JP2008076123A - On-vehicle navigation apparatus and control method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a car navigation technique for effectively improving accuracy in determining a position of the own vehicle, in a simple manner using two systems of GPS reception means. <P>SOLUTION: A switching means 88 carries out a switching process of calculating average values (position and direction) of a first own-vehicle positional information and a second own-vehicle positional information and adopting them as the position of the own vehicle, instead of results from a map-matching process, in such the case that the positioning accuracy obtained by two GPS receivers is so good as to be equal to or more than a prescribed standard, and positions of the first own-vehicle positional information and the second own-vehicle positional information are close to each other within a prescribed region, and no road information (e. g. , road link) exists in the prescribed region. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement in navigation technology.

  In recent years, with the development of electronic technology, the spread of navigation devices for in-vehicle use is remarkable. The navigation device is mounted on a vehicle such as an automobile, and based on the map data, the position of the vehicle specified by GPS or the like is displayed on the surrounding map, or the destination specified by the user by facility search or cursor is used. The route is searched and calculated, and guidance guidance such as turning directions and turning left and right at intersections is performed with map display and synthesized voice.

  For the calculation of the vehicle position in such a navigation device, generally, the absolute position (for example, position coordinates) of the vehicle is calculated using a GPS receiver, and various sensors are used as the relative position of the vehicle. For example, the speed is obtained from the vehicle speed pulse, and the heading from the gyro is obtained. And the own vehicle position with a position and a direction is obtained from the combination of these absolute positions and relative positions.

  However, the vehicle position obtained in this way is numerical data. On the other hand, the map data used for map display or the like is a line corresponding to a road section (called a link) between intersections (called nodes) corresponding to intersections or inflection points. This is a geometric data structure of connecting with, and represents the network structure of roads and intersections.

  For this reason, it is generally necessary to specify which road on the road the vehicle position, which is only numerical data, corresponds to, and this is called map matching. That is, map matching is to identify the vehicle position calculated as a numerical value to the nearest link or node on the map data that is the basis of the map display on the screen.

Various proposals for improving the accuracy of map matching are also known. For example, when road link data and polygonal area data and parking lot entrance / exit data are stored and the current position is detected by GPS, the vehicle turns right or When turning left and entering the polygonal area, the map matching on the road link is canceled (for example, refer to Patent Document 1), or when it is determined that the vehicle is traveling outside the road from the consistency of the road data and the traveling locus, There is also a method of outputting the estimated current position as a vehicle position without performing position correction (see, for example, Patent Document 2).
Japanese Patent No. 3418080 Japanese Patent No. 3698002

  However, the conventional technologies as described above are based on the premise that the content of the map data matches the actual road conditions, and roads newly established after the creation time of the map data or parking lots that are neither roads nor map data. When driving, there is a problem that map matching to the wrong road may cause confusion.

  As a countermeasure to this problem, when the positioning accuracy of the GPS receiver is high (for example, 3D positioning and the DOP value is low, etc.), map matching is intentionally stopped, and the vehicle position obtained as numerical data There was also a suggestion to use as it is for map display. Here, DOP (Dilution of Precision) is a deterioration index expressing GPS positioning accuracy, and means that the smaller the value, the higher the accuracy.

  However, even in this case, in a radio wave environment in which multipath fading occurs in which the waveform is distorted due to interference with the reflected wave, the positioning result of the GPS receiver may be mistakenly recognized. There was a problem providing location.

  The present invention solves the above-mentioned problems of the prior art, and its purpose is to provide a car navigation technique that effectively improves the accuracy of the vehicle position determination by a simple method using two GPS receiving means. Is to provide.

  In order to achieve the above object, according to one aspect of the present invention, in an in-vehicle navigation device that calculates and displays a vehicle position, two GPS receivers and a first vehicle position from one of the GPS receivers. First position information acquisition means for receiving information, second position information acquisition means for receiving second vehicle position information from the other GPS receiver, and road information storage for storing road information indicating the position of the road Means, map matching means for map-matching at least one of the vehicle position information to any of the road information, and first determination for determining positioning accuracy of the first and second vehicle position information Means, second determination means for determining whether the first host vehicle position information and the second host vehicle position information are within a predetermined range, and the positioning accuracy is better than a predetermined reference, and The first vehicle position If the information and the position of the second vehicle position information are within the predetermined range and the road information does not exist within the predetermined range, the first self-vehicle position is replaced with the map matching result. And switching means for calculating an average value of the vehicle position information and the second vehicle position information and setting it as the vehicle position.

  In this way, based on the positioning results of the two GPS receivers, if the positioning accuracy is good and the position is close, but there is no road link nearby, the average of the position and direction of the two positioning results is calculated. Employing this, and using map matching in other cases, makes it possible to effectively avoid position errors due to unreasonable map matching.

  In another aspect of the present invention, the road information is road link information and road node information. Thus, by using the link corresponding to the road section and the information of the node corresponding to the intersection or the inflection point, appropriate processing accuracy without excess or deficiency is realized.

  Another aspect of the present invention is further characterized in that the first vehicle position information and the second vehicle position information are absolute position information and direction information, respectively. As described above, by determining the absolute position and azimuth information as the two systems of GPS positioning results, it is possible to effectively improve the determination accuracy for both the position and the orientation.

  Another aspect of the present invention is further characterized in that the first determination means determines the positioning accuracy by a DOP value acquired from the GPS receiver. As described above, the determination accuracy can be easily improved by determining the measurement accuracy based on the accuracy index value based on the arrangement of the GPS satellites used for positioning.

  In another aspect of the present invention, the predetermined range is a range within a predetermined radius centered on the first or second vehicle position information. In this way, by determining whether the two vehicle positions are close to each other or the road link based on a circular range with a predetermined radius, high-precision processing can be performed with simple processing based on consistent standards. It can be easily mounted.

  The method and the computer program also conform to the above embodiments.

  As described above, according to the present invention, it is possible to provide a car navigation technique that can effectively improve the accuracy of vehicle position determination by a simple method using two systems of GPS receiving means.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. Note that assumptions common to the explanation in the background art and problems are omitted as appropriate.

[1. Constitution〕
The in-vehicle navigation device (hereinafter referred to as “this device”) in the present embodiment calculates and displays the position of the vehicle, and as shown in the configuration diagram of FIG. , Two GPS receivers R1 and R2, a beacon receiver 2 and FM multiplex receiver 3 for receiving VICS information, a road information storage means 4, a display 5, a speaker 6, and the like.

  Of these, the antennas of the two GPS receivers R1 and R2 are not shown in the figure, but are installed spatially separated from each other, with an interval longer than the wavelength of the frequency used in GPS, For example, it is desirable to install the vehicle at the front and rear, or right and left. However, the processing content in each GPS receiver may be common, and basically, the same type product may be used mutually and positioning may be performed independently.

  The road information storage means 4 is a drive device such as a CD, DVD, HD or the like that stores road information representing the position of the road. This road information includes road link information and road node information as in the conventional case. Constitute.

  The main unit 1 includes a CPU 8 that is an arithmetic control unit of a computer, a storage device 9 such as a memory, a graphic render 10 for display, a user interface 11 that receives an operation with a touch panel function of the display 5, guidance guidance, It has a sound output device 12 for outputting a signal sound or the like to the speaker 6, various sensors 13, a road information storage means 4, and a decoder 14 for exchanging information. These parts are connected by a system bus.

  Among these, the CPU 8 realizes the respective means 81 to 88 shown in FIG. 1 by a predetermined program incorporated in advance, and each of these means realizes and executes a function and action as described below in the present embodiment. Means.

[2. Action)
Whether the vehicle position determination in the present embodiment configured as described above adopts the map matching result or the average value of the vehicle position based on two GPS receivers under the following conditions: Switch. Specifically, when using map matching, the two absolute positional relationships are not close to each other even when the positioning accuracy of the two GPS receivers is poor and when the positioning accuracy of the two GPS receivers is good. Alternatively, when two absolute positional relationships are close but there is a link nearby, map matching is employed.

  In addition, as a premise of the switching determination, the positioning calculation method in each GPS receiver may be the same as in the past, and the CPU 8 processes the vehicle position information in which various sensor outputs are added to the positioning results obtained by each GPS receiver. The switching judgment is made by. An example of the processing procedure is shown in FIG. Further, the table of FIG. 3 shows a more specific case classification as to whether map matching (result) is adopted or an average value based on two GPS receivers is adopted.

  In the example of the flowchart of FIG. 2 and the table of FIG. 3, as a positioning result in each GPS receiver, the positioning position of the GPS receiver R1 is a point (coordinates Xa, Ya), and the positioning position of the GPS receiver 2 is b point. It is assumed that (coordinates Xb, Yb), and an arbitrarily set radius α (for example, 10 m) is used as the predetermined range as a determination reference. In this case, the positioning accuracy of the two GPS receivers is good, and the other point exists within the radius α centered on the point a or b, but only when there is no link within the radius α from the center point. The average value (position and azimuth) of two GPS receivers is employed, and map matching is employed in other cases.

  Here, the positioning accuracy is good, for example, it is desirable to set the DOP value to be equal to or less than a predetermined value in the 3D positioning state even in the case where the positioning accuracy is inferior among the two GPS receivers. Specific criteria are free. In addition, as a mean value based on the two GPS receivers, a specific reference for calculation can be set. For example, the average position of the two position coordinates is the positioning position coordinates of the two GPS receivers. The middle position (midpoint) etc. of the line segment connecting Moreover, as an average azimuth | direction, if the difference is within 180 degrees between each azimuth | direction in two GPS receivers, the average value will be used.

  As a processing procedure, as shown in the flowchart of FIG. 2, when the navigation apparatus (this apparatus) is powered on (step S01), first, the vehicle position calculation using the GPS and the sensor is performed. Specifically, the GPS receiver R1 outputs a positioning result (position a, azimuth θa) (step S02), and the GPS receiver R2 outputs a positioning result (position b, azimuth θb) (step S02).

  Then, the first position information acquisition unit 81 obtains first vehicle position information based on the positioning result (position a, azimuth θa) of the GPS receiver R1 and various sensor information obtained from the various sensors 13 ( First position information acquisition process in step S04).

  Further, the second position information acquisition means 82 obtains second vehicle position information based on the positioning result (position b, direction θb) of the receiver R2 and various sensor information obtained from the various sensors 13 (step) Second position information acquisition process in S04).

  Each of the first vehicle position information and the second vehicle position information includes absolute position information and azimuth information. For example, the first vehicle position information is obtained by correcting the positioning result (position a, direction θa) obtained from the GPS receiver 1 in consideration of sensor information.

  Next, it is determined whether or not map matching can be adopted. That is, the first determination unit 86 determines the positioning accuracy for each of the two GPS receivers R1 and R2 based on the DOP value (Dilution of Precision) acquired from each of them (first determination process), and the second The determination unit 87 determines whether the first vehicle position information and the second vehicle position information are within a predetermined range (second determination process). Here, the predetermined range is, for example, a range within a predetermined radius α centered on the first or second host vehicle position information.

  And the switching means 88 has the positioning accuracy by two GPS receivers better than a predetermined reference, and the positions of the first vehicle position information and the second vehicle position information are within the predetermined range. When the road information (for example, road link) does not exist within the predetermined range, the average value of the first vehicle position information and the second vehicle position information is used instead of the map matching result. (Position and direction) are calculated and adopted as the vehicle position (switching process).

  Specifically, if the measurement accuracy of the two GPS receivers is not good (step S05), the process proceeds to map matching adoption (step S11). If the measurement precision is good (step S05), the process proceeds to the next determination. That is, the other position (point) b exists within the radius α around the position (point) a (step S06), and any road link exists within the radius α around the point a. If not, the average value (position and orientation) of the two GPS receivers is adopted (step S10).

  The other position (point) a exists within the radius α with the position (point) b as the center (step S08), and any road link exists within the radius α with the point b as the center. If not, the average value (position and orientation) of the two GPS receivers is adopted (step S10).

  That is, in cases other than these, the map matching result by the map matching means 85 is used (step S11), and the map matching means 85 uses either the first or second vehicle position information or the average of both. Map matching processing is performed as appropriate to map the value to any of the road information.

  In other words, the basic idea of the above determination is that the position obtained by each of the two GPS receivers is close to each other (within the radius α centered on each position point). If there is no road (link) of the map data within the radius α, the position and direction obtained by the GPS receiver can be trusted, and the average value is Adopted. In the above description, the road link is described, but the same may be applied to the node. If the condition for adopting the average is not satisfied, the map matching is performed as usual.

  As described above, when the positioning accuracy of the two GPS receivers is good and the positions of the respective positioning results are close to each other, it is determined that the positioning of the GPS receiver is reliable, and the GPS positioning result (position By adopting (and azimuth), erroneous map matching can be effectively prevented even when there is no link (such as traveling on a new road or traveling on a parking lot). In addition, the vehicle position accuracy is improved and the driver's position accuracy is improved, which has been caused by relying on the positioning accuracy of the GPS receiver at the place where map matching should be performed. It is possible to provide a safe car navigation device without causing it.

[3. effect〕
As described above, according to the present embodiment, it is possible to contribute to the reduction of confusion in the erroneous vehicle position display to the driver, and thus the improvement of driving safety. That is, based on the positioning results of the two GPS receivers as described above, when the positioning accuracy is good and the position is close, but there is no road link nearby, the position and direction of the two positioning results By adopting the average of the above and using map matching in other cases, it is possible to effectively avoid position errors due to excessive map matching.

  In particular, in the present embodiment, appropriate processing accuracy without excess or deficiency is realized by using links corresponding to road sections and node information corresponding to intersections and inflection points. In the present embodiment, the determination accuracy can be effectively improved for both the position and the orientation by targeting the information on the absolute position and direction as the GPS positioning results of the two systems.

  Furthermore, in this embodiment, the determination accuracy can be easily improved by determining the measurement accuracy based on the accuracy index value based on the arrangement of the GPS satellites used for positioning. In addition, in the present embodiment, the determination of whether the two vehicle positions are close to each other or the road link is performed based on a circular range having a predetermined radius, so that the processing can be easily performed with a simple process based on a consistent standard. Accurate processing can be easily implemented.

The functional block diagram which shows the structure of embodiment of this invention. The flowchart which shows the process sequence in embodiment of this invention. The figure which shows the proper use with the map matching in embodiment of this invention, and the average value of two receivers.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Main unit 2 ... Beacon receiver 3 ... FM multiplex receiver 4 ... Road information storage means 5 ... Display 6 ... Speaker 9 ... Storage device 10 ... Graphic render 11 ... User interface 12 ... Audio output device 13 ... Various sensors 14 ... Decoder 81 ... first position information acquisition means 82 ... second position information acquisition means 85 ... map matching means 86 ... first determination means 87 ... second determination means 88 ... switching means R1, R2 ... GPS receiver

Claims (6)

In the in-vehicle navigation device that calculates and displays the vehicle position,
Two GPS receivers,
First position information acquisition means for receiving first vehicle position information from one of the GPS receivers;
Second position information acquisition means for receiving second vehicle position information from the other GPS receiver;
Road information storage means for storing road information representing the position of the road;
Map matching means for map-matching at least one of the own vehicle position information and any of the road information;
First determination means for determining positioning accuracy of the first and second own vehicle position information;
Second determination means for determining whether the first vehicle position information and the second vehicle position information are within a predetermined range;
The positioning accuracy is better than a predetermined reference, the positions of the first vehicle position information and the second vehicle position information are within the predetermined range, and the road information is within the predetermined range. Switching means for calculating an average value of the first vehicle position information and the second vehicle position information and setting it as the vehicle position instead of the map matching result,
A vehicle-mounted navigation device comprising: The road information is
Road link information and road node information,
The in-vehicle navigation device according to claim 1. The first vehicle position information and the second vehicle position information are respectively
Absolute position information and orientation information,
The in-vehicle navigation device according to claim 1 or 2. The first determination means determines the positioning accuracy as follows:
Determining with a DOP value acquired from the GPS receiver;
The in-vehicle navigation device according to any one of claims 1 to 3. The predetermined range is a range within a predetermined radius with the first or second vehicle position information as a center,
The in-vehicle navigation device according to any one of claims 1 to 4, wherein: A method for controlling an in-vehicle navigation device comprising road information storage means for storing road information representing the position of a road and two GPS receivers, and calculating and displaying the position of the host vehicle,
A first position information acquisition process for receiving first vehicle position information from one of the GPS receivers;
A second position information acquisition process for receiving second vehicle position information from the other GPS receiver;
A map matching process for map-matching at least one of the vehicle position information and any of the road information;
A first determination process for determining positioning accuracy of the first and second vehicle position information;
A second determination process for determining whether the first vehicle position information and the second vehicle position information are within a predetermined range;
The positioning accuracy is better than a predetermined reference, the positions of the first vehicle position information and the second vehicle position information are within the predetermined range, and the road information is within the predetermined range. Switching process to calculate the average value of the first vehicle position information and the second vehicle position information to be the vehicle position instead of the map matching result,
Is executed by an arithmetic control unit of a computer.

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