JP2828034B2 - Navigation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a navigation device for detecting the position of a vehicle such as an automobile and displaying the detected position together with a map of the vicinity.

[0002]

2. Description of the Related Art In recent years, various navigation devices have been developed for use in automobiles. For example, the position of the vehicle is determined by detecting the direction of travel of the vehicle from the starting point, the amount of travel, and the like, and a road map near the determined vehicle position is obtained from a large-capacity storage device such as a CD ROM device. On the screen of the CRT based on the Such a method of detecting a position from the traveling state of the own vehicle is called inertial navigation or self-sustained navigation.In the position detection by the inertial navigation, a deviation between an actual traveling position and a detected position is caused as the traveling distance increases. There was a risk of occurrence. For this reason, for example, as disclosed in JP-A-61-57982, the position detected by inertial navigation is collated with road map data, and when the detected position deviates from the road, the vehicle position is corrected on a nearby road. It has been proposed to perform so-called map matching.

[0003]

However, when this map matching is performed, the detection error of the own vehicle position may increase. That is, since the map matching always tries to pull the position of the vehicle to the road registered in the map data, if there are a plurality of adjacent roads, the position of the vehicle may be pulled to another road, Even if you enter a back road or a new road that is not registered in the map data, your vehicle position may not deviate from the registered road, and even if you enter a place other than the road such as a gas station or parking lot, it will be displayed Sometimes the position did not change on the road. Further, since the driver tries to pull into the forcibly registered road, the display position may suddenly move irrespective of the traveling state of the vehicle, and the display state is not good.
Furthermore, since the stored road map data is an approximate value of the actual road, it does not always match the actual road condition, and the vehicle position obtained by the inertial navigation is more correct. There was also.

SUMMARY OF THE INVENTION [0004] In view of the foregoing, it is an object of the present invention to improve the reliability of a navigation system by displaying a good position of a vehicle in accordance with a traveling state.

[0005]

The navigation apparatus according to the present invention comprises, as shown in FIG. 1, position detecting means 1 and 2 for detecting the current position of a moving object, and storage means 3 for storing road map information. An arithmetic processing unit 11 for calculating current position information based on the position detection information supplied from the position detection unit 3 and the road map information read from the storage unit 3; A display means for displaying a position on the road map based on the current position information; a first detection position based on the position detection information obtained by the position detection means, A second detection position in which the first detection position is corrected on the registered road is set based on the road map stored in the means 3, and a predetermined calculation is performed based on the first and second detection positions. If that third sets the detection position, the third detection position is displayed on the display unit 4 as the current position information, it can not be set the second detection position,
The first detection position is displayed on the display means 4 as the current position information.

According to this configuration, when the detected current position is corrected by the road map data, if the detected position is far from the registered road, the display is performed so as to be gradually drawn into the registered road. As the position changes,
If map matching cannot be performed, the detected position is displayed as the current position, and good map matching that respects the detected position is performed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the navigation device according to the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the entire navigation apparatus of the present embodiment. In FIG. 1, reference numeral 1 denotes a direction detecting device for detecting the traveling direction of an automobile (not shown), and reference numeral 2 denotes a traveling amount detection for detecting a traveling amount. The device is shown. As the direction detecting device 1, a geomagnetic sensor or a gyroscope is used, and as the travel distance detecting device 2, a distance meter that detects rotation of a tire or the like is used.

In the figure, reference numeral 3 denotes a CD ROM device.
The CD ROM device 3 is equipped with a CD ROM storing nationwide road map information and the like converted into vector data, and is stored in the CD ROM according to an instruction from a CD ROM controller 13 in the arithmetic processing unit 10 described later. The read predetermined information is read out by the CD ROM device 3. In this example, the road information stored in the CD ROM includes major roads (hereinafter referred to as registered roads) used for map matching described later and roads not used for map matching such as back roads and alleys. Is stored separately.

The detection information obtained by the direction detection device 1 and the travel distance detection device 2 and the road map information read by the CD ROM device 3 are supplied to the arithmetic processing device 10.
The arithmetic processing device 10 includes a current position calculation circuit 11 to which direction detection information and travel distance detection information are supplied, and the current position calculation circuit 11 calculates a current position by inertial navigation based on both detection information. In this case, an operation key 5 for setting a coordinate position before the start of traveling of the own vehicle is connected to the arithmetic processing unit 10, and coordinate position information at the start of traveling set by the operation key 5 is stored in the system. The current position calculation circuit 11 is supplied via the controller 15. Then, the current position calculation circuit 11 moves the coordinate position from the coordinate position at the start of the travel by an amount indicated by the direction detection information and the travel distance detection information, and obtains the current position by the inertial navigation.

The road map information read by the CD ROM device 3 is stored in a buffer memory 1 in the arithmetic processing unit 10.
The current position calculation circuit 11 supplies the current position calculation circuit 11 with the current position calculation circuit 11 based on the registered road information in the road map information. . As a correction operation in this case, when the coordinate position obtained by the inertial navigation is within a range of, for example, several tens of meters from the registered road, a calculation process described later is performed to bring the current position closer to the registered road. When the coordinate position obtained by the inertial navigation is more than several tens of meters from the registered road, it is determined that the vehicle is traveling on an unregistered road, and the coordinate position obtained by the inertial navigation is set as the current position. Do not perform correction work by map matching.

The current position information set by the current position calculation circuit 11 is supplied to the display controller 14. This display controller 1
Reference numeral 4 denotes a circuit for controlling display of a road map or the like performed by the display device 4 based on a command from the system controller 15.
A road map is displayed on the display device 4 by the road map information supplied to the display controller 14 via the display controller 2, and the current vehicle position is displayed on the display map based on the current position information supplied to the display controller 14. Is displayed. In this case, the reading of the road map information from the CD ROM device 3 is performed by the current position calculation circuit 1.
The system controller 15 determines the current position obtained in step 1 and stores the road map information near the current position in the CD RO.
This is performed under the control of the M controller 13. This CD RO
Display device 4 based on road map information from M device 3
In the road map display at, all back roads and the like not used for map matching are displayed as long as the roads are stored in the CD ROM.

Here, when the present position is displayed on such a road map, the operation of determining the present position performed by the current position calculating circuit 11 is shown in the flowchart of FIG. The coordinates of the current position (hereinafter, referred to as point A) are set by operating the operation keys 5. This A
From the point, the current position is moved according to the traveling state of the own vehicle. When traveling starts, detection information is supplied from the direction detecting device 1 and the traveling amount detecting device 2 every unit time. Then, the current position (hereinafter referred to as point B ') is obtained by inertial navigation based on the supplied traveling direction detection information and traveling amount detection information. At this time, the road map information near the current position B 'by the inertial navigation is read from the CD ROM device 3, and the current position B' is used as the coordinate position on the registered road used for the map matching (or the map matching). (Coordinate position near the road that can be considered as registered on the road)
Is determined.

At this time, if it is determined that the current position B 'is on the registered road (including the case where the road is on the road by map matching), the current position B' is corrected on the road by map matching (hereinafter referred to as point B). ). That is, as shown in FIG. 3, when the current position B 'of the vehicle departed from the registered point A on the road R by inertial navigation is a point about several meters away from the road R, the point B' , The point B closest to the road R is calculated. Then, as shown in FIG. 4A, point B ′ and point B are connected by a straight line,
A point B "is set on this straight line. At this time, the point B" is set by a length t. [AB] 'proportional to the length [AB]' (= d) from the point A to the point B '. (= T · d) is obtained, and a position approaching the point B from the point B ′ by the time t · d is set as a point B ″. However, as shown in FIG. If the distance is longer than the distance, the point B on the road R is B ″
Point.

The point B ″ obtained in this way is represented on a map.
The current position is set, and from the point B ", the next current
Find your location. Here, the traveling direction of the own vehicle from the point B "
Need to be set. This traveling direction is along the road R
Ω_a, The traveling direction ω of the point B ′_B′
= Ω_a+ Dω (see FIG. 3). Progress at this point B '
Direction ω_B′ Is the road at point B, as shown in FIGS.
Traveling direction ω along R _BAt a predetermined angle ω_errJust approached
The given direction is the traveling direction of point B ".
Row direction ω_B″ = Ω_B'-Ω_errSet as in this case,
Predetermined angle ω_errIs determined from the accuracy of the direction detecting device 1. An example
For example, a geomagnetic sensor was used as the direction detection device 1.
Sometimes, it is determined according to the performance of this geomagnetic sensor,
When using a gyroscope, this gyroscope
Offset drift, scale factor error, etc.
It is decided in consideration of.

In this way, the current vehicle position B "point and the traveling direction ω _B " at this point _B "are calculated, and the coordinate position of the point B" is displayed on the road map displayed on the display device 4. Display as current position.

The above description is for the case where the registered road is near the current position and the up-matching can be performed (that is, the above-mentioned point B can be set). However, the current position B 'by the inertial navigation is registered. When the point B cannot be set on the registered road far from the registered road, the current position B 'by the inertial navigation is determined as the current position as shown in the flowchart of FIG. The position is continuously set, and the position obtained by the inertial navigation is displayed on a road map.

Then, based on the road map information near the position obtained by the inertial navigation, it is determined whether there is a registered road near the current position. At this time, if there is a registered road, it is determined whether a position can be set on the registered road by map matching. If a position can be set on the registered road, the map matching is used. The current position is set as the current position. Then, after the own vehicle position is set by this map matching, the process returns to the first step of the flowchart of FIG.
The operation of correcting the detection position by the above-described inertial navigation with the detection position by the map matching is performed. Alternatively, when the traveling state from the own vehicle position obtained by the map matching is far from the registered road, the position detection is performed again only by the inertial navigation.

Next, a description will be given of a state in which the navigation device of the present embodiment actually displays the traveling position on the road map. First, the coordinate position of the starting point is input by the operation key 5. When the coordinate position of the starting point is supplied to the arithmetic processing unit 10, road map information near the coordinate position is stored in a CD.
The ROM controller 13 reads from the CD ROM mounted on the CD ROM device 3 and displays a road map near the starting point on the display device 4. And after the car equipped with this device starts running from the starting point,
The display range of the road map is moved in accordance with the own vehicle position obtained by the current position calculation circuit 11.

In this embodiment, for example, when the starting point is on the registered road, when the position detected by the inertial navigation deviates from the registered road, the position detected by the inertial navigation is detected by map matching. The vehicle travels while the coordinate position between the position and the designated position is set as the own vehicle position. That is, as shown in FIG. 7, for example, starting from the registered point A on the road R, when the point B 'obtained by the inertial navigation deviates from the road R by several to several tens of meters, this B' The following two points can be considered as causes of the difference between the point and the point B on the road R.

The case where the true traveling position is on the road R and the point B ′ is obtained by the detection error of the direction detecting device 1 and the traveling amount detecting device 2. When the vehicle travels on an unregistered road that is separated from the road R at an acute angle, and the point B ′ indicates an accurate traveling position.

Here, in the state where the point B 'and the point B have been obtained, it is impossible to determine which is the correct position. Therefore, the point B "between the points is set by the above-mentioned operation (the procedure of the flowchart of FIG. 2). The own vehicle position is obtained from the point B ″. Then, as shown in FIG. 7, a point C "is set between the current position C 'by the next inertial navigation and the point C on the road by the map matching. Find the current position.

By setting the current position in this way, when the vehicle deviates from the registered road R due to the above-described cause (detection error of the direction detecting device 1 or the traveling amount detecting device 2), for example, FIG. As shown in the figure, the vehicle positions B ", C", and D ", which are sequentially calculated according to the traveling of the vehicle, gradually approach the road R, and eventually the vehicle position returns to the road R, The error is eliminated, and the road R registered for the above-described reason (because the vehicle has entered another road that branches off at an acute angle)
When the vehicle deviates from the road, for example, as shown in FIG. 8B, it is assumed that the vehicle travels on an unregistered non-main road R ′ (this road R ′ is displayed on a road map).
Unless this road R 'is parallel to the road R, the above-mentioned B "
Even if the correction is made by the point C and the point ‥‥, the position of the own vehicle moves away from the road R, and the position cannot be set on the road R by the map matching. Judging that it is running,
Position detection is performed only by inertial navigation, and the detected current position is displayed on a road map. Then, the display position is on the road R 'by the position detection based only on the inertial navigation.

As described above, according to the navigation apparatus of the present embodiment, when the detected position is corrected by map matching, the position is corrected in consideration of the detection state. There is no accumulation of errors in running, and when driving on a backstreet with narrow roads or entering another road at an acute angle, it may be mistaken for other roads as in the case of only map matching And the reliability of the display position is high. In this case, for example, even when the vehicle temporarily leaves the road at a gas station or a parking lot, the display position is away from the road. For example, as shown in FIG. 8, the display position on the road map changes smoothly, and the display position does not fluctuate rapidly on the road unlike the conventional map matching, and the display position does not move unnaturally. do not do.

In the above-described embodiment, when switching to position detection using only inertial navigation on the way, subsequent position detection is performed by inertial navigation from a point at which map matching is possible (for example, point C 'in FIG. 8B). I tried to do
For example, in the case of FIG. 8B, the detected position only by the inertial navigation from the point A which has begun to deviate from the road R is stored, and when it is determined that the map matching can be performed at the point C ', the stored point A is used. May be switched to the current position by the inertial navigation alone.

Further, the present invention is not limited to the above embodiment,
It goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0027]

According to the present invention, good map matching that respects the detected position is performed, there is no accumulation of errors due to long-time running, and the map matching does not mistake for another road. There are reliable benefits. When the detected position is far away from the road, the position is displayed in a good state in which the detected position is respected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing one embodiment of a navigation device of the present invention.

FIG. 2 is a flowchart for explaining the example of FIG. 1;

FIG. 3 is an explanatory diagram showing a detection state in the example of FIG. 1;

FIG. 4 is an explanatory diagram showing a detection state in the example of FIG. 1;

FIG. 5 is an explanatory diagram showing a detection state in the example of FIG. 1;

FIG. 6 is an explanatory diagram showing a detection state in the example of FIG. 1;

FIG. 7 is an explanatory diagram showing a detection state in the example of FIG. 1;

FIG. 8 is an explanatory diagram showing a detection state in the example of FIG. 1;

[Explanation of symbols]

1 direction detector, 2 travel detector, 3 CDR
OM device, 4 display device, 10 processing unit, 11 current position calculation circuit

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) G01C 21/00

Claims (1)

(57) [Claims] 1. A position detecting means for detecting a current position of a moving object, a storing means for storing road map information, a position detecting information supplied from the position detecting means, and a road map read from the storing means. Computing processing means for calculating current position information based on the information; and display means for displaying a road map based on the road map information and displaying a position on the road map based on the current position information. A first detection position based on the position detection information obtained by the position detection means, and a second detection position corrected on the registered road based on the road map stored in the storage means. Is set, and a third detection position is set by a predetermined calculation based on the first and second detection positions. The third detection position is set as the current position information in the table. It is displayed on the unit, if it can not set the second detection position, the navigation device the first detection position so as to be displayed on the display means as the current position information.