JP2012101621A - Railroad-crossing obstacle detector and obstacle detection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a railroad-crossing obstacle detector and an obstacle detection method that prevent misdetection of an obstacle due to effects of weather such as rain.SOLUTION: The level of reflected waves obtained by transmitting radio waves to a detection area is collated with one or more reference patterns, specified on the basis of weather conditions such as light rain and heavy rain, so as to select and determine the reference pattern fitting to the actual weather condition. As a result of the comparison, an obstacle is detected on the basis of the matched reference pattern, thereby preventing false detection of an obstacle due to diffused reflection of radio waves caused by weather such as rain.

Description

  The present invention relates to a level crossing obstacle detection apparatus and an obstacle detection method for detecting an obstacle left in a level crossing by radio waves such as millimeter waves.

  The optical level crossing obstacle detection device detects an obstacle by blocking the light of the sensor device, so that there is a problem that it is difficult to detect a small object such as a human being or a wheelchair entering the space between the optical axes. It was. On the other hand, as disclosed in Patent Document 1, for example, a crossing obstacle detection device that detects an obstacle left in a crossing by a millimeter wave has been developed.

  The millimeter-wave level crossing obstacle detection device emits millimeter waves to the detection area and detects the reflected waves from the obstacles, so that even small objects can be detected reliably, and large objects such as automobiles can be detected. Can be detected as well.

  However, since the millimeter wave type railroad crossing obstacle detection device detects an obstacle based on the reflected wave, it is likely to be affected by weather such as rain and may cause erroneous detection due to irregular reflection. This problem does not exist only in the detection system using millimeter waves, and there are cases where radio waves in other wavelength bands are used.

Japanese Patent Laid-Open No. 2006-174677

  An object of the present invention is to provide a crossing obstacle detection device and an obstacle detection method capable of preventing erroneous detection of an obstacle due to the influence of weather such as rain.

  In order to solve the above-described problem, a crossing obstacle detection device according to the present invention includes a transmission / reception unit, a signal processing unit, and a storage unit. The transmission / reception unit transmits radio waves to the detection area and receives the reflected waves.

  As a feature of the crossing obstacle detection device according to the present invention, the storage unit stores one or more reference patterns defined based on weather conditions regarding the level of the reflected wave, and the signal processing unit includes: The level of the reflected wave is compared with the one or more reference patterns, and an obstacle is detected based on the matching reference patterns.

  According to the crossing obstacle detection device according to the present invention, the level of the reflected wave obtained by transmitting the radio wave to the detection area is collated with one or more reference patterns defined based on weather conditions such as light rain and heavy rain. Therefore, it is possible to select and determine a reference pattern that matches the actual weather conditions. As a result of the comparison, the crossing obstacle detection device according to the present invention detects an obstacle based on the matching reference pattern, thereby preventing erroneous detection of the obstacle due to irregular reflection of radio waves caused by weather such as rain. can do.

  The obstacle detection method according to the present invention detects an obstacle in a crossing by transmitting a radio wave to a detection area and receiving the reflected wave. The feature of this detection method is that, with respect to the level of the reflected wave, one or more reference patterns defined based on weather conditions are stored, and the level of the reflected wave is compared with the one or more reference patterns. The obstacle is detected based on the matching reference pattern.

  Since the obstacle detection method according to the present invention has the same configuration as the above-described crossing obstacle detection device, the same effects can be obtained.

  As described above, according to the present invention, it is possible to provide a crossing obstacle detection device and an obstacle detection method capable of preventing erroneous detection of an obstacle due to the influence of weather such as rain.

1 shows a structure of a level crossing to which a crossing obstacle detection device according to the present invention is applied. The structure of a level crossing obstacle detection device is shown. The level change of the reflected wave with respect to the distance from a sensor apparatus in case a threshold value is selected is shown. The level change of the reflected wave with respect to the distance from the sensor device when the first reference pattern is selected is shown. The level change of the reflected wave with respect to the distance from the sensor device when the second reference pattern is selected is shown. The level change of the reflected wave with respect to the distance from the sensor apparatus when the third reference pattern is selected is shown. The operation | movement flow of a signal processing part is shown.

  FIG. 1 shows a structure of a level crossing to which a level crossing obstacle detection apparatus according to the present invention is applied. The railroad crossing is a crossing of the railroad track 6 and the railroad crossing 4 perpendicularly, and is provided with breakers 31a and 31b and barriers 32a and 32b. This area is defined as a detection area S. The crossing obstacle detection device according to the present invention detects an obstacle 51 such as an automobile or a human being left in the detection region S when the train approaches, and includes sensor devices 1a and 1b, a plurality of reflectors 2, and the like. including.

  The sensor device 1a is installed near one corner of the detection region S, and the sensor device 1b is installed at a diagonal position of the detection region S with respect to the installation position of the sensor device 1a. Moreover, each reflector 2 is installed so as to face the sensor devices 1a and 1b with the detection region S interposed therebetween. The sensor devices 1a and 1b and the reflecting plate 2 are arranged according to the construction limit line standard of the track 6.

  The sensor device 1a transmits a radio wave to each of the fan-shaped regions Sd to Sf (see the region surrounded by the dotted line in FIG. 1) to detect the obstacle 51, and the sensor device 1b includes the fan-shaped regions Sa to Sf. Detection is performed by transmitting radio waves to each of the Scs. Thus, the detection area S is covered with the areas Sa to Sf.

  The reflector 2 is disposed in each of these regions Sa to Sf, reflects the radio wave transmitted by the sensor devices 1a and 1b, and is used for self-diagnosis of the sensor devices 1a and 1b. However, the reflector 2 is disposed outside the detection region S so that it is not erroneously detected as an obstacle.

  FIG. 2 shows a configuration of a crossing obstacle detection device. Here, only a configuration corresponding to one of the regions Sd to Sf of the sensor device 1a is shown as a representative, but the same applies to the other regions Sd to Sf, and the same applies to the other sensor device 1b. Configuration is provided.

  The sensor device 1 a includes an antenna unit 10, a transmission unit 12 and a reception unit 13 that constitute a transmission / reception unit, a signal processing unit 11, and a storage unit 14.

  The signal processing unit 11 is an arithmetic processing circuit including a CPU and the like, and controls the entire obstacle detection operation. The signal processing unit 11 receives the approach notification signal ACT for notifying the approach of the train from the instrument box installed along the track 6, and outputs the transmission instruction signal T to the transmission unit 12 in response to this.

  The transmission unit 12 is an analog signal generation circuit, and transmits a radio wave W1 to the detection region S via the antenna unit 10 in accordance with the transmission instruction signal T. The antenna unit 10 includes an antenna array including a plurality of antennas 101.

  The antenna unit 10 transmits the radio wave W <b> 1 sequentially from each antenna 101 toward the regions Sd to Sf in accordance with the control from the transmission unit 12. The radio wave W1 is obtained by sweeping a plurality of frequencies corresponding to each distance when the regions Sd to Sf are divided for each unit distance. The unit distance should be determined according to the design, and is 0.5 (m) here, for example. As the radio wave W1, it is preferable to employ the millimeter wave as described above.

  The radio wave W1 is reflected by the obstacle 51 to be detected to generate a reflected wave W2, and as described above, the reflected wave W3 caused by irregular reflection due to weather conditions such as rain, snow, fog, etc. (see reference numeral 52). Also occurs. In addition, although the reflected wave also exists from the reflecting plate 2, it is not illustrated for convenience.

  The receiving unit 13 receives the reflected waves W2 and W3 with respect to the radio wave W1 from the antenna unit 10 and converts them into a beat signal R obtained by taking the difference between the radio wave W1 of the transmitting unit 12 and outputs it to the signal processing unit 11. To do.

  The signal processing unit 11 performs a Fourier transform on the beat signal R, calculates a signal level (mV) for each frequency, and detects the obstacle 51 based on this. In detection, the signal processing unit 11 selects and references a predetermined threshold value or one or more reference patterns stored in the storage unit 14.

  The storage unit 14 is a device that stores digital data such as a memory and a hard disk, and is configured to be able to read and write reference patterns from the outside via a communication interface including a light emitting element and a light receiving element. .

  When the obstacle 51 is detected, the signal processing unit 11 outputs a detection signal ALM to the instrument box. As a result, a stop instruction can be given to the train approaching the railroad crossing to prevent an accident.

FIG. 3 shows an example of the level change of the reflected wave with respect to the distance from the sensor devices 1a and 1b obtained by the analysis processing in the signal processing unit 11. Symbols x _i (i = 1, 2,..., N) shown on the horizontal axis represent the levels of the reflected waves W2 and W3 at the individual unit distances ΔL corresponding to the above-described plurality of frequencies.

Curves P1, P2, and P3 are reference patterns defined on the basis of the weather conditions with respect to the level of the reflected wave W3 caused by irregular reflection. The reference patterns P1, P2, and P3 are a set of index values y _i (i = 1, 2,..., N) defined for each unit distance ΔL based on actually measured data and stored as described above. Held in the section 14.

  For example, taking rain as an example, the first reference pattern P1 indicates the pattern of each reflection level in the case of light rain, the second reference pattern P2 in the case of heavy rain, and the third reference pattern P3 in the case of heavy rain. The reflection level is high. Of course, for other weather conditions such as snow and fog, a reference pattern corresponding to each degree such as light snow, heavy snow, and heavy fog can be defined.

  FIG. 3 shows an example of good weather conditions where there is no rain, snow, fog or the like. At this time, the noise level due to irregular reflection is extremely low over the entire distance, and does not coincide with any of the reference patterns P1, P2, P3.

  In this case, the signal processing unit 11 detects the obstacle 51 based on the predetermined threshold value TH. Specifically, when the level 61 of the reflected wave W2 greater than the threshold value TH exists in the distance range L (see FIG. 1) in the region Sd to Sf that overlaps the detection region S, the signal processing unit 11 causes the obstacle 51 to be detected. To detect. Here, the threshold value TH is appropriately set according to the design. The level of the reflected wave from the reflecting plate 2 is not shown for convenience, but is present outside the distance range L, so that the obstacle 51 is not erroneously detected.

  Next, FIG. 4 shows an example of weather conditions such as light rain, light snow, and light fog. At this time, the noise level due to irregular reflection increases over the entire distance and matches the first reference pattern P1. Since the reflection level at this time exceeds the threshold value TH, as described above, there is a problem in that the obstacle 51 is erroneously detected.

Therefore, the signal processing unit 11 detects the obstacle 51 based on the first reference pattern P1 instead of the threshold value TH. Specifically, in the distance range L, the signal processing unit 11 has a level 61 of the reflected wave W2 that is greater than the level obtained by adding the margin value ΔV (mV) to the index value y _i (mV) of the first reference pattern P1. Then, the obstacle 51 is detected.

Here, the margin value ΔV (mV) is a value that should be appropriately determined based on the reference pattern P1. However, the obstacle detection method is not limited to the one using such a margin value ΔV, but uses analysis of the distribution of the reflection level x _i (i = 1, 2,..., N). It's okay.

  Next, FIG. 5 shows an example of weather conditions such as heavy rain, heavy snow, and heavy fog. At this time, the noise level due to irregular reflection further increases over the entire distance and matches the second reference pattern P2. Obstacle detection in this case is performed in the same manner as in FIG. 4 based on the second reference pattern P2.

  Next, FIG. 6 shows an example of weather conditions such as heavy rain, heavy snow, and ice fog. At this time, the noise level due to irregular reflection further increases over the entire distance and matches the third reference pattern P3. Obstacle detection in this case is performed in the same manner as in FIG. 3 based on the third reference pattern P3.

  However, in this case, as shown in the figure, it is conceivable that the reflection level due to the irregular reflection exceeds the reflected wave level of the obstacle 51, and the obstacle detection becomes substantially impossible. However, in such a case, there is no problem because the train operation itself is considered to be stopped and at least erroneous detection is prevented.

As described above, the feature of the crossing obstacle detection device according to the present invention is that the levels of the reflected waves W2 and W3 are collated with one or more reference patterns P1, P2, and P3, and the matching reference patterns P1, P2, and P3 are matched. The obstacle 51 is detected based on this. In this regard, FIG. 7 shows a collation process of the levels x _i (i = 1, 2,..., N) of the reflected waves W2, W3 and the reference patterns P1, P2, P3 in the signal processing unit 11. ing.

In order to follow the change in the weather condition, the signal processing unit 11 detects the level x _i (i = 1, 2,..., N) of the detected reflected waves W2, W3 and one or more reference patterns P1, P2, P3. The matching frequency Q indicating the degree of coincidence is calculated (reference symbols St10, St20, St30), and the level of the reflected waves W2, W3 is compared by comparing the matching frequency Q with a predetermined value R (reference symbols St11, St21, St31). It is determined whether x _i (i = 1, 2,..., n) matches any of the first to third reference patterns P1, P2, P3. Specifically, when the matching frequency Q ≦ R, the signal processing unit 11 has the reflection levels x _i (i = 1, 2,..., N) having the first to third reference patterns P1, P2, P3. Is determined to match. Here, the predetermined value R should be appropriately determined on the basis of the actual measurement result of the matching frequency Q under various weather conditions.

  The signal processing unit 11 sets the reference patterns P1, P2, and P3 to be used for obstacle detection when the matching reference patterns P1, P2, and P3 exist (reference characters St12, St22, and St33). When there is no matching reference pattern P1, P2, P3, the threshold value TH is set to be used for obstacle detection (reference St4).

  In this process, the matching frequency Q is calculated by the following equation 1.

Formula 1

Here, the parameter n is the number of divisions of the entire distance of the detection region S, that is, the number of unit distances ΔL, as understood with reference to FIGS. 3 to 6, and about x _i and y _i , As already mentioned.

  According to Equation 1, an accurate matching frequency Q can be suitably obtained according to the sample variance calculation method. The matching process using the matching frequency Q may be executed after notification of the approach of the train, but it is desirable that the matching process is periodically executed in order to provide a margin for the operation timing of the apparatus.

  In the present embodiment, the collation process is performed for each of the areas Sa to Sf by the individual signal processing unit 11, but may be performed for the entire areas Sa to Sf. In other words, the single processing unit calculates the total matching frequency Q in the regions Sa to Sf, so that it is not a one-dimensional determination for each of the individual regions Sa to Sf but two-dimensionally as the entire detection region S. This makes it possible to make intelligent judgments and realize more sophisticated collation processing.

  Furthermore, in the present embodiment, an example in which three levels of reference patterns P1, P2, and P3 are provided has been described. However, the present invention is not limited to this, and four or more levels of reference patterns may be set.

  As described above, according to the crossing obstacle detection device according to the present invention, the levels of the reflected waves W2 and W3 obtained by transmitting the radio wave W1 to the detection area S are changed to weather conditions such as light rain and heavy rain. Since the comparison is made with one or more reference patterns P1, P2, P3 defined based on the reference patterns, the reference patterns P1, P2, P3 suitable for the actual weather conditions can be selected and determined. Since the crossing obstacle detection device according to the present invention detects the obstacle 51 based on the matching reference patterns P1, P2, and P3 as a result of the comparison, the obstacle caused by irregular reflection of radio waves caused by weather such as rain. It is possible to prevent erroneous detection of objects.

  Also, the obstacle detection method according to the present invention transmits the radio wave W1 to the detection area S and receives the reflected waves W2 and W3, as in the above-described crossing obstacle detection device. Is detected. The feature of this detection method is that, with respect to the level of the reflected wave W3, one or more reference patterns P1, P2, P3 defined based on weather conditions are stored, and the level of the reflected waves W2, W3 is set to 1 or more. Compared with the reference patterns P1, P2, and P3, an obstacle is detected based on the matching reference patterns P1, P2, and P3.

  Preferably, in this detection method, a matching frequency Q indicating the degree of coincidence between the levels of the reflected waves W2 and W3 and one or more reference patterns P1, P2 and P3 is calculated, and the matching frequency Q is compared with a predetermined value R. Thus, it is preferable to determine whether or not the levels of the reflected waves W2 and W3 match the reference patterns P1, P2 and P3.

  Since the obstacle detection method according to the present invention has the same configuration as that of the crossing obstacle detection device described above, the same effects can be obtained.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.

11 Signal processing unit 12, 13 Transmission / reception unit 14 Storage unit 51 Obstacle W1 Radio wave W2, W3 Reflected wave S Detection area Q Matching frequency R Predetermined value TH Threshold P1, P2, P3 Reference pattern ΔL Unit distance

Claims (4)

A crossing obstacle detection device including a transmission / reception unit, a signal processing unit, and a storage unit,
The transmission / reception unit transmits radio waves to the detection area, receives the reflected waves,
The storage unit stores one or more reference patterns defined based on weather conditions regarding the level of the reflected wave,
The signal processing unit compares the level of the reflected wave with the one or more reference patterns, and detects an obstacle based on the matching reference patterns.
Railroad crossing obstacle detection device. A crossing obstacle detection device according to claim 1,
The signal processing unit calculates a matching frequency indicating a degree of coincidence between the level of the reflected wave and the one or more reference patterns, and compares the matching frequency with a predetermined value so that the level of the reflected wave is the reference level. Determine whether it matches the pattern,
Railroad crossing obstacle detection device. An obstacle detection method for detecting an obstacle in a level crossing by transmitting a radio wave to a detection area and receiving a reflected wave thereof,
With respect to the level of the reflected wave, one or more reference patterns defined based on weather conditions are stored,
Collating the level of the reflected wave with the one or more reference patterns and detecting an obstacle based on the matching reference patterns;
Obstacle detection method. The obstacle detection method according to claim 3,
Whether or not the level of the reflected wave matches the reference pattern by calculating a matching frequency indicating the degree of matching between the level of the reflected wave and the one or more reference patterns, and comparing the matching frequency with a predetermined value. To determine,
Obstacle detection method.

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