JP2001188990A - Vehicle sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle sensor which is easily installed and hardly affected by disturbance such as stains, meteorological conditions, etc. SOLUTION: A transmitting antenna 4 and a receiving antenna 6 for a radio wave of specific frequency are arranged across an automobile 8. The reception intensity of the radio wave, sent by the transmitting antenna 4, at the receiving antenna 6 is measured to detent whether or not an automobile is prevent between both the antennas 4 and 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle sensor for detecting the presence or absence of a vehicle in a parking lot or a passage.

[0002]

2. Description of the Related Art In recent years, with the enlargement of commercial facilities, the location of suburbs, and the like, the use of private cars for shopping has increased, and facilities have to be equipped with a large parking lot near a sales area. However, as the parking lot becomes larger, it becomes difficult for the driver trying to park to find an empty parking space. It took a long time, and this was one of the causes of so-called parking congestion. Depending on the parking lot, a large number of guidance staff may be deployed to search for empty space on behalf of the driver and provide guidance, but the labor cost of the guidance staff is a large burden.

On the other hand, in the case of an indoor parking lot, an ultrasonic sensor of a reflected wave detection type is installed on the ceiling of each parking frame, and the reflection time of the ultrasonic wave reflected on the ceiling of the vehicle and the empty vehicle when the vehicle is present. In such a case, means for detecting the presence or absence of the vehicle by comparing the time of reflection of the ultrasonic wave reflected on the floor surface is generally used.

On the other hand, in an outdoor parking lot, Japanese Unexamined Patent Publication No.
As in 3202068, there has been proposed a method of installing a drip-proof ultrasonic sensor on the floor of a parking lot and detecting the presence or absence of a vehicle based on the presence or absence of the reflection.

In recent years, toll parking lots having means for mechanically preventing individual vehicles from escaping, such as in vacant lots in cities, have been increasing. , Magnetic sensors are mainly employed. In the case of an infrared sensor, one of the infrared light receiving / emitting sections is placed on the floor of the parking lot corresponding to the approximate center of the detection target vehicle, and a column of about 1 meter is set up diagonally behind the parked vehicle. By providing the infrared light path between these two points, and being shielded by the vehicle,
The method of detecting the presence of a vehicle is used. On the other hand, in the case of the magnetic sensor, a loop coil for detecting magnetism that changes depending on the presence or absence of the vehicle is embedded in a position corresponding to the center of the parked vehicle.

An ultrasonic sensor using the above-described ultrasonic wave is:
It cannot be used outdoors without a ceiling, and the upper surface of the detection vehicle is so smooth that it cannot be accurately detected unless ultrasonic waves hit an appropriate place of the vehicle due to disturbance such as crosswind.

The above-mentioned vehicle sensor using infrared rays must be subjected to a construction work for erecting a pillar on a road surface in order to enable the vehicle to be reliably shut off. In addition, there is a drawback that it cannot be installed in a place where excavation work cannot be easily performed to protect a waterproof layer. In addition, since infrared light is used to receive light, there is a problem in that when the sun is at a low position, such as at sunrise or sunset, false detection occurs when sunlight directly enters the light receiving unit. However, there has been a problem that accurate detection cannot be performed when it is blocked by dirt, snow, mischief, or the like.

On the other hand, the above-described vehicle sensor utilizing the fact that the induced magnetism changes due to the presence of the vehicle body is not affected by dirt or snow, but the loop coil is embedded in the lower road surface of the detection target vehicle. Therefore, in general, it is necessary to dig a groove having a width of about 1 m on each side and a depth of about 10 cm,
This also has the problems that the construction cost is high and that it cannot be installed in a place where cutting cannot be performed.

Further, an ultrasonic sensor unit having a transmitter and a receiver is installed on a parking road surface, and when the vehicle is parked, about half of the ultrasonic wave transmitted from the transmitter is reflected on the road surface and appropriately. A road-mounted ultrasonic sensor has been proposed which detects a presence or absence of a vehicle by receiving, with a receiver, a large number of reflected sounds which are dispersed and hit the bottom of the vehicle and hit the bottom of the vehicle having many irregularities (JP-A-Hei. 9-131421). Although this road-mounted ultrasonic sensor is easy to construct, it uses the reflection of ultrasonic waves, so accurate detection can be achieved when the ultrasonic transmitter / receiver is blocked by snow or mischief, similar to infrared light. It has the disadvantage that it cannot be done. In addition, in the case of blocking infrared rays, such a disturbance has the same detection result as that of a vehicle in existence, whereas when reflection of infrared rays or ultrasonic waves is used, it is determined that an empty vehicle exists when disturbance exists. Therefore, when employed in a billing system, there is a disadvantage that unauthorized escape is easily permitted.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle sensor which can be easily installed and is hardly affected by disturbances such as dirt and weather conditions.

[0011]

According to a first aspect of the present invention, a transmitting antenna and a receiving antenna for radio waves of a specific frequency are arranged so as to sandwich a vehicle to be detected between the two antennas, and transmitted from the transmitting antenna. And a vehicle sensor for measuring whether or not a vehicle is present between the transmitting antenna and the receiving antenna by measuring the reception intensity of the radio wave of the frequency at the receiving antenna.

According to the first aspect of the present invention, an antenna for transmitting and receiving radio waves is provided as a vehicle detecting means so as to sandwich the vehicle at positions above, below, right and left, front and rear of the parking position of the vehicle. A radio wave emitted from the transmitting antenna is blocked and attenuated so as to reach the receiving antenna, and a means for measuring the receiving intensity from the receiving antenna is used.

The measuring means has a determination function of determining whether or not a vehicle is present in a detection area of the antenna by analyzing a reception antenna and an amplifier suitable for capturing the radio wave and a change in reception intensity. Have.

The transmitting and receiving antennas can be installed in pairs on each parking frame. One of the transmitting and receiving antennas has a continuous shape extending over a plurality of parking positions corresponding to the shape of the parking lot. It is also possible to correspond to a transmitting or receiving antenna. For example, it is also possible to arrange a transmitting antenna capable of covering a plurality of parking frames on a ceiling portion, and to install a vehicle sensor having a receiving antenna on the floor of each parking frame. Conversely, when receiving antennas that can cover a plurality of parking frames are arranged on the ceiling and a transmitting device having a transmitting antenna is installed on the floor of each parking frame, the reception content of the receiving antennas should be analyzed. Thus, the presence or absence of a parked vehicle for each parking frame can be determined. in this case,
By changing the frequency in the transmission radio wave for each parking frame, or putting code information specific to each parking frame in the transmission radio wave, or changing the transmission timing for each parking frame, it is possible to determine which information is from which parking frame. Can be determined. In particular, in the case of collective reception, by providing a self-power generation function such as a battery or a solar cell on the transmitting side installed on the floor or the like, there is an advantage that connection is not required.

According to a second aspect of the present invention, in the vehicle sensor according to the first aspect, the transmitting antenna is an existing GPS satellite, and uses an existing GPS satellite wave as a transmission-side radio wave. Of a plurality of GPS satellite waves that can be received by the satellite, attention is focused on several satellites having a large elevation angle and strong radio wave intensity when the vehicle is empty, and the radio wave intensity from the several satellites is compared between when the vehicle is in the vehicle and when the vehicle is empty. A vehicle sensor is characterized in that the presence or absence of a vehicle is determined by comparison.

According to the present invention, an existing GPS satellite is used as a radio wave transmitter. This method is effective in an outdoor parking lot. When a GPS satellite is used, the receiving antenna is installed, for example, on the floor of a parking lot covered by a parked vehicle. The determination circuit when using a GPS satellite extracts several satellites suitable for vehicle detection from communication waves received from a plurality of satellites received at the same time. It has a function to determine whether it exists. Even when a GPS satellite is used, it is needless to say that the presence or absence of the vehicle can be determined by using only the intensity change of the entire received radio wave as a judgment material without analyzing the signal from the satellite. Further, although the determination means using the amount of passage of radio waves is strong against dirt and the like, there is a concern that it cannot be used if the antenna part is completely submerged. For this reason, even in the existing GPS antenna,
The upper surface portion of the antenna is formed in a convex shape with a material such as resin that allows radio waves to easily pass therethrough, thereby reducing water from remaining on the upper surface. When the antenna unit of the vehicle sensor is also placed on the floor surface, particularly when it is installed outdoors, the central part may be similarly convex to prevent water from staying on the upper part.

According to a third aspect of the present invention, in the vehicle sensor according to the first aspect, one of the transmitting antenna and the receiving antenna is housed in a sensor unit, and the sensor unit is installed on a floor, and the sensor unit is mounted on the floor. An antenna housed inside the sensor unit is arranged in the sensor unit so as to be displaced from a center position on a plane.

According to the third aspect of the present invention, for example, the antenna accommodated inside the sensor unit installed on the floor is displaced from the center of the plane in the sensor unit. When the center of the sensor unit upper surface is formed in a convex shape as described above, the center of the convex shape and the arrangement center of the antenna are arranged so as not to coincide with each other. The effect of placing an empty can in the center can be reduced.

According to a fourth aspect of the present invention, in the vehicle sensor according to the first aspect, one of the transmitting antenna and the receiving antenna is housed in a sensor unit, and the sensor unit is installed on a floor surface, The vehicle sensor is provided with a detachable projection on the upper part of the vehicle.

According to the fourth aspect of the present invention, in regions where snow is removed by a bulldozer or the like during snowfall, protrusions such as wheel stoppers are not installed as much as possible so as not to hinder the work. In this case, the projections for preventing the water from staying in the way are in the way, so install the sensor unit installed on the floor including the receiving antenna in the hole drilled on the road surface, and make an appropriate projection shape except during snowfall. By disposing the holding member thereover to avoid the effects of submergence and removing this projection when snow is snowing, the snow removal work is facilitated.

For the sake of simplicity, all the vehicles to be detected have been described as parked vehicles. However, places where it is necessary to confirm the presence or absence of vehicles, for example, entrance gates and passages, so-called drive-through entrance ordering places, It goes without saying that the vehicle sensor according to the present invention is also effective in the vehicle passage section.

[0022]

According to the first aspect of the present invention, it is possible to obtain a vehicle sensor which can be easily installed and is hardly affected by disturbances such as dirt and weather conditions, and can be used in a parking lot of a billing system.

According to the second aspect of the present invention, since an existing GPS satellite is used as a radio wave transmitter, a separate radio wave transmitter is not required, and the cost is reduced.

According to the third aspect of the present invention, it is possible to reduce the influence of an empty can or the like set up at the center of the convex shape of the sensor unit due to mischief or the like, and it can be used in a parking lot having a charging system.

According to the fourth aspect of the present invention, the sensor unit does not need to be affected by water immersion, and the snow removing operation is facilitated by removing the projection when snow is accumulated.

[0026]

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

FIG. 1 shows a state where the vehicle sensor 2 according to the first embodiment is operating. This vehicle sensor 2 is for indoor use, a transmitting antenna 4 is provided on the ceiling, a parking frame floor 1 of a parking lot.
0 is provided with a receiving antenna 6. One transmission antenna 4 is provided above each parking frame. One receiving antenna 6 is also installed in each parking frame.
The transmitting antenna 4 and the receiving antenna 6 are connected to the parking frame by the automobile 8.
When the vehicle is parked, the transmitting antenna 4 and the receiving antenna 6 are installed at a position where the automobile 8 is sandwiched from above and below. The same applies to the second to fourth embodiments to be described later. However, the transmitting antenna 4 is connected to a generating means (not shown) that generates a strong radio wave at a frequency that does not violate the Radio Control Law. The radio wave transmitted from the antenna 4 is received by the receiving antenna 6 and the reception intensity is measured.
If the reception intensity is equal to or higher than the predetermined intensity, it is determined that the vehicle 8 does not exist. If the reception intensity is lower than the predetermined intensity, it is determined that the vehicle is blocking radio waves and the vehicle 8 is present. According to this embodiment and the following second to fifth embodiments, since radio waves are used, they are resistant to disturbances such as dirt and weather conditions.

FIG. 2 shows a state in which the vehicle sensor 2 according to the second embodiment is operating. This vehicle sensor 2 is also for indoor use, and has a transmitting antenna 4 on the ceiling, a parking frame floor surface 1 of the parking lot.
0 is provided with a receiving antenna 6. The transmitting antenna 4 is formed in a series over the parking frames. One receiving antenna 6 is installed in each parking frame. The transmission antenna 4 and the reception antenna 6 are installed at positions where the transmission antenna 4 and the reception antenna 6 sandwich the vehicle 8 from above and below when the vehicle 8 is parked in the parking frame. According to the present embodiment, it is possible to efficiently transmit radio waves in a parking lot in which parking frames are frequently arranged side by side.

FIG. 3 shows a state in which the vehicle sensor 2 according to the third embodiment is operating. This vehicle sensor 2 is also for indoor use, and has a receiving antenna 6 on the ceiling and a parking frame floor 1 of a parking lot.
At 0, a transmission antenna 4 is installed. The receiving antenna 6 is formed in a series over the upper portions of the plurality of parking frames. One transmitting antenna 4 is provided in each parking frame. The transmission antenna 4 and the reception antenna 6 are installed at positions where the transmission antenna 4 and the reception antenna 6 sandwich the vehicle 8 from above and below when the vehicle 8 is parked in the parking frame. According to the present embodiment, it is possible to efficiently receive radio waves in a parking lot in which parking frames are frequently arranged side by side. In this case, by analyzing the content received by the receiving antenna 6 by the above-described means, it is possible to identify from which parking frame the call originated from the receiving side.

FIG. 4 shows a state in which the vehicle sensor 2 according to the fourth embodiment is operating. This vehicle sensor 2 can be applied both indoors and outdoors. A transmitting antenna 4 and a receiving antenna 6 are respectively provided upright on both sides in the width direction of the automobile 8. The transmitting antenna 4 and the receiving antenna 6 are provided as a pair in each parking frame. The transmission antenna 4 and the reception antenna 6 are installed at positions where the transmission antenna 4 and the reception antenna 6 sandwich the vehicle 8 from the width direction of the vehicle when the vehicle 8 is parked in the parking frame. According to the present embodiment, the present invention can be applied to indoors, rooftops, and outdoors.

FIG. 5 shows a state in which the vehicle sensor 2 according to the fifth embodiment is operating. In the present embodiment, an existing GPS satellite is used as the transmission antenna 4. GPS
There are 24 satellites 12, and each satellite orbits the earth at an appropriate distance from each other. For this reason, a plurality of GPS satellites 12 are always present in the sky above any place on the ground at any time. The receiving antenna 6 is installed on the parking frame floor 10 of the parking lot. One receiving antenna 6 is installed in each parking frame. When the car 8 is parked in the parking frame, the receiving antenna 6
The vehicle 8 is installed in such a position as to sandwich the automobile 8 from above and below by a GPS satellite 12 and a receiving antenna 6 having a large elevation angle, which will be described later. The reception antenna 6 receives a radio wave transmitted from the GPS satellite 12, and the reception intensity of the radio wave is measured to determine the presence or absence of the automobile.

When a strong radio wave shield such as an automobile exists on the vehicle sensor (receiving antenna 6) of the present embodiment, the radio wave from the GPS satellite 12 is greatly attenuated and received by the receiving antenna 6. . On the other hand, as shown in FIG.
In snowfall to the extent that people, dust, and parking lots can be used, radio waves from the GPS satellites 12 are received by the receiving antenna 6 with almost no attenuation. In FIG. 5, the receiving antenna 6 at the position where the person stands is located in the parking frame next to the parking frame where the car 8 is parked.

FIG. 6 shows a GPS satellite 1 with and without an automobile 8 on a vehicle sensor (receiving antenna 6).
2 shows an example of measuring the intensity of the reception wave from the second embodiment. On the horizontal axis, the numbers of the satellites that can be captured simultaneously are arranged in descending order of the elevation angles of the satellite positions, and the vertical axis shows the reception intensity of the radio wave from each satellite at the receiving antenna position. As can be seen from this graph, it is possible to receive radio waves from about eight satellites including those with a small elevation angle, but when the vehicle is empty, the radio waves from the satellites with a large elevation angle are strongly received. However, when the vehicle 8 is located on the vehicle sensor (the receiving antenna 6), the attenuation of the radio wave increases as the elevation angle of the satellite increases. This is because the radio wave that has been directly received is cut off by the automobile 8 and the radio wave that has sneak in due to reflection or the like is received. Since the communication wave from the GPS satellite 12 has a very high linearity of 1575.42 MHz,
The radio wave intensity other than the direct wave becomes sufficiently low.

FIG. 7 shows the GP according to the fifth embodiment.
FIG. 3 is a block diagram showing a determination circuit after an S satellite wave is received by a receiving antenna. Radio waves transmitted from the GPS satellites 12 are received by the receiving antenna 6. The received radio waves are amplified by the separation / amplification circuit. Since the amplified data includes data of GPS satellite radio waves from various angles and the like, it is necessary to extract radio waves of satellites suitable for detecting automobiles. Therefore, the code of the amplified data is analyzed by the code analysis circuit. The data necessary for the determination of the presence of the vehicle among the data subjected to the code analysis turns to the presence determination circuit,
It is determined whether the vehicle is present based on the intensity transition of the data. The determination result reaches the determination result notifying circuit, and is notified to a place requiring the determination result. Of course, the presence or absence of an automobile may be determined using the change in the intensity of the entire received radio wave as the determination material without performing the code analysis.

According to the fifth embodiment, the construction cost of the transmitting antenna is not required, and only the installation work of the receiving antenna 6 is sufficient, so that the cost is reduced.

FIG. 8 shows an example in which, when the receiving antenna 6 is accommodated in the sensor unit 14, the receiving antenna 6 is displaced from the central axis in the longitudinal direction of the sensor unit 14 in plan view. FIG. 3B is a plan view, and FIG. When the receiving antenna 6 is installed on an outdoor floor or a road surface (hereinafter referred to as a “floor surface”), if water accumulates on the floor or the like due to rainfall or the like, the receiving antenna 6 is submerged, which hinders use. . This is particularly true in the case of the receiving antenna of the GPS satellite. For this reason, a convex shape (projection 16) is formed on the upper surface of the receiving antenna 6 with a material such as a resin through which radio waves can easily pass, thereby preventing water from remaining on the upper surface. At this time, if the receiving antenna 6 is disposed at the center in the sensor unit 14, the top is located at the center of the convex shape, and therefore, the receiving antenna 6 exists immediately below the top of the convex shape. When the vehicle sensor is combined with the charging system, the parking lot user sometimes places an empty can or the like in front of the top of the convex shape due to mischief or the like. As in this example, the receiving antenna 6 is connected to the sensor unit 1.
By disposing in the width direction from the top of the convex shape of No. 4, the influence of such mischief can be reduced.

FIG. 9 shows an example of a vehicle sensor installed as a measure against snowfall. In areas where snow is removed with a bulldozer or the like during snowfall, protrusions on the road surface are made as little as possible so as not to hinder the snow removal work. Therefore, the above-mentioned convex shape for preventing water from staying is not an obstacle, so that the entire sensor unit 14 containing the receiving antenna 6 is installed in a hole formed in a road surface. That is, the sensor unit 14 is installed lower than the road surface.

FIG. 10 shows an example in which a convex shape is attached to the vehicle sensor shown in FIG. 9 to prevent submergence during periods other than the snow season. A member having an appropriate convex shape (projection 1
6) is disposed on the sensor unit 14 to avoid the influence of submergence, and by removing the protrusion 16 when snowing, it is not necessary to obstruct the snow removal operation.

In each of the above embodiments, an example of a vehicle is described as a vehicle. However, the present invention is not limited to a vehicle but may be applied to a mobile body.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which a vehicle sensor according to a first embodiment is operating.

FIG. 2 is a diagram showing a state in which a vehicle sensor according to a second embodiment is operating.

FIG. 3 is a diagram showing a state in which a vehicle sensor according to a third embodiment is operating.

FIG. 4 is a diagram illustrating a state in which a vehicle sensor according to a fourth embodiment is operating.

FIG. 5 is a diagram showing a state in which a vehicle sensor according to a fifth embodiment is operating.

FIG. 6 is a diagram showing an example of measuring the intensity of a received wave from a GPS satellite when a vehicle is present on a vehicle sensor (receiving antenna) and when the vehicle is not present;

FIG. 7 is a block diagram showing a determination circuit after a GPS satellite radio wave is received by a receiving antenna in the fifth embodiment.

FIGS. 8A and 8B are diagrams illustrating an example in which a receiving antenna is displaced from the center of a sensor unit, wherein FIG. 8A is a plan view and FIG. 8B is a side view.

FIG. 9 is a side sectional view showing an example of a vehicle sensor installed for snow cover.

FIG. 10 is a side sectional view showing an example in which a convex shape is attached to the upper part of the vehicle sensor shown in FIG. 9;

[Description of Signs] 2 Vehicle sensor 4 Transmitting antenna 6 Receiving antenna 8 Automobile 10 Floor surface 12 GPS satellite 14 Sensor unit 16 Projection

Claims (4)

[Claims] 1. A receiving antenna for a radio wave of a specific frequency, which is arranged so as to sandwich a vehicle to be detected between the antennas and a receiving antenna of the radio wave of a specific frequency. The vehicle sensor detects whether there is a vehicle between the transmitting antenna and the receiving antenna by measuring the vehicle antenna. 2. The vehicle sensor according to claim 1, wherein the transmitting antenna is an existing GPS satellite, an existing GPS satellite wave is used as a transmission-side radio wave, and a plurality of GPSs that can be received at the time of determining the presence or absence of the vehicle. Of the satellite waves, attention is paid to several satellites having a large elevation angle and strong radio wave intensity when the vehicle is empty, and the radio wave intensity from the several satellites is compared between when the vehicle is in the vehicle and when the vehicle is empty. A vehicle sensor for performing presence / absence determination. 3. The vehicle sensor according to claim 1, wherein one of the transmitting antenna and the receiving antenna is housed in a sensor unit, and the sensor unit is installed on a floor surface and is housed in the sensor unit. Is disposed in the sensor unit so as to be deviated from the center position of the plane. 4. The vehicle sensor according to claim 1, wherein one of the transmitting antenna and the receiving antenna is housed in a sensor unit, the sensor unit is installed on a floor, and is detachably mounted on an upper part of the sensor unit. A vehicle sensor provided with a simple projection.