JPS5823591B2 - Mobile position detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for detecting, on the ground side, the position of a mobile object traveling on a fixed travel path, and particularly relates to a device for detecting the position of a mobile object traveling on a certain travel path on the ground side. Related to improvements in body position detection devices.

In a conventional guided wireless moving body position detection device, for example, a parallel two-wire guide line is laid along a running route, and
The guide wires are crossed at appropriate intervals and an amplitude fluctuation detection circuit is connected to one end of the guide wire.

On the other hand, the moving body is provided with a loop coil antenna coupled to a transmitter of a specific frequency and a guide wire, and a signal wave of the specific frequency is transmitted from the loop coil to the guide wire.

In this way, when the moving body travels, the signal wave from the loop coil antenna at the above-mentioned crossing position becomes zero due to phase cancellation, so this is detected by the amplitude fluctuation detection circuit on the ground side, and the number of times of this detection is counted. Devices that detect the position of moving objects on a road have been proposed, but since such devices detect fluctuations in the amplitude of signal waves at intersection points, if noise is mixed in, they may frequently make false detections and cause false detections. However, in order to make the unit of position detection smaller and more precise, it is necessary to shorten the crossing interval of the guiding wire, but if the crossing interval is shortened, the guiding wire and loop coil The transmission loss between
In addition, if the length of the loop coil is shortened accordingly, the transmission loss will increase, so the practical minimum value of the crossover interval is approximately 1.
It was m.

The present invention was made to eliminate the above-mentioned drawbacks.
This will be explained in detail below.

In the present invention, the length in the direction of the guide line of the loop coil antenna coupled to the guide wire laid along the travel route and the crossing interval of the guide wires are set to optimal values to minimize coupling loss. is equipped with an oscillator with an assigned specific frequency, a transmitter that outputs a modulated wave by AM or FM modulating the oscillation output or its phase-shifted output with a wave obtained by dividing the output by n, and multiple loop coil antennas. At the ground station (hereinafter referred to as the ground station), a phase composite wave signal is obtained from the guided wire output coupled with the multiple antennas, and from this one modulated wave component is extracted and multiplied by n to produce a frequency equal to a specific frequency and synchronized with the modulated wave. A reference phase signal wave is generated, and the other one detects the phase difference between the phase composite wave and the reference phase wave or the reference phase wave shifted by a certain amount, and detects the position of the moving object based on this. Embodiments of the present invention will now be described in more detail.

FIG. 1 is a diagram showing an example of the configuration of a portion of the apparatus of the present invention mounted on a moving body, and FIG. 2 is a diagram showing an example of the configuration of ground-side equipment.

In Figure 1, the specific frequency (referred to as ro) is within the dashed line.
In the transmitter (XTR) including this oscillator 1, 2 is 1/n (
n is an integer greater than or equal to 2) frequency divider, 3 is a sine wave amplifier, 4a,
4b and 4c are amplitude modulators (MOD)5. γ, 9 is the output amplifier (PA), 6°8 is the phase shifter (PS), 10, 1
1 and 12 are loop coil antennas (LC).

Now, the output of oscillator 1 is output in parallel to frequency divider 2, modulator 4a, and phase shifters 6 and 8, but in frequency divider 2, t/n
(n is an integer greater than or equal to 2).

/n wave is output to the modulator 4a as a sine wave of a required level in the amplifier 3 at the next stage.

Although the modulator 4a performs amplitude modulation (AM) in this example, the fa large input f from the oscillator 1 is used.

/n wave after amplitude modulation (modulation rate is about 30%) PA
5 is output.

On the other hand, the role of the phase shifter (PS) 6.8 is to sequentially shift the phase between the currents flowing through the plurality of loop coil antennas 10 to 12. Now, when the number of loop coil antennas is N, the phase shifter has an input f.

Shift the phase of the wave by π/N radians. If N is an odd number, this phase shift may be in steps of 2π/N radians.

In the example of Figure 1, if there are two antennas, 10 and 11, P
The phase shift amount of S6 is π/2 radian, and the antenna force is 510
．． 11.12, the phase amounts at PS6 and PS8 are π/3 and 2π/3 or 2π/3 and 4π/3, respectively.
shall be.

In this way, f is phase-shifted according to the number of loop coil antennas.

The wave is AMed with the fo/n wave from the amplifier (AMP) 3.

The modulated wave is PA5°PA7. The signals are supplied to loop coil antennas io, ii, and 12 through PA9, respectively.

Note that the carrier wave f in the signal power supplied to each loop coil antenna.

The phases of the modulated wave f are sequentially shifted by a constant value as described above.

/n is in phase for all antennas.

In addition, the loop coil antenna is arranged in a line in the running direction,
The interval may be selected as Mi (M is an integer such as 1, 2.3, etc.), or 2M' only when N is an odd number.

Next, the ground station equipment shown in FIG. 2 will be explained.

In the figure, 13 is a crossed parallel two-wire induction wire laid along the running path, 14 is a terminating resistor, 15 is a coupler (for example, a coupling transformer), and 16 is an acid-proof filter and amplifier (AM with BPF).
P), 11 is amplitude modulation wave detector 1 (DET), 1B is B
PF, 19 is a phase discriminator (PI)), 20 is a low-pass filter (LPF), 21 is a frequency divider (D I V ), 22 is (
23.25 is a phase discriminator (PD), 24.26 is an LPF, and 21 is a phase shifter (PS).

Further, regarding the guide lines, LS is the position detection section, and e is the intersection interval, and the lengths are equal.

Further, el t e2 indicates a position detection (level) output.

In FIG. 2, the composite wave of waves with different phases induced from the mobile antenna to the guide wire 13 is combined;
The AMP 16 limits the band and amplifies it to the required level.

A part of the signal is envelope-detected by the wave detector 11, and the other part is input to the phase discriminators PD23 and PD25.

First, f is the envelope detection output of the wave detector 11.

/n wave is f. The phase discriminator PD is sent to the BPF 18 whose center frequency is /n to improve the S/N ratio.
Enter in I9.

Another input of this PD19 is the frequency f of VCO22.
f □ from the frequency divider 21 that divides the output of o' into 1/n.
' / n wave, I for phase difference discrimination output of PD19
After noise and phase jitter are removed by the PF 20, the signal becomes a control input for the VCO 22.

That is, 19°20.2L22 constitutes a known PLL (phase locked loop) circuit, and the amplitude modulated wave f.

The [0” wave synchronized with n times /n is sent from the VCO 22 to the PD 2 through the phase discriminator PD 23 and the phase shifter PS2γ.
Output to 5.

Since the PFi8 and PLL circuits have their own specific amount of phase shift, a phase compensation circuit is inserted on the input side of the phase discriminators PD23 and PD25 to adjust them so as to obtain an ideal state.

It is necessary to keep it.

Further, the phase shifter PS2γ provides a phase shift of π/2, and the reason for this will be explained in the operation description below.

Now, a transmitter and a loop coil antenna configured as shown in Figure 1 are installed on the moving object, and a loop coil antenna is installed on the ground side by laying a guide wire as shown in Figure 2 in the required section of the road. The phase composite wave signal from the moving object is received by the detection circuits 16 to 21 in Fig. 2, and the position is detected.The operation is shown in Fig. 3. This is explained by

Figure 3 shows the case where the guide wire 13 is made of two intersecting parallel wires with a crossing interval l and laid in the necessary section, and the interval between the two loop coil antennas 10 and 11 provided on the moving body is l/2. In the example, the induced voltage changes by π radians when moving by e along the induction line, so f is input to the antennas 10 and 11.

It is assumed that +π/2 phase is performed in the phase thick PS6 so that the phase difference of the waves is π/2.

Therefore, on the ground side, the coupler 15 connects antennas 10 and 1.
To 1.

However, in the relationship between the two antennas and the intersecting position of the guiding wire shown in Fig. 3, the antenna 10 is located on the first intersecting point in the figure (actually facing each other). The induced voltage (signal) due to antenna 10 is not generated and the signal from antenna 11 is generated.

Output.

If the signal phase at this time is 10 medical Fujian, that is, +Σ phase, then the moving object moves to the right in the figure, and the antennas 10 and 1
1 exists within the same crossing section, the antenna 11 is +
Since the i-phase remains unchanged and the antenna 10 is in the zero phase, the coupler 1
The signal phase of the output of antenna 5 becomes +1 phase, and the signal phase of the output of antenna 1 becomes +1 phase.
1 moves above the intersection, the output of the coupler 15 goes to the O phase, and when it moves further and is in a position narrowing the intersection in the center of the figure between the antennas 10 and 11, it goes to the -τ phase, and then the output of the coupler 15 goes to the -τ phase. 10
If it moves to the center intersection, it becomes -L phase.

In this way, as the mobile object, that is, the antennas 10 and 11 move in order to the right, the antenna 410 moves through the π, π, and 10×π phases, and then moves by 24, and then returns to the original +10. People.

(These are easily understood by vector composition.

) Also, when the moving object moves to the left in the figure, 3x, π, 3π, -1 from the earthwork, contrary to the right direction.

, 2 4 4 2 4.0, returns to +100 after +a.

The amplitude envelope of the signal at this time is the two antennas 10 and 1.
f to the 1 signal level when either 1 exists on the intersection or the phase combination level of two signals other than on the intersection.

/n waves are superimposed. In this way, since the distance of 2e is one period and the guiding line is a crossed parallel two-wire system,
When either of the two antennas is coupled before or after the intersection, the coupling loss with the antenna increases rapidly and there is a π phase shift with the intersection as a boundary, so in the example shown in Figure 3 above, the moving object is When driving at high speed, 0.0 when one antenna is at the intersection. ±7. By rapidly shifting each phase of π, the coupling loss becomes constant when both antennas are located outside the intersection, so ±1. This means that each phase of ten days π continues.

- Next, the operation of the position detectors 16 to 21 in this case will be explained.

As described above, the phase composite waves from the loop coil antennas 10 and 11 of the moving body are received by the guide wire shown in FIG. 2 and inputted from the coupler 15 to the BPF and signal amplifier 16.

This BPF is f. The input signal wave whose band has been limited by this is amplified to the required level by DET17, PD23. Output to PD25.

First, in the amplitude modulation wave detector DET1γ, f is detected as described above.

Detect the /n wave and use the PLL circuit according to 19 to 22) f
.

/n synchronized with wave and f. f equal to. A wave is generated and fed into one of the inputs of the phase discriminator PD23 as a reference phase wave.

Another input to this PD23 is the above phase composite wave,
An output corresponding to the phase difference with the reference phase wave passes through the LPF 24 and is output as el.

i In the example shown in Fig. 3, when the input signal is +7 phase, the output of the PD 23 is assumed to be the output e1 after passing through the LPF 24 as shown in the level diagram e1 of Fig. 3 to the "0" level. When moving to the right at a constant speed + ' + Ot
-1 In each phase, el outputs (-+) level. Output each level.

Also, near the ±Σ phase, el changes suddenly from zero, but e1
The output becomes zero level at the intersection.

Therefore, if this e1 output is led to a square wave conversion circuit whose conversion point is, for example, 0 level, a square wave will be obtained, and since it changes to H and L levels alternately at each intersection, the intersection position can be detected.

Next, the reference phase wave f.

' is earthwork phase-shifted by a phase shifter PS27 and input to a phase discriminator PD25, and the phase difference with the input from the amplifier 16 to PD25 is determined and outputted as e2 through the LPF26.

e2 is the difference between cl and el2, that is, a different output with 7 phases, and e
Similarly to l, when the signal is guided to a square wave conversion circuit whose zero level is the conversion point, a square wave whose conversion point is the center position of the two intersections of the guiding lines is obtained.

Therefore, from the combination of the above two square wave outputs by elle2, as shown in d of FIG. 00 in section (3), 01 in section (4)
The respective code outputs are obtained, and position detection is performed by dividing the section of guide line length 2e into four.

Note that since the phase composite wave output of the signal amplifier 16 is an amplitude modulated wave, the outputs of the PD 23 and PD 25 have f.

The /n wave is superimposed, but it is removed by the LPFs 24 and 26, and f is sent to el l e2.

/n wave has no effect. As explained above, in the example in which two antennas io and ii are used, the receiving side phase composite wave is 0. Since code conversion is obtained for each phase of 1-2π, detection of four positions per two intersections is possible.

Next, the optimum value for minimizing the coupling loss between the length along the guide wire of the loop coil antenna and the crossing interval between the guide wires is that for the length L of the antenna, the crossing interval e is at least 2L or more, and the minimum value of L is is 1.2 to 13 for the spacing between two guide wires.
Double it.

In addition, considering the relative deviation between the center line of the guide line and the center line of the antenna when the moving object is running, there is a limit to how narrow the line spacing of the guide lines can be. There are restrictions depending on the purpose.

To divide the intersection area into more parts, increase the number of antennas, perform a phase shift commensurate with the number of antennas, and output the signal wave from the mobile side. On the ground position detection side, N phase discriminators, LPFs, and If N-1 phase chics are added, the output el l e2...
It will be easily understood that the location subdivision code can be obtained from ...e.

(Since the final subdivision method is complicated, the method shown in FIG. 4 is generally advantageous.

) If it is impossible to arrange multiple antennas in the same intersection section 4, the antenna spacing may be the sum of an integral multiple of e. For example, 11 in FIG. 3 is the antenna 10 and 3e/3e.
This is the second antenna placed at a spacing of 2.

In this way, when the range is an odd multiple of e, the output of the guide wire is polarized by π phase, so the rotation is opposite to the above phase rotation, but with two antennas, there are two intersections and four positions. The fact that detection is possible is the same as above.

Next, FIG. 4 will be explained.

The example shown in Fig. 3 detects the position in a so-called step-like manner, which improves the accuracy of detecting the crossing position by generating a steep phase shift before and after the coupling of the intersection between the antenna and the guide wire. Figure 4 shows the position detection performed in a straight line.

When the guide wire 13 is formed into a diamond shape as shown in Fig. 4, it has been experimentally shown that the coupling loss between the loop coil antenna and the diamond-shaped two-wire guide wire is inversely proportional to the distance between the two guide wires. It is also known that, for this reason, when the antenna is moved along the guide line, the coupling loss changes approximating a sine wave.

Now, there are three loop coil antennas 10, 11, and 12 on the moving object side as shown in Figure 1, and the antenna spacing is set to 2e/3, and the phase difference of the signal given between each loop coil by PS6 and PSB is calculated. The phase shift amount of PS6 and PSB is +2π to make each 2π/3 radian.
/3 and -2π/3.

The reason for this is that it is determined by the spacing and position of the antennas 10, 11° and 12 shown in Figure 4. If antenna 10 is O phase, antenna 11 is +2π/3 phase, and antenna 12 is a cross of antenna 11 and the opposite phase. Since it is in the section, amplitude modulated waves having a phase difference of -2π/3 phases are output.

Accordingly, the signal coupled and induced in the guide wire 13 becomes a phase composite wave, but at the antenna position shown in FIG. 4, it becomes a +π phase composite wave.

If the moving object is moving, for example, to the right, based on the relationship between the antenna 10 and the guide wire 13,
When the antenna 10 moves by 1/3 from the position shown in FIG. , /3 is reached, -100 phase, similarly, the moving distance is l, and in 1-H6, 1-yd, it changes as -1 phase, -1π phase, and clay foot π phase, respectively.
6 6 do.

The coupling loss of the antennas 10, 11, 12 with the guide wire 13 changes in an approximately sinusoidal manner, and the coupler 15 from the guide wire changes.
Although the phase deviation of the phase synthesized wave outputted through the waveform changes in the shape of an approximate sine wave with a distance of 2e as one period, the amplitude is constant due to amplitude modulation by the fo/n wave.

(The reason why the amplitude is constant is that the composite value of three sine waves with mutually different phases is always constant.

) It is also clear that when the moving body moves in the opposite direction to the left, it is deviated in the opposite direction to the above-mentioned phase rotation direction.

Next, the operation of the position detector is similar to that configured in 16 to 21 above, but the method of detecting phase deviation is completely the same as in FIG. 2, f.

/n wave component is extracted and f. ' Synchronize the waves and create a reference phase signal, phase valve.

A separate PD23 detects the phase difference between the input composite wave and the reference phase signal, and the output e1 whose level changes as shown in Fig. 4 e1 is obtained through the LPF24. As the phase changes, the output of the discriminator also changes in the shape of an approximate main sinusoidal wave.

In the case of phase shifter 2T, f.

' wave is input to the phase difference discriminator PD25 as a reference phase signal after ten-factor deviation, so the phase difference with the input composite wave is different from el - that is, the distance is Σ, as shown in Fig. 4 β e2. Everything that things output is the same.

. LPF 24 and LPF 26 are for removing fo/n wave components, and when the outputs of <el and 02, which are the same as in the case of Fig. 3, are input to a square wave converter that tosses the zero level to the slice level, 2 is obtained. 24 square wave outputs are obtained.
Detection of 4 positions divided into 4 areas.

will be held.

Furthermore, the above was an example of generating two phase discrimination outputs from a composite wave input using two reference phase signals with a hundred different phases, but -(m is 1, 2, 3... m reference phase signals whose phases are shifted by an integer of .

When used, it is possible to detect positions divided into 2 m within the 2e section,
An absolute address with 2e as one cycle can be assigned.

Although both FIG. 3 and FIG. 4 have described position detection within two intersecting sections of length 2e, in reality, sections of length 2e are consecutively provided, and the position of the moving object in each section is detected. is necessary.

The method of detecting the position of an intersection is publicly known. For example, if a separate device detects an intersection as a moving object moves and counts the number of times the intersection is detected, it can be used to determine which of the 24 sections the moving object is in. The position can be detected in units of 4/2 m.

Further, the loop coil antennas 10, 11, 12, etc. are not limited to air-core loop coils, and any antenna having the characteristics of the above-mentioned loop antennas, such as a combination of magnetic core bar antennas, can be used.

As explained in detail above, the present invention uses two parallel lines or two diamond-shaped guide lines that intersect periodically, and enables the position detection of a moving object divided within the intersecting interval. The guide wires to be laid along the road are simple, and the installation and maintenance costs are significantly lower than those using conventional multiple guide wires.

Moreover, since the position detection method uses a phase difference detection method using continuous signals, it is resistant to noise and provides highly accurate detection, and the respective circuits of the transmitter and position detector have become cheaper due to the recent development of integrated circuits. Since it is available, it has the advantage of being an overall economical device, and this application is also used to detect the position, speed, and stop position (information) of a moving object with high precision in automatic travel control of a moving object. The practical effects are remarkable.

[Brief explanation of drawings]

Figure 1 is a diagram showing an example of the configuration of equipment mounted on a moving body of the device of the present invention, Figure 2 is a diagram showing an example of the configuration of ground-side equipment, and Figure 3 is a diagram of the configuration when using the equipment shown in Figures 1 and 2. Operation explanatory diagram, Figure 4 is diamond 2
It is an explanatory diagram of operation when a wire type guide wire is used. ; 1, 22... oscillator, 2, 21...
・Frequency divider, 3...Amplifier, 4a, 4bt4c・
...Modulator, 5゜1.9 ...Amplifier, 6
,8,2γ... Phase shifter, 10.11,12
・・・・・・Loop coil antenna, 13・・・・・・
Guide wire, 16... BPF and amplifier, 1γ...
...Detector, 18...BPF, 19,23
．． 25...Phase difference discriminator (PD), 20, 2
4, 26...LPF0

Claims (1)

[Scope of Claims] 1. As a device for detecting the position of a moving object moving on a fixed travel path on the ground fixed side, the device extends along the travel path and divides the travel path into fixed lengths (1) of each section. Cross-type two-wire guide wires that are crossed at each boundary point and have one end terminated with a resistor, the intersecting distance e of the guide wires in the tension direction of the guide wires placed on a moving body, and the number N of antennas. M-' (M is 1, 2
．． A plurality of M loop coil antennas arranged in a line at intervals of N 21 or M only when N is an odd number and coupled to the above-mentioned guide wire, and an oscillator with a specific frequency fo. , this oscillator output as ■/
A frequency divider that divides the frequency into n (n is an integer greater than or equal to 2), the oscillator output as it is, and the phase shifted by π/N radians or 2r radians, respectively, are amplitude-modulated at the output of the frequency divider. A mobile body side equipment comprising a transmitter including a plurality of phase shifters, modulators, and amplifiers that modulates and amplifies the frequency and applies it to each of the N loop antennas in the order of arrangement, and from each of the loop coil antennas. f obtained by demodulating the composite wave of signals guided by the guide wire. /n wave with frequency f. Frequency f which is synchronized to f. +1 (fo”=fo) oscillation circuit and f from the above oscillator. 7 waves and this with a constant phase π/m (m is an integer of 1 or more)
connected to the other end of the guide wire, which is equipped with a plurality of phase difference discriminators whose other inputs are a composite wave of the signals, each of which is connected to the other end of the guide wire. and a ground-side position detector, wherein the phase difference discriminator of the position detector obtains an output at a level corresponding to a position within two crossing sections of the guide line. .