JPH0779183A - Road side beacon equipment and beacon system using the road side beacon equipment - Google Patents

Abstract

PURPOSE:To provide road side beacon equipment easily installed to a garage of an ordinary house. CONSTITUTION:A road side beacon equipment 1a is installed in a garage 31 of an ordinary home 30. The road side beacon-equipment la emits a signal including various information. The signal is emitted with a transmission output (e.g. -60.3(dBm)) not requiring the approval of opening of a radio station. Thus, the size of the road side beacon equipment 1a is made small and the power consumption is reduced and application and update procedure attended with the opening of a radio station are not required, then the load of a person desiring to open the road side beacon equipment la is relieved. Since the road side beacon equipment is installed easily to a garage of an ordinary home or a factory or the like, the road side beacon equipment is popularized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roadside beacon device whose main purpose is to calibrate the position of a vehicle, and particularly to a roadside beacon device which can be suitably installed not only on roads but also in garages of ordinary households, drive-ins, gas stations and the like. It is about. The present invention also relates to a beacon system using the roadside beacon device.

[0002]

2. Description of the Related Art Conventionally, in order to support the driving of a vehicle on an unfamiliar land, a navigation device for displaying the current position of the vehicle on a display device such as a CRT together with a road map around the vehicle is installed in the vehicle. It is installed and used. In such a navigation device, generally, the current position of the vehicle is detected based on the outputs of the distance sensor and the azimuth sensor, a road map around the detected current position is read from the road map memory, and the current position is read together with the current position. Displayed on the display device.

By the way, in the above navigation device, the current position displayed on the display device is significantly larger than the actual position due to the increase in the traveling distance of the vehicle due to the errors which the distance sensor and the direction sensor necessarily have. There is a risk that it will shift to. A beacon system has been conventionally devised for the purpose of solving such a problem. In a beacon system, a roadside beacon device is arranged at every predetermined distance of a road traffic network. This roadside beacon device emits a signal including position information and road direction information to the road. The vehicle traveling on the road receives this signal when it comes directly under the roadside beacon device and takes it into the navigation device, calibrates the current position of the vehicle to the position of the roadside beacon device, and corrects the direction of the vehicle. Can be calibrated. The signal radiated from the roadside beacon device includes branch point information, guidance information, traffic jam information, road regulation information, emergency information, parking lot information, and the like, in addition to the position information and road direction information.

By the way, the roadside beacon device according to the above-mentioned prior art is arranged at a predetermined position on a general road. On the other hand, if it is possible to calibrate the position and obtain various kinds of information before departure, it will be useful for passengers of the vehicle. For example, when a passenger wants to travel to a relatively close place, if he / she can know the road condition to the destination before departure, he / she can select an appropriate road and travel efficiently. In addition, if the vehicle is parked in a parking lot whose position is not registered in the road map stored in the road map memory and the position of the parking lot is known before departure, the position must be calibrated before departure. It can be carried out.
Therefore, recently, it has been proposed to install a roadside beacon device in a garage, a drive-in, a gas station or the like of a general household.

[0005]

On the other hand, the above-mentioned roadside beacon device secures a radiation area to some extent, or the minimum received power in a vehicle, for example, -65.
To secure the received power of (dBm), for example, 2.35.
A signal is radiated with a transmission output of (dBm) (≈ 1.72 (mW)) or more (detailed calculation method will be described later). Therefore, the roadside beacon device has a large equipment scale and consumes a large amount of power, which leads to an increase in cost.

Further, this transmission output is an output that requires permission to open a wireless station under the current Radio Law. Therefore, when the above-mentioned roadside beacon device is to be installed as it is in a garage or the like of a general household, it is necessary to apply for the opening of a wireless station to an administrative institution and obtain permission. Also,
Similarly, when performing the renewal procedure, you must apply to the administrative agency and obtain permission. Therefore, complicated procedures and fees are required, which puts a burden on a person who wants to install the roadside beacon device. Therefore, there is a problem that the roadside beacon device cannot be easily installed.

Therefore, an object of the present invention is to provide a small and inexpensive roadside beacon device and beacon system which can be easily installed in a garage, a drive-in, a gas station, etc. of a general household.

[0008]

In order to achieve the above object, a roadside beacon device according to a first aspect of the present invention comprises a storage means in which information including position information is stored in advance, and information stored in the storage means. A roadside beacon device including a modulation means for modulating to a format suitable for transmission, a transmission means for transmitting the information modulated by the modulation means, and an antenna, wherein the transmission means has a very high transmission output for the information. A signal to which data indicating low is added is transmitted from the antenna with an extremely low transmission output.

According to a second aspect of the present invention, in the roadside beacon device, the transmitting means transmits the signal with a transmission output such that the electric field strength at a point 3 m away from the roadside beacon device becomes 35 dBμV / m or less. Is characterized in that. Further, the roadside beacon device according to claim 3 is characterized in that the antenna is composed of one antenna.

In addition, the beacon system according to claim 4 is connected to the roadside beacon device according to claim 1, 2 or 3 through a public communication line network and provides various information to the roadside beacon device. A providing device, a detection unit that is provided on the roadside beacon device and automatically detects the presence or absence of a vehicle, and requests the information providing device to provide information when the vehicle is detected by the detecting unit. When a vehicle is detected by the detection means, the signal output means outputs a signal requesting the information providing apparatus to provide information, and the information providing apparatus outputs the signal. Upon reception, various information is provided to the roadside beacon device.

The beacon device according to claim 5 is connected to the roadside beacon device according to claim 1, 2 or 3 through a public communication line network, and provides various information to the roadside beacon device. A providing device, and an operation unit that is provided on the roadside beacon device side and is manually operated by the installer or user of the roadside beacon device, and
Signal output means for outputting a signal requesting the information providing device to provide information when the operating means is operated, and when the operating means is operated, information is provided to the information providing device. The request signal is output from the signal output means, and the information providing device, upon receiving this signal, provides various information to the roadside beacon device.

Further, a beacon system according to a sixth aspect of the present invention is used by being mounted on a vehicle and the roadside beacon device according to the first, second or third aspect, and receiving a signal transmitted from the roadside beacon device. Receiving means, data presence / absence determining means for determining whether or not the signal received by the receiving means includes data indicating that the transmission output is extremely low, and the level of the signal received by the receiving means. Is determined to be equal to or higher than a predetermined threshold level, and when the data presence / absence determining means determines that the data is included, and the level determining means receives the data. Position detecting means for detecting the position based on the position information included in the received signal when it is determined that the level of the signal is equal to or higher than the threshold level. Characterized in that it comprises a vehicle device having and.

[0013]

In the structure according to the above-mentioned claim 1, from the antenna,
A signal containing data indicating a very low transmit power is transmitted at a very low transmit power. Therefore, the roadside beacon device can be downsized and the power consumption can be suppressed low. Further, the transmission output is set to an output that does not require permission for opening a wireless station, for example. The specific numerical value is that the electric field strength at a point 3 m away from the roadside beacon device is 35, as in the configuration described in claim 2, for example.
The output can be set to be dB μV / m or less. If the transmission output is set to such an output, when installing the roadside beacon device, it is not necessary to apply to the administrative agency for permission to open the wireless station. Therefore, a person who wants to install the roadside beacon device does not need the procedure and expense. for that reason,
Roadside beacon devices can be easily installed in garages, drive-ins of general households, gas stations, premises of factories, etc.

Further, according to the third aspect of the invention, since the signal transmitted from the antenna has a very low transmission output, the transmission region is narrow and highly accurate position detection can be performed as it is. Therefore, since it is not necessary to perform beam splitting using two antennas, the configuration of the roadside beacon device can be simplified. In addition, claim 4
In the configuration described, when the vehicle is detected by the detection means,
A signal that requests the information providing device to provide information is output from the signal output means. Upon receiving this signal, the information providing device provides various information to the roadside beacon device.
That is, since the public communication line network is used only when the vehicle can receive the information, it is possible to reduce the frequency of use of the public communication line network.

According to the fifth aspect of the present invention, a signal requesting the provision of information is output to the information providing device by the person installing the roadside beacon device or the driver of the vehicle operating the operating means. . Upon receiving this signal, the information providing device provides various information to the roadside beacon device.
Therefore, also in this case, the same operation as that of the above-mentioned claim 5 is achieved.

In this case, when the roadside beacon device is installed at a drive-in station or a gas station, information can be provided for a fee. Further, in the configuration according to claim 6, the signal is received by the receiving means mounted on the vehicle. When the signal is received, the data presence / absence determining means determines whether or not the signal received indicates that the transmission output is extremely low, and at the same time, the level determining means determines the level of the received signal. Is determined to be equal to or higher than the threshold level. As a result, when the data is included and the level is equal to or higher than the threshold level, the position is detected based on the position information included in the received signal.

That is, since the transmission output of the signal transmitted from the roadside beacon device is extremely low, the transmission area is narrow, and therefore highly accurate position detection can be realized.

[0018]

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 3 is a block diagram showing the configuration of the beacon system. This beacon system
Various information is provided to the roadside beacon device 1a of the present invention, a known roadside beacon device 1b arranged at a predetermined position of the road traffic network, and the roadside beacon device 1a and the roadside beacon device 1b via the public telephone network 2. The information providing enterprise 3 for doing so and the vehicle-mounted device 4 mounted on the vehicle.

1 and 2 are views showing an example of installation of the roadside beacon device 1a, (a) of each drawing is a plan view,
(b) shows a perspective view. The roadside beacon device 1a is installed at a place where the vehicle stops or at an extremely low speed (for example, 5 km / h).
It is installed and used in a place where it travels at less than / h).
That is, the roadside beacon device 1a is, for example, as shown in FIG.
As shown in (b), near the entrance of the garage 31 of the general household 30, and as shown in FIGS. 2 (a) and 2 (b), the drive-in 32
It will be installed near the doorway. In addition, it can be installed, for example, at a gas station or on the premises of a factory.

FIG. 4 is a block diagram showing the configuration of the roadside beacon device 1a. The roadside beacon device 1a includes a data modulation / demodulation unit 5 and a transmission data processing unit 6, and an operation unit 7 is connected to the transmission data processing unit 6. When the installer of the roadside beacon device 1a, the driver of the vehicle, or the like wants to obtain information from the information providing enterprise 3, when the operation unit 7 is operated, the transmission data processing unit 6 gives a start command to the data modulation / demodulation unit 5, From the data modem 5 to the public telephone line network 2
A signal is sent to the information providing enterprise 3 via. Then, various information is provided from the information providing enterprise 3 to the data modulation / demodulation unit 5 via the public telephone line network 2, the information is demodulated by the data modulation / demodulation unit 5, and then provided to the transmission data processing unit 6. .

The information provided by the information providing enterprise 3 is
So-called dynamic information that changes over time, such as caution information that calls attention, an emergency message that directs subsequent actions, obstacle information that informs an accident occurring in the front, and the requirement for a typical destination. Simple travel time information that represents time, simple graphic information that graphically represents the traffic information of the road traffic network mainly consisting of main trunk lines, parking information, event regulation link information that represents the occurrence event of each link, There is traffic congestion link information that represents traffic congestion information for each link.

A storage unit 8 is connected to the transmission data processing unit 6. So-called static information that does not change with time is stored in advance in the storage unit 8. The static information includes:
For example, there is position information indicating a place where the roadside beacon device 1a is installed and map / guidance information around the position. The transmission data processing unit 6 processes the dynamic information provided from the data modulation / demodulation unit 5 and the static information stored in the storage unit 8 into a frame format described later, and then provides the data transmission unit 9.

An oscillator 10 for oscillating a carrier signal (frequency 2.5 (GHz)) is connected to the data transmitter 9. In the data transmission unit 9, the transmission data processing unit 6
Information is modulated by the signal oscillated from the oscillator 10, and the modulated signal is given to the beacon antenna 11 and radiated. The modulation method used in the data transmitter 9 is GMSK, PSK, FSK, A
For example, SK modulation.

The signal radiated from the beacon antenna 11 is radiated with an extremely low transmission output that does not require permission to open the wireless station. According to the current Radio Law, in order to eliminate the need for permission to open a radio station, if the radio wave radiated from the beacon antenna 11 has a frequency higher than 322 (MHz) and lower than 10 (GHz), it is 3 m away from the beacon antenna 11. It is stipulated that the electric field strength at the point must be 35 (dBμV / m) or less (Article 6-1 of the Radio Law Enforcement Regulations).
Item 1). Therefore, since the signal radiated from the beacon antenna 11 is 2.5 (GHz), the transmission output has an electric field strength of 35 (dBμV / m) at a point 3 m away.
) The output should be as follows.

As an example of the above transmission output, when an antenna having an antenna gain of 7 dBm is used as the beacon antenna 11, -60.3 (dBm) (≈9.33).
× 10 ⁻⁷ (mW)). In this way, the signal radiated from the beacon antenna 11 is radiated with an extremely low transmission output that does not require permission, so that the radiation area is very narrow. Needless to say, this value changes depending on the antenna gain when the beacon antennas 11 having different antenna gains are used.

An attenuator (not shown) is connected to the beacon antenna 11, and an installer of the roadside beacon device 1a, a driver of a vehicle or the like can change the entire transmission output by operating the attenuator. Figure 5
FIG. 3 is a diagram showing a configuration of a signal radiated from beacon antenna 11. The signal radiated from the beacon antenna 11 is composed of a synchronization code 40, a header section 41, an actual data section 42 and a CRC code 43, as shown in FIG. The sync code 40 is a code for indicating the beginning of a frame, and the CRC code 43 is an error detection code for each frame.

The header section 41 is, as shown in FIG.
Low-output beacon data 41a indicating that the roadside beacon device 1a emits a signal with a transmission output that does not require permission, and there is a place where the roadside beacon device 1a is installed 2
The next mesh code 41b, the normalized coordinates 41c representing the XY coordinates of the place where the roadside beacon device 1a is installed, and the information service list 41d indicating all kinds of information provided from the roadside beacon device 1a are provided. The low output beacon data 41a is composed of a code that is not originally possible, and is composed of all "1", for example. The secondary mesh is a mesh map obtained by vertically and horizontally dividing the Japan map into a plurality of pieces, and the secondary mesh code is a number attached to each mesh map.

The header section 41 also has a large section ID 41e for specifying the type of information corresponding to the frame, a large section internal frame number 41f indicating the number of all frames of the type information corresponding to the large section ID 41e, In the large-segment frame number 41f, a large-segment frame number 41g indicating which frame this frame corresponds to,
An effective frame length 41h indicating the effective size of the actual data portion 42 in this frame is provided.

The signal radiated from the publicly known roadside beacon device 1b has substantially the same configuration as the above, but the low output beacon data 41a is a beacon number for identifying the roadside beacon device 1b. Only the points differ. In addition, as a method of indicating that the roadside beacon device 1a emits a signal with a transmission output that does not require permission,
There is a method of setting the large classification ID 41e to low output beacon data, and a method of adding a code corresponding to the low output beacon data to the information service list 41d.

FIG. 6 is a block diagram showing the configuration of the roadside beacon device 1b. The roadside beacon device 1b has a conventionally well-known structure, and will be briefly described. The information processed in the frame format by the transmission data processing unit 6 is given to the data transmission unit 9 and the position data generation unit 13. The position data generator 13 is for generating an electric signal having an amplitude corresponding to the position data included in the given information, and the electric signal is given to the AM modulator 14.

A data transmission section 9 is connected to the AM modulation section 14, and the AM modulation section 14 is for subjecting the signal modulated by the data transmission section 9 to AM modulation. Specifically, the AM modulator 14 divides the modulated signal supplied from the data transmitter 9 into two parts, and the divided signals are inversed to each other according to the amplitude of the electric signal supplied from the position data generator 12. AM modulation of the phase is performed. Therefore,
The AM modulation unit 14 generates a signal including the signal component given from the data transmission unit 9 and the AM modulation component. Thereafter, the respective signals are transmitted to the two beacon antennas 15a, 15a.
b, and as shown in FIG. 7, the roadside beacon device 1
It is radiated separately in the front-back direction of the road 16 centered on b. By radiating in this way, the reception level of the signal component in the vehicle traveling on the road 16 becomes lower toward the emission region end with the point a as the apex, and the reception level of the AM modulation component sharply decreases at the point a ( For example, JP-A-4
See Japanese Patent No. 81596. ). Since the roadside beacon device 1b always emits a signal, the operation unit 7
Is not prepared.

As described above, the roadside beacon device 1b radiates a signal with a transmission output of, for example, 2.35 (dBm) (≈1.72 (mW)). This output is much larger than the transmission output of the roadside beacon device 1a. The reason for making such a large output is that the roadside beacon device 1b is installed to give information to the vehicle traveling on the road, so that the traveling vehicle can receive the signal at a sufficient reception level. This is because

FIG. 8 is a block diagram showing the configuration of the vehicle-mounted device 4. The in-vehicle device 4 includes the roadside beacon devices 1a and 1b.
It is possible to process signals radiated from any of the above. First, a case of processing a signal radiated from the roadside beacon device 1b will be described. When the vehicle-mounted antenna 28 receives the signal radiated from the roadside beacon device 1b, the signal is demodulated by the data demodulation unit 17. As a result, in the data demodulation unit 17, the AM modulation component,
Data corresponding to the signal component and various information is extracted, and the AM modulation component is supplied to the AM modulation component demodulation unit 19, while
The signal component is given to the data processing unit 20. Further, data corresponding to various information is given to the data processing unit 21, and given from the data processing unit 20 to the navigation processing unit 21. The AM modulation component demodulator 19 receives the given A
The M-modulation component is demodulated to extract position data, and the position data is given to the data processing unit 20. This AM
The modulation component demodulation unit 19 is used only when the vehicle-mounted antenna 18 receives a signal emitted from the roadside beacon device 1b.

The data processing unit 20 detects the position. This position detection is performed only when the vehicle reaches directly below the roadside beacon device 1b and when the level of the signal component received by the vehicle-mounted antenna 18 is equal to or higher than a predetermined threshold level. This is performed based on the position data given from the demodulation unit 19. When the vehicle reaches just below the roadside beacon device 1b, as described above,
The reception level of the AM modulation component drops sharply. Therefore, the data processing unit 20 detects that the reception level of the AM modulation component has decreased, and thereby determines that the vehicle has just reached the roadside beacon device 1b.

Next, the case of processing the signal radiated from the roadside beacon 1a will be described. The signal radiated from the roadside beacon device 1a is the in-vehicle antenna 18
When the signal is received by, the signal is demodulated by the data demodulation unit 17, and the data corresponding to the signal component and various information obtained as a result is given to the data processing unit 20. The data corresponding to the above-mentioned various information is given to the navigation processing unit 21 in the same manner as described above. In addition, the data processing unit 20
Then, the position is detected in the same manner as described above. This position detection is performed based on the position data included in the signal provided from the data demodulation unit 17 only when the level of the signal component received by the vehicle-mounted antenna 18 is equal to or higher than a predetermined threshold level. Here, the reason why the position detection condition is that the vehicle has just arrived below the roadside beacon device 1a is that the emission area of the roadside beacon device 1a is narrow because the transmission output is extremely low, and the vehicle-mounted antenna 18 receives a signal. This is because the start position may be regarded as being directly below the roadside beacon device 1a.

The position detection in the data processing unit 20 differs depending on which of the roadside beacon devices 1a and 1b is radiating the signal received by the on-vehicle antenna 18, as described above. In the data processing unit 20, the method of determining which of the roadside beacon devices 1a and 1b is radiating the signal received by the vehicle-mounted antenna 18 is as follows. It is done depending on whether or not it is done. This low output beacon data is included in the signal emitted from the roadside beacon device 1a, and is not included in the signal emitted from the roadside beacon device 1b. Therefore, the data processing unit 20 can determine which of the roadside beacon devices 1a and 1b radiated the received signal by detecting the presence or absence of the low output beacon data. The position detected by the data processing unit 20 is
It is given to the navigation processing unit 21.

The navigation processing unit 21 is connected to a distance sensor 22 such as a wheel speed sensor for detecting the traveling distance and traveling direction of the vehicle and a direction sensor 23 such as a gyro. The navigation processing unit 21 detects the current position of the vehicle based on the outputs of the sensors 22 and 23. When the current position is detected, a road map around the current position is read from the CD-ROM 24 and given to the display unit 25 such as a CRT together with the current position. Display 25
Then, the current position is overlaid and displayed on the road map.

In the navigation processing unit 21, when the position detected by the data processing unit 20 is given, the current position detected by the navigation processing unit 21 is calibrated to the given position, and the calibrated position is Display 25
Is displayed. Further, the navigation processing section 21 causes the display section 25 to display various information given from the data processing section 20 in response to a request from the outside.

In the following, it will be described that in the vehicle-mounted device 4, stable signal reception and high-accuracy position detection can be performed with the outputs of the roadside beacon devices 1a and 1b emitting signals. First, the case of the roadside beacon device 1b will be described. The signal emitted from the roadside beacon device 1b is received by the vehicle-mounted device 4 mounted on the traveling vehicle. In order to realize stable signal reception and highly accurate position detection, the vehicle-mounted device 4 mounted on this traveling vehicle requires at least -65 (dBm) received power. On the other hand, for example, the roadside beacon device 1b
Side feed line loss L _t is 3 (dB) and antenna gain G _t is 7
(DBi), 35.20 (m) from the roadside beacon device 1b
Propagation loss L _d at a distance of 71.35 (dB), antenna gain G _r of the vehicle-mounted device 4 side at 4 (dB _i ), feeder line loss L
Transmission loss L from the roadside beacon unit 1b in the case of the _r 4 and (dB) up to vehicle device _{4, L = -L t + G t} -L d + G r -L r = -67.35 (dB) ‥‥ It becomes (1). Therefore, under the above conditions, the transmission output P _t of the roadside beacon device 1b is −65 + 67.35 = 2.35.
If (dBm) (≈1.72 (mW)) or more, the in-vehicle device 4 can realize stable signal reception and highly accurate position detection.

On the other hand, it is radiated from the roadside beacon device 1a.
The signal that is transmitted is transmitted with a transmission output that does not require permission to open the wireless station.
As described above, its transmission output is
The electric field strength E at a point 3 m away from the installation 1a is 35
It is the transmission output that is less than (dBμV / m). First, this
Based on the field strength E, the transmission output P of the roadside beacon device 1a
_tAnd the received power P at the vehicle-mounted device 4_rAsk for an example.

When the electric field strength E is converted into a reception input voltage V (V) in the vehicle-mounted device 4, V = λ / 4π × √ (R · G _r / 30) × E (1) Here, λ is the wavelength (m 2), R is the impedance (Ω), and G _r is the above antenna gain. When the logarithm of this equation (1) is taken, it becomes 20logV = 20log (λ / 4π) + 10log (R / 30) + 10logG _r + 20logE (2). Where λ = c / f = 3.0 × 10 ⁸ /2.5
× 10 ⁹ = 0.12 and, and substituting R = 50, the _{20logV = -40.4 + 2.2 + 10logG r} + 20logE ‥‥ (3). When this equation (3) is expressed in decibels, the received input voltage V (dBμV) is as shown in the following equation (4).

V = E + G _r −38.2 (4) Here, the above condition E = 35 (dBμV / m) and G _r = 4.
Substituting (dBi) gives V = 0.8 (dBμV).
Next, the received input voltage V is converted into the received power P _r (dBm). When the received input voltage V is expressed in voltage, V = 0.
8 (dBμV) = 1.1 × 10 ⁻⁶ (V). here,
From the relationship P = V ² / R, the ^{_{P r = (1.1 × 10 -6}} ) 2 /50=0.024×10 -12 = 24 × 10 -15 ‥‥ (5). If this is expressed in decibels, it becomes the following formula (6).

P _r = 24 × 10 ^-15 (W) = 13.8-150 (dBw) = -136.2 (dBw) =-106.2 (dBm) (6) That is, the roadside beacon device 1a When the electric field strength E at a point 3 m away from is 35 (dBμV / m 2) or less and the antenna gain G _t of the beacon antenna 11 is 7 (dB), the signal radiated from the roadside beacon device 1a in the vehicle-mounted device 4 is The received power P _r is −106.2 (dBm).

Next, the transmission output P _t of the roadside beacon device 1a for obtaining the received power P _r in the vehicle-mounted device 4 is obtained. The transmission output P _t of the roadside beacon device 1 a is calculated by using the feed line loss L _t , the antenna gain G _t , the propagation loss L _d , the antenna gain G _r , and the feed line loss L _r as shown in the following equation (7). Become. _{P t = P r - (-} L t + G t -L d + G r -L r) becomes a ‥‥ (7). Here, P _r = 106.2, L _t = 3, G _t =
Substituting 7, G _r = 4, L _r = 4 into the equation (7), P _t = −106.2-(− 3 + 7−L _d + 4−4) = − 110.2 + L _d (8) Becomes Since the above L _d is represented by 20 log (4πr / λ), substituting r = 3 and λ = 0.12, L _d = 4
It is 9.9. Therefore, the P _t is -60.3 (dBm
). That is, the roadside beacon device 1a is -60.
Transmission output P of 3 (dBm) (≒ 9.33 × 10 ^-7 (mW))
If a signal is emitted at _t , the in-vehicle device 4 receives the received power P
It is possible to obtain _r (= -106.2 (dBm)). Further, from this result, the transmission output P of the roadside beacon device 1a
_t is 62.65 (dB compared to the roadside beacon device 1b
It turns out that m) must also be lowered.

Here, since it is assumed that the roadside beacon device 1a of the present invention is installed in a garage of a general household,
Set the distance between the roadside beacon device 1a and the in-vehicle device 4 to 1
It is possible to approach as close as (m). for that reason,
In the above transmission output, the reception power P _r when r is 1 (m) is as follows: P _r = P _t + (− L _t + G _t −20 log (4πr / λ) + G _r −L _r ) = − 60. 3 + (-3 + 7-40.4 + 4-4) =-60.3-36.4 = -96.7 (dBm) (9).

As described above, the received powers P _r for r = 3 and r = 1 are obtained. These received powers P _r are usually
If the vehicle is running, it is difficult for the vehicle-mounted device 4 to perform stable signal reception and highly accurate position detection.
However, the value is sufficient when the vehicle is stopped or travels at an extremely low speed. FIG. 9 is a diagram showing measured values of the bit error rate BER with respect to the received power P _r . This measured value represents the result of measurement with both the beacon antenna 11 of the roadside beacon device 1a and the vehicle-mounted antenna 18 of the vehicle-mounted device 4 fixed in the anechoic chamber.

Referring to this figure, the received power P _r is -9.
The bit error rate BER at 6.7 (dBm) is 4 × 1
It will be about 0 ^-3 . The bit error rate BER is a sufficient value for the in-vehicle device 4 to perform stable signal reception and highly accurate position detection. That is, each antenna 1
When 1, 18 are fixed, that is, when the roadside beacon device 1a is installed in a garage of a general household and the vehicle is stopped, stable signal reception and high accuracy are _achieved even with the received power P _r. It is possible to detect various positions.

As described above, according to the beacon system of this embodiment, the roadside beacon device 1a emits a signal with an extremely low transmission output, so that the roadside beacon device 1a can be made compact and inexpensive. Further, since the roadside beacon device 1a has a low transmission output and a narrow radiation area, only one beacon antenna 11 is provided. That is,
It is possible to keep the price of the roadside beacon device main body lower than in the past. Therefore, the roadside beacon device 1a can be made small and inexpensive. In addition, it is not necessary to apply for permission / renewal for opening a wireless station. Therefore, the procedure and expense are unnecessary, and the burden on the person who wants to install the roadside beacon device 1a can be reduced. Therefore, a small and inexpensive roadside beacon device can be easily installed in a garage, a gas station, a drive-in, etc. of a general household.

Although the embodiments have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiment, when the information providing enterprise 3 is requested to provide information, the installer of the roadside beacon device 1a, the driver of the vehicle, or the like operates the operation unit 7, but
For example, the information provision request may be automatically made. In order to realize this, as shown by a broken line in FIG. 4, a vehicle detector 50 as a detection means is provided in an appropriate place around the place where the roadside beacon device 1a is installed, and the vehicle detector 50 and the transmission data are transmitted. The processing unit 6 is connected. Then, the vehicle is moved to the detection range of the vehicle detector 50. Then, the vehicle detector 50 detects the vehicle and sends a signal to the transmission data processing unit 6. When the transmission data processing unit 6 receives this signal, the transmission data processing unit 6 gives a start command to the data modulation / demodulation unit 5, and the data modulation / demodulation unit 5 Automatically transmits a signal to the information providing enterprise 3.

Further, in the above embodiment, the configuration example in which the information providing enterprise 3 is connected to the roadside beacon device 1a as the beacon system via the public telephone line network 2, but for example, the information providing enterprise 3 is used. You may install the roadside beacon apparatus 1a independently, without connecting. In such a case, the roadside beacon device 1a emits a signal containing only static information stored in the storage unit 8.

Further, in the above-mentioned embodiment, the vehicle-mounted device 4 is constructed so that the position can be detected based on the signal radiated from both the roadside beacon device 1a and the roadside beacon device 1b. The position may be detected only based on the signal radiated from 1a. In order to realize this, the AM modulation component demodulation unit
It suffices to adopt a configuration excluding 9.

In addition, various design changes can be made without departing from the spirit of the present invention.

[0053]

As described above, according to the roadside beacon device of the present invention, since the signal is transmitted at an extremely low transmission output, the roadside beacon device can be downsized and the power consumption can be suppressed low. In addition, there is no need to obtain permission to open a wireless station, and application and renewal procedures and fees associated with opening a wireless station are unnecessary. Therefore, the burden on the person who installs the roadside beacon device can be reduced, so that the roadside beacon device can be easily installed in a garage, a drive-in, a gas station or the like of a general household. Therefore, the roadside beacon device can be popularized.

In particular, according to the structure of claim 3, since the signal is transmitted from one antenna, the structure of the roadside beacon device can be simplified as compared with the conventional one. Therefore, the price of the roadside beacon device can be kept low, and the burden on the person who installs the roadside beacon device can be further reduced. Further, according to the beacon system of the fourth and fifth aspects, since the public communication line network is used only when necessary, it is possible to selectively and inexpensively transmit information to the vehicle.

[Brief description of drawings]

FIG. 1 is a diagram showing an installation example of a roadside beacon device of the present invention.

FIG. 2 is a diagram showing an installation example of a roadside beacon device of the present invention.

FIG. 3 is a block diagram showing a configuration of a beacon system.

FIG. 4 is a block diagram showing a configuration of a roadside beacon device.

FIG. 5 is a diagram showing a configuration of a signal transmitted from the roadside beacon device.

FIG. 6 is a block diagram showing a configuration of a roadside beacon device.

FIG. 7 is a diagram showing a radiation region of a signal transmitted from a roadside beacon device.

FIG. 8 is a block diagram showing a configuration of an in-vehicle device.

FIG. 9 is a diagram showing a measured value of a bit error rate with respect to received power in an in-vehicle device.

[Explanation of symbols]

 1a, 1b Roadside beacon device 2 Public telephone line network 3 Information provider 4 In-vehicle device 6 Transmission data processing unit 7 Operation unit 8 Storage unit 9 Data transmission unit 15a, 15b Beacon antenna 20 Data processing unit 41a Low output beacon data 50 Vehicle Detector

Claims (6)

[Claims] 1. A storage unit, which is installed and used in a place where a vehicle is stopped or travels at an extremely low speed, in which information including position information is stored in advance, and at least information stored in the storage unit. A roadside beacon device including a modulation unit that modulates into a format suitable for transmission, a transmission unit that transmits information modulated by the modulation unit, and an antenna, wherein the transmission unit has an extremely high transmission output for the information. A roadside beacon device, wherein a signal to which data indicating low is added is transmitted from the antenna with an extremely low transmission output. 2. The transmitting means has an electric field strength of 35 dBμV / m at a point 3 m away from the roadside beacon device.
The roadside beacon device according to claim 1, wherein the signal is transmitted with the following transmission output. 3. The roadside beacon device according to claim 1, wherein the antenna comprises one antenna. 4. An information providing device which is connected to the roadside beacon device according to claim 1, 2 or 3 through a public communication line network and provides various information to the roadside beacon device, and the roadside beacon device side. A detection means for automatically detecting the presence or absence of a vehicle, and a signal output means for outputting a signal requesting the information providing device to provide information when the vehicle is detected by the detection means. Including, when the vehicle is detected by the detection means, a signal requesting the information providing device to provide information is output from the signal output means, and the information providing device receives the signal, and the roadside beacon device receives various signals. Beacon system characterized by providing information of. 5. An information providing device which is connected to the roadside beacon device according to claim 1, 2 or 3 through a public communication network and provides various information to the roadside beacon device, and the roadside beacon device side. And an operation means for the installer or user of the roadside beacon device to manually operate, and a signal requesting the information providing device to provide information when the operation device is operated. When the operation means is operated, a signal requesting the information providing device to provide information is output from the signal output device, and the information providing device receives the signal, A beacon system characterized by providing various information to a beacon device. 6. The roadside beacon device according to claim 1, 2 or 3, a receiving means used for being mounted on a vehicle for receiving a signal transmitted from the roadside beacon device, and receiving by the receiving means. Data presence / absence determining means for determining whether or not data indicating that the transmission output is extremely low is included in the received signal, and the level of the signal received by the receiving means is equal to or higher than a predetermined threshold level. A level discriminating means for discriminating whether or not there is a signal, and the level of the signal received by the level discriminating means is equal to or higher than the threshold level when the data discriminating means determines that the data is included. And an in-vehicle device having position detecting means for detecting the position based on the position information included in the received signal. Beacon system to do.