JPH06243388A - Beacon position detecting and correcting device of vics - Google Patents

Abstract

PURPOSE:To display road distance data obtained from a beacon without any error by correcting the detection error of the beacon position corresponding to the speed of a vehicle. CONSTITUTION:A correction value for the detection error of the beacon position generated as a reception level decreases right below the beacon is stored corresponding to the speed of the vehicle, and the detection error of the beacon position is corrected corresponding to the speed of the vehicle. Namely, when a VICS beacon receiver receives data of the beacon in this case, reception data on a distance LO to an intersection is sent to a speed correction part 4 (computer). Further, the beacon position once detected is sent to the speed correction part 4. Then the received data LO is corrected with the error of the beacon corresponding to the vehicle speed at the time of beacon position detection. Further, the received data are corrected with an antenna error based upon antenna fitting position information.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a VICS beacon receiver used in a navigation system mounted on a vehicle, and relates to correcting an error in road distance data based on a beacon position.

[0002]

2. Description of the Related Art Conventionally, as a technique in such a field, a navigation system mounted on a vehicle basically calculates a current position by integrating a movement distance from a starting point and a change in a traveling direction, and calculates the present position on a map. It is provided with a function of displaying a position, an azimuth, and, in some cases, a travel history on a vehicle-mounted LCD or the like. In order to display a map, it has an in-vehicle map database stored in a CD-ROM or the like. Further, as means for transmitting information outside the vehicle to the vehicle, a vehicle information communication system (V
ICS; Vehicle Information Communication System
), A spot communication road device called a “beacon” is installed every 2 to 5 km on the road, and communication is performed between this and the on-vehicle device. This beacon is used to convey the position of a communication point, the shape of an intersection, or changing road traffic information to a navigation system.

FIG. 5 is a diagram for explaining a transmission signal from a beacon. As shown in this figure, the antenna of the beacon sends out radio waves in the direction in which the vehicle is coming from one side and in the opposite direction. The VICS receiver mounted on the vehicle traveling on the road receives the radio waves. The radio wave from the antenna of the beacon contains different information (for example, destination guidance) depending on the traveling direction of the vehicle, but the radio wave transmitted to one side is received by the vehicle coming from the opposite direction and is not processed. is there. That is, in the beacon, for example, a vehicle coming from one direction is FM-modulated with AM1 data, and a vehicle coming from the opposite direction is FM-modulated with AM2 data.
M1 data and AM2 data are amplitude-modulated by a square wave whose phase is opposite to that of FM modulation. The AM1 data and the AM2 data have, for example, 47 data cycles.
The frame is composed of 128 bytes, one frame is 16 ms, the blank period is 2 ms, and the data is transmitted at a data rate of about 64 kbps. The amplitude modulation component of the square wave has a frequency of 1 kHz. In the in-phase region for one direction, the AM1 data frame is synchronized with the rising edge of the amplitude modulation component, and in the opposite phase region for the opposite direction, the AM2 data frame is synchronized with the falling edge of the amplitude modulation signal. Thus, the VIC is identified by identifying the traveling direction.
The S receiver is receiving road information. Further, when the vehicle passes directly below the antenna of the beacon, the phase of the amplitude modulation component is inverted, so this is detected to detect the position of the beacon.

FIG. 6 is a diagram for explaining the relationship between the received direction data and the beacon detection position. As shown in this figure,
The contents of the AM1 data and the AM2 data include, for example, distance L0 (m) information from this position to the intersection with reference to the time of beacon position detection. Necessary information of this intersection, intersection name, destination in each direction. Etc. When the information passes through the beacon, the intersection information is displayed in synchronization with the beacon position detection.

[0005]

By the way, in the conventional beacon position detecting device of the vehicle information communication system, the level of the AM modulation component is lowered in the vicinity immediately below the beacon, and an area where phase detection cannot be performed occurs, or the phase is not detected. An error occurs in beacon position detection due to the vehicle traveling for the time required for change detection. However, because the intersection information is displayed in synchronization with beacon position detection,
During this time, the vehicle travels a certain distance ΔL and then the beacon position is detected. This means that the beacon position is displaced in the traveling direction by the distance ΔL, and therefore the intersection information is also displayed in the traveling direction displaced by the distance ΔL. Therefore, there is an error in the distance to the intersection, and when traveling the displayed distance, it will pass the actual intersection,
There is a problem that it can not be used as appropriate information and may give misunderstandings.

Therefore, the present invention has been made in view of the above problems and is capable of correcting a beacon position error due to a decrease in the level of an AM modulation component in the vicinity of the position directly below the beacon in the road distance data obtained from the beacon. The purpose is to provide.

[0007]

In order to solve the above problems, the present invention is a beacon that is frequency-modulated or phase-modulated with road information data and further amplitude-modulated with square waves having mutually opposite phases in synchronization with the modulated data. In a device that receives a radio wave transmitted from a device and detects a beacon position based on a change in the phase, a correction value for a beacon position detection error that occurs due to a decrease in the reception level immediately below the beacon, etc. is a vehicle equipped with the device. Is stored so as to correspond to the vehicle speed, and the detection error of the beacon position is corrected according to the vehicle speed.

Further, the correction value for the detection error of the beacon position caused by the decrease of the reception level immediately below the beacon is stored so as to correspond to the antenna position of the vehicle equipped with the device, and the correction value is stored in accordance with the antenna position information. Correct the beacon position detection error.

[0009]

According to the beacon position detection / correction device for VICS of the present invention, the correction value for the detection error of the beacon position, which is caused by the decrease of the reception level immediately below the beacon and the like, is shown in the vehicle equipped with the device. It is confirmed that it corresponds to the speed, it is stored, and by correcting the detection error of this beacon position according to the speed of the vehicle, it is possible to display the road distance data obtained from the beacon without error and use it as appropriate information It became so. In addition, it was confirmed by a running experiment that the correction value for the detection error of the beacon position caused by the decrease in the reception level immediately below the beacon, etc. was stored in the antenna position of the vehicle equipped with the device, and this was stored, and the antenna position information was stored. By correcting the detection error of the beacon position according to, the road distance data obtained from the beacon can be displayed without error and can be used as appropriate information.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram illustrating an outline of a VICS receiver and a navigation system according to an embodiment of the present invention. As shown in the figure, the VICS beacon receiver 1 mounted on the vehicle receives the radio wave from the above-mentioned beacon,
The navigation system 2 is configured as described above,
Distance data is extracted by inputting received data of information such as intersections from the VICS beacon receiver 1 and a beacon position detection signal, and further inputting vehicle speed information (speed information) such as vehicle running pulses and antenna mounting position information of the vehicle. It is intended to correct the beacon position when doing.

FIG. 2 is a diagram showing the configuration of the beacon position detection / correction device in the navigation system 2 of FIG. 1, and FIG. 3 is a diagram for explaining the beacon position detection error.
As shown in this FIG. 3, when the vehicle progresses from the in-phase region to the out-of-phase region, the reception level of the VICS beacon receiver 1 is below the level required for phase detection immediately below the beacon antenna, and the phase is undetermined in the range of A. Therefore, the range of the region B in which the vehicle has traveled during the time required for the reverse phase detection is required even when passing through this region. That is, it is predicted that the error ΔL1 of the beacon position has a correlation with the traveling speed of the vehicle, and the inventor of the present application has obtained the correlation as follows by a traveling experiment, and further has a correlation with the mounting state of the vehicle antenna. Was clarified as follows.

In an experiment of running the vehicle speed, for example, when the vehicle speed is 20 km / h, the beacon position error ΔL1 = 0 m, and when the vehicle speed is 40 km / h, ΔL1 = + 1 m. , Vehicle speed is 60km / h
In the case of, ΔL1 = + 2m, and the vehicle speed is 80k.
In the case of m / h, ΔL1 = + 5m. Furthermore, at the position of the vehicle antenna, the antenna error Δ when it is on the roof
L2 = 0 m, ΔL2 = −3 m in the front, and ΔL2 = −2 m in the rear. The correction data thus obtained for the vehicle in advance is stored in the storage unit 3 of FIG. 2 as a table with the vehicle speed as a parameter. This storage unit 3 is a ROM (Read only m
emory). When the beacon position is detected, the speed correction unit 4 in FIG. 2 reads the error of the beacon position from the storage unit 3 based on the speed information (vehicle speed) such as the traveling pulse and performs the interpolation processing to perform the beacon position error ΔL1.
Ask for. Distance from this beacon position to the intersection (L
0) is corrected as follows.

L = L0-.DELTA.L1 The antenna position correction unit 5 provided after the speed correction unit 4
In this case, the antenna error .DELTA.L2 is read from the storage unit 3 by the switch that gives the antenna mounting position information and the distance (L0) from the beacon position to the intersection is corrected as follows. L = L0 + ΔL2 Further, this may be added to the result obtained by the speed correction unit 4 as follows to perform correction.

L = L0-ΔL1 + ΔL2 The distance to the intersection corrected in this way is displayed on the display unit 6. The speed correction unit 4 and the antenna position correction unit 5
Is formed on a computer. FIG. 4 is a diagram illustrating a series of operations of the beacon position detection / correction device according to the embodiment of the present invention. In step 1 of the figure, when the VICS beacon receiver 1 receives the beacon data, it transmits the received data of the distance (L0) to the intersection to the speed correction unit 4 (computer).

In step 2, when the beacon position is detected in the same manner as in step 1, this is transmitted to the speed correction unit 4 (computer). In step 3, the beacon position error (Δ
The received data (L0) is corrected by L1). Furthermore, the antenna error (Δ
The received data is further corrected by L2).

[0016]

As described above, according to the present invention, it has been confirmed by running experiments that the detection error of the beacon position caused by the decrease of the reception level immediately below the beacon corresponds to the speed of the vehicle. Since the road distance data is corrected by the detection error, the display of the road distance data obtained from the beacon can be reduced without error.In addition, the traveling test shows that the detection error of the beacon position also corresponds to the antenna position attached to the vehicle. Since it is confirmed and the road distance data is corrected with this detection error, the display of the road distance data obtained from the beacon can be further reduced without error.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an outline of a VICS beacon receiver and a navigation system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a beacon position detection / correction device in the navigation system 2 of FIG.

FIG. 3 is a diagram illustrating a beacon position detection error.

FIG. 4 is a flowchart illustrating a series of operations of the beacon position detection / correction device according to the embodiment of the present invention.

FIG. 5 is a diagram illustrating a transmission signal from a beacon.

FIG. 6 is a diagram showing a relationship between received direction data and a beacon detection position.

[Explanation of symbols]

 1 ... VICS beacon receiver 2 ... Navigation system 3 ... Storage unit 4 ... Speed correction unit 5 ... Antenna position correction unit 6 ... Display unit

Claims (2)

[Claims] 1. A beacon position based on a change in the phase received from a beacon that is frequency-modulated or phase-modulated with road information data and is amplitude-modulated with square waves having mutually opposite phases in synchronization with the modulated data. In the device that detects the, the correction value for the detection error of the beacon position that occurs due to the decrease of the reception level immediately below the beacon is stored so as to correspond to the speed of the vehicle equipped with the device, and it is stored according to the speed of the vehicle. V for correcting the detection error of this beacon position
ICS beacon position detection / correction device. 2. A correction value for a detection error of a beacon position caused by a decrease in reception level immediately below the beacon is stored so as to correspond to an antenna position of a vehicle equipped with the device, and the correction value is stored according to the antenna position information. VICS beacon position detection / correction device for correcting detection error of beacon position.