JPS63222215A - Position detector for vehicle - Google Patents

Abstract

PURPOSE:To accurately detect a position, by a method wherein the present positions calculated by a range finder and magnet on a vehicle are stored and averaged at every signal from the transmitting station on a road side and the position data when the vehicle issues to the outside of a receiving zone is corrected on the basis of the position data of the transmitting station. CONSTITUTION:A key input part 205 is operated to read map data from an external memory apparatus 206 and a scheduled course is displayed on a CRT 200. A CPU 201 takes-in the data of a distance sensor 202 and earth magnetism azimuth sensor 203 through a sensor interface 204 to operate the present position. The present position is stored each time when the radio signal of a definite time interval from the sign post provided on the road side of a running course is inputted to the CPU 201 through an antenna 201, a receiving circuit 211 and a receiving interface 212. The position data stored in the receiving zone of the signal from the sign post by a vehicle are averaged. The average value before the vehicle issues from the receiving zone is added to the position data of the sign post and corrected to be displayed on the CRT 200. By this method, a position is accurately detected.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention is directed to a roadside transmitting station (hereinafter referred to as a "sign post").
The present invention relates to a device that detects the current position of a vehicle using radio waves received from a vehicle.

(Prior art) Conventionally, as a device for detecting the current position of a vehicle,
No. 8-16283 is known.

In this known example, a vehicle is equipped with a geomagnetic direction sensor and a distance sensor, and also includes means for correcting the current value of the vehicle based on radio waves transmitted from a sign post.

(Problem to be solved by the invention) By the way, in the conventional position correction using a sign post, the reach range of the radio waves from the sign post, that is, the radio wave reception area is several hundred meters, so the sign post There was a problem in that position correction was performed based on the received radio waves at the position before the sign post was installed, and an error occurred due to the difference between the reception position and the installation position of the sign post. (Objective of the invention) The present invention has been made in view of the above problems, and
The purpose is to provide a vehicle position detection device that can accurately correct the current position using a sign post.

(Configuration of the Invention) In order to achieve the above object, a vehicle position detection device according to the present invention is configured as shown in FIG.

In the figure, the current position detecting means a detects the current position of the vehicle using a geomagnetic azimuth sensor and a distance sensor.

The position data storage means stores the information of the current position detection means a from the time when the vehicle entered the radio wave reception range of the roadside transmitting station C.

Roughly speaking, when the vehicle moves out of the radio wave reception area of the roadside transmitting station C, the average position calculation calculation means d averages the X and Y components of the information stored in the storage means.

In addition, the vector calculation means e calculates a moving pattern 1 to 1 of the current position relative to the average position from the average position from the average position calculation means d and the position when the vehicle goes out of the radio wave reception area of the roadside transmitting station C. Calculate.

Then, the position correction means f corrects the position of the vehicle by adding the vector obtained from the vector calculation means e to the position data of the sign post.

(Function) In the present invention, the average position within the radio wave reception area from the sign post is determined, the movement vector of the position when going outside the radio wave reception area is calculated, and this movement vector is added to the position data from the sign post. The position of the vehicle is then corrected.

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

FIG. 2 shows a block diagram of the present invention, in which the current travel position and travel trajectory of the vehicle are displayed on a map to provide travel guidance.

These displays are performed on a display section 200 composed of a CRT or the like, and the current traveling position of the vehicle is determined by a CPU 201. In this CPU 201, the distance sensor 2
02 and the detection signals from the geomagnetic direction sensor 203 are input via the sensor interface 204, and are integrated and processed to determine the current position of the vehicle relative to the reference position. Note that the reference position can be given to the CPU 201 from a key input unit 205 that includes a keyboard or the like.

Note that the map data displayed on the display unit 200 is stored in an external storage device 20 such as a compact disk device or ROM.
The map stored in the VRAM 207 and displayed on the display unit 200 is displayed via the VRAM 207.゛Furthermore, the processing of the CPU 201 is
According to the contents stored in the system ROM 208, R
Display control of the display unit 200 is performed using the AM 209.

In the figure, 210 is a receiving antenna for receiving radio waves transmitted from a sign post, which will be described later.The signal received by this receiving antenna 210 is processed by a receiving circuit 211 such as amplification, and then sent via a receiving interface 212. It is designed to be input to the CPU 20'l.

FIG. 3 shows the configuration of the sign post 300,
This sign post 300 has a storage circuit 301 that stores transmission data. An omnidirectional transmitting antenna 302 that transmits radio waves containing the transmitted data, and this transmitting antenna 3
It is composed of a transmitting circuit 303 for transmitting from 02.

Furthermore, FIG. 4 shows the contents of the transmission from the sign post 300, and the number and X and Y coordinate position of the block area to which the sign post 300 belongs are included as the contents of the transmitted radio wave. As shown in FIG. 5, this transmission radio wave is repeatedly oscillated during 100 m5ec, including transmission and pauses. Therefore, if the vehicle transit time within the radio wave reception area is T m5ec, then T/1
The number of signals converted into an integer of 00 (rounded down to the decimal point) will be received.

Note that the transmitted radio waves with this content are modulated at several hundred KHz, and the installation interval of the sign posts is 2 to 5 km.

The operation of this embodiment will be explained below using a flowchart.

The flowchart in FIG. 6 is a general flow,
First, as initial processing, flags and counters are cleared and the center position of the geomagnetic azimuth sensor is set (step 600). Next, the current traveling position of the vehicle is set by operating the key human power section 205 (step 602).
), a map to which a position serving as a reference for vehicle travel guidance belongs is displayed, and the reference position is displayed on the map (step 604).

Thereafter, when each interrupt permission process for the integral calculation interrupt process (step 606), the radio wave reception position interrupt process (step 608), and the interval timer interrupt process (step 610) is performed (step 612), the vehicle It is determined whether there is movement (step 614).

In this judgment, if movement of the vehicle is confirmed (YES in step 614), an update process is performed on the screen in accordance with the movement (step 616). Further, if the vehicle does not move (No in step 614), the update process is not performed.

FIG. 7 shows the integral calculation interrupt processing (step 60 in FIG. 6).
6) is shown.

In this process, the geomagnetic direction sensor 203 first reads the driving direction θ of the vehicle (step 700), and then the distance sensor 202 reads the X direction component ΔX and Y A directional component ΔY is determined (step 702).

Finally, these components are added to the cumulative distance in the X direction and the cumulative distance in the Y direction, and these cumulative distances are updated (step 704), and the updating process of step 616 in FIG. 6 described above is performed.

Next, the radio wave reception interrupt process (step 608 in FIG. 6) will be explained based on FIG. 8.

This process starts when the receiving antenna 210 mounted on the vehicle starts receiving the radio waves transmitted from the sign post 300. Whether or not the signal has been received is determined based on whether the output voltage of the receiving antenna at the time of reception has reached a certain value or higher.

In this process, when reception starts, a reception flag is set (step 800), and the reception data shown in FIGS. 4 and 5 is read (step 802).
.

Next, it is determined whether the continuation flag is set (step 804). This judgment is based on signpost 3
This is to check whether or not the mobile phone has entered the range of receiving radio waves from 00, and when it enters the range of receiving radio waves, the above-mentioned continuation flag is set. Therefore, before entering this radio reception range,
Continuation flag is not set. Therefore, when the continuation flag is not set, step 804 is turned off (O), interval timer interrupt processing (step 610 in FIG. 6) is permitted (step 806), and the continuation flag is set (step 808). When this continuation flag is set, steps 806 and 808 described above are bypassed.

Finally, the current position of the vehicle at the time of interruption of this process (X.

Y) Push data onto the stack and increment the stack counter (step 810).

FIG. 9 shows interval timer interrupt processing, in which an interrupt is performed every 100 m5ec after the interval timer is started in step 806 of FIG. 8 described above.

The relationship between this interrupt and the radio wave reception interrupt will be explained using the time chart of FIG. 10.

The upper row of this figure shows the interrupt when radio waves are received within the reception range of the sign post 300, and the middle row shows the interval timer interrupt.
The time is shown at the bottom.

As is clear from this time chart, the interrupt when receiving radio waves is 1001I when entering the reception range of the sign post 300.
This is done for each ISeC. When this interrupt is performed, the received data in step 802 in FIG. 8 described above is read, and the first interrupt provides the start timing for the interval timer interrupt.

When the vehicle moves out of the reception area of the sign post 300, this interruption upon reception of radio waves ends. This end point is detected by interval timer interrupt processing.

In other words, when the sign post 300 comes within the reception range, a reception interrupt is started (time A), and when the first reception process is performed, an interval timer interrupt is started (time B).
). After that, while the vehicle is within the reception range, the radio wave reception interrupt and the interval timer interrupt are synchronized (time, F
). Also, while the radio wave reception interrupt is being performed, the 8th
The reception flag at step 800 in the figure is set.

The set state of this flag is determined immediately after the interval timer interrupt processing (step 900).

In this judgment, if the reception flag is set (
Receive flag -1), unset this receive flag step 902). However, when the vehicle goes out of the reception range of the sign post 300, the interruption when receiving radio waves is no longer performed, and the reception flag is no longer set (reception flag - ○).
.

As a result, it is determined that the vehicle has gone out of the receiving range, and the process proceeds to the following steps to correct the position.

Here, in order to facilitate the explanation of the step of position correction, the explanation will be made with reference to FIG. 11, which shows the positional relationship between the sign post and the vehicle in the vicinity of the sign post.

In the figure, R represents the road and is shown as a solid line, and a sign post 300 is set up on the roadside, and a circle S drawn with this sign post 300 as the center indicates the radio wave reach range from the sign post 300, that is, the radio wave reception range. It represents.

FIG. 11 (a>) shows a state in which the vehicle has entered the radio wave reception range on a return line R' that deviates from the actual road R.

In this case, the vehicle is 100m5e from the sign post 300.
The radio waves emitted every c are marked O on the travel trajectory R' (a+ ~
aS), and the position data resulting from the reception is
It is pushed onto the stack in step 810 of FIG.

Now, after that, when the vehicle goes out of the reception area, that is, when it goes out of the circle S, the reception flag in step 900 is unset as described above (step 900 is O), and the X The average value (XC, Yc) of the position data of the direction component and the Y direction component is calculated (step 903).

The position of this average value (XC, YC) is shown at O mark aO in FIG. 11(b).

Next, the current position of the vehicle when the vehicle goes out of the reception range <X
, Y) (○mark b outside circle S) (step 906)
, roughly the above average value (XG, "v'c) and the current position (
A movement vector (X-XC, Y-YC) is determined from (X, Y) (step 908).

Note that both vectors are indicated by arrows A in FIG. 11 (b>).

In addition, position data from the sign post 300 (Xs,
Step 9'IO>, the above movement vector (X-Xc, Y-Y
c) and corrected position (Xn).

Yn) is determined (step 912). Note that this correction position (Xn, Yn) is indicated by the 0 mark C in FIG. 11(b).

Next, the above current position @ (X, Y) is changed to the corrected position (Xn, Y
n) (step 914), and then rewrites the continuation flag and stack counter (steps 806 and 81 in FIG. 8).
0) is cleared in step 916>, and finally, interval timer interrupts are disallowed in step 918), preparations are made for entering the receiving range of the new sign post.

As explained above, according to this embodiment, a signal is received multiple times within the radio wave reception range, and the position data at the time of these receptions is stacked, and when the vehicle moves out of the radio wave reception range, the signal is stacked. In addition to calculating the average value from the position data, since the sign post is in the center of the radio reception area, using that average position as a reference, calculate the movement vector from the average position to the position at the time when you go out of the radio reception area. The vehicle position is corrected to the exact path position of the sign post received from the sign post plus the above movement vector, so if the vehicle actually moves from the assumed position of the sign post. By determining the direction and distance, it is possible to accurately correct the position using position data from the sign post.

In this example, the movement vector from the average position to the position at the time of going out of radio reception range was corrected based on the position added to the position data from the sign post, but the movement vector from the position at the time of going out of range to the average position was corrected based on the position added to the position data from the sign post. The current position may be corrected based on the position obtained by adding the distance of the negative movement vector and the direction obtained by converting the direction of the negative movement vector by 180 degrees to the position data from the sign post.

In the above-described embodiment, the stacked position data within the radio wave reception area is averaged, and the average position is used as the vector starting point. However, the number of transmissions and receptions within the radio wave reception area is simply 2.
This can also be easily done by dividing the vector into two parts and using the point of the two divisions as the vector starting point. For example, if the signal is received from the sign post 8 times (8 circles) in the radio reception range S in Fig. 11 (A>), the fourth reception point is the starting point of the vector.In this case, the radio wave reception There is an advantage that there is no need to stack position data within the area and average it.

(Effects) According to the present invention, the average position of the vehicle within the radio reception range of the sign post is determined, the movement vector of the position at the time when the vehicle leaves the radio reception range with respect to this position is determined, and this vector is transferred from the sign post to the vehicle. Since the position is corrected in addition to the received position data, it is possible to accurately correct the position using radio waves received from the sign post.

[Brief explanation of drawings]

Figure 1 is a diagram corresponding to claims, Figure 2 is a block diagram showing the configuration of the present invention, Figure 3 is an explanatory diagram of the configuration of the sign post, and Figure 4 is a diagram showing the configuration of the sign post.
The figure is a transmission guide map of the sign post, Figure 5 is an explanatory diagram for explaining the radio wave transmission timing of the sign post, and Figures 6-
Figure 9 is a flowchart showing the processing procedure of the CPU;
FIG. 11 is a time chart showing the relationship between radio wave reception and interval timer interruption, and FIG. 11 is an explanatory diagram showing the relationship between the sign post and the vehicle travel trajectory. 200...Display device 201...CPU 202...Vehicle speed sensor 203...Geomagnetic direction sensor 205...Key human power section 206...External storage device 208...System ROM 209...RAM No. Fig. 1 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 1 O Fig. 1
OFigure 11 (O) (b)

Claims (1)

[Claims] (1) Current position detection means that detects the current position of the vehicle using a distance sensor and a geomagnetic direction sensor, and position data detected by the current position detection means at regular intervals within the radio wave reception area from the roadside transmitting station. a position data storage means for storing the position data; an average position calculation means for calculating the average position of the stored position data within the radio wave reception area; and an average position calculation means for calculating the average position of the stored position data within the radio wave reception area; The vehicle comprises a vector calculating means for calculating a movement vector, and a position correcting means for correcting the current position by adding the vector to the position information of the roadside transmitting station when the vehicle moves out of the radio wave reception range of the roadside transmitting station. Features of vehicle position detection device.