JP3152381B2 - Vehicle detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle detection device.

[0002]

2. Description of the Related Art A conventional vehicle detecting device uses a pair of rails as a track circuit, and determines whether or not a transmission signal transmitted from one end of the track circuit can be received by the other end of the track circuit. It is determined whether “Yes” or “No”. When the vehicle is located between the transmission point and the reception point of the track circuit, most of the transmission signal transmitted from the transmission point is returned to the transmission point due to short-circuit between the rails of the axle, and the transmission signal reaches the other end It is no longer possible, and it is determined that the vehicle is “present” in the closed section. If the vehicle is not on the line, the transmission signal transmitted from the transmission point reaches the reception point, and it is determined that the vehicle is “absent” in the closed section. The reference level is set at an intermediate value between the two reception voltage levels. For example, the reference level is set to a level indicating whether or not the track relay can be excited. Therefore, when the track relay cannot be excited, the track relay drops (contact open).
Then, when a vehicle detection signal indicating that the vehicle is “present” is output in the closed section and the track relay can be excited, the track relay is lifted (contact conduction), and the vehicle is detected as “absent” in the closed section. Outputs a vehicle detection signal. Such a vehicle detection device is described in detail in pages 3 to 5 of "Electrical Overview for Railway Engineers, Signal Series No. 9, Track Circuit" (published by Japan Railway Electrical Engineering Association).

[0003] The conventional vehicle detection device detects a vehicle in each closed section. However, with the recent advancement of vehicle control, at a measurement position (hereinafter referred to as a "measurement point") in the closed section. A vehicle detection device for detecting a vehicle is required. In the case of configuring such a vehicle detection device, generally, a current power receiving method of detecting a vehicle based on a reception current level at a measurement point is employed. In the current detection type vehicle detection device, when the vehicle enters the closed section, the impedance of the track circuit is reduced due to the short circuit between the axle rails. It rises above the current level. As the vehicle travels through the block and approaches the measurement point, the impedance of the track circuit becomes smaller and the received current level further rises. When the vehicle passes the measurement point, it becomes difficult for the vehicle to flow backward due to a short circuit between the gauges of the axle, so that the reception current level decreases. Therefore, the vehicle detection device sets the reference level lower than the normal reception current level and higher than the lowest reception current level after the vehicle has passed the measurement point, and the reception current level becomes equal to or lower than the reference level. Car detection is performed when it has decreased.

[0004] The reception current level in normal times and the reception current level when the vehicle is on the track are different from those in the case of rain or snow when the weather condition is rain or snow. Decreases with increasing current. In addition, the received current level when the vehicle runs at high speed increases the axle short-circuit resistance as compared to when the vehicle runs at low speed, and increases due to a decrease in gauge current. For this reason, the reference level is set to a fixed level slightly lower than the minimum reception current level in normal times due to rain or the like in consideration of the worst state.

[0005]

However, the conventional vehicle detection device has the following problems. (A) The reference level is fixed to a certain level slightly lower than the minimum reception current level in normal times in consideration of leakage current due to rain or the like. Therefore, if a few axles do not pass the measurement point, vehicle detection is performed. Can not do. For this reason, a substantial measurement point (a vehicle detection position that outputs a vehicle detection signal indicating that the vehicle is "present") moves forward of the course from the set measurement point. (B) If the received current level rises due to fine weather, the vehicle detection position moves further forward on the course. (C) Even when the vehicle travels at a high speed, the received current level increases, so that the vehicle detection point further moves forward. (D) Moreover, in the vicinity of the reference level, the level change of the reception current level with respect to the traveling distance of the vehicle becomes small. Therefore, when the reception current level rises due to fine weather or high-speed traveling of the vehicle, the vehicle detection point moves forward. Move greatly to the side. For this reason, the vehicle detection accuracy decreases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle detection device which is hardly affected by weather conditions and vehicle speed.

Therefore, another object of the present invention is to provide a vehicle detection device with high vehicle detection accuracy.

[0008]

In order to solve the above-mentioned problems, a vehicle detection device according to the present invention includes a closed section, a transmission circuit, a reception circuit, and a processing circuit. The closed section includes a pair of rails and has a measurement point at a vehicle detection position inside. The transmission circuit is connected to one end of the closed section that is located ahead of the course of the vehicle, and transmits a transmission signal to the pair of rails. The receiving circuit receives the transmission signal at the measurement point and outputs a reception signal. The processing circuit has a reference level for determining the presence or absence of a vehicle, the received signal is input, when the level of the received signal is increasing, the reference level is increased according to the amount of increase, After the level of the reception signal changes from the rising trend to the falling trend, the reference level is held, and when the level of the reception signal becomes lower than the reference level, the vehicle detection signal of the vehicle `` Yes '' is output. Output.

[0009] Preferably, the processing circuit preferably increases the reference level when the level of the reception signal becomes lower than the initial reference level after the reception signal changes from the rising trend to the falling trend. Is adjusted to the first reference level, and thereafter, when the level of the received signal becomes higher than the first reference level, a vehicle detection signal of the vehicle “absent” is output.

[0010] More preferably, the processing circuit is configured to input a vehicle entry signal indicating that the vehicle has entered the closed section and to increase the reception signal.
Raise the reference level.

[0011]

The closed section includes a pair of rails and has a measurement point at the vehicle detection position. The transmission circuit is connected to one end side of a closed section corresponding to the front of the vehicle, and transmits a transmission signal to a pair of rails. The receiving circuit receives a transmission signal at a measurement point and outputs a reception signal. For this reason,
When the vehicle approaches the measurement point, the level of the received signal increases according to the approach of the vehicle. When the vehicle passes the measurement point, the level of the received signal decreases stepwise according to the number of axles that have passed.

The processing circuit has a reference level for determining the presence or absence of a vehicle. When a received signal is input and the level of the received signal is increasing, the reference circuit increases the reference level according to the amount of increase. For this reason, when the reference level is set to a level slightly lower than the minimum reception signal level in normal times in consideration of leakage current due to rain, etc., and when the reception signal level rises due to sunny or high-speed running of the vehicle In this case, the reference level can be raised to an appropriate level according to the amount of increase. As a result, a vehicle detection device that is less affected by weather conditions and vehicle speed can be obtained. Further, while the vehicle is approaching the measurement point, the level of the received signal does not fall below the reference level, and the vehicle detection signal indicating that the vehicle is “present” is not output.

[0013] The processing circuit holds the reference level after the level of the received signal changes from the rising trend to the falling trend, and when the level of the received signal becomes lower than the reference level,
It outputs a vehicle detection signal of the vehicle “Yes”. For example, when the level of the received signal is increasing, the reference level is determined by subtracting the level change of the received signal when the leading axle (first axle) passes the measurement point from the level of the received signal. Is set slightly higher,
When the axle passes the measurement point, the level of the received signal becomes lower than the reference level, and a vehicle detection signal indicating that the vehicle is "present" is obtained. Therefore, a vehicle detection signal is obtained when the first axle passes the measurement point, and a vehicle detection device with high vehicle detection accuracy can be obtained.

[0014] Further, at a position ahead of the measurement point, a level change of the received signal due to a short circuit between the gauges is large, and the interval between the first axle and the second axle is narrow. Therefore, vehicle detection is performed when the second axle passes. Even when the reference level is adjusted as described above, a vehicle detection device with high vehicle detection accuracy can be obtained.

[0015] When the level of the received signal becomes lower than the initial reference level after the level of the received signal changes from the rising trend to the downward trend, the processing circuit sets the raised reference level to the initial reference level. Then, when the level of the received signal becomes higher than the initial reference level, a vehicle detection signal indicating that the vehicle is “absent” is output. In this preferred example, the level of the received signal does not become higher than the reference level until the rearmost axle passes the closed boundary of the closed section, and the rearmost axle passes the closed boundary of the closed section. At this point, the level of the received signal becomes higher than the reference level, and a vehicle detection signal indicating that the vehicle is “absent” is obtained. Thus, a vehicle detection device with high vehicle detection accuracy can be obtained.

The processing circuit increases the reference level when a vehicle entry signal indicating that the vehicle has entered the closed section is input and the level of the received signal tends to increase. In this preferred example, the presence of the vehicle in the closed section is guaranteed, and the reference level is increased only when the level of the received signal is increasing. Therefore, the level of the received signal is increasing due to noise or the like. Therefore, a vehicle detection device that does not change the reference level and is not easily affected by noise or the like can be obtained.

[0017]

FIG. 1 is a block diagram showing the configuration of a vehicle detection device according to the present invention, and FIG. 2 is a sectional view taken along line B2-B2 in FIG. The vehicle detection device according to the present invention includes the closed section 2
T, a transmission circuit 2, a reception circuit 3, and a processing circuit 4. Reference numeral 1 is a track, 5 is a vehicle, and 62 is a track relay circuit. The track 1 includes closed sections 1T to 3T.
The respective closed boundaries of the closed sections 1T to 3T may or may not be insulated. The embodiment shows a case in which it is insulated. The orbit relay circuit 62 is configured in the same manner as in the related art.

The closed section 2T includes a pair of rails 11 and 12
And has a measurement point B which is a vehicle detection position inside.
Reference numerals A and C indicate the block boundaries of the block section 2T.

The transmission circuit 2 is connected to one end of a closed section 2T which is located in front of the path of the vehicle 5 and has a pair of rails 11,
12, the transmission signal S1 is transmitted. Transmission circuit 2 of embodiment
Has a signal generation circuit 21. Reference numeral 22 denotes an impedance bond. The signal generation circuit 21 converts the carrier having the carrier frequency fm into the signal frequency f corresponding to the closed section 2T.
The amplitude modulation is performed by the two signal waves, and the modulated signal is output as a transmission signal S1. The transmission signal S1 is input to the secondary winding of the impedance bond 22, and the impedance bond 22 transmits the transmission signal S1 to the pair of rails 11 and 12 via the primary winding. Reference symbol Is
1, Is2 is an orbital current flowing through the measurement point B based on the transmission signal S1. The orbital currents Is1 and Is2 are opposite to each other and have the same current value.

The receiving circuit 3 receives the transmission signal S1 at the measurement point B and outputs a reception signal S2. The receiving circuit 3 of the embodiment has a receiving coil 31 and a receiving coil 32. The receiving coil 31 is electromagnetically coupled with the magnetic flux φ1 by the orbital current Is1, and outputs a reception signal S21 according to the orbital current Is1 (received current). The receiving coil 32 is electromagnetically coupled to the magnetic flux φ2 by the orbital current Is2, and the orbital current Is2
2 (received current). The reception signal S21 and the reception signal S22 are added to form a reception signal S2.

The processing circuit 4 has a reference level Ik for judging the presence or absence of the vehicle 5, and receives the received signal S2. After the level Ik is increased and the level Ir of the reception signal S2 changes from the rising trend to the downward trend, the reference level Ik is held. The “present” vehicle detection signal S3 is output. The reference level Ik is, for example, when the level Ir of the received signal S2 is increasing, when the leading axle (first axle) 51 passes the measurement point B from the level Ir of the received signal S2. Is set to a level slightly higher than the level obtained by subtracting the level change ΔIr21 of the received signal S2. Further, the reference level Ik is the level Ir of the received signal S2 and the reference level I.
k may be set so as to decrease as the amount of rise increases, or the level I of the reception signal S2 for the preceding vehicle may be reduced.
The amount of change in r may be predicted from the amount of change in r by the learning function and set in accordance with the amount of change. When the distance between the block boundary A and the measurement point B is long, the adjustment start of the reference level Ik may be delayed. Here, the upward tendency means that even when the level Ir of the reception signal S2 may decrease when viewed microscopically, when viewed as a whole,
This means that the level Ir of the reception signal S2 increases.

The processing circuit 4 determines the level Ir of the received signal S2.
Changes from the rising trend to the falling trend, and when the level Ir of the received signal S2 becomes lower than the first reference level Ik0, the raised reference level Ik is changed to the first reference level Ik0.
It is adjusted to k0, and then, when the level Ir of the reception signal S2 becomes higher than the first reference level Ik0, the vehicle detection signal S3 of the vehicle "absence" is output.

The processing circuit 4 increases the reference level Ik when the vehicle entry signal S4 indicating that the vehicle 5 has entered the closed section 2T is input and the level Ir of the reception signal S2 tends to increase. Let it. Vehicle entry signal S4
Is provided at a contact point TR1 of the track relay TR. Contact T
R1 falls (opens) when the vehicle 5 is on the closed section 2T, and lifts (conducts) when the vehicle 5 is not on the closed section 2T. Therefore, the processing circuit 4 has the contact TR1
Is falling, and the level Ir of the received signal S2 is increasing, the reference level Ik is increased.

FIG. 3 is a specific circuit diagram of the processing circuit.
In the figure, the same reference numerals as those in FIG. 1 indicate the same components. Reference numeral 41 denotes a bandpass filter, 4
2 is a detection circuit, 43 is a selection amplification circuit, 44 is a level determination circuit, 45 is an amplification circuit, 46 is a rectification circuit, and BR is a vehicle detection relay. The band-pass filter 41 allows the reception signal S2 (modulated signal) included in the frequency band of the carrier frequency fm to pass. The detection circuit 42 detects the received signal S2. The selective amplification circuit 43 selectively amplifies a signal wave of the frequency signal f2 obtained by detection (hereinafter, referred to as a frequency signal f2).

The level judging circuit 44 detects the vehicle entry signal S4
Is input and the level Ir of the amplified frequency signal f2 is increasing, the reference level Ik is increased according to the amount of increase, and the level Ir of the amplified frequency signal f2 is decreased from the increasing trend. After turning to the tendency, the reference level Ik is maintained, and when the level Ir of the frequency signal f2 becomes lower than the reference level Ik, the vehicle 5 moves to the measurement point B.
Is determined to have “entered”. When it is determined that the vehicle 5 has “entered” the measurement point B, the frequency signal f2 is cut off. After the level Ir of the amplified frequency signal f2 changes from the rising trend to the falling trend, the level Ir of the frequency signal f2 is changed.
Is lower than the first reference level Ik0, the raised reference level Ik is adjusted to the first reference level Ik0, and then the level Ir of the frequency signal f2 becomes higher than the first reference level Ik0. Then, it is determined that the vehicle 5 has “entered” the closed section 2T. When it is determined that the vehicle 5 has “entered” the closed section 2T, the frequency signal f2
Is output. The level determination circuit 44 is usually constituted by a microcomputer.

Thereafter, the frequency signal f2 is supplied to the amplifying circuit 45.
And is rectified by the rectifier circuit 46 to excite the vehicle detection relay BR. The contact point BR1 falls (opens) when the vehicle is “present”, and lifts (conducts) when the vehicle is “absent”, and forms a vehicle detection signal S3.

FIG. 4 is a diagram showing the relationship between the vehicle position and the reception level of the reception signal and the reference level. The figure shows the case when it is sunny. In the drawings, the same reference numerals as those in FIGS. 1 to 3 indicate the same components. FIG. 4 will be described with reference to FIGS.

As described above, the closed section 2T includes the pair of rails 11 and 12, and has the measuring point B inside which the vehicle is to be detected. The transmission circuit 2 is connected to one end of a closed section 2T which is located in front of the path of the vehicle 5 and has a pair of rails 1.
The transmission signal S1 is transmitted to the first and the second transmission units. The receiving circuit 3 receives the transmission signal S1 at the measurement point B and outputs a reception signal S2. Therefore, when the vehicle 5 enters the closed boundary A, the pair of rails 11 and 12 are short-circuited between the gauges by the first axle 51, and the level Ir of the received signal S2 rises from the level Ir0 to the level Ir1. The level Ir0 changes according to the leakage current in the closed section 2T,
It is high when it is sunny and low when it is rainy. When the vehicle 5 approaches the measurement point B, the impedance of the track circuit further decreases due to the short circuit between the gauges, and the level Ir of the reception signal S2 is increased.
Rises from Ir1 to the level Ir2 in accordance with the approach of the vehicle 5. When the vehicle 5 passes the measurement point B, the reception signal S2
Level Ir decreases stepwise according to the number of axles that have passed. The level Ir21 indicates the level of the received signal S2 when the first axle 51 passes, and the level Ir22 indicates the level of the received signal S2 when the second axle 52 passes. When the vehicle 5 advances through the closed boundary C, the short circuit between the gauges disappears,
The level Ir of the received signal S2 rises to the level Ir0.

Although not shown, when the vehicle 5 travels at a high speed, the level Ir of the received signal S2 slightly decreases when approaching the measurement point B as compared with when traveling at a low speed. After passing, the level Ir of the received signal S2 slightly increases. As compared with the case of rain or the like, the level Ir of the received signal S2 becomes higher both when approaching the measurement point B and after passing through the measurement point B.

The processing circuit 4 has a reference level Ik for judging the presence or absence of the vehicle 5. When the reception signal S2 is input and the level Ir of the reception signal S2 is increasing, the reference level Ik is determined according to the amount of increase. Increase Ik. For this reason, considering the leakage current due to rain or the like, when the reference level Ik0 is set to a level slightly lower than the minimum reception signal level Ir0 in normal times, the level Ir of the reception signal S2 due to sunny or high-speed running of the vehicle. Rises, the reference level Ik can be raised to an appropriate level according to the amount of rise. As a result, a vehicle detection device that is less affected by weather conditions and vehicle speed can be obtained. While the vehicle 5 is approaching the measurement point B, the level Ir of the received signal S2 does not fall below the reference level Ik, and the vehicle detection signal S3 of the vehicle “present” is not output.

The processing circuit 4 determines the level Ir of the received signal S2.
Has changed from an upward trend to a downward trend, the reference level I
k, and the level Ir of the received signal S2 is equal to the reference level I.
When it becomes lower than k, a vehicle detection signal S3 indicating that the vehicle is "present" is output. For example, when the level Ir of the reception signal S2 is increasing, the reference level Ik is changed to the reception signal S2.
2, the level change Δr2 of the received signal S2 when the leading axle (first axle) 51 passes through the measurement point B from the level Ir.
When the first axle 51 passes through the measurement point B, the level Ir21 of the reception signal S2 becomes lower than the reference level Ik when the first axle 51 passes the measurement point B, and the level of the vehicle “presence” is set. The vehicle detection signal S3 is obtained. For this reason, when the first axle 51 passes the measurement point B, the vehicle detection signal S3 is obtained, and a vehicle detection device with high vehicle detection accuracy is obtained.

The level change Δr21 of the received signal S2 is
Stored as a constant. Further, the constant may be changed by the learning function based on the change Δr21 in the case of the preceding vehicle.

Further, a level change of the reception signal S2 due to a short circuit between the gauges is large before the measurement point B and the distance L1 between the first axle 51 and the second axle 52 is small.
Even when the reference level Ik is adjusted so as to perform vehicle detection when the second axle 52 passes, a vehicle detection device with high vehicle detection accuracy can be obtained.

The processing circuit 4 determines the level Ir of the received signal S2.
Changes from the rising trend to the falling trend, and when the level Ir of the received signal S2 becomes lower than the first reference level Ik0, the raised reference level Ik is changed to the first reference level Ik0.
The level is adjusted to k0, and thereafter, when the level Ir of the received signal S2 becomes higher than the first reference level Ik0, a vehicle detection signal S2 indicating that the vehicle is "absent" is output. For this reason,
Until the rearmost axle passes the closed boundary C of the closed section 2T, the level Ir of the received signal S2 does not become higher than the reference level Ik, and the rearmost axle passes the closed boundary C of the closed section 2T. At the point when the level I of the received signal S2 is
r becomes higher than the reference level Ik, and a vehicle detection signal S3 indicating that the vehicle is “absent” is obtained. Thus, a vehicle detection device with high vehicle detection accuracy can be obtained.

The processing circuit 4 receives a vehicle entry signal S4 indicating the presence or absence of the vehicle 5 in the closed section 2T, and
When the level Ir of the received signal S2 is increasing, the reference level IK is increased. According to this configuration, the presence of the vehicle 5 in the closed section 2T is guaranteed, and the reference level Ik is increased only when the level Ir of the received signal S2 is increasing. Even when the level Ir tends to increase, a vehicle detection device that does not change the reference level Ik due to noise or the like and is less susceptible to noise or the like can be obtained.

FIG. 5 is a sectional view of another receiving circuit. In the drawings, the same reference numerals as those in FIGS. 1 and 2 indicate the same components. The receiving circuit 3 includes a loop coil 33. The loop coil 33 is electromagnetically coupled with the magnetic fluxes φ1 and φ2 by the orbital currents Is1 and Is2, and outputs a reception signal S2 corresponding to the reception current.

FIG. 6 is a circuit diagram of still another receiving circuit.
In the figure, the same reference numerals as those in FIG. 1 indicate the same components. The receiving circuit 3 includes a capacitor 34, a voltage detection coil 35, and a current detection coil 36. The capacitor 34 and the voltage detection coil 35 are connected in series, and receive the gauge voltage Vb at the measurement point B. Current detection coil 36
Is electromagnetically coupled with the magnetic flux by the current Ib flowing through the voltage detection coil 35 based on the rail voltage Vb and the magnetic flux by the orbital currents Is1 and Is2 flowing through the rails 11 and 12, and receives the sum of the current Ib and the orbital currents Is1 and Is2. The signal S2 is output. That is, the reception circuit 3 receives the reception voltage (gauge voltage Vb) and the reception current (orbital currents Is1, Is
The reception signal S2 corresponding to 2) is output. Received signal S2
When the vehicle 5 does not exist in the closed section 2T, there is no short circuit between the rails, so that the track currents Is1 and Is2 are small, and mainly the current Ib flowing through the voltage detection coil 35 is used. When the vehicle 5 is in the closed section 2T, the rails are short-circuited, the track currents Is1, Is2 increase, and the current Ib
And the orbital currents Is1 and Is2. For this reason, when the vehicle 5 approaches the measurement point B, the orbital currents Is1, Is2 increase with the approach of the vehicle 5, and the level of the reception signal S2 tends to increase.

When the closed boundaries A and C are not insulated,
The other points are the same except that the level Ir of the received signal S2 does not change from the level Ir0 to the level Ir1 when the vehicle 5 enters the closing boundary A. Therefore, even when the closed boundaries A and C are not insulated, as described above,
The features and advantages of the present invention can be obtained.

[0039]

As described above, according to the present invention, the following effects can be obtained. (A) It is possible to provide a vehicle detection device that is less affected by weather conditions and vehicle speed. (B) A vehicle detection device with high vehicle detection accuracy can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a vehicle detection device according to the present invention.

FIG. 2 is a cross-sectional view taken along line B2-B2 in FIG.

FIG. 3 is a specific circuit diagram of a processing circuit constituting the vehicle detection device according to the present invention.

FIG. 4 is a diagram illustrating a relationship between a vehicle position, a reception level of a reception signal, and a reference level.

FIG. 5 is a cross-sectional view of another receiving circuit constituting the vehicle detection device according to the present invention.

FIG. 6 is a circuit diagram of still another receiving circuit constituting the vehicle detection device according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 track 11, 12 rail 1T-3T closed section 2 transmission circuit 3 reception circuit 4 processing circuit 5 vehicle S1 transmission signal S2 reception signal S3 vehicle detection signal S4, S5 vehicle approach signal A, C block boundary B measurement point

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B61L 1/18 B61L 23/16

Claims (3)

(57) [Claims] 1. A blockage section, a transmission circuit, a reception circuit,
And a processing circuit, wherein the closed section includes a pair of rails, has a measurement point serving as a vehicle detection position inside, the transmission circuit, the blockage hits ahead of the path of the vehicle The transmission circuit is connected to one end of the section and transmits a transmission signal to the pair of rails. The reception circuit receives the transmission signal at the measurement point and outputs a reception signal. Has a reference level for determining the presence or absence of the vehicle, and when the reception signal is input and the level of the reception signal is increasing, the reference level is increased in accordance with an increase amount, and the reception level is increased. After the signal level has changed from the rising trend to the falling trend, the reference level is held, and when the level of the reception signal becomes lower than the reference level, a vehicle detection signal of the vehicle “Yes” is output. Vehicle detection device. 2. The vehicle detection device according to claim 1, wherein the processing circuit is configured to set the level of the received signal to the first reference level after the level of the received signal changes from a rising trend to a falling trend. If it becomes lower, the raised reference level is adjusted to the first reference level, and then
A vehicle detection device that outputs a vehicle detection signal of a vehicle “absence” when a level of the reception signal becomes higher than the first reference level. 3. The vehicle detection device according to claim 1, wherein the processing circuit receives a vehicle entry signal indicating that a vehicle has entered the closed section, and receives the received signal. A vehicle detection device that raises the reference level when the level is increasing.