JPS62279496A - Current running position detector for vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of the Invention) The present invention relates to a device that detects the current traveling position of a vehicle using radio waves transmitted from a roadside transmitting station.

(Background of the Invention) In a system that calculates and displays the vehicle's current running position relative to a reference position in the process of integrating the running direction and distance of the vehicle, this type of device is used to calculate the current running position. Modifications have been made, and in the conventional device of the system shown in Japanese Patent Application Laid-Open No. 58-16283, when the transmission radio waves from the roadside transmitting station are received, the installation position of the roadside transmitting station extracted from the received signal is It is detected and set as the current driving position.

However, since the radio waves transmitted by the roadside transmitting station are received even several hundred meters before the installation position, in this conventional device, the current running (1 position detection setting) is performed at the receiving position, and therefore the detection position and the actual position are There is a difference between
Therefore, there is a problem in that the position calculation accuracy of the above system is reduced.

(Object of the invention) The present invention has been made in view of the above-mentioned conventional problems, and
The purpose is to provide this type of device that can detect the current traveling position of a vehicle with high precision.

(Structure of the Invention) In order to achieve the above object, an apparatus according to the present invention is structured as shown in FIG.

In the figure, radio waves are transmitted from roadside transmitting station a in the direction of each road, and these radio waves include information indicating the question position of roadside transmitting station a (installation position information) and information identifying each road (road identification information).

Each radio wave transmitted by the roadside transmitting station a is received by the receiving means, and the station installation position information extraction means C extracts the installation position information from the received signal.

The field strength monitoring means d monitors the field strength of the transmitted radio waves, and the road identification information extraction means e extracts the road identification information of the road to which the radio waves were transmitted from the received signal of the transmitted radio waves with the highest field strength. ing.

Further, the road orientation storage means f stores road orientations corresponding to the roads indicated by each road identification information, and the current driving position orientation setting means q extracts new road identification information using the road identification information extraction means e. When the roadside transmitting station a is installed, the installation position of the roadside transmitting station a indicated by the installation position information is set as the current driving position of the vehicle, and the stored road orientation corresponding to the road identification information is set as the current driving orientation of the vehicle.

(Description of Embodiments) Hereinafter, preferred embodiments of the apparatus according to the present invention will be described based on the drawings.

As shown in Figure 2 (A>, (B)), 10 sign posts are erected at intersections and roadsides, and there are approximately 24 sign posts across Japan.
It is said that there are 10,000.

A transmitting antenna (Yagi antenna) 12 is directed from the sign post 10 toward each road, and the maximum reach of its transmitted radio waves is about 200 m, and its width in the width direction is 10 to 50 m, the same as the road width.

A transmitter 14 is attached to the signpost 10, and the transmitter 14 is shown in FIG.

In the figure, the antenna 12 is supplied with power by a transmitting circuit 16, and a storage circuit (ROM in this case) 18 stores the transmission contents shown in FIG.

As can be understood from FIG. 4, the radio waves transmitted by the sign post 10 contain a number for identifying the sign post.

Coordinate data (XSI), YSI) indicating the installation location
).

and road code (binary code), and its installation location is said to have originated near the southern tip of Kyushu.

Based on these coordinates, the installation position of the sign post 10 is specified in units of 10 m square, and therefore, the position is extremely accurate.

Roughly speaking, the road code is used as identification information for each road. For example, in Figure 2 (A>), the road code (1, 1), (
0, O), (0, 1>, (1, O), road 15A,
15B and 150.15D are road codes (1, ○) in FIG. 2 (B).

(0,0> indicates roads 15E and 15F, respectively.

In addition, these radio waves are sent to each antenna 12 of the sign post 10.
The information is transmitted sequentially in a time-division manner at predetermined intervals, and the transmission interval is 100 seconds.

Further, the transmission signal including the data shown in FIG. 4 is FM modulated at 40QMH2 by the transmission circuit 16, and the power feeding output of the transmission circuit 16 to the antenna 12 is set to 20 to 30 mW.

The radio waves transmitted from the nine post 10 described above are received by the receiving antenna 22 installed on the vehicle 20 in FIG. 5, and as understood from the figure, the receiving antenna 22 is non-directional. .

For this reason, the receiving antenna 22 receives all radio waves transmitted from the sign post 10 to each road, and since the antenna 12 is directed toward each road, The received strength of the radio waves transmitted towards the station is the highest among the transmitted radio waves.

FIG. 6 shows a device that is mounted on a vehicle 20 and displays its current traveling position, and a receiving circuit 24 demodulates the received signal from the antenna 22.

Then, in this receiving circuit 24, X, Y coordinate data (XS,
YS) and the road code are extracted together with data indicating the sign post number, and are provided to the receiving interface 26.

Further, the direction sensor 28 (in this embodiment, it is a yaw rate sensor, but a geomagnetic sensor shade can also be used) detects the running direction of the vehicle 20, and the distance sensor 13o indicates that the vehicle 20 has traveled a predetermined distance. A distance pulse is obtained each time the vehicle travels.

Rough direction sensor 28 detection signal and distance sensor 30
The distance pulses are given to the sensor interface 32, and the CPU 34 processes the data taken in from the sensor interface 32 to determine the current traveling position of the vehicle 20 relative to the reference position.

Its current running position (hereinafter also referred to as relative position) is stored in an external memory (compact disk, ROM or ROM card).
30 is set in the VRAM 38 together with map information prepared in advance, and the relative position thereof is displayed on the CRT 40 together with the travel trajectory on the map.

Roughly, a touch panel 42 is provided on the front surface of the CRT 40, and its operation signals are given to an input operation section 46 together with a switching signal from a main switch 44.

A reference position for the relative position is set in the CPU 34 based on the data from the input operation section 46, and as a result, the CRT 40
Then, the traveling trajectory of the vehicle 20 is displayed on the map starting from the reference position.

In addition, the CPU 34 determines the installation position (XSp,
Ysp) is set as the reference position of the relative position,
Furthermore, when the passing of the sign post 10 is confirmed while the vehicle 20 is running, the relative position is changed to the installation position (XSI), YSp).

Here, the electric field strength detection circuit 48 detects the electric field strength of each radio wave transmitted from the sign post 10, and the detection signal is sent to the CPU 3 via the receiving interface 26.
4 is given.

Then, in the CPU 34, when the road code of the one with the maximum field strength among the radio waves transmitted from the sign bosses 1 to 10 becomes a new one, the vehicle 20 is set to the sign boss r-10.
It is determined that the sign post 10 has passed the set position (XSI), YSI)).
is detected and set as the position (relative position) of the vehicle at the time of this determination.

In addition, the external memory 49 stores data (hexadecimal) indicating the road direction corresponding to the road indicated by each road code, as shown in the table below. The direction is shown.

For example, in FIG. 2, roads 15A and 15B.

The directions of 15C, 15D, 15E, and 15F are 270' and O' according to the road direction data for them.

90', 180', and 180° Q6, respectively, and the vehicle 20 travels toward the sign post 10 on the road indicated by the road code in the direction indicated by the road orientation data.

Table 1 Note that the CPU 34 is composed of an 8-bit microprocessor, and its calculations are performed using the RAM 52 according to the contents stored in the ROM 50.

This embodiment has the above configuration, and its operation will be explained below.

When the ON operation of the main switch 44 is confirmed (affirmative determination in step 100 in the general flow of FIG. 7), it is determined whether or not the radio wave transmitted from the sign post 10 is being received (step 102).

If reception of the sign post transmission radio wave is not confirmed (negative determination in step 102), departure point setting processing (step 104) is performed.

In this process, FIGS. 8(A), (B), and (C).

(D) is displayed according to the operation of the touch panel 42 according to the procedure shown in FIG.
), (B), (C), (D), and (E) are used, and as a result, the starting position of the vehicle 20 is specified.

Furthermore, the departure direction of the vehicle 20 is taught to the CPU 34 by operating the input operation section 46 .

Also, when the main switch 44 is turned on, the sign post 1
If reception of the transmitted radio wave of 0 is confirmed (affirmative determination in step 102), departure point specifying processing using the sign post 10 is performed (step 106).

In this process, the installation position data (XSI), YSI) of the nine posts 10 in FIG.
(A> Step 108), the position data (X, Y) of the current position register indicating the current traveling position of the vehicle 20 is rewritten to the position data (Xsp, Ysp) (Step 110).

Then, the direction data corresponding to the road road code of the transmitted radio wave with the highest field strength is read from the external memory 49 (step 109 in FIG. 11(B)), and the data in the angle register indicating the current traveling direction of the vehicle 20 is It is rewritten to direction data (step 111).

As described above, the touch panel 42 and the input operation section 4
6 manually (step 104) or automatically using the radio waves transmitted by the sign post 10 and the external memory 49 (step 106), when the departure point and departure direction of the vehicle 20 are specified, the departure point is determined. Map data indicating an enlarged display map for one screen to which it belongs and maps for eight surrounding screens are read from the external memory 36 to the VRAM 38 (step 112).

Next, display processing of the current position and traveling trajectory (step 114)
) is started, and in this process, the process shown in FIG. 12 is repeatedly performed every time a distance pulse from the distance sensor 20 is generated.

In the process shown in the figure, the running direction θ of the vehicle 20 detected by the direction sensor 28 is read (step 116), and the vehicle running direction θ is transferred to the angle buffer of the RAM 52 (step 117). In addition, in that angle buffer, vehicle 2005
The latest running direction θ is accumulated over the 0 meter running section.

Then, the distance ΔD CO3θ, Δ□Sinθ that the vehicle 20 moved in the X direction and the Y direction during the generation interval of the distance pulse
is calculated (step 118), and the amount of movement is calculated using data (X, Y) indicating the position of the vehicle 20 relative to the MU fixed departure point.(Δ[)cosθ.

ΔDSinθ) is integrated and its new relative position (X,
The contents of the current position register are rewritten to Y) (step 120).

Roughly speaking, the contents of this current position register (X, Y) are VRA
It is transferred to M38 (step 122) and its position (X,
Y) is displayed on the CRT 40.

As a result, the current traveling position (X
, Y) and the travel trajectory are displayed on the map (see step 114 in FIG. 7).

Thereafter, when the current position of the vehicle 20 determined by the process shown in FIG. (
Step 124), the display process of the current driving position and the driving trajectory (step 114), and the map update process (step 124) are repeatedly performed until the main switch 44 is turned off (negative determination in step 126). It will be done.

In the process of displaying the current position and travel trajectory (step 114), the process shown in FIG. 13 is repeated at regular intervals.

In this process, the reception of the signpost transmission radio waves is monitored (step 128>, and if the reception is confirmed (
(affirmative determination in step 128), sign post 1
No. 0 is read (step 130).

Then, it is determined whether or not the sign post number is the same as that in the previous processing cycle.Step 132
), if it is confirmed that they are the same (affirmative determination in step 132), all road codes extracted from each radio wave are read (step 134).

Once signal strength registers are prepared for each of the road codes (step 136), the field strength of each transmitted radio wave is read (step 138).

Next, when it was confirmed that one of the electric field strengths was higher than that in the previous '2a Rishumei when the vehicle approached in Signbost 10/\ (affirmative determination in step 140), the electric field strength became higher. Only the contents of the signal strength register are rewritten to that strength (step 142).

When the end of the process (step 142) is confirmed (affirmative determination in step 144), the road code with the highest electric field strength is selected (step 146), and this code is the same as the code selected in the previous process cycle. It is determined whether or not (step 148).

If it is confirmed that these road codes are not the same (negative determination at step 148), it is determined whether the maximum signal code register into which the road code with the highest electric field strength is written is in the clear state. A determination is made (step 150).

At that time, if this register is cleared and a road code is selected for the first time (step 146) (affirmative determination in step 150), the road code of the transmitted radio wave with the highest field strength is stored in that register. The road direction data of the transmitted radio wave with the highest field strength is then read and written into the angle register (step 153).

Further, if the road code has already been written in the maximum signal code register (negative determination at step 150), it is determined that the vehicle 20 has passed 'Impost 'IO'2, and the sign The installation position data (XSI), YSI) of the post 10 is read (step 15).
4).

Then, the position data (X, Y) of the current position register indicating the current traveling position of the vehicle 20 is rewritten to position data (Xsp, Ysp) of the power mortar ± impost installation position (step 156), and the contents of the current position register are rewritten. is VRAM38
(step 158), and each of the registers mentioned above is cleared (step 160).

When the rough data transfer (step 158) is performed, a correction value calculation process for the detected direction (step 16) is performed.
2) is performed.

FIG. 14 shows the contents of this process (step 162), in which the sign post number and the road code of the maximum signal code register are first read (step 164).
.

Using them, the road direction data is stored in the external memory 49.
The direction indicated by the data is the direction of the road on which the vehicle 20 is traveling toward the sign post 10.

Roughly speaking, all the travel directions θ of the 50-meter travel section are read out from the angle buffer described above (Step 117 in Figure 12), and their average value is determined (Step 166). The road orientation indicated by the data is compared (step 168).

At that time, if the difference between them is more than a predetermined value (for example, if the error in the driving direction θ with respect to the road direction is 10% or more)
In step 170, it is determined that the accumulated error in the running direction θ is unacceptable, and this difference is registered as the correction value α for the running direction θ (step 172).

Briefly, in the current position calculation process shown in FIG. 12, when the traveling direction θ is read (step 116), the detected direction is corrected by adding this correction value α to the traveling direction θ (step 174). ), the current position of the vehicle 20 is determined using the accurate traveling direction θ obtained by the correction.

Incidentally, when the vehicle 20 enters the receivable area of the sign post transmission radio wave for the first time (negative determination in step 132), the contents of the register that stores the sign post number are updated to the sign boss 1 to number. (Step 1
76), signal strength register cleared (step 178)
After that, the above operations are repeated.

As explained above, according to this embodiment, the vehicle 20 with the highest field strength among the radio waves transmitted by the signpost is extracted from the road code included in the radio waves transmitted. When the road code is different, it is determined that the vehicle 20 has passed through the signpost installation position, and at that time, the data (X, Y) indicating the current driving position of the vehicle 20 is Since the data indicating the position (Xsp, Ysp) is corrected, each time the vehicle 20 passes each sign post 10, the accurate current driving position (
X, Y) are detected and set.

Therefore, the current traveling position (X, Y) and its trajectory can be accurately displayed on the map, making it possible to reliably guide the vehicle 20 to its destination.

Further, according to this embodiment, the sign post installation position can be changed to the vehicle 2.
0 passes, the direction of the road on which the vehicle 20 is traveling is read from the external memory 49, and the vehicle 2
The driving direction θ is set as 0, and the correction value α of the driving direction θ with respect to the road direction is determined, and the driving direction θ is corrected by the correction value α, so that the cumulative error of the detected direction is It becomes possible to more accurately display the current traveling position (X, Y) and its trajectory.

Note that when a geomagnetic azimuth sensor is used instead of the direction sensor 28, errors in the detected azimuth due to disturbances in the terrestrial magnetism and magnetization of the vehicle body are absorbed every time the sign post 10 passes.

In addition, as shown in FIG.
4. Transmission circuit 56. By adding a transmitting antenna 58 to the device of this embodiment, it becomes possible to use this device in an AVM system.

Further, in this embodiment, the traveling position and traveling trajectory of the vehicle 20 are displayed on the map, but
2, etc., the present invention is applied to a vehicle route guidance device (or vehicle route guidance device) that instructs the vehicle 20 in the direction in which the vehicle 20 should pass the intersection before the vehicle 20 reaches the intersection on the set route. is also suitable.

(Effects of the Invention) As explained above, according to the present invention, when the j-neck identification information extracted from the radio waves having the highest field strength among the radio waves transmitted from the roadside transmitting station becomes different, The installed position of the roadside transmitting station that is detected from the transmitted radio waves is detected and set as the vehicle's current position, and the road direction read using the road identification information of the radio wave is set as the vehicle's driving direction. It becomes possible to measure the current traveling position with extremely high accuracy.

[Brief explanation of drawings]

Figure 1 is a complaint correspondence diagram, Figure 2 is a diagram of the installation position of the sign post and transmission directional characteristics β1, and Figure 3 is a diagram of the transmitter 14.
Fig. 4 is an explanatory diagram of the configuration of the signpost transmission radio wave, Fig. 5 is an explanatory diagram of the directivity characteristics of the vehicle side receiving antenna, and Fig. 6 is a block diagram showing an example of a device to which the present invention is applied. , FIG. 7 is a flowchart for explaining the operation of the embodiment in FIG. 6, FIG. 8 is an illustration for explaining an example of display by operating the touch panel in FIG. FIG. 10 is an explanatory diagram of the storage contents of the external memory in FIG. 6, FIG. 11 is a flowchart for explaining the departure point identification process using the signpost, FIG. 12 is a flowchart for explaining the current position calculation process, and FIG. 13 is the signpost 1 ~
Flowchart for explaining current position calculation process, No.
FIG. 14 is a flowchart for explaining the correction value calculation process for the detected orientation, and FIG. 15 is a block diagram showing an example of a device to which the present invention is applied. 10... Sign post 12... Transmitting antenna 14... Transmitter 20... Vehicle 22... Receiving antenna 24... Receiving circuit 2B... Direction sensor 34... CPU 36... External memory 38...VRAM 40...CRT 42...Touch panel 44...Main switch 46...Input operation section 48...Field strength detection circuit 49...External memory 50...ROM 52 ...RAM 56...Transmission circuit 58...Transmission antenna patent applicant Nissan Motor Co., Ltd.] Agent: Patent attorney Shigenori Wada! , :゛, j:;1-2! Figure 1 Figure 8 Do8 No (D) Figure 11 + Al Figure 12

Claims (1)

[Claims] (1) Receiving means for receiving radio waves transmitted in the direction of each road from the roadside transmitting station; station location information extraction means for extracting the installation location information of the roadside transmitting station from the received signal; and monitoring the electric field strength of the transmitted radio waves. a road identification information extraction means for extracting road identification information of the road to which the radio wave was transmitted from the received signal of the transmitted radio wave having the highest field strength; road orientation storage means for storing a road orientation based on the road orientation; A current traveling position detecting device for a vehicle, comprising: current traveling position/direction setting means for respectively setting a stored road direction as a traveling direction of the vehicle.