JP2542385B2 - Vehicle current position detection method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle current position detection method, and more specifically, it detects a current position when a vehicle traveling on a road traffic network passes a specific point. The present invention relates to a new vehicle current position detection method.

<Prior Art> Conventionally, as a vehicle current position detection method, a method of detecting the current position by detecting and totalizing the traveling distance and traveling direction at each time point, and an AVM system for commercial vehicles such as taxis ,
Also, a system has been proposed or put into practical use in which a beacon, a sign post, etc. are installed to radiate position information and the like toward a vehicle.

Explaining in more detail, the above-mentioned method always mounts the mileage detecting device, the traveling azimuth detecting device, and the integrating device on the vehicle, and performs initial setting at the start of traveling, so that the current position is always maintained. Can be continuously detected, and since it is not necessary to install a special transmitting / receiving device along the road traffic network, the configuration of the entire system can be simplified.

Further, the above system allows data transmission by relatively weak radio waves between the ground fixed station side and the vehicle side, and can detect the current position based on the transmitted data. That is, the antenna connected to the ground fixed station is installed at a predetermined position on the road traffic network, and the current position can be detected based on the data received when the vehicle passes by the antenna. In addition, since the physical installation position of the antenna is set accurately in advance, it is possible to improve the detection accuracy of the current position.

<Problems to be Solved by the Invention> In the above method, since the errors that the traveling distance detection device and the traveling direction detection device inevitably have are accumulated with traveling, the current position detection error is Since the distance increases with the distance traveled and the degree of error is completely unknown, there is a problem in that it is impossible to accurately detect the current position after traveling a certain amount or more.

Also, in the above system, the AVM transmitter,
Since it is essential to install a beacon transmitter and the like, there are problems that the system becomes complicated as a whole and that it costs a lot to construct the system.
More specifically, since these systems are intended to detect a discontinuous current position from the beginning, if the installation intervals of the AVM transmitter and beacon transmitter are too large, the current position will be changed. The distance from the detection to the detection of the next current position becomes too long, and it cannot be practically used as a system for detecting the current position. And if you reduce the installation interval to eliminate such problems, you should install
Since the number of AVM transmitters, beacon transmitters, etc. increases remarkably and the system becomes extremely complicated as a whole, there is a problem that it takes a lot of time and effort to construct and maintain the system.

Further, in the above system, since data transmission is performed by radio waves, interference with other radio waves, deterioration of data transmission quality due to multipath fading phenomenon, etc. are caused, and current position detection accuracy deteriorates. There is also.

<Objects of the Invention> The present invention has been made in view of the above problems, and an object of the present invention is to provide a vehicle current position detection method in which system construction is simple and current position detection accuracy can be improved. I am trying.

<Means for Solving Problems> A vehicle current position detection method of the first invention for achieving the above object is a vehicle transmitted from a vehicle detector installed at a predetermined position of a road traffic network. An ultrasonic wave signal for sensing is modulated uniquely to the installation position, and a receiver is mounted on the vehicle, and the receiver receives the modulated ultrasonic wave signal and receives the received ultrasonic wave. With reference to the extraction means for extracting a unique modulation signal from the signal, the storage means storing the correspondence relationship between the data corresponding to the plurality of modulation signals and the installation position, and the correspondence relationship stored in this storage means,
Identification means for identifying the installation position stored in association with the data corresponding to the unique modulated signal extracted by the extraction means, and position setting with the installation position identified by the identification means as the current vehicle position And means.

However, the specific modulation may be pulse modulation having a specific cycle or modulation based on a signal having a specific frequency.

In order to achieve the above object, the vehicle current position detection method of the second invention is an ultrasonic signal having a frequency unique to the installation position from a vehicle detector installed at a predetermined position of the road traffic network. And a receiver mounted on the vehicle, the receiver receives the ultrasonic signal, and obtains a unique frequency from the received ultrasonic signal, and supports a plurality of modulated signals. The storage means storing the correspondence relationship between the data to be installed and the installation position and the correspondence relationship stored in the storage means are referred to, and the installation is stored in association with the unique frequency acquired by the acquisition means. It includes a specifying unit that specifies the position and a position setting unit that sets the installation position specified by the specifying unit as the current position of the vehicle.

<Operation> With the vehicle current position detection method according to the first aspect of the present invention,
The ultrasonic signal to be transmitted from the vehicle detector is uniquely modulated, and the modulated ultrasonic signal is transmitted. On the other hand, the receiver mounted on the vehicle receives the modulated ultrasonic wave signal and extracts a unique modulated signal from the received ultrasonic wave signal. Then, of the complicated installation positions, the installation position stored in association with the data corresponding to the extracted modulated signal is specified, and the specified installation position is set as the current position of the vehicle.

The vehicle detector is already installed on the main highway. Therefore, it is not necessary to add new roadside equipment.

Moreover, an ultrasonic signal is emitted from the vehicle detector with considerably high directivity. Therefore, the current position of the vehicle can be detected with practical accuracy.

Note that, as the above-mentioned unique modulation, for example, pulse modulation having a unique cycle or modulation based on a signal having a unique frequency can be considered.

Further, according to the vehicle current position detection method of the second aspect of the invention described above, the vehicle detector radiates an ultrasonic signal of a specific frequency. On the other hand, the receiver mounted on the vehicle receives the ultrasonic signal, and a specific frequency is acquired from the received ultrasonic signal. Then, the installation position stored in association with the data corresponding to the acquired frequency is specified from among the plurality of installation positions, and the specified installation position is set as the current position of the vehicle.

As described above, according to the vehicle current position detection method of the second invention, the vehicle current position can be acquired only by providing the vehicle detector as the roadside equipment. Therefore, the vehicle current position detection method of the first invention described above. Has the same effect as.

<Example> Hereinafter, an example will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view showing an embodiment of a vehicle current position detection system of the first invention, in which a pillar (3) is erected in proximity to a road (2) on which the vehicle (1) travels. At the same time, the ultrasonic head (5) is attached to a predetermined position of the support member (4) connected to the upper end of the column (3). A transmitter / receiver device (6) is provided at a predetermined position of the pillar (3), and an ultrasonic receiving microphone (7) is attached to the roof of the vehicle (1), and the receiver (8) is mounted on the vehicle (1). ) And the ultrasonic microphone (7) are connected.

FIG. 2 is a block diagram showing an electrical configuration of the transmitter / receiver, and a clock generator (9) and a clock signal output from the clock generator (9) are input to generate a signal of a frequency of about 27 KHZ. A frequency converter (10) for
A pulse generation unit (11) that generates a pulse signal with a period (for example, a period of 40 to 50 msec) peculiar to the installation position, and a modulation unit (12) that performs pulse modulation on a signal having a frequency of about 27 KHZ based on the pulse signal (12). ), An amplifier (13) for amplifying the pulse modulation signal to a predetermined level, and the modulation signal amplified by the amplifier (13) is supplied to one winding, and the signal generated in the other winding is applied to the ultrasonic head. To the input / output transformer (14), a tuning amplifier (15) that receives the received signal generated in one winding of the input / output transformer (14), and an output from the tuning amplifier (15). It is composed of a pulse shift detection unit (16) that receives the amplified signal as an input and detects a pulse shift with respect to the modulation signal, and a determination unit (17) that determines the presence or absence of the vehicle (1) based on the pulse shift detection signal. There is.

The frequency converter (10), the pulse generator (11),
The modulation unit (12), the pulse shift detection unit (16), the determination unit (17), and the like can be configured by a microprocessor or the like.

FIG. 3 is a block diagram showing an electrical configuration of the receiving device, which includes an amplifier (18) for amplifying a reception signal output from the reception microphone (7) and a bandpass for removing a noise component from the amplified signal. A filter (19), a waveform shaping section (20) for inputting a signal output from the band pass filter (19), a level determination section (21), and a waveform shaping section (2
Frequency counter (2 that receives the signal output from 0)
2), the location of the vehicle detector and the position memory (23) that stores the frequency count number data corresponding to the location in advance, and the level determination signal from the level determination unit (21) as a control signal. , A logical operation part (24) for comparing the output signal from the frequency counter (22) and the contents of the position memory (23).

The frequency counter (22), position memory (23),
Also, the logical operation unit (24) and the like can be configured by a microprocessor or the like.

Further, in this embodiment, the frequency counter (22) and the position memory (23) function as an extracting means and a storing means, respectively. Also, the logical operation unit (24)
Functions as a specifying unit and a position setting unit.

The operation of the vehicle current position detection system configured as described above is as follows.

In the transmitter / receiver (6), the frequency conversion unit (10) generates a signal having a frequency of about 27 KHZ, and the pulse generation unit (11) fixes a fixed period at the installation position (for example, a period of about 40 to 50 msec). Of the pulse signal is generated, and the frequency is reduced by the modulator (12) based on the pulse signal.
Applying pulse modulation to the 27KHZ signal, ultrasonic head (5)
The ultrasonic signal is always radiated downward through. Since the ultrasonic signal is reflected by the road (2) or the vehicle (1), the reflected ultrasonic signal is received by the ultrasonic head (5) and tuned and amplified by the tuning amplifier (15). The pulse shift with respect to the modulation signal is detected by applying the pulse width to the pulse shift detector (16). Then, based on the pulse shift detection signal, the presence / absence of the vehicle (1) can be determined by the determination unit (17). That is, the original vehicle rolling-out operation can be performed, and it is used as a signal for traffic control.

Further, when the vehicle (1) is located almost directly under the ultrasonic head (5), the ultrasonic signal can be received by the receiving microphone (7) and an electric signal corresponding to the ultrasonic signal can be generated. it can. Then, the electric signal corresponding to the ultrasonic signal is amplified by the amplifier (18) and the noise component is removed by the bandpass filter (19), and is directly transmitted to the waveform shaping section (20) and the level determination section (21). Supplied.

In the waveform shaping section (20), a rectangular wave signal is generated by performing waveform shaping on the input signal,
By being supplied to the frequency counter (22) as it is, count number data corresponding to the frequency is generated.
In the level determination section (21), it is determined whether or not the reception level of the ultrasonic signal is equal to or higher than a predetermined level, that is, whether or not the ultrasonic signal is positioned immediately below the ultrasonic head (5). When it is determined that the level is equal to or higher than the predetermined level, the control signal is supplied to the logical operation unit (24) to perform the logical operation. Then, the logical operation part (24) sequentially compares the count number data with a plurality of count number data stored in advance in the position memory (23), and detects a vehicle corresponding to the matching frequency count number data. It is possible to extract the installation location data of the container and output it as the vehicle current position detection data.

Therefore, by supplying the vehicle current position detection data to a location device (not shown) or the like, the vehicle current position can be displayed on the road map.

Further, as is clear from the above description, since the vehicle detectors are already installed at least on the main highways, it is possible to perform pulse modulation having a unique period on each vehicle detector. It is sufficient, and the required labor can be significantly reduced.

In this case, when the microprocessor is used as the control circuit of the vehicle detector, it is only necessary to replace the conventional control program with a control program capable of performing pulse modulation having a cycle specific to the ultrasonic signal for vehicle detection. Specifically, it is only necessary to replace the memory IC in which the control program is written.

Further, depending on the road network, the installation of vehicle detectors may be sparse, but it is very inconvenient because the vehicle will pass directly below the vehicle detector with a very high probability by traveling to some extent. There is no.

The first aspect of the invention is not limited to the above-described embodiment. For example, instead of radiating a pulse-modulated ultrasonic signal, the amplitude is based on a signal having a frequency unique to the installation position of the vehicle detector. It is possible to radiate an ultrasonic wave signal that has been subjected to modulation, frequency modulation, and the like, and various design changes can be made within the scope of the present invention.

FIG. 4 is a schematic block diagram showing an electrical configuration of a main part of a transmission / reception device on the vehicle detector side adopted in the vehicle current position detection system of the second invention. The clock generation part (31) and the clock generation part. The clock signal output from the unit (31) is used as an input, and the frequency conversion unit (32) that generates a signal of a frequency unique to the installation position (for example, about 27 KHZ) and the signal of the natural frequency are amplified to a predetermined level. And an input / output transformer (34) that supplies the modulation signal amplified by the amplifier (33) to one winding and supplies the signal generated in the other winding to the ultrasonic head. It is configured.

FIG. 5 is a schematic block diagram showing an electrical configuration of a vehicle-side receiving device adopted in the vehicle current position detection system of the invention of FIG. 2, and amplifies a received signal output from the receiving microphone (7). An amplifier (40), a bandpass filter (41) that removes a noise component from the amplified signal, a waveform shaping section (42) that receives the signal output from the bandpass filter (41), and a level determination section. (43), a frequency counter (44) to which the signal output from the waveform shaping section (42) is input, the installation location of the vehicle detector, and frequency count number data corresponding to the installation location are stored in advance. The position memory (45) and the level determination signal from the level determination unit (43) are used as control signals to control the frequency counter (4
4) and a logical operation section (46) for comparing the output signal from the position memory (45) with the output signal.

Therefore, in the case of this embodiment, since the signal of the specific frequency generated in the transceiver on the vehicle detector side is supplied to the ultrasonic head (5), the ultrasonic signal of the specific frequency is always radiated. Will continue.

Then, when the vehicle (1) passes directly under the ultrasonic head (5), the reception level of the ultrasonic signal becomes high, so that the logical operation unit (46) can be operated.
In this case, since the received signal is converted into a rectangular wave by the waveform shaping section (42) and the count number data is generated by the frequency counter (44), the frequency count number data stored in the position memory (45) By comparing, the installation location data of the vehicle detector corresponding to the matching frequency count number data can be extracted and output as the vehicle current position detection data.

Therefore, by supplying the vehicle current position detection data to a location device (not shown) or the like, the vehicle current position can be displayed on the road map.

<Effects of the Invention> As described above, according to the present invention, the characteristic peculiar to the installation position from the ultrasonic signal peculiar to the installation position radiated from the vehicle sensor installed on at least the main highway on the vehicle side. Since the installation position corresponding to the extracted features is set as the current position of the vehicle, the existing vehicle detector can be finely modified without adding new roadside equipment, or All you have to do is replace it. Therefore, the huge cost required to install the roadside equipment can be significantly reduced. Therefore, the system can be constructed easily and extremely economically.

Moreover, since the vehicle detector emits an ultrasonic signal for vehicle detection with considerably high directivity, it does not hinder the original use of the vehicle detector and detects the current position of the vehicle with practical accuracy. it can.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the relationship between a vehicle detector and a vehicle, FIG. 2 is a block diagram showing an example of an electrical configuration of a transceiver device on the vehicle detector side in the invention of FIG. 1, and FIG. FIG. 4 is a block diagram showing an example of an electrical configuration of a vehicle-side receiving device in the invention of FIG. 1, FIG. 4 is a block diagram showing an example of an electrical configuration of a main part of a vehicle-sensor-side transmitting / receiving device in the second invention, FIG. 5 is a block diagram showing an example of an electrical configuration of a vehicle-side receiving device in the second invention. (1) ... vehicle, (5) ... ultrasonic head, (6) ... transmission / reception device, (7) ... reception microphone, (8) ... reception device, (12) ... modulation section, (32) ) …… Frequency converter

Claims (4)

(57) [Claims] 1. An ultrasonic signal for vehicle detection transmitted from a vehicle detector installed at a predetermined position of a road traffic network is modulated unique to the installation position, and a receiver is mounted on the vehicle. The receiver receives the modulated ultrasonic wave signal, and extracts means for extracting a unique modulated signal from the received ultrasonic wave signal, and data corresponding to the plurality of modulated signals and an installation position. By referring to the storage means in which the correspondence relationship is stored and the correspondence relationship stored in the storage means, the installation position stored in association with the data corresponding to the unique modulation signal extracted by the extraction means is stored. Specifying means to specify,
A vehicle current position detection method, comprising: a position setting unit that sets the installation position specified by the specifying unit as the current position of the vehicle. 2. The vehicle current position detection system according to claim 1, wherein the unique modulation is pulse modulation having a unique cycle. 3. The vehicle current position detection system according to claim 1, wherein the unique modulation is based on a signal having a unique frequency. 4. A vehicle detector installed at a predetermined position of a road traffic network emits an ultrasonic signal having a frequency unique to the installation position, and a receiver is mounted on the vehicle. Acquiring means for receiving the ultrasonic signal and acquiring a specific frequency from the received ultrasonic signal,
Corresponding to the unique frequency acquired by the acquisition means by referring to the storage means storing the correspondence relationship between the data corresponding to the plurality of modulated signals and the installation position and the correspondence relationship stored in the storage means. A vehicle current position detection method, comprising: a specifying unit that specifies the installed position stored in the memory; and a position setting unit that sets the installation position specified by the specifying unit as the current position of the vehicle.