JPH10104344A - Reflector for vehicle position detection and its detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To separate a distance between a position marker for position detection of a vehicle and the vehicle to some degree and make it difficult to influence fluctuation of a signal level. SOLUTION: A detection wave 6 is transmitted by a radio wave having wave length of, e.g. a milli-wave or more from a detection sensor 5 mounted on a vehicle 4. A marker 1 which is a reflector for reflecting the radio wave is alternatively arranged as the markers 1A, 1B of a marker A row and a marker B row on both the sides of a travel route 3 in which the vehicle 4 travels. Reflection waves from each markers 1A, 1B are alternatively received as shown in (b), and if the travelling direction of the vehicle 4 is corrected so as to be equal to a receiving level, the vehicle 4 can travel on the travel path 3 of the center of the marker A row and the marker B row.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is installed on a road surface on which a traveling route of a vehicle is set in advance and has a characteristic of reflecting a radio wave transmitted from the vehicle or a search wave by an ultrasonic wave. The present invention relates to a vehicle position detecting reflector for detecting a vehicle position by receiving a wave and a detecting device therefor.

[0002]

2. Description of the Related Art Conventionally, a position marker is previously set on a road or the like in order to guide a traveling route of a vehicle, and a magnetic sensor is mounted on the vehicle to detect a position of the vehicle based on the position marker. Is generally known. Further, Japanese Utility Model Laid-Open No. 1-109910 discloses a technique of laying a light reflecting tape on a runway and providing a set of two light sensors not more than the width of the reflecting tape on a vehicle to detect a vehicle attitude. I have. In addition, there is also known a technique in which a road surface is photographed by an in-vehicle camera, a white line in a photographed screen is extracted, and a relative position of the vehicle with respect to the white line is detected.

[0003]

However, when using a magnetic sensor, it is difficult to keep the distance between the position marker and the magnetic sensor far. Therefore, once the position of the vehicle deviates from the position on the position marker, it is very difficult to return to the position on the position marker. Especially,
When the traveling speed of the vehicle increases, it becomes very difficult to guide the vehicle along the traveling route.

When a light reflecting tape is used, sufficient light reflection may not be obtained due to contamination of the tape. In addition, on the actual road surface, not indoors, there is an effect of rain, snow, etc., especially in the case of rainy weather, because light is well reflected not only by light reflection tape but also by water pools on the road surface, etc.
There is also a problem that the vehicle position cannot be detected with high accuracy. Similarly, when an in-vehicle camera is used, the vehicle is easily affected by the weather, and in rainy weather, etc., there is a problem that the contrast between the white line and other portions of the road surface cannot be sufficiently obtained, and the white line cannot be accurately extracted. .

Therefore, there is a concept of detecting a vehicle position by radar sensing using radio waves having a wavelength of millimeter waves or more, ultrasonic waves, or the like. That is, a reflector is provided at a predetermined position on the road surface, for example, at the center of the road surface, a transceiver for radio waves or ultrasonic waves is provided on the vehicle, and the presence or absence of the reflector is detected from the reflection intensity of the transmitted search wave to detect the vehicle position. How to However, in a system in which a reflector is provided at the center of the road surface, etc., the traveling route is corrected so that the reception intensity of the reflected wave is maximized, and the on-vehicle sensor is controlled on the position marker. When the reflection intensity fluctuates and the reception level of the reflected wave fluctuates, there is a possibility that the vehicle may be erroneously recognized as deviating from the position marker even if the vehicle travels correctly on the position marker. If the travel route deviates from the position marker, it becomes difficult to determine the direction in which the travel route of the vehicle is corrected.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the receiving sensitivity without being affected by the surrounding environment such as the weather, to allow a certain distance from a position marker, and to detect a position which is hardly affected by a change in a reflected signal level. It is an object of the present invention to provide a reflector for use and a detection device therefor.

[0007]

SUMMARY OF THE INVENTION The present invention reflects a search wave transmitted from a vehicle, which is installed in advance in a plurality of rows along a travel route of the vehicle, and receives the reflected wave at the vehicle to determine the vehicle position. A reflector for detection, wherein a plurality of rows of reflectors are intermittently arranged at intervals in a width direction perpendicular to the direction of the travel route and according to different regularities in each row. Is a reflector for detecting the vehicle position. According to the present invention, a plurality of rows of reflectors are installed in advance along the traveling route of the vehicle, and the reflectors are intermittently arranged in each row according to different regularities. If the reflected wave from the reflector is received, each column can be specified based on the regularity. Since the plurality of rows of reflectors are arranged at intervals in the width direction perpendicular to the direction of the traveling path, the relative reflected wave reception level also changes according to the relative positional relationship with the vehicle. Transmit the search wave from the vehicle,
Since the position of the vehicle with respect to the rows of the plurality of reflectors is detected based on the reception level of the reflected wave, the reflector can be used as a position marker, and the distance between the vehicle and the vehicle can be increased to some extent. Are relatively compared, it is possible to reduce the influence of the fluctuation of the reception level of the absolute reflected wave and improve the accuracy of position detection.

In the present invention, the traveling path is provided between two reflector rows arranged according to different regularities. According to the present invention, since the vehicle travels between two reflector rows arranged according to different regularities, the traveling direction is controlled so that the reception levels of the reflected waves from both reflector rows are equal. For example, it is possible to accurately detect the position along the traveling route.

In the present invention, two adjacent rows of the reflectors having different regularities are arranged so that when one row has a reflector, the other row forms a gap between the reflectors. And reflectors are arranged. According to the present invention, in a row of reflectors having different regularities, the ratio of the length of the reflector along the traveling path to the length of the gap between the reflectors is different, so that the reception level of the reflected wave is different. The duty ratio between the section where the reflection wave is large and the section where the reception level of the reflected wave is low differs between the rows of the reflectors, and the rows of the reflectors can be easily identified based on this.

Further, in the present invention, in two adjacent rows of the reflectors having different regularities, when one row has a reflector, the other row forms a gap between the reflectors. And reflectors are arranged. According to the present invention, in a row of two adjacent reflectors, when a reflector is present in one row, a gap between the reflectors is formed in the other row. The reflected wave can be easily separated.

Further, in the present invention, when there is no reflector in the one row, a plurality of reflectors exist in the other row. According to the present invention, in each row of reflectors having different regularities, the repetition length in units of the sum of the portion where the reflector exists along the traveling route and the portion of the gap between the reflectors is constant. In addition, since the difference between the columns is different, the period of the change in the reception level of the reflected wave is different between the columns, and a plurality of columns can be easily identified.

In the present invention, in each of the rows of the reflectors having different regularities, the repetition length in units of the sum of the portion where the reflector exists along the traveling path and the gap between the reflectors is used. It is characterized in that it is constant and differs between the columns. According to the present invention, the information related to the running of the vehicle is coded according to a preset rule by intermittent reflectors along the direction of the running route, so that it is possible to obtain information while the vehicle is running. it can. The information to be coded may include, for example, various road information such as a speed limit.

[0013] The invention is also directed to a method wherein at least one row of reflectors, the intermittent reflectors along the direction of the travel path are coded according to a predetermined rule so as to indicate information relating to the running of the vehicle. It is characterized by having been done. According to the present invention, a row of a plurality of reflectors installed in advance along the traveling route of the vehicle has a change in the reception level from the reflected wave,
Since the frequency varies according to the regularity of the reflectors in each row, the reflected waves in each row are identified by the identification means. The detecting means detects the position of the vehicle with respect to each row of the reflectors based on the reception level of the reflected waves from each row identified by the identification means. Therefore, the reception level of the reflected waves from each row due to the weather or the like. Can be accurately detected based on the rows of the plurality of reflectors.

Further, the present invention is an apparatus for detecting a reflector for detecting the position of a vehicle, wherein the identification means identifies a reflected wave from each row of the reflector based on regularity, and the identification means identifies the reflected wave. Detecting means for detecting the position of the vehicle with respect to each row of the reflectors based on the reception level of the reflected waves from each row of the reflectors. . According to the present invention, the rows of the reflectors are identified based on the regularity by the identification means, and the detection means can detect the position of the vehicle based on the reception level of the reflected wave from each row.

Further, the present invention is an apparatus for detecting a reflector for detecting a vehicle position, wherein the identification means identifies a reflected wave from each row of the reflector on the basis of regularity, and is identified by the identification means. Detecting means for detecting the position of the vehicle with respect to each row of the reflectors based on the reception level of the reflected wave from each row of the reflectors, and corresponding to the increase or decrease of the traveling speed of the vehicle, the cycle is shortened or Clock generating means for generating an extended clock signal; and reading means for reading the coded information from a reflected wave from a reflector in synchronization with the clock signal generated by the clock generating means. It is a detection device of a reflector for detecting a vehicle position. According to the present invention, the clock generating means generates a clock signal whose period is shortened or extended in response to the increase or decrease of the running speed of the vehicle, and the reading means synchronizes the clock signal with the code from the reflector. Read the coded information.
If the period of the clock signal is constant, coded information may be erroneously read in accordance with fluctuations in the traveling speed of the vehicle, but the period of the clock signal changes in accordance with the traveling speed of the vehicle. The converted information can be read accurately.

[0016]

FIG. 1 shows a schematic configuration of an embodiment of the present invention. As shown in FIG. 1 (a), a marker 1 which is a reflector for reflecting a radio wave having a wavelength equal to or longer than a millimeter wave is provided on both sides of a road 3 provided on a road surface 2 with markers 1A and B in a marker A row. They are alternately arranged as 1B rows. The vehicle 4 traveling along the track 3 includes:
A detection sensor 5 is mounted, and transmits a radio wave as a search wave 6 toward the marker 1 and receives a reflected wave 7 from the marker 1. When the vehicle 4 travels along the runway 3, the reception level of the reflected wave 7 changes as shown in FIG. For example, a diagonal line ascending to the right indicates the reception level of the reflected wave from the marker B row, and a diagonal line ascending to the right indicates the reception level of the reflected wave from the marker A column. In this case, marker B
The row is closer to the vehicle 4 and the reception level is higher.

FIG. 2 shows the relative positional relationship between the reception levels of the reflected waves from the rows of the two markers 1 and the rows of the markers A and B and the detection sensor 5. If the reflection directivities of the marker 1A in the marker A row and the marker 1B in the marker B row are the same, the traveling direction of the vehicle 4 is controlled so that the reception levels of the reflected waves from the marker A row and the marker B row become equal. Then, the detection sensor 5 can be easily guided and guided on the track 3 at the center of the marker A row and the marker B row. FIG.
As shown in (a), the reception level of the reflected signal from the marker 1A and the marker 1B becomes equal on the center runway 3, and the reception level of the reflected wave from the marker on the shifted side becomes stronger when the marker is shifted to one side. The position of the detection sensor 5 can be detected by the ratio of the reception levels. That is, as shown in FIG. 2B, in FIG.
Since the reception level of the reflected wave from the marker B row where B intermittently continues is higher than the reception level of the reflected wave from the marker A row, the detection sensor 5 approaches the marker B row. You can see that there is.

FIG. 3 shows a schematic configuration of another embodiment of the present invention. As shown in FIG. 3A, the length of the marker 11 of the present embodiment in the traveling direction is different between the marker 11A in the marker A row and the marker 11B in the marker B row. Vehicle 4
3B is detected by the signal detection device 12 as a signal representing a reception level as shown in FIG. In FIG. 3B, the marker 11 in the marker A row is indicated by diagonally lower right and upper right diagonal lines.
The reception levels of the reflected waves from the markers 11B in the rows A and B are shown. When the vehicle 4 is traveling at a constant speed, the reception times t _A and t _B of the reflected waves from the markers 11A and 11B are also constant in proportion to the lengths of the markers 11A and 11B. FIG. 3 (a)
The signal detection time observation device 13 observes the time when the reception level of the reflected wave exists to some extent, identifies the marker A column and the marker B column, and provides a signal representing the identification result to the arithmetic device 14. In the arithmetic unit 14, the signal detection time observation unit 13
, The reception levels of the reflected waves from the rows of the markers A and B are separated, and the comparison of the reception levels causes the detection sensor 5 to be located closer to either side of the rows of the markers A and B. Judge.

FIG. 4 shows a schematic configuration of still another embodiment of the present invention. As shown in (a), in the marker 21 of the present embodiment, a marker 21A is arranged as a marker A column and a marker 21B is arranged as a marker B column. In the marker 21B, the length of the existing portion and the length of the gap portion are substantially equal, and as shown in (b), the change in the reception level of the reflected wave has a duty ratio of about 50%. There are a plurality of, for example, three, markers 21A in the marker A row in the gap between the markers 21B in the marker B row, and the markers 21B in the marker B row.
Does not exist where there is. Therefore, as shown in (b), three peaks are detected in a portion where the reflected wave from the marker 21B in the marker B row does not exist. The row of markers A and the row of markers B also have different periods of changes in the reception level, so that they can be easily identified.

FIG. 5 shows a schematic configuration of still another embodiment of the present invention. In the present embodiment, as shown in FIG.
A is compared with the repetition period of the marker 31B in the marker B row,
It is arranged to repeat at shorter distances. Unlike the embodiment of FIG. 4, the section in which the marker 31B of the marker B row exists also has the marker 31A of the marker A row. Therefore, the reception levels of the reflected waves from both marker rows are as shown in FIG. As shown in the drawing, a portion overlapping in time occurs due to interference. However, the marker 31A of the marker A row and the marker B row
And the marker 31B, since each vehicle speed V is constant, respectively also periodically T _A and T _B if constant, considering the frequency axis, as shown in FIG. 5 (c), 1 / T _B and 1 / T _The signals can be easily separated as signals each having a frequency of _A. Such separation from time to frequency can be easily performed by a fast Fourier transform (FFT) operation or the like.

FIG. 6 shows a schematic configuration of still another embodiment of the present invention. In the present embodiment, the marker 41 is
Marker 41A in marker A row and marker 41B in marker B row
Are arranged such that a plurality of reflectors are present at one gap portion. As for the marker 41A in the marker A row and the marker 41B in the marker B row, when one does not exist, the other exists plurally, and the number of each is different.
Can be easily identified.

FIG. 7 shows a schematic configuration of still another embodiment of the present invention. In the present embodiment, as shown in FIG. 7A, the markers 51 are arranged so as to indicate information coded according to a predetermined rule. The coded information represented by the marker 51 is based on the length of the marker 51 and the interval between the markers 51, for example, road information, for example, information indicating a speed limit, a type of road, and the like in accordance with a rule such as a barcode. As shown.
As shown in (a), the signal from the detection sensor 5 is given to the reading device 52, and reading as information is performed.

FIG. 8 shows the principle of operation of the reader 52 shown in FIG. FIG. 8A shows waveforms of a signal obtained by converting the signal representing the reception level of FIG. 7B into a voltage and a clock signal from the clock generation circuit 53. The AND signal and the clock signal are ANDed by the AND gate circuit 54, and various kinds of coded information are extracted as shown in FIG. 8C. For example, "10100" is related to the vehicle speed. If the information is a speed limit, in particular, control is performed so that the traveling speed of the vehicle does not exceed the speed limit.

FIG. 9 shows another embodiment of the present invention.
The basic concept for reliably detecting the marker 51 as shown in FIG. 7A even when the running speed of the vehicle changes is shown. As shown in FIG. 9A, a vehicle speed pulse is derived from the vehicle at a cycle corresponding to the vehicle speed. The vehicle speed pulse is
The time interval becomes shorter as the traveling speed of the vehicle increases. As shown in FIG. 9B, the original clock signal is generated in synchronization with the vehicle speed pulse. When the clock signal shown in (b) is divided into 1/2 by a binary counter or the like,
As shown in (c), a signal whose logic level is inverted every time the clock signal of (b) is applied is obtained. If only the rising part is taken out, a clock signal having a cycle of １ ／ is obtained as shown in FIG. FIG. 7 (a)
The coding of the marker 51 shown in FIG.
A and the reflector 51B having a short length, the repetition period of the reflector 51B having a short length is adjusted to the cycle of the clock signal shown in FIG. If the clock signal shown in FIG. 9D is used, it is possible to make a determination according to the clock signals shown in FIGS. 9B and 9D, respectively, and the coded information as shown in FIG. Can be easily taken out.

In the embodiment described above, the detection sensor 5 mounted on the vehicle 4 transmits a radio wave having a wavelength equal to or longer than a millimeter wave as a search wave, and transmits the markers 1, 11, and
Although the reflected waves reflected from 21, 41 and 51 are received, it is also possible to transmit ultrasonic waves from the detection sensor 5 and receive reflected ultrasonic waves. Since the propagation speed of the ultrasonic wave is smaller than the propagation speed and is close to the traveling speed of the vehicle, the Doppler effect can be used more remarkably.

In the embodiment shown in FIGS. 1 to 6,
Although the track 3 on which the vehicle 4 travels is provided at the center of the two marker rows, a plurality of marker rows can be arranged on one side of the track 3 in the width direction. Even in such a case, if a plurality of marker rows can be identified, the position of the vehicle can be easily detected based on the reception level ratio and the like, and the vehicle along the preset route can be detected. Guidance can be provided effectively.

[0027]

As described above, according to the present invention, reflectors for reflecting a search wave transmitted from a vehicle and receiving the reflected wave at the vehicle are provided along the traveling route of the vehicle as a plurality of rows. Therefore, if the sensitivity of the reflected wave reception is improved, the distance between the reflector as a position marker and the vehicle can be increased to some extent, and the reception of the reflected waves from a plurality of rows of reflectors can be achieved. By comparing the levels relatively, it is possible to detect the position of the vehicle that is less susceptible to fluctuations in the reception levels from the individual reflectors. Since a plurality of rows of reflectors are installed in advance, even if only one position sensor is mounted on the vehicle, the position of the vehicle can be detected, and the cost can be reduced. By detecting the position of the vehicle in this way, it is possible to not only guide the traveling route of the vehicle,
When the traveling route of the vehicle shifts due to the driver's sneezing or the like, a system or the like that detects the driver's sneezing or the like from the deviation of the running route and issues a warning can be easily realized.

According to the present invention, if the position of the vehicle is controlled to be at the center of the two rows of the reflectors, the vehicle can travel on the traveling route. As the distance to one of the reflector rows increases, the reception level of the reflected wave from the closer reflector row increases, and the reception level of the reflected wave from the farther reflector decreases. The traveling route of the vehicle can be easily corrected based on the level change.

Further, according to the present invention, since the ratio between the length of the intermittent reflectors along the running path and the length of the gap between the reflectors, which are intermittent in the rows of the reflectors, is different, the duty ratio of the change in the reception level can be easily obtained. Can identify the rows of reflectors,
The position of the vehicle can be accurately and easily detected based on the rows of the reflectors provided at intervals in the width direction of the traveling route.

According to the present invention, in two adjacent rows of reflectors, when reflectors exist in one row, the reflectors are arranged so as to form a gap between the reflectors in the other row. Therefore, it is possible to prevent the reflection signal from the reflector from being buffered, or to prevent another signal from being buried when one of the signals is too large. Thereby, the reflected waves from the two are always received, and the vehicle position can be reliably detected.

Further, according to the present invention, when there is no reflector in one row, a plurality of reflectors exist in the other row, so that the row of the other reflector can be easily identified.

According to the present invention, in each of the rows having different regularities, the sum of the length of the reflector and the length of the gap is constant and different in each row. Are different in the period of change of the reception level, and each column can be easily identified.

Further, according to the present invention, since the information encoded in advance is indicated by the row of the reflectors, the information relating to the traveling of the vehicle can be obtained together with the detection of the vehicle position.

Further, according to the present invention, the plurality of reflector rows are identified by the identification means on the basis of the regularity of the reflected waves, and the rows for the respective reflectors are identified based on the reception level of the reflected waves from each identified row. Since the detecting means detects the position of the vehicle,
The distance between the rows of reflectors and the vehicle can be increased to some extent, and even if the reception levels of the reflected waves from the individual rows of reflectors fluctuate, the reception levels of a plurality of rows are relatively compared. Accurate position detection can be performed.

According to the present invention, there is provided a clock generating means for shortening or extending the cycle of the clock signal in response to an increase or decrease in the running speed of the vehicle. , The coded information related to the running of the vehicle can be reliably read, and the vehicle can be appropriately driven according to the information.

[Brief description of the drawings]

FIG. 1 is a simplified plan view and a waveform diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 2 is a simplified front sectional view and a graph showing a schematic configuration of the embodiment of FIG. 1;

FIG. 3 is a simplified plan view showing a schematic configuration of another embodiment of the present invention, and a graph showing an example of a reception level of a reflected wave from a reflector in each column.

FIG. 4 is a simplified plan view showing a schematic configuration of still another embodiment of the present invention, and a graph showing a change in the reception level thereof.

FIG. 5 is a simplified plan view showing a schematic configuration of still another embodiment of the present invention, a graph showing a change in reception level, and a graph showing a received signal in a frequency domain.

FIG. 6 is a simplified plan view showing an arrangement state of markers 41 according to still another embodiment of the present invention.

FIG. 7 is a simplified plan view showing a schematic configuration of still another embodiment of the present invention, and a graph showing a temporal change of a reception level.

8 is a time chart showing a signal obtained by converting a change in the reception level of the reflected wave corresponding to the marker 51 shown in FIG. 7A into a voltage and a clock signal for reading a code, FIG.
FIG. 3A is a block diagram illustrating a schematic electrical configuration of a reading device 52, and FIG. 3B is a diagram illustrating an example of coded information read by the reading device 52.

9 is a time chart illustrating a relationship between a vehicle speed pulse applied to a clock generation circuit 53 of the reading device 52 of FIG. 8 and a generated clock signal.

[Explanation of symbols]

1, 1A, 1B; 11, 11A, 11B; 21, 21
A, 21B; 31, 31A, 31B; 41, 41A, 4
1B; 51, 51A, 51B Marker 2 Road surface 3 Runway 4 Vehicle 5 Detection sensor 6 Search wave 7 Reflected wave 12 Signal detection device 13 Signal detection time observation device 14 Arithmetic device 52 Reading device 53 Clock generation circuit 54 AND gate circuit

Claims (9)

[Claims] 1. A reflector which is installed beforehand in a plurality of rows along a traveling route of a vehicle, reflects a search wave transmitted from the vehicle, receives the reflected wave at the vehicle, and detects a vehicle position. The reflectors for vehicle position detection, wherein the reflectors in a plurality of rows are intermittently arranged at intervals in a width direction perpendicular to the direction of the traveling path and according to different regularities in each row. . 2. The vehicle position detecting reflector according to claim 1, wherein the traveling path is provided between two reflector rows arranged according to different regularities. 3. The array of reflectors having different regularities has different ratios between a length of the reflector along the traveling path and a length of a gap between the reflectors. Or the reflector for vehicle position detection according to 2. 4. In two adjacent rows of reflectors having different regularities, a reflector is provided such that when one row has a reflector, the other row forms a gap between the reflectors. The reflector for vehicle position detection according to any one of claims 1 to 3, wherein the reflectors are arranged. 5. The vehicle position detecting reflector according to claim 4, wherein when there is no reflector in said one row, a plurality of reflectors are present in said other row. 6. In each row of the reflectors having different regularities,
The repetition length in units of the sum of a portion where the reflector exists along the traveling path and a portion of the gap between the reflectors is constant, and differs between rows.
The vehicle position detecting reflector according to any one of claims 1 to 3. 7. In at least one row of reflectors, the intermittent reflectors along the direction of the travel path are coded according to preset rules to indicate information related to the travel of the vehicle. The vehicle position detecting reflector according to any one of claims 1 to 6, wherein: 8. An apparatus for detecting a vehicle position detecting reflector according to claim 1, wherein a reflected wave from each row of the reflector is identified based on the regularity. A vehicle position comprising: identification means; and detection means for detecting a position of the vehicle with respect to each row of the reflectors based on a reception level of a reflected wave from each row of the reflectors identified by the identification means. Detector for detecting reflector. 9. An apparatus for detecting a vehicle position detecting reflector according to claim 7, wherein the identification means identifies reflected waves from each row of the reflector based on the regularity, and the identification means. Detecting means for detecting the position of the vehicle with respect to each row of the reflectors based on the reception level of the reflected wave from each row of the reflectors identified by And a reading means for reading the coded information from a reflected wave from the reflector in synchronization with the clock signal generated by the clock generating means. A reflector for a vehicle position detecting reflector, characterized in that: