JPH05258141A - Gate sensor - Google Patents

Abstract

PURPOSE:To provide a gate sensor which ban accurately clock the gate passing time of plural measured bodies passing an arbitrary place on a gate. CONSTITUTION:A magnetic field source 11 is arrange at the gate 12 or near the gate. A magnetic bearing sensor 14 detecting the direction of a magnetic field affected by the magnetic field source 11, a timer 15 clocking detected time when the magnetic bearing sensor 14 detects a prescribed direction and a recorder 16 recording time clocked by the timer 15 are arranged at the measured body 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate sensor used in athletics, horse racing, bicycle races and the like.

[0002]

2. Description of the Related Art In athletics and horse racing, it is necessary to individually measure the time when a person, a horse or the like (object to be measured) passes through a gate.

By the way, when the passing position of the object to be measured is determined as in the case of 100 m competition, for example, an optical sensor of a light blocking type is arranged at the gate position on each course to measure the individual object to be measured. However, in the case of an open course such as long-distance running or horse racing, the gate passage time of each measured object cannot be timed.

Therefore, in such a case, it is considered to use the Doppler method.

As shown in FIG. 11, each device under test 1 has a transmitter (not shown) for transmitting its own frequency, and a receiver 3 for receiving this is arranged at the end of the gate 2. To do. The receiver 3 detects that the reception frequency changes according to the changing speed of the relative position between the DUT 1 and the receiver 3, and measures the time when the DUT 1 passes through the gate 2.

That is, the rate of change Δl of the relative distance 1 between the device under test 1 and the receiver 3 decreases from T1 to T0, and
, "0", and increases from T0 to T2. The reception frequency in these cases is the frequency transmitted by the oscillator f0
Then, from T1 to T0, f0 + α, which approaches f0 as it approaches T0, f0 at T0, and f0 -α at T0 to T2. Therefore, the passage of the gate 2 can be recognized by detecting the frequency f0 transmitted by the transmitter.

However, the frequency f transmitted by the transmitter is f.
0 fluctuates due to temperature changes, and f near T0
Since the value of α of 0 ± α is extremely small, the frequency f0 detected by the receiver 3 needs to have a certain width. For this reason, as shown in FIG. 12, the so-called dead zone due to the width of f0 becomes wider as the gate 2 passing position of the DUT 1 becomes farther from the receiver 3. That is, the measurement accuracy changes depending on the position where the gate 2 passes. This becomes more noticeable as the moving speed of the DUT 1 becomes slower as shown in the figure, and cannot be measured, for example, when the moving speed is 30 km / hour or less.

Specifically, as shown in FIG. 13, the moving speed of the object to be measured 1 is V, the relative speed Vs to the receiver, and the angle between the moving direction of the object to be measured 1 and the receiver is ψ °. Then, Vs = V cos ψ ° Here, if the moving speed V of the DUT 1 is 60 Km / h and the measurement limit speed is 30 Km / h, the angle ψ between the point recognized as the gate and the receiver is ψ = cos ⁻¹ 30/60 = 60 ° Further, when the moving speed V of the DUT 1 is 40 Km / h, ψ = cos ⁻¹ 40/60 = 41.4 ° Therefore, the value cannot be exceeded by the error.

[0009]

As described above, in the prior art,
In the case of an open course such as long-distance running or horse racing, there is a problem that the gate passing time of each measured object cannot be measured. Therefore, it is possible to use the Doppler method, but there is a problem that the accuracy is poor.

The present invention has been made in view of the above circumstances, and provides a gate sensor capable of accurately measuring the gate passing time of each of a plurality of objects to be measured which pass an arbitrary position on the gate. The purpose is to do.

[0011]

In order to achieve the above-mentioned object, a gate sensor of the present invention is provided with (a) a gate or a magnetic field source arranged near the gate and (b) a magnetic field source to be measured. Further, a magnetic azimuth sensor that detects the direction of the magnetic field affected by the magnetic field source, a timer that counts the time detected when this magnetic azimuth sensor detects a predetermined direction, and a time measured by this timer. And a recorder for recording.

[0012]

The predetermined position detected by the magnetic azimuth sensor is matched with the position passing through the gate in advance. Therefore, when the magnetic azimuth sensor detects a predetermined position, the detected time is the time when the gate has passed. Therefore, if such a time is measured by a timer and recorded in a recorder, the gate passing time of the measured object can be measured.

If one set of the magnetic direction sensor, the timer and the recorder is provided for each object to be measured, each gate passing time of the object can be measured. Further, since the magnetic direction sensor is used, the gate passing time can be accurately measured.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the structure of a gate sensor according to an embodiment of the present invention.

In the figure, reference numeral 11 denotes a magnetic field source buried in the ground near the gate 12. This magnetic field source 1
1 may be either an electromagnet or a permanent magnet, and may be a single pole (regardless of N pole or S pole) or 2 poles, but at the passage point of the magnetic direction sensor described later. ,
The magnetic azimuth sensor needs a magnetic flux density that can detect a magnetic field generated by the magnetic field source even if the influence of the geomagnetism is included.

A magnetic azimuth sensor 14, a timer 15 and a recorder 16 are arranged on the object to be measured 13.

The magnetic azimuth sensor 14 detects the direction of the magnetic field affected by the magnetic field source 11. The timer 15 measures the time detected when the magnetic direction sensor 14 detects a predetermined direction. The recorder 16 records the time measured by the timer 15.

Here, the direction of the magnetic field affected by the magnetic field source 11 is, for example, as shown in FIG. 2, the magnetic field C which is a combination of the magnetic field A generated by the magnetic field source 11 and the magnetic field B generated by the geomagnetism. However, as shown in FIG. 3, when the direction of the geomagnetism is perpendicular to the paper surface, the direction of the magnetic field affected by the magnetic field source 11 is only the magnetic field A by the magnetic field source 11.

The magnetic azimuth sensor 14 uses the composite magnetic field C
The direction (A when the direction of the geomagnetism is perpendicular to the paper surface) is detected.

Therefore, for example, as shown in FIG.
When the combined magnetic field C is in the direction directly above 90 ° on the gate 12, the time when the magnetic azimuth sensor 14 indicates that direction is measured by the timer 15, and this time is recorded by the recorder 16.
If it is recorded in, it is possible to record the time when the DUT 13 has passed over the gate 12.

If each set of the magnetic azimuth sensor 14, the timer 15 and the recorder 16 is provided in each measured object 13, the time when each measured object 13 passes through the gate can be recorded.

Next, another embodiment of the present invention will be described.

As shown in FIGS. 4 to 7, depending on the direction of the magnets that form the magnetic field source 11 or the combination of the magnets, the direction in which the magnetic orientation sensor 14 indicates at each position differs. The influence of geomagnetism is ignored here.

Here, as shown in FIG. 8, when the directions a to d indicated by the magnetic direction sensor 14 are determined, the magnetic direction sensor 1
4, d → a → b in FIG. 4 and b → c → d in FIG.
In FIG. 6, c → d → a, and in FIG. 7, a → b → c.

Therefore, if the time when the magnetic direction sensor 14 indicates each direction is measured by the timer 15 and these times are recorded in the recorder 16, for example, the moving speed of each measured object 13 can be measured. You can

The magnetic field source 11 may be scattered across the course as shown in FIG. 9 or may be long so as to cross the course as shown in FIG.

The magnetic field source 11 may be arranged on the course.

[0029]

As described above, according to the present invention,
Arrange the magnetic field source near the gate or the gate, and record the time when the magnetic azimuth sensor placed on each object to be measured shows the predetermined direction. It is possible to accurately measure the gate passing time of each of the plurality of measured objects that pass through the position (1), and the gate passing time can be accurately measured.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a gate sensor according to an embodiment of the present invention.

FIG. 2 is a diagram showing a direction of a magnetic field affected by a magnetic field source shown in FIG.

FIG. 3 is a diagram showing directions of a magnetic field affected by the magnetic field source shown in FIG.

FIG. 4 is a diagram for explaining another embodiment of the present invention.

FIG. 5 is a diagram for explaining another embodiment of the present invention.

FIG. 6 is a diagram for explaining another embodiment of the present invention.

FIG. 7 is a diagram for explaining another embodiment of the present invention.

FIG. 8 is a diagram for explaining another embodiment of the present invention.

FIG. 9 is a diagram for explaining another embodiment of the present invention.

FIG. 10 is a diagram for explaining another embodiment of the present invention.

FIG. 11 is a diagram for explaining a conventional technique based on the Doppler method.

FIG. 12 is a diagram for explaining a conventional technique using the Doppler method.

FIG. 13 is a diagram for explaining a conventional technique using the Doppler method.

[Explanation of symbols]

11 ... Magnetic field source, 13 ... Object to be measured, 14 ... Magnetic direction sensor, 15 ... Timer, 16 ... Recorder.

Claims (1)

[Claims] 1. A magnetic field source arranged at (a) a gate or in the vicinity of the gate, and (b) a magnetic direction sensor arranged at a body to be measured for detecting a direction of a magnetic field affected by the magnetic field source. A gate sensor, comprising: a timer for counting the time detected when the magnetic direction sensor detects a predetermined direction, and a recorder for recording the time counted by the timer.