JP4392074B2 - Car navigation system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle-mounted navigation device, and more particularly, to a navigation device that identifies a moving route that overlaps in the vertical direction when determining the current position of a vehicle.
[0002]
[Prior art]
In the conventional navigation technology, the current position of the host vehicle is determined using the direction information detected by the gyro sensor, the vehicle speed information detected by the vehicle speed sensor, the vehicle position calculated from the GPS signal detected by the GPS receiver, and the like. It was.
[0003]
In addition, in order to further improve the accuracy of determining the current position, map matching processing is performed using the vehicle position detected by the various sensors and map information on the route that the vehicle can pass through stored in the map database. To determine the location of the vehicle on the route.
[0004]
[Problems to be solved by the invention]
However, the position of the own vehicle required by the conventional navigation technology is generally a position on a plane.
[0005]
For this reason, as shown in FIG. 1, when there are routes 20 and 30 overlapping in the vertical direction, even if it is detected that the plane position of the vehicle is the point 110, the altitude at the point 110 is Unless information is taken into account, it is difficult to identify whether the vehicle is actually traveling on the route 20 or the route 30.
[0006]
Examples of such a structure having a route overlapping in the vertical direction include an expressway and a parking building.
[0007]
Altitude information can be obtained by simultaneously receiving GPS signals from four or more GPS satellites. However, it is often difficult to continue receiving GPS signals from four GPS satellites in an urban area where there are structures that overlap in the vertical direction as described above.
[0008]
An object of the present invention is to provide an in-vehicle navigation device capable of determining the position of the own vehicle more accurately by selecting the route in which the own vehicle exists from a plurality of routes overlapping in the vertical direction on the same point. Is to provide.
[0009]
Another object of the present invention is a map database suitable for use in the vehicle-mounted navigation device according to the present invention, wherein there is a route overlapping each other in the vertical direction and the altitude of the map element corresponding to a part of the route. The object is to provide a map database storing information as part of map information.
[0010]
[Means for Solving the Problems]
To achieve the above object, the present invention provides a plane position detecting means for detecting a plane position of the own vehicle, an altitude calculating means for calculating an altitude at the plane position using atmospheric pressure and atmospheric density, When one altitude information corresponding to the plane position is included in the map data, the altitude information is determined as an altitude at the plane position, and a plurality of altitude information corresponding to the plane position is included in the map data The altitude information close to the altitude calculated by the altitude calculating means is determined as the altitude at the plane position, and the altitude determined by the altitude determining means is used at the plane position. Position selection means for selecting a route in which the host vehicle is located from among a plurality of routes that can overlap in the vertical direction, and a position for determining the current position of the host vehicle on the selected route And updating means for updating the atmospheric density using the altitude determined by the altitude determining means, and the altitude calculating means uses the atmospheric density updated by the updating means to Is calculated according to the equation “hd = (Po−P) / (ρg)” (hd is altitude, Po is 1 atm, P is atmospheric pressure, g is gravitational acceleration, ρ is atmospheric density), and the updating means The atmospheric density is updated according to an equation of “ρ = (Po−P) / (gh)” (h is an altitude determined by the altitude determining means).
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of an in-vehicle navigation device to which the present invention is applied will be described with reference to the drawings.
[0015]
The navigation apparatus of this embodiment is provided with the arithmetic processing part 1, the map database 2, the graphic controller 3, and the display 4, as shown, for example in FIG.
[0016]
The arithmetic processing unit 1 is composed of a CPU, a memory, and the like, and determines the current position by the process described below based on information output from the various sensors 5 to 8, and the obtained current position information The necessary map information is read from the map database 3 based on the data, and the data for generating an image to be displayed on the display 4 with the current location mark superimposed thereon is generated and sent to the graphic controller 3. This is a central configuration for processing.
[0017]
The graphics controller 3 develops graphics of the sent image data, and displays a navigation image indicating the current position of the vehicle on the display 4 constituted by a CRT or a liquid crystal display.
[0018]
The map database 2 includes a large-capacity storage medium such as a DVD-ROM (Digital Video Disk-Read Only Memory), a CD-ROM (Compact Disk-Read Only Memory), or an IC (Integrated Circuit) card. In response to this, the data stored in the large-capacity storage medium is read out, and a reading process for notifying this to the arithmetic processing unit 1 is performed.
[0019]
Furthermore, the navigation device of the present embodiment measures the angle at which the moving body rotates as a sensor used to detect the position in moving body navigation, and includes a gyro 5 composed of an optical fiber gyroscope, a vibrating gyroscope, etc. A vehicle speed sensor 8 that measures the distance from the product of the circumference and the number of rotations of the wheel that is measured, and a satellite that receives a signal from a GPS satellite and sets the change rate of the distance and distance between the moving body and the GPS satellite to three or more satellites Is provided with a GPS receiver 7 that measures the current position, traveling direction, and traveling direction of the moving body.
[0020]
Furthermore, in the present embodiment, a pressure sensor 6 is provided that detects atmospheric pressure data in order to obtain the current altitude of the vehicle, which is required in the map matching process considering altitude information described below.
[0021]
Next, the current position determination process in consideration of altitude information, which is executed by the arithmetic processing unit 1, will be described in detail with reference to the flowchart of FIG.
[0022]
This process is repeated at a predetermined cycle. First, the azimuth data, GPS data, vehicle speed data, and atmospheric pressure data detected by the sensors 5 to 8 are captured (step 300).
[0023]
Next, the current altitude hd is calculated from the following formula using the atmospheric pressure data P detected this time and the atmospheric density ρ calculated in the previous main processing (step 301).
[0024]
hd = (Po−P) / (ρg) (Equation 1)
Here, Po is 1 atm, and g is gravitational acceleration. It is assumed that the atmospheric density ρ is initialized by initially setting the reference altitude / reference atmospheric density determined manually or automatically by a predetermined method when the power is turned on.
[0025]
Next, the current position of the host vehicle is provisionally determined using the azimuth data, vehicle speed data, and GPS data acquired in step 300 (step 302). The provisional position determined here is a position on the ground plane (xy plane), and altitude data in the z direction at this point is not taken into consideration.
[0026]
Next, the map information corresponding to the provisional position on the plane determined in step 302 is read from the map database 2, and it is checked whether altitude information is included in the map information (step 303). If altitude information is not included (No in step 303), the process proceeds to step 312 to execute a map matching process performed in a well-known navigation process to determine the current position.
[0027]
On the other hand, if altitude information is included (Yes in step 303), it is checked whether there is one or more altitude information corresponding to the provisional position (step 304), and only one altitude information is present. If YES, go to step 309.
[0028]
In the present embodiment, the map information for indicating each map element constituting the map data stored in the map database 2 includes information including altitude information from the importance and topographical viewpoint of the map element. There is something that cannot be done. For example, for a parking building or highway where there is a route or a part of the route that allows vehicles that overlap in the vertical direction to enter, a plurality of altitude information is stored as part of the map information according to each route. In addition, for structures that do not have a route that overlaps in the vertical direction, for a building with a high degree of importance, or a place that becomes a reference or reference point in terms of topography, one altitude information that represents the structure is displayed as a map. Store as part of the information.
[0029]
In step 305, a plurality of altitude information hm1 and hm2 corresponding to the same provisional position are acquired from the read map information. These altitude information hm1 and hm2 are compared with the altitude hd calculated in step 301 using the atmospheric pressure detected in step 300 (step 306), and altitude information closer to the calculated altitude hd is the current altitude information of the host vehicle. Is determined as the altitude h (steps 307 and 308).
[0030]
Next, map matching is performed in consideration of the determined altitude h (step 309). Specifically, for example, there are a plurality of road pieces or route pieces (x, y dimensions) corresponding to the provisional position obtained in step 302 in a well-known map matching process, and there are any of them. If a weight higher than the level is not obtained, the altitude (z dimension) of each road segment is also checked, and matching is performed to a road segment or route segment having an altitude closer to the altitude calculated in step 301.
[0031]
That is, according to the present embodiment, only the same reliability can be obtained for any road piece or route piece that is a selection candidate, and even if there is a high possibility of mismatching in the past, altitude information is obtained. By taking into account, it is possible to achieve an effect that could not be obtained by the prior art that a more accurate map matching process can be realized.
[0032]
Further, the map matching processing considering altitude information that can be used in the present invention is not limited to the above example, and other methods may be used as long as the map matching processing is performed using altitude information. It doesn't matter what you have. For example, it is good also as a structure which comprises map data and the driving | running | working locus | trajectory of a vehicle by three-dimensional data (plane position and altitude information), respectively, and implements a three-dimensional map matching process about these. Further, when selecting one of a plurality of road pieces to be selected in the conventional map matching process, the road piece is represented by three-dimensional data, It is good also as a structure which compares and compares the road piece close | similar three-dimensionally.
[0033]
In addition, when performing three-dimensional matching in this way, the determination accuracy of a sensor that collects position determination data on a horizontal surface, such as a gyro, and the determination accuracy of altitude information to be used (in this example, detection of a pressure sensor) The weight coefficient in the altitude direction may be adjusted according to the accuracy.
[0034]
Further, using the altitude h determined in step 307 or 308, the value of the atmospheric density ρ is updated from the following equation (step 310).
[0035]
ρ = (Po−P) / (gh) (Equation 2)
Finally, based on the result of the map matching process considering the altitude information in step 309 or the map matching process in step 312, the current position of the host vehicle is determined (step 311), the process returns to step 300, and the above process is repeated. .
[0036]
According to this processing example, it is possible to execute map matching processing using altitude information obtained by using the pressure sensor 6, and it is possible to improve the determination accuracy of the current position of the host vehicle.
[0037]
In particular, by using altitude information, it is possible to identify whether you are traveling on a highway or a general road directly below it, park your car in a parking building, etc. Therefore, when the vehicle position is displayed, the vehicle position can be displayed with higher accuracy.
[0038]
In this processing example, in the processing of steps 305 to 308, a processing example assuming that the altitude information is two will be described. However, even when three or more altitude information is included, the same processing as in this processing example is performed. Can be processed by various methods.
[0039]
In the present embodiment, the pressure is detected using the pressure sensor 6 and the altitude of the own vehicle is determined. However, another altitude detecting means may be used. However, if a pressure sensor is used, the required point data can be obtained directly. For this reason, in this embodiment, the processing load can be reduced compared to the method of measuring the amount of change for a certain period when the altitude is detected using an acceleration sensor or the like and adding the change. it can.
[0040]
【The invention's effect】
According to the vehicle-mounted navigation device of the present invention, the current position of the own vehicle is determined with higher accuracy by selecting the route in which the own vehicle exists from a plurality of routes that overlap in the vertical direction on the same point. be able to.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a state of paths overlapping in a vertical direction.
FIG. 2 is a block diagram showing an embodiment of a navigation device according to the present invention.
FIG. 3 is a flowchart showing an example of navigation processing performed by the navigation device of FIG. 2;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Arithmetic processing part, 2 ... Map database, 3 ... Graphic controller, 4 ... Display, 5 ... Gyro, 6 ... Pressure sensor, 7 ... GPS receiver, 8 ... Wheel speed sensor.

Claims (1)

A plane position detecting means for detecting a plane position of the own vehicle;
Altitude calculating means for calculating the altitude at the planar position using atmospheric pressure and atmospheric density;
When one altitude information corresponding to the plane position is included in the map data, the altitude information is determined as the altitude at the plane position,
When a plurality of altitude information corresponding to the plane position is included in map data, altitude determining means for determining altitude information close to the altitude calculated by the altitude calculating means as the altitude at the plane position;
Route selection means for selecting a route where the host vehicle is located from a plurality of accessible routes overlapping in the vertical direction at the planar position using the height determined by the height determination means;
Position determining means for determining the current position of the host vehicle on the selected route;
Update means for updating the atmospheric density using the altitude determined by the altitude determining means;
With
The altitude calculating means includes
Using the atmospheric density updated by the updating means, the altitude is
hd = (Po−P) / (ρg)
(Hd is altitude, Po is 1 atm, P is atmospheric, g is gravitational acceleration, and ρ is atmospheric density)
Calculated according to the formula
The updating means includes
The atmospheric density,
ρ = (Po−P) / (gh)
(H is altitude the altitude determining means has determined)
Update according to the formula
An in-vehicle navigation device characterized by the above.

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