JP2008046767A - Location detection device, location detection program and location detection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely detect the location of a vehicle. <P>SOLUTION: After it is decided that a vehicle has entered a down-link zone (S101: YES), whether or not the vehicle has left the down-link zone is decided (S106), and when it is decided that the vehicle has left the down-link zone, location decision notification indicating that the vehicle has left the down-link zone is output (S107). Thus, it is possible to grasp the timing in which the vehicle has left the down-link zone, and to grasp the relative location of an optical beacon and the vehicle. As a result, it is possible to precisely detect the location of the vehicle. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to vehicle position detection using an infrastructure such as an optical beacon.

  2. Description of the Related Art Conventionally, VICS (Vehicle Information and Communication System), which is a system that transmits road traffic information processed at a center in real time and displays the information on an in-vehicle device such as a navigation device, is known. In VICS, two-way communication using infrared rays is performed with a vehicle by using an optical beacon installed on a traveling path of the vehicle, and road traffic information is provided to the vehicle.

Patent Document 1 discloses a configuration for detecting the number of signals present on a route to a guidance target intersection using an optical beacon.
JP 2000-346666 A

  In recent years, as a safe driving support information providing service, studies are being made in various directions to provide emergency information collected by roadside sensors to a vehicle immediately and support safe driving of drivers and pedestrians. For example, a safe driving support system (DSSS: Driving Safety Support System) has been studied as a service using an optical beacon.

  With such a flow, it may be possible to control the timing of information display to the driver based on the position of the vehicle, or to use the position of the vehicle as a braking timing, which has not been considered much in conventional VICS. The accuracy of vehicle position detection tends to be regarded as important.

Note that the configuration described in Patent Document 1 is merely for detecting the number of signals present on the route to the guidance target intersection, and cannot accurately detect the position of the vehicle.
The present invention has been made in view of these problems, and an object thereof is to accurately detect the position of a vehicle.

The position detection apparatus according to claim 1 of the present invention, which has been made to achieve the above object, is used in a state of being mounted on a vehicle, and includes a receiving means and a detecting means.
In the position detection apparatus of the present invention, the receiving means receives information transmitted from the roadside device using infrared rays. And a detection means detects the timing which the vehicle left from the receiving zone which can receive the information from a roadside machine based on the information received by a receiving means.

According to the position detection device having such a configuration, the position of the vehicle can be detected with high accuracy.
That is, information transmission using infrared rays (infrared communication) has higher directivity than information transmission using radio waves, and a reception zone, which is an area where information can be received, is formed relatively accurately. In general, in a road-to-vehicle system that performs infrared communication, an information transmission unit of a road device is disposed above the vehicle, and transmits information to the vehicle at a position before the vehicle passes the road device. That is, the reception zone is located in front of the road unit with reference to the traveling direction of the vehicle.

  For this reason, the timing at which the vehicle exits the reception zone is higher than the timing at which the vehicle enters the reception zone, and the elevation angle of the information transmission unit of the road unit viewed from the vehicle side is increased, and the information transmission unit of the vehicle and the road unit And the distance is shortened.

  As described above, the elevation angle of the information transmission unit of the road unit viewed from the vehicle side is increased, thereby reducing the influence of the variation in the information reception position (position in the vertical direction) on the vehicle side on the position along the traveling direction of the vehicle. can do. In addition, since the distance between the vehicle and the information transmission unit of the on-road unit is shortened, the influence due to the difference in the transmittance of the glass of the vehicle and the variation in the direction of the optical axis can be reduced.

  Therefore, according to the position detection device of the present invention, it is possible to detect the timing at which the vehicle leaves the reception zone, in other words, the relative position of the vehicle with respect to the road unit relatively accurately. As a result, the position of the vehicle can be detected with high accuracy.

Here, as a roadside machine, for example, as described in claim 2, an optical beacon is put into practical use, and the present invention can be configured using a road-to-vehicle system using an optical beacon.
By the way, it is conceivable that the timing at which the vehicle leaves the reception zone is, for example, a timing at which a state in which information transmitted from a road device can be received is changed to a state in which the information cannot be received. However, in reality, it does not change instantaneously from a state where normal information can be received to a state where no information can be received at all, but a state where normal (abnormal) information is received from a state where normal information can be received. Then, the state shifts to a state where no information can be received.

  Therefore, in the position detection device according to the third aspect, the detection means determines that the vehicle has left the reception zone when a predetermined number of abnormal information is continuously received by the reception means. In this way, it is possible to detect the timing of transition from a state in which normal information can be received to a state in which normal information cannot be received.

  In particular, since it is a condition that a predetermined number of abnormal information has been continuously received, it is possible to prevent erroneous determination that the vehicle has left even though the vehicle has not left the reception zone. . That is, for example, abnormal information may be received despite the presence of a vehicle in the reception zone due to the influence of a wiper, etc., so it is erroneously determined that the vehicle has left the reception zone in such a case. It is possible to set a predetermined number so as not to.

  Next, the position detection program according to claim 4 is used in a state where it is mounted on a vehicle, and functions as a detection means by using a computer provided with reception means for receiving information transmitted from a road unit using infrared rays. It is something to be made. Here, the detecting means is means for detecting the timing at which the vehicle leaves the receiving zone that can receive information from the on-road equipment based on information received by the receiving means.

  According to such a position detection program, the position detection apparatus according to claim 1 can be constructed using a computer, and thereby the above-described effects can be obtained. In particular, the program can be distributed using a network or the like, and since the replacement of the program is easier than the replacement of the components, the function of the position detection device can be easily improved.

  Next, a position detection method according to claim 5 is a position detection method for detecting the position of a vehicle, which receives information transmitted from a road device using infrared rays, and based on the received information, The timing at which the vehicle leaves the reception zone where information from the vehicle can be received is detected.

  According to such a position detection method, the position of the vehicle can be accurately detected for the reason described above.

Embodiments to which the present invention is applied will be described below with reference to the drawings.
[1. overall structure]
FIG. 1 is a block diagram illustrating a configuration of an in-vehicle device 10 as a position detection device according to an embodiment.

  The in-vehicle device 10 is used in a state where it is mounted on a vehicle, and both use infrared rays (specifically, near infrared rays) with an optical beacon as a road unit installed on a traveling road of the vehicle. It is for performing communication. As shown in FIG. 1, the in-vehicle device 10 includes an optical beacon antenna (communication terminal) 20 and a navigation ECU (Electronic Control Unit) 30, which are respectively transmitted and received signal lines 11, 12 is connected. In the present embodiment, the vehicle-mounted device 10 is described as being built in the navigation device, but the vehicle-mounted device 10 may be externally attached separately from the navigation device.

  The optical beacon antenna 20 includes an LED 21 that is a light emitting element for transmission, a photodiode (PD) 22 that is a light receiving element for reception, and interface circuits 23 and 24, respectively. The optical beacon antenna 20 is installed on the dashboard of the vehicle in order to facilitate two-way communication with the optical beacon. The installation position of the optical beacon antenna 20 is not limited to this.

  The navigation ECU 30 is mainly configured by an optical beacon transmission / reception processing circuit 40 configured by an ASIC (Application Specific Integrated Circuit) and the CPU 50. The optical beacon transmission / reception processing circuit 40 includes a transmission port 41 for outputting uplink data to the LED 21 of the optical beacon antenna 20 and a reception port 42 for inputting downlink data received by the PD 22.

  Uplink data output from the transmission port 41 is converted by the interface circuit 61 and transmitted to the optical beacon antenna 20 via the transmission signal line 11. On the other hand, the downlink data received by the optical beacon antenna 20 is transmitted to the navigation ECU 30 via the reception signal line 12, converted by the interface circuit 62, and input to the reception port 42 of the optical beacon transmission / reception processing circuit 40.

  The CPU 50 executes various arithmetic processes for realizing a map display function and a route search function in the navigation ECU 30. In addition, the CPU 50 has a function of writing and recording data as necessary to the SRAM 70 in which the program is installed.

[2. Optical beacon communication zone]
Next, a communication zone formed by the light beacon projector / receiver 80 will be described with reference to FIG.

  The light beacon light emitter / receiver 80 is installed directly above the traveling path of the vehicle and performs two-way communication using near-infrared rays with a vehicle (on-vehicle device 10) existing in a communication zone formed on the traveling path. It is configured as follows. Specifically, an uplink (UL) zone in which information can be transmitted from the vehicle to the projector / receiver 80 and a downlink (DL) zone in which information can be transmitted from the projector / receiver 80 to the vehicle are formed. The uplink zone is formed narrower than the downlink zone, and the optical beacon antenna 20 enters the zone of the uplink zone and the downlink zone as the vehicle travels, and after exiting the uplink zone, the downlink You will leave the zone. Further, both the uplink zone and the downlink zone are formed at positions before the light projector / receiver 80 with reference to the traveling direction of the vehicle.

  The in-vehicle device 10 of the present embodiment pays attention to the positional relationship between the projector / receiver 80 and the communication zone (specifically, the downlink zone), and performs highly accurate position evaluation based on the timing when the vehicle exits the communication zone. It is realized.

[3. Position assessment process]
Next, the position evaluation process executed by the CPU 50 of the navigation ECU 30 will be described using the flowchart of FIG. This position evaluation process is executed at a predetermined cycle (for example, at intervals of several tens of milliseconds).

  When the position evaluation process is started, first, in S101, it is determined whether or not the vehicle has entered the downlink zone. Specifically, when normal information (frame) is received from the optical beacon, it is determined that the vehicle has entered the downlink zone.

If it is determined in S101 that the vehicle has not entered the downlink zone, the position evaluation process is terminated.
On the other hand, if it is determined in S101 that the vehicle has entered the downlink zone, the process proceeds to S102, and processing for transmitting information such as the vehicle ID (identification information unique to the vehicle) from the vehicle to the optical beacon (uplink) )I do.

  Subsequently, in S103, it is determined whether or not the uplink is successful. Specifically, when information on a response to the information transmitted in S102 (information including the transmitted vehicle ID) is received, it is determined that the uplink is successful.

If it is determined in S103 that the uplink has not been successful, the process proceeds to S104, and it is determined whether or not the uplink has been performed a predetermined number of times (a preset number of times).
If it is determined in S104 that the uplink has not been performed a predetermined number of times, the process returns to S102 and uplink is performed.

On the other hand, if it is determined in S104 that the uplink has been performed a specified number of times, the process proceeds to S106.
If it is determined in S103 that the uplink is successful, the process proceeds to S105, and processing for receiving response information for the uplink is performed. Thereafter, the process proceeds to S106.

  In S106, it is determined whether or not the vehicle has left the downlink zone. If it is determined that the vehicle has left, the process proceeds to S107. Specifically, it is determined that the vehicle has left the downlink zone when a predetermined number (three in this embodiment) of abnormal information (abnormal DL frames) is continuously received.

  In S107, a position confirmation notification to the effect that the vehicle has left the downlink zone is made, and the position evaluation process is terminated. In this embodiment, a position confirmation notification is sent to an application for detecting the position of the vehicle. By doing in this way, the timing at which the vehicle leaves the downlink zone can be grasped, and thereby the relative position between the optical beacon and the vehicle can be grasped. For this reason, if the position information is acquired from the optical beacon and the position confirmation notification is made at the timing when the vehicle leaves the downlink zone, the position of the vehicle can be detected with high accuracy on the side receiving the position confirmation notification.

[4. Effects of the embodiment]
As described above, the in-vehicle device 10 of the present embodiment detects the timing at which the vehicle leaves the downlink zone based on information transmitted from the optical beacon using near infrared rays. Here, since the communication zone of the optical beacon is formed relatively accurately, the relative position between the optical beacon and the vehicle can be relatively accurately grasped based on the timing when the vehicle leaves the downlink zone. As a result, the position of the vehicle (for example, the distance to the intersection) can be detected with high accuracy.

  In particular, in the in-vehicle device of the present embodiment, the timing of leaving the downlink zone is detected, so that the position of the vehicle can be detected with high accuracy. That is, as the detectable timing, in addition to the timing to exit from the downlink zone, the timing to enter the downlink zone, the timing to enter the uplink zone, and the timing to exit from the uplink zone can be considered. Among these positions, the position of exiting the down zone is the position where the elevation angle of the light projector / receiver 80 viewed from the optical beacon antenna 20 is the largest. In other words, the influence on the position along the traveling direction of the vehicle due to the difference in the vertical position of the optical beacon antenna 20 is minimized. Therefore, even if the installation height of the optical beacon antenna 20 is different between the large vehicle and the small vehicle, the influence on the position detection accuracy due to this can be reduced. In addition, the position to exit from the downlink zone is the position where the distance between the optical beacon antenna 20 and the light projector / receiver 80 is the shortest. Therefore, the influence by the difference in the transmittance of the vehicle windshield (the transmittance of near infrared rays) can be reduced. Moreover, the influence by the difference in the attachment angle (direction of an optical axis) of the optical beacon antenna 20 can also be made small.

  Furthermore, in the in-vehicle device 10 of the present embodiment, it is determined that the vehicle has left the downlink zone when a predetermined number of abnormal information is continuously received. For this reason, it is possible to prevent erroneous determination that the vehicle has exited even though the vehicle has not exited the downlink zone.

[5. Correspondence with Claims]
In the in-vehicle device 10 of the present embodiment, the optical beacon antenna 20 corresponds to the receiving means of the present invention, and the navigation ECU 30 (specifically, the CPU 50) that executes the process of S106 in the position evaluation process (FIG. 3). Corresponds to the detection means of the present invention.

[6. Other forms]
As mentioned above, although one Embodiment of this invention was described, it cannot be overemphasized that this invention can take a various form.

  That is, in the in-vehicle device 10 of the above-described embodiment, it is determined that the vehicle has left the downlink zone when a predetermined number of abnormal information is continuously received. However, the present invention is not limited to this. . For example, it may be determined that the vehicle has left the downlink zone when the information of the optical beacon antenna 20 is not received.

It is a block diagram which shows the structure of the vehicle-mounted apparatus of embodiment. It is explanatory drawing of the communication zone formed with the light projector / receiver of an optical beacon. It is a flowchart of a position evaluation process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... In-vehicle apparatus, 11 ... Transmission signal line, 12 ... Reception signal line, 20 ... Optical beacon antenna, 21 ... LED, 22 ... Photodiode, 23, 24 ... Interface circuit, 30 ... Navigation ECU, 40 ... Optical beacon transmission / reception processing Circuit 41 ... Transmission port 42 ... Reception port 61,62 ... Interface circuit

Claims (5)

A position detection device used in a state of being mounted on a vehicle,
Receiving means for receiving information transmitted from the roadside device using infrared rays;
Detecting means for detecting the timing at which the vehicle exits from a receiving zone capable of receiving information from the road unit based on information received by the receiving means;
A position detection device comprising: The position detection device according to claim 1, wherein the reception unit is configured to receive information from an optical beacon as the road device. 3. The detection unit according to claim 1, wherein the detection unit determines that the vehicle has left the reception zone when a predetermined number of abnormal information is continuously received by the reception unit. 4. Position detection device. A computer equipped with a receiving means for receiving information transmitted using infrared rays from a road device, used in a state mounted on a vehicle,
A position detection program that functions as a detection unit that detects a timing at which the vehicle exits from a reception zone capable of receiving information from the road unit based on information received by the reception unit. A position detection method for detecting the position of a vehicle,
Position detection characterized in that it receives information transmitted from the road unit using infrared rays, and detects the timing at which the vehicle exits from a reception zone capable of receiving information from the road unit based on the received information. Method.

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