JP2778240B2 - Navigation device using inter-vehicle communication - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement of a navigation device mounted on a vehicle, which detects a position of the vehicle and displays the position on a screen to support the traveling of the vehicle. More specifically,
The present invention relates to a navigation device capable of acquiring vehicle position data transmitted from another vehicle using inter-vehicle communication and correcting the position of the own vehicle.

<Prior Art> Conventionally, as a method of detecting a position of a vehicle traveling on an arbitrary part of a road traffic network, a traveling distance sensor and a direction sensor (one of a geomagnetic sensor and a turning angular velocity sensor) are used. A processing device for performing necessary processing on output signals from both sensors, and a display device for displaying a vehicle position on a screen, and a distance change amount Δl and a direction θ ( Geomagnetic sensor),
Alternatively, dead reckoning navigation has been proposed in which estimated position data of a vehicle is obtained using the azimuth change amount Δθ (in the case of a turning angular velocity sensor). In this method, for example, an east-west component Δx (= Δl × cos θ) and a north-south direction component Δy (= Δl × sin θ) of Δl are calculated based on Δl and θ, and the previous position output data (Px ′, Py ′) is calculated. ) For the above components Δx, Δy
Is added, the current position output data (Px, P
y).

However, there is a drawback that errors included in the obtained estimated position data are accumulated due to errors inherently possessed by the traveling distance sensor and the direction sensor.

For this reason, on the assumption that the vehicle travels on the road, the estimated position data obtained by the dead reckoning navigation is compared with the road map data stored in the memory in advance,
A map matching method in which a deviation amount of the estimated position data from a road is calculated as a cumulative error, a correction of the cumulative error is performed on the estimated position data, and the estimated position data is made to match the road data has been put to practical use. (Japanese Unexamined Patent Publication No.
No. 53112).

Furthermore, in any case where the dead reckoning navigation adopts any of the map matching methods, a roadside antenna is arranged beside a road in order to improve the accuracy of distance data and azimuth data,
A roadside speaker system in which a signal including position data and road direction data is radiated from this roadside antenna only in a relatively narrow range and the above signal is received by an onboard antenna mounted on the vehicle to calibrate the position and direction of the vehicle is also proposed. Have been.

Further, using a satellite navigation system such as a GPS (Clobal Positioning System), the propagation delay time of radio waves emitted from three or four orbiting satellites is measured to determine the absolute position of the vehicle.

Regardless of which method is used, as described above, to know the position and orientation of the vehicle, the vehicle is equipped with a device that implements a position detection method with advanced functions (hereinafter referred to as a navigation device). There is a need to. Such a navigation device, for example, for a device that adopts a map matching method, is calculated by a road map memory and a processing device, in addition to the traveling distance sensor, the azimuth sensor, the processing device for position calculation, and the display device. An arithmetic correction device that determines the similarity between the vehicle position and the road and corrects the position of the vehicle is required. Furthermore, a roadside beacon receiver is required if the roadside beacon method is adopted, and a GPS receiver is required if the GPS method is adopted.

If the above-described navigation device is mounted on a vehicle, the current position of the vehicle can be grasped at a glance on a display, so that even when traveling on an unknown road, the vehicle reaches the destination without getting lost be able to.

<Problems to be Solved by the Invention> However, the error of the position data obtained from the navigation device mounted on the vehicle by the vehicle always accompanies whatever method is adopted.

For example, it is well known that when passing a railroad crossing, an iron bridge, a valley of a high-rise building, or the like, the amount of magnetization of the vehicle body changes and an error occurs in the data of the geomagnetic sensor. In addition, the gyro data, regardless of the type of gyro used, has an offset value that fluctuates under the influence of changes in temperature and humidity.Therefore, when integrating angular velocity data obtained with the gyro, errors are also integrated. It is also known that the wrong direction is output. Also, when the map matching method is adopted, if the distance between the estimated position of the vehicle obtained from the direction sensor, the mileage sensor, and the like and the road on the map is too large, it is not possible to correct the position of the vehicle on the road. Impossible. Therefore, in this case, the map data is useless. Furthermore, even if an attempt is made to use a roadside beacon to correct the position of the vehicle, not all roads have roadside beacons and only a few roads have roadside beacons at present. . Even if you try to receive radio waves from GPS, you may not always receive them in a satisfactory state due to the effects of obstacles on the ground.

As described above, even if the navigation device is mounted on the vehicle, the reliability of the obtained position data cannot be said to be perfect, so that the vehicle needs to correct the obtained position data.

In particular, if the vehicle is equipped with a navigation device that is as simple as possible, for example, a navigation device that only uses dead reckoning, in order to reduce the burden on the economy and the like, the position detection error also tends to increase. Issues are getting closer and closer.

An object of the present invention is to provide a navigation device that enables a vehicle to acquire accurate position data and travel on a predetermined route without error by using inter-vehicle communication.

<Means and Actions for Solving the Problems> (1) A navigation device according to the present invention for achieving the above object includes a travel distance sensor, a direction sensor, and a vehicle obtained from the travel distance sensor and the direction sensor. Position detecting means for detecting the position of the vehicle based on the traveling distance data and the azimuth data, receiving means for receiving the position data of the other vehicle transmitted from a navigation device mounted on the other vehicle, and receiving means Correction means for correcting the vehicle position detected by the position detection means based on the position data received by the control means (claim 1).

According to the first aspect of the present invention, the vehicle equipped with the navigation device uses the position detecting means to determine the position of the own vehicle based on the mileage data and the azimuth data of the own vehicle obtained from the mileage sensor and the azimuth sensor. In addition to being able to detect, the position data of the other vehicle can be acquired from the navigation device mounted on the other vehicle through the receiving means, and the position data of the own vehicle can be corrected.

Then, by correcting the data based on the data obtained by the navigation device of another vehicle, the reliability of the data obtained by the navigation device of the own vehicle can be improved.

Therefore, for example, even a navigation device that employs a relatively low-accuracy detection method can obtain data of another vehicle and improve the reliability of the data of the own vehicle. It is possible to acquire sufficiently accurate data as in the case where the navigation device adopting the above is mounted. Therefore, as compared with a case where a navigation device adopting a highly accurate detection method is mounted, the same result as that in which the configuration of the navigation device is simplified and the cost is reduced can be obtained.

(2) In the navigation device according to the present invention, in addition to the one described in claim 1, transmission means for transmitting the position data of the vehicle detected by the position detection means to a navigation device mounted on another vehicle is provided. It may be included (claim 2).

According to this, by transmitting the position data obtained by the own vehicle from the transmission means, it becomes possible to cause the navigation device of another vehicle that has received the transmitted data to correct the position data.

That is, according to this navigation device, the position data of the other vehicle is acquired from the navigation device mounted on the other vehicle through the receiving unit, the position data of the own vehicle is corrected, and the position data of the own vehicle is obtained through the transmitting unit. By transmitting the position data, it is possible to correct the position data of the navigation device of another vehicle.

Therefore, when a plurality of vehicles equipped with the navigation device according to claim 2 are traveling, data can be exchanged when approaching or the like, and the position detection accuracy can be mutually increased.

(3) The "navigation device mounted on another vehicle" described in claim 1 is a travel distance sensor, a direction sensor, and vehicle travel distance data and direction data obtained from the travel distance sensor and the direction sensor. And a transmitting means for transmitting position data of the vehicle detected by the position detecting means.

According to this, the navigation device according to the third aspect transmits the position data obtained by the own vehicle from the transmission means, and the navigation device according to the first aspect receives the transmitted data. It becomes possible to correct the position data of the vehicle.

It should be noted that the navigation device according to the third aspect does not necessarily need to include a receiving unit, and may be a navigation device dedicated to transmission. If the transmission-only navigation device is mounted, data transmission to other vehicles is performed exclusively. For example, data from a navigation device that employs a detection method with relatively high accuracy is often low in reliability even if data is received from another vehicle. Is low.
Therefore, by eliminating the receiving means from the beginning, the configuration of the apparatus can be simplified and the cost can be reduced.

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

FIG. 1 is an overall configuration diagram showing an embodiment of a navigation device using inter-vehicle communication. Hereinafter, vehicles equipped with the navigation device of the present invention are represented by reference numerals A and B.

To the vehicle A, a navigation device 1A that detects the current position of the vehicle A and displays the current position on the screen, and data acquired by the navigation device 1A are transmitted,
Infrared transceiver 6A for receiving position data of vehicle B transmitted from another vehicle B equipped with a navigation device
It is equipped with.

The navigation device 1A includes a wheel speed sensor 4A that detects the rotational speeds of both the left and right wheels (this sensor is used as a traveling distance sensor), a geomagnetic sensor 2A, and a gyro 3A (the turning angular speed is read as a phase change of interference light. Various sensors such as an optical fiber gyro, a vibration gyro that detects a turning angular velocity by using a cantilever vibration technology of a piezo electric element, a mechanical gyro, etc., which is used as a turning angular velocity sensor) are connected. Is done.

The navigation device 1A includes a geomagnetic sensor 2A, a gyro
The locator 11A that calculates the estimated orientation of the vehicle based on the output data detected by the 3A and the current position of the vehicle by a map matching method in combination with the distance data of the wheel speed sensor 4A, and the current position of the vehicle, It includes a controller 14A that superimposes the map read from the map memory 15A on the display 16A and that interfaces with the keyboard 17A.

The locator 11A specifically obtains the number of rotations of the wheels by counting the number of output pulse signals from the wheel speed sensor 4A with a counter, and counts output data from the counter by a multiplier. Estimate the vehicle by calculating the mileage output data per unit time by multiplying by a predetermined constant indicating the distance per count, and calculating the azimuth output data of the vehicle by calculating the relative change of the azimuth from the gyro 3A. Find the position, controller 14A
To obtain predetermined road map data, compare the estimated vehicle position with the estimated position of the vehicle, evaluate the degree of correlation with the road map data, correct the estimated position of the vehicle, and set the current direction of the vehicle on the road. . Therefore, locator 11A functions as “position detecting means”.

Locator 11A can also appropriately correct the vehicle position of its own vehicle using the position and orientation data of another vehicle received by transceiver 6A. That is, in this case, the locator
11A functions as "correction means".

The road map memory 15A includes a semiconductor memory, a cassette tape, a CD-ROM, an IC memory, a DAT, and the like, in which road map data including data including a combination of nodes and links is stored in advance. is there. The road map data is obtained by dividing a Japanese road map into a mesh shape and storing each mesh unit. Note that, in addition to the link data and the node data, background data such as a railway, a river, a place name column, a famous facility, a point registered in advance by a driver, and contour lines may be included.

The display 16A uses a CRT, a liquid crystal display, and the like to display a road map and a position and a direction of the vehicle while the vehicle is traveling.

The controller 14A includes a graphic processing processor, an image processing memory, and the like, and searches for a map on the display 16A, switches the scale, performs scrolling, and the like.

The position data and direction data of the vehicle to be displayed on the display 16A, and the mesh number data of the displayed road map are sent to the transceiver 6A through the controller 14A and are radiated to the space by infrared rays.

Further, the transmitter / receiver 6A can also receive the infrared rays emitted from the transmitter / receiver 6B of another vehicle B and acquire the data of the vehicle B.

The other vehicle B is equipped with a navigation device having the same configuration as that of the vehicle A, and is therefore indicated by the same number. However, in order to distinguish between the vehicles A and B, the suffix B is used instead of the suffix A. Although the vehicle B is illustrated as an oncoming vehicle to the vehicle A in FIG. 1, it may be a vehicle that translates.

According to the above embodiment, the navigation device 1A of the vehicle A
Calculates the position and direction of the vehicle while traveling or stopped, specifies the position of the vehicle on the map road, and displays a vector indicating the position and direction of the vehicle on the display 16 of the vehicle A together with the map. , And the position data of the vehicle A at all times, together with the mesh number data of the displayed road map,
Fired through transceiver 6A.

When the vehicle B passes the vehicle A, the vehicle B receives the position data and the mesh number data of the vehicle A through the transceiver 6B. The locator 11B of the vehicle B determines the vehicle position of the vehicle A based on the current position PA of the vehicle A indicated in the received data and the estimated position PB calculated in the vehicle by, for example, an algorithm shown in FIG. Fix and controller
Output to 14B.

That is, in FIG. 2, in step S1, another vehicle A
In step S2, the distance d from the vehicle position PB to the road is determined by comparing the estimated position PB of the vehicle B with the road pattern. And the distance d
But it is determined whether or not shorter than a certain threshold d _0.

Generally, the estimated position PB of the vehicle calculated based on the output data detected by the geomagnetic sensor 2B and the gyro 3B
If, smaller than the threshold locations d ₀ distance d is constant between the actual vehicle position on the road, the map matching method, the correlation coefficient between the estimated position PB and the road (estimated position PB
Is given, the probability that the actual vehicle position is on the road. For example, it is represented by a function of the distance from the estimated position to one point on the shortest road. Is repeatedly calculated, the estimated position PB of the vehicle can be reliably obtained on the road (see JP-A-48-53112). However, the distance d
When There is larger than the threshold value d _0, to calculate the correlation coefficient between the road probability rapidly decreases, which can be narrowed even the position of the vehicle on a particular road, finally be calculated again Cannot match the road. If this happens, own vehicle B
Needs to be corrected using some data.

When the necessity of data correction is determined as described above (step S3), the process proceeds to step S4, and the position of the own vehicle is corrected using the position data PA of another vehicle A acquired in step S1 (step S4). .

Although various correction methods are conceivable, for example, the position data PB of the own vehicle may be replaced with the position data PA of the vehicle A. Alternatively, the average of both positions may be taken.

Thus, the navigation device 1B of the vehicle B
The vehicle B can be corrected based on the position data of the vehicle A, and the position can be displayed on the display 16B. The road map to be displayed can be quickly determined based on the received mesh number data. Thereafter, the vehicle B can calculate the new position and direction of the own vehicle by using the map as the starting point using the map matching method, and can continue the self-contained navigation.

The position data obtained by the inter-vehicle communication is the position of the vehicle A, not the position of the vehicle B. Therefore, vehicle A
No matter how accurate the position PA is, the vehicle
An error corresponding to the distance between A and B always follows. Since this error is determined by the communicable distance of the transceivers 6A and 6B, by appropriately adjusting the transmission output and the reception sensitivity of the transceivers 6A and 6B, the error of the vehicle position can be reduced to a practical range. Can be stopped (since infrared is used, it can be set freely within 100m).

In the above embodiment, the type of data communicated between the vehicles is not limited to the above. For example, the navigation device 1A of the vehicle A may evaluate the error of the calculated vehicle position and send it out as error data. Locator 11B of vehicle B that has received data of vehicle A
May be compared with the error included in the estimated position obtained by the own vehicle, and the data with the smaller error may be adopted.
In this case as well, it goes without saying that the error of the distance between vehicles determined by the communicable distance of the transceivers 6A and 6B must be added to the error of the vehicle position calculated by the vehicle A.

Further, in the above-described embodiment, the navigation devices mounted on the vehicle A and the vehicle B are assumed to be the same, but the navigation devices using different systems may be used. For example, vehicle A is a map matching method,
The vehicle B may employ a simple dead reckoning navigation. In this case, since the vehicle B cannot compare the pattern with the map, the position of the vehicle detected by the vehicle B is always
A considerable error is included. Therefore, when the transmission data of the vehicle A adopting the map matching method (the data indicating that the method adopted by the vehicle A is the map matching method needs to be included in the data) is unconditionally received. The data of the vehicle A may be taken in. Further, in this case, even if position data having a large error is transmitted from the vehicle B, the degree of utilization is low, so that the navigation device 1B and the transceiver 6B of the vehicle B do not need to have a transmission function.

In general, a vehicle equipped with a navigation device having a relatively large detection error may be dedicated to reception, and a vehicle equipped with a navigation device having a relatively small detection error preferably has a transmission function. Further, if the gating apparatus has a very small detection error and does not need to take in data from another navigation apparatus and has high accuracy, it may be dedicated to transmission. To illustrate this in a table,
It is as shown in Table 1.

Further, in the above embodiment, the data transmission medium from the vehicle A to the vehicle B is infrared, but other means such as visible light, wireless such as VHF and UHF, and ultrasonic waves may be used. However, regardless of which method is used, an error generated in inter-vehicle communication usually increases when the possible distance is too large, and the error decreases when the possible distance is small, but the opportunity for inter-vehicle communication and the communication time decrease. Therefore, it is preferable to determine the communicable distance by performing an operation test or the like.

Further, in the above embodiment, the data is always transmitted from the vehicle A, but the present invention is not limited to this. Vehicle B
For example, when it is determined that the error of the vehicle position calculated by the user increases and it is necessary to correct the error based on other data, the vehicle B
, And when vehicle A receives this signal, it may transmit its own data for the first time.

Further, in the above embodiment, the relation between the vehicle A and the vehicle B is not limited. In short, any vehicle that can exchange position data etc. between vehicles may be used,
The vehicle A and the vehicle B may be vehicles that have accidentally passed each other. In addition, for example, vehicles such as a police car, an ambulance, a fire truck, a sightseeing bus, a truck, a mixer truck, a taxi, and the like, which are group-moving toward the same destination, may be used.

In the above embodiment, when the receiver of the vehicle B receives the data, it is preferable that the distance and the direction between the vehicle A and the vehicle B can be identified. According to this, when correcting the vehicle position acquired by the locator device mounted on the own vehicle, the correction result can be further corrected using the identified distance and direction. Accordingly, the vehicle B can correct the position and direction of the own vehicle using the distance and direction between the vehicles, and thus can obtain more accurate position data of the own vehicle.

In the above embodiment, the data transmitted from the vehicle is the position data of the vehicle and the mesh number data, but the mesh number data is not always necessary.

Further, the transmitted data may include, in addition to the vehicle position data, data directly or indirectly related to position detection, such as the type of position detection method adopted by the own vehicle, traffic congestion information, and emergency / abnormal display. It may be.

<Effect of the Invention> As described above, according to the navigation device using the inter-vehicle communication of the present invention, position data is received from another vehicle, and the position of the own vehicle is determined based on the position obtained by the navigation device of the other vehicle. By correcting the position, the reliability of the position data obtained by the navigation device of the own vehicle can be greatly improved.

Therefore, even if the position detection method of the navigation device used in the own vehicle is relatively low in accuracy, if the position detection method of the navigation device mounted in another vehicle is relatively high in accuracy, the result is In this case, the result is the same as the improvement in the accuracy of the navigation device mounted on the own vehicle, and it is economically advantageous since the own vehicle does not need to be equipped with an advanced navigation device.

In addition, a navigation device having a function of receiving position data from another vehicle and a transmission function of transmitting position data to another vehicle, if a plurality of vehicles equipped with this type of navigation device are traveling, Since data can be exchanged when approaching, etc., and the position can be corrected, the position detection accuracy can be substantially improved without installing a device with particularly high position detection accuracy in the navigation device installed in each car. Can be enhanced.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a navigation device, and FIG. 2 is a flowchart showing a procedure for taking in data of another vehicle and correcting the position of the own vehicle. A, B… Vehicle, 1A, 1B… Navigation device, 2A, 2B… Geomagnetic sensor, 3A, 3B… Gyro, 4A, 4B… Wheel speed sensor, 6A, 6B… Transceiver, 11A, 11B ……locator

Continuation of the front page (56) References JP-A-62-38378 (JP, A) JP-A-60-191399 (JP, A) JP-A-58-223015 (JP, A) JP-A-3-126199 (JP) , A) JP-A-4-70999 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G01C 21/00

Claims (3)

(57) [Claims] 1. A navigation device mounted on a vehicle for detecting a position of the vehicle and displaying the detected position on a screen to assist the vehicle in traveling. The navigation device includes: a traveling distance sensor; a direction sensor; Position detecting means for detecting the position of the vehicle based on the traveling distance data and the direction data of the vehicle obtained from the direction sensor, and receiving the position data of the other vehicle transmitted from a navigation device mounted on another vehicle And a correcting means for correcting the vehicle position detected by the position detecting means based on the position data received by the receiving means. 2. The navigation device according to claim 1, further comprising a transmission unit that transmits the position data of the vehicle detected by the position detection unit to a navigation device mounted on another vehicle. A navigation device using inter-vehicle communication. 3. The navigation device according to claim 1, wherein the navigation device mounted on the other vehicle includes a traveling distance sensor, a direction sensor, and traveling distance data of the vehicle obtained from the traveling distance sensor and the direction sensor. A navigation device using inter-vehicle communication, comprising: a position detecting means for detecting the position of the vehicle based on the azimuth data; and a transmitting means for transmitting the position data of the vehicle detected by the position detecting means.