos2π(z−2π/3)/P・e ^j 〓 ^ot
......(23) Perform the following signal processing on these voltages to obtain the positive sequence voltage.
Deriving Vp1 (z) and negative phase voltage Vn1 (z) can be expressed as in the following equation.

Vp1 (z) = Vu1 (z) + e ^-j2 〓 ^/3 Vv1 (z) +e ^j2 〓 ^/3 Vw1 (z) Vn1 (z) = Vu1 (z) + e ^j2 〓 ^/3 Vv1 (z) +e ^-j2 〓 ^/3 Vw1(z) ......(24) The following equation can be obtained immediately from equations (23) and (24).

Vp1 (z) = (3/2) k3e ^j2 〓 ^z/P Vn1 (z) = (3/2) k3e ^-j2 〓 ^z/P ...... (25) Vp1 (z) or Vn1 (z) and carrier wave By comparing the phase with the reference signal derived from the power supply, Φ1(z) in the following equation can be obtained.

Φ1(z)=∠Vp1(z)−∠e ^j 〓 ^ot =−(∠Vn1(z)−∠e ^j 〓 ^ot ) =2πz/P……(26) In other words, through the measurement of Φ1(z) , the moving body position z can be continuously known at a period of P.

Further, Φ1(z) can be obtained by the following digital method.

The following equation is immediately obtained from equations (23) to (26).

(2π/P)z=Φ1(z)=tan ^-1 [(√3/2){
−V2e(z)+V3e(z)} /{V1e(z)−(1/2)(V2e(z)+V3e(z)
))}]...(27) In other words, the value of |V110(z)|~|V230(z)| is converted into a digital quantity, and the calculation on the right side of equation (27) is processed digitally to move. The body position z can be continuously known at a period of P.

Although the present invention is applicable to detecting the position of various moving bodies, it can be particularly suitably applied to automatic operation of linear motor cars.

In this case, the guided radio line can be formed by laying a conductor in a predetermined shape parallel to the track of the linear motor car, but the propulsion coil of the linear motor car can also be used.

FIG. 5 shows an example in which a linear conductor s is provided in parallel to the propulsion coil of a linear motor car. The rectangular loop coils u, v, w form the motor poles, and the loop coils u, v, w have 0
When a traveling wave magnetic field is created by passing a current of about 30 Hz in positive or negative phase, this acts on the electromagnets on the vehicle and generates thrust. Each loop coil u, v, w forming this propulsion coil has a periodic structure of P, and three conductors (11, 12 in Fig. 4) arranged at intervals of P/3 in the longitudinal direction. , 13)
By using it in accordance with the above, a guided radio line can be constructed.

In this case, by using two antennas as in the present invention, even-order harmonic components can be removed, so position detection errors can be eliminated.

That is, as is clear from FIG. 5, the length L' of each loop coil u, v, w is less than P/3,
Therefore, the voltage between each conductor can no longer be said to be sinusoidal with respect to z. For example, the relationship between V10(z) and z is shown in Figure 7. When the antenna passes directly above the coil, V10(z) takes a maximum value, and in the vicinity it takes on a shape close to a half-sine wave. However, it takes a minimum value at the midpoint of adjacent coils, and exhibits a flat shape over a wide range in the vicinity. In this way, if a waveform with severe vertical asymmetry is subjected to Fourier expansion, it will contain extremely large even-order harmonic components, causing position detection errors, but this drawback can be resolved by using two antennas. can.

[Embodiment of the Invention] An embodiment of the present invention will be described based on FIGS. 4 and 6.

FIG. 6 shows an example of the configuration of a signal processing device connected to the terminal of the line 15.
21-2a, 21-3a, 21-1b, 21-2
b, 21-3b is a bandpass wave generator, 22-1a,
22-2a, 22-3a, 22-1b, 22-2
b, 22-3b are detectors, 23-1a, 23-2
a, 23-3a, 23-1b, 23-2b, 23
-3b is an AD converter, 24 is a digital computer, and 25 is a digital converter.

Antennas 16-1 and 16 excited by high-frequency power sources (not shown) at frequencies f1 and f2, respectively.
When a magnetic field is formed by -2, a voltage corresponding to each frequency is induced between each conductor 11, 12, 13, and 14 by this magnetic field.

Here, conductors 11 and 14, 12 and 14, 13
and 14 are selectively received by the signal processing device shown in FIG. 6 installed at the terminal of the line 15 and subjected to the following signal processing.

Voltage for frequency f1 between conductors 11 and 14
Noise voltage is removed from V110(z) by a bandpass detector 21-1a, and then linearly detected by a detector 22-1a and guided to an AD converter 23-1a. Similarly, the voltage V120 (z) between the conductors 12 and 14 and the voltage V130 (z) between the conductors 13 and 14 are also applied to the bandpass wave detectors 21-2a, 21-3a, and the wave detector 22.
AD converter 23-2 through -2a and 22-3a
a, 23-3a. Similarly, the voltages V210 (z), V220 (z), and V230 (z) regarding the frequency f2 are also applied to the band pass wave generators 21-1b, 21-2b,
21-3, detector 22-1b, 22-2b, 22
-3b to AD converter 23-1b, 23-2
b, led to 23-3b. AD converter 23-1
The signals converted into digital quantities in a to 23-3b are led to a digital computer 24.

In the digital computer 24, the calculations to obtain V1e(z), V2e(z), and V3e(z) in equation (21) and the calculation to obtain the phase angle Φ1(z) in equation (27) are digitally processed, and the results are is displayed on the digital display 25.

As the conductor shape of the guided radio line used in the present invention, in FIG. 4, a trapezoidal wave shape,
In FIG. 5, rectangular coils are connected in a chain, but the conductor shape may be triangular or rectangular. Further, the structure is not limited to a flat structure as shown in FIGS. 4 and 5, but may be a spiral structure.

In addition, although the explanation has been given using a linear motor car as an example of application of the present invention, the present invention is not limited to this, but is applicable to railway vehicles, various new transportation systems, cranes, and transport vehicles that move along a fixed running route. It is widely applicable to detecting the position of moving objects.

[Effects of the Invention] As explained above, according to the present invention, the detection period of the moving body position can be made equal to the period P of the conductor shape of the guided radio line. That is, compared to the conventional method in which the detection period is P/2, the same detection period can be obtained even if the conductor period is halved. Therefore, manufacturing of the line becomes easy and the cost of the line can be reduced. In addition, if the period of the conductor is shortened, the size of the mobile tower-mounted antenna can be reduced proportionally.
The antenna can be easily attached to the vehicle body, and there is no need to provide a large cutout in the vehicle body, which eliminates concerns regarding the strength of the vehicle body.

Further, the present invention calculates the difference between the voltages at frequencies f1 and f2, thereby making it possible to remove even-order harmonic components and eliminate position detection errors.

When the present invention is applied to the position detection of a linear motor car, the ground propulsion coil can be used for multiple purposes as a guided radio line for position detection, and it can greatly contribute to the economicalization of the system configuration. .

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the conventional method, Fig. 2 is an explanatory diagram of the relationship between the moving object position z and the phase difference, and Fig. 3 is a position detection diagram using a guided radio line similar to the present invention and a single antenna. Fig. 4 is an explanatory diagram of the principle of the present invention and an embodiment of the present invention; Fig. 5 is a schematic explanatory diagram of the case where a ground propulsion coil of a linear motor car is used as the guided radio line of the present invention; Fig. 6 is an explanatory diagram of the method; The figure is an explanatory diagram of one embodiment of the signal processing device used in the present invention, and FIG. 7 is an explanatory diagram of the waveform of voltage induced between conductors. 11, 12, 13: conductor, 14: linear conductor,
15: Guided radio line, 16-1, 16-2: Mobile tower antenna, 21-1a, 21-2a, 21
-3a, 21-1b, 21-2b, 21-3b:
Bandpass wave generator, 22-1a, 22-2a, 22
-3a, 22-1b, 22-2b, 22-3b:
Detector, 23-1a, 23-2a, 23-3a,
23-1b, 23-2b, 23-3b: AD converter, 24: digital computer, 25: digital display.

Claims (1)

[Claims] 1. Three conductors having a P periodic structure and arranged with each conductor shifted by P/3 in the longitudinal direction; An inductive radio line consisting of a straight conductor parallel to the conductor is laid, and two antennas are mounted on the moving body at an interval of P/2, and the two antennas each have different frequencies f1 and f2. The inductive radio line is excited with an alternating magnetic field generated by passing an alternating current of z), V120(z), V130(z)) and frequency f2 (these are respectively V210(z), V220(z), V230(z)) and their envelopes are detected by linear detection. Find the line (envelope curve corresponding to each voltage above, respectively |V110(z)|,
｜V120(z)｜, ｜V130(z)｜, ｜V210(z)｜, ｜
V220(z)｜, |V230(z)｜), convert these quantities into digital quantities, and obtain V1e(z) = |V110(z) | − | V210(z) | V2e(z) = |V120(z)|−|V220(z)|V3e(z)=|V130(z)|−|V230(z)|, then z=(P/2π)tan ^-1 [(√3/ 2) {−V2e(z)+V3
e(z)}/{V1e(z)−(1/2)(V2e(z)+V3e(
z))}] A moving object position detection method characterized in that the position of a moving object is continuously detected at a period P by performing the following calculation. (V110(z) and V210(z) are the voltages induced between the same lines, and V120(z), V220(z), and V130
The same applies to (z) and V230(z). )