JP2675146B2 - Navigation device for vehicles - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicular navigation device that estimates and calculates a traveling position of a vehicle and displays the calculated traveling position together with a road map in an area where the vehicle travels. .

2. Description of the Related Art A vehicle navigation system mounted on a vehicle has been proposed as an on-road driving assistance system in the field of automobile traffic. As disclosed in Japanese Patent Application Laid-Open No. 61-209316, for example, a vehicle navigation system includes a vehicle destination set in advance by a driver, a scheduled route to the destination, and a current position of the vehicle. Is displayed in an image together with a road map having a predetermined scale so that the driver can guide the vehicle to the destination in accordance with the image display.

In the operation of such a vehicle navigation system, it is necessary to detect the position of the traveling vehicle moment by moment, but the current position of the vehicle is roughly classified by using, for example, an artificial satellite. A method of receiving external information such as GPS signals that can be received from an artificial satellite in the Global Positioning System (GPS), which is a radio navigation system, and identifying the vehicle position based on the received external information. Without using information, for example, based on the detection output of the vehicle speed sensor that can calculate the traveling distance of the vehicle and the detection output of the geomagnetic sensor that corresponds to the direction of the vehicle, the position of the vehicle relative to the reference position The method of estimating and calculating

When external information is used to detect the position of the vehicle, the advantage of detecting the absolute position of the vehicle is obtained, but on the other hand, for example, external information such as GPS signals may occur due to reception interference caused by various radio wave obstacles on the ground. Is not received, so that there is a disadvantage that the position of the vehicle is not detected. Therefore, even if a method of using external information for vehicle position detection is adopted, based on the detection output of the vehicle speed sensor and the detection output of the geomagnetic sensor in order to cope with the situation where the external information is not properly received. The method of estimating and calculating the position of the vehicle is often used together.

In the case where a vehicle navigation system is constructed in which the position of the vehicle traveling based on the detection output of the vehicle speed sensor and the detection output of the geomagnetic sensor, that is, the vehicle position is estimated and calculated, The relative position of the vehicle, which is estimated and calculated from the detection output and the detection output of the geomagnetic sensor, and a plurality of node points set in advance corresponding to the road network and data about a traveling link between two adjacent node points are stored. By sequentially referring to the position represented by the map data read from the database, the position on the road network will be obtained, which is a self-contained navigation
It is called a system.

In such a self-contained navigation system, the vehicle position is periodically estimated and calculated, for example, using the departure position as a relative position with the reference position, and is sequentially displayed on the road map displayed as an image based on the map data. Therefore, the errors involved in the calculation of each vehicle position may be accumulated, and the deviation of the vehicle position shown on the road map from the actual traveling position may gradually increase. Therefore, the Showa filed earlier by the applicant of the present application
Japanese Patent Application No. 166026 (Japanese Patent Application No. 63-166026, 1988 7)
(Applied on May 5th), when the vehicle position is estimated and calculated and the image is displayed together with the road map, the calculation based on the detection output of the vehicle speed sensor and the detection output of the geomagnetic sensor is performed with reference to the map data, The estimated position on the road map, which is represented by the map data that can be the vehicle position, is calculated, and for each estimated position, an evaluation value is calculated that indicates the degree of possibility of being the position of the vehicle with respect to the closest node point ahead of it. Then, the one having the best evaluation value among the node points corresponding to each inferred position is selected, and the one having the selected node point among the inferred positions as the closest node point ahead is selected as the road. Deviation of the vehicle position shown on the road map from the actual execution position by selecting as the vehicle position to be shown on the map A system has to be avoided that gradually increases have been proposed.

(Problems to be Solved by the Invention) As described above, the node point having the best evaluation value is selected from among the node points corresponding to the respective estimated positions on the road map, and the selected node point is selected as the destination. In a system in which the estimated position that is the closest node point is selected as the vehicle position to be shown on the road map, the number of node points corresponding to each estimated position on the road map becomes large. Therefore, there is a tendency that the calculation processing of calculating the evaluation value for each node point and selecting the node point based on the calculated evaluation value imposes an excessive burden on the calculation processing unit. In addition, it takes a relatively long time, which may reduce the accuracy of the vehicle position shown on the road map.

In view of such a point, the present invention calculates the position of a traveling vehicle as a vehicle position on a road map represented by map data, and configures an autonomous navigation system that displays an image together with the road map. It is possible to prevent the deviation of the vehicle position shown above from the actual traveling position from gradually increasing, and moreover, the arithmetic processing for calculating the vehicle position on the road map imposes an excessive burden on the arithmetic processing unit. It is an object of the present invention to provide a vehicular navigation device that is capable of reducing the risk of the occurrence of such a situation and the situation in which such arithmetic processing takes a relatively long time.

(Means for Solving the Problems) In order to achieve the above-mentioned object, a vehicle navigation device according to the present invention is a vehicle navigation system in which a vehicle travels between a plurality of node points and between two adjacent node points on a road network. A map data storage unit that stores map data related to links, a running state detecting unit that detects a running state of a vehicle, a satellite signal in a satellite navigation system, and a vehicle position based on the received satellite signal. The satellite signal processing unit that obtains the position data, the calculation processing unit that obtains the display vehicle position to be displayed on the road map represented by the map data, and the display vehicle position that is obtained from the calculation processing unit are retrieved from the map data storage unit. Image display means for displaying together with the road map represented by the map data, Data representing the traveling state of the vehicle obtained based on the detection output from the state detection means, specifically, the calculation based on the data representing the traveling distance and direction of the vehicle, the map data retrieved from the map data storage unit The position of the vehicle represented by the position estimation calculation means and the position data obtained from the satellite signal processing unit for obtaining the estimated position on the road map represented by the map data that can be the position of the vehicle, and the road represented by the map data. Of the estimated positions obtained by the reference position setting means and the position estimation calculation means obtained as the reference position on the map, those having a distance from the reference position within a predetermined value are selected. For each inferred position, it may be the position of the vehicle with respect to the closest node point in front of it. Node point evaluation value calculating means for obtaining an evaluation value indicating the degree of sex, and one of the node points for each of the selected estimated positions based on the evaluation value, and the selected node point among the selected estimated positions And a position selecting means for selecting the closest node point as the display vehicle position.

(Operation) In the vehicle navigation device according to the present invention configured as described above, in the arithmetic processing unit, an operation based on the detection output from the traveling state detecting means is performed with reference to the map data, The estimated position on the road map, which is represented by the map data that can be the vehicle position, is calculated, and for each estimated position, an evaluation value is calculated that indicates the degree of possibility of being the position of the vehicle with respect to the closest node point ahead of it. Then, select a specific one of the node points corresponding to each of the estimated positions based on the evaluation value,
The estimated position is the position obtained from the satellite signal processing unit when selecting the one of the estimated positions that has the selected node point as the closest node point in the forward direction as the display vehicle position to be shown on the road map. The distance from the reference position set based on the data is limited to those within a predetermined value. Therefore, the number of node points for which the evaluation value is calculated is limited, and the calculation process for selecting the display vehicle position may impose an excessive burden on the calculation processing unit, and the calculation process is relatively difficult. The situation that requires a long time will be reduced respectively, and the limitation of the estimated position is performed based on the reference position set based on the position data obtained from the satellite signal processing unit.
Since such a reference position has a high possibility of corresponding to the actual position of the vehicle, the restriction of the estimated position can be prevented from adversely affecting the calculation processing result by the calculation processing unit. .

(Example) FIG. 1 schematically shows an example of a vehicle navigation device according to the present invention.

This example is supposed to be mounted on a vehicle, and performs a geomagnetic sensor 11 that serves as a direction sensor that detects the direction of the vehicle, a vehicle speed sensor 12 that detects the traveling speed of the vehicle, and a current location setting process for the vehicle. Each of the position setting data input unit 13 for inputting data at the time of execution, and the road network in which a traveling link which is a traveling path between a plurality of node points and two adjacent node points in an area where the vehicle travels is set. A map data storage memory 14 in which various data regarding the nodes and each running link is stored as map data is provided, and the geomagnetic sensor 11, the vehicle speed sensor 12, the position setting data input unit 13, and the map data storage memory 14 are provided. It is supposed that the arithmetic processing unit 15 connected to is provided. In addition, G from the satellite in GPS
GPS signal receiving unit 17 with the antenna 16 for receiving the PS signal Sg, and calculates the absolute position of the vehicle based on the received GPS signal Sg, the coefficient for positioning error estimation in GPS GDOP A GPS signal processing unit 18 that performs a process for calculating is also provided, and the GPS signal processing unit 18 is connected to the arithmetic processing unit 15.

Then, the arithmetic processing unit 15, the detection output Dx from the geomagnetic sensor 11, the detection output Ds from the vehicle speed sensor 12, the current setting data Di representing the position and direction of the vehicle from the position setting data input unit 13, map data The map data Dm read out from the storage memory 14, the position data Dg representing the absolute position of the vehicle from the GPS signal processing unit 18, and the signal GPOS representing the value of GDOP are respectively supplied. When the map data Dm is read from the map data storage memory 14, the map selection signal Cm is supplied from the arithmetic processing unit 15 to the map data storage memory 14 and is necessary from the map data Dm stored in the map data storage memory 14. The data that should be read is the map selection signal Cm
It is selected according to.

The calculation processing unit 15 includes a position estimation calculation unit 21, a reference position setting unit 22, an estimated position selection unit 23, and a node point evaluation place calculation unit.
24 and a position selection means 25 are built in.

The position estimation calculation means 21 is data representing the direction of the vehicle obtained based on the detection output Dx from the geomagnetic sensor 11,
Data representing the traveling distance of the vehicle obtained based on the detection output Ds from the vehicle speed sensor 12 and calculation based on the current position setting data Di input from the position setting data input unit 13 are read from the map data storage memory 14. The position of the vehicle is a relative position with respect to the reference position set by the current value setting data Di input from the position setting data input unit 13 and is represented by the map data Dm. The operation to obtain the estimated position on the road map is performed periodically. The estimated position is
Usually, a plurality is calculated.

Reference position setting means 22 is an operation for obtaining the position of the vehicle represented by the position data Dg obtained from the GPS signal processing unit 18 as a reference position on the road map represented by the map data Dm read from the map data storage memory 14. I do.

Estimated position selection means 23, on the road map represented by the map data Dm read from the map data storage memory 14, centered on the reference position obtained by the reference position setting means 22, from the GPS signal processing unit 18 Signal GPO
Radius R that can be changed according to the value of GDOP represented by S
Set an area surrounded by a circle with. At that time, the radius R becomes larger as the value of GDOP becomes larger, that is, the GPS signal processing unit 18
The larger the error range of the position of the vehicle represented by the position data Dg obtained from, the larger the error range. Then, the estimated position selection means 23 further selects, from among the plurality of estimated positions obtained by the position estimation calculation means 21, those within an area surrounded by a circle having a radius R centered on the reference position. To choose as.

Then, the node point evaluation value calculation means 24 determines the position of the vehicle with respect to the nearest node point (hereinafter, referred to as a candidate node point) that is ahead of each of the selected estimated positions selected by the estimated position selection means 23. The position selecting means 25 calculates one of the candidate node points for each of the selected estimated positions, for example, the node point evaluation value calculating means 24. The selected evaluation value having the best evaluation value is selected, and the selected estimated position corresponding to the selected candidate node point is selected as the display vehicle position.

Further, the arithmetic processing unit 15 forms the position signal DP corresponding to the display vehicle position obtained by the position selection unit 25, and outputs the obtained position signal DP, and the above-mentioned map selection. The map selection signal forming means 27 for transmitting the signal Cm is also incorporated.

An image display control unit 19 is connected to the arithmetic processing unit 15, and the image display control unit 19 reads from the map storage memory 14 in response to the map selection signal Cm from the map selection signal forming means 27. The generated map data Dm and the position signal DP from the position signal forming means 26 are supplied. The image display control unit 19 forms an image display signal SD based on the map data Dm and the position signal DP and supplies the image display signal SD to the image display unit 20, whereby the vehicle represented by the map data Dm is displayed on the image display unit 20. The road map in the area where the vehicle travels is displayed, and the vehicle position corresponding to the position signal DP is displayed.

When the navigation operation state is taken under such a configuration, first, the map selection signal Cm from the map selection signal forming means 27 in the arithmetic processing section 15 is supplied to the map data storage memory 14, and the map data is stored. Storage memory 14
From the map data Dm about the road network in which a plurality of node points and travel links in the area where the vehicle at that time is traveling is read out, and is represented by the read map data Dm in the image display unit 20, A road map is displayed in the area where the vehicle travels.

Then, from the position signal forming means 26 in the arithmetic processing section 15, among the estimated positions calculated by the position estimation calculating means 21, to the one which is the display vehicle position through the processing by the estimated position selecting means 23 and the position selecting means 25. Corresponding position signal DP
Is sent to the image display control unit 19, and as a result, the position of the vehicle is displayed on the image display unit 20 so as to be superimposed on the road map with the display vehicle position.

The plurality of estimated positions periodically calculated by the position estimation calculation means 21 are, for example, as shown by (1) to (5) in FIG. 2, XY on the road map represented by the map data Dm. It is obtained as something expressed with coordinates. Then, in such a case, by the reference position setting means 22, the position of the vehicle represented by the position data Dg obtained from the GPS signal processing unit 18 is set as the reference position Ps (Xs, Ys) on the road map, and, The estimated position selecting means 23 sets an area Ar in a circle having a radius R centered on the reference position Ps, and estimates positions (1) to (5).
Estimated positions (2), (3), and (5) within the area Ar are selected and set as the selected estimated positions. In such a case,
The radius R is G represented by the signal GPOS from the GPS signal processing unit 18.
The distance is obtained by multiplying the DOP value, for example, “4”, “6”, “8”, “10”, etc., by a predetermined coefficient α. In addition, GDOP
The values of “4”, “6”, “8” and “10” means that the GPS signal
The error range for the position of the vehicle detected by Sg is
This means that the diameters are approximately 36 m, 50 m, 100 m and 300 m, respectively.

Next, as shown in FIG. 2, the node point evaluation value calculating means 24 calculates the candidate positions for the estimated positions (2), (3), and (5), which are the selected estimated positions. An evaluation value indicating the degree of possibility of being regarded as the position of the vehicle is calculated. Such evaluation value is calculated by the above-mentioned Japanese Patent Application No. 166026 in 1988 (Japanese Patent Application No.
-166026, filed on July 5, 1988). As a result, the arithmetic processing unit 15
In the above, data representing each of the selected estimated position, the candidate node point for each selected estimated position, and the evaluation value of each candidate node point is arranged in the form of a data table as shown in Table-A below, for example. To be done.

In this case, the candidate node points and have the evaluation values of 60, 90 and 80, respectively, and the candidate node point has the best evaluation value.

Then, by the position selecting means 25, candidate node points,
The candidate node point having the best evaluation value of and is selected, and the estimated position (3) which is the selected estimated position corresponding to the candidate node point is transmitted as the display vehicle position.

As a result, the position signal forming means 26 causes the position selecting means 25 to
The position signal DP corresponding to the estimated position (3) selected as the display vehicle position is formed by the image display control unit 19
To send to. As a result, on the image display unit 20, the estimated position (3) is displayed as the vehicle position in a superimposed manner on the road map.

In this way, among a plurality of estimated positions obtained by the position estimation calculation means 21, those related to the setting of the candidate node point and the calculation of the evaluation value for each candidate node point,
By limiting the distance from the reference position set based on the position data Dg obtained from the GPS signal processing unit 18 to be within a predetermined value, the number of candidate node points for which the evaluation value is calculated is limited. As a result, the calculation processing for calculating the display vehicle position is carried out in a relatively short time without the calculation processing section 15 being overloaded. In addition, the limit of the estimated position is limited by the GPS signal processing unit 18
Since a reference position set based on the position data Dg obtained from the center is used as a center, and an area within a circle having a predetermined radius R set according to the value of GDOP at that time is used,
Of the plurality of estimated positions obtained by the position estimation calculating means 21, there is no fear that the one to be selected as the display vehicle position is excluded.

The arithmetic processing unit 15 that performs the operation as described above is configured by using a microcomputer. However, in such a case, the microcomputer performs the operation of estimating and calculating a plurality of estimated positions and limiting the number of them. An example of the program executed in step 1 will be described with reference to the flowchart shown in FIG.

The program shown in the flow chart of FIG. 3 is supposed to be started every predetermined period, and after the start, initial setting is made in step 41, and the following step
At 42, the input signal is captured.

Next, in step 43, data representing the vehicle direction obtained based on the detection output Dx from the geomagnetic sensor 11, data representing the traveling distance of the vehicle obtained based on the detection output Ds from the vehicle speed sensor 12, and The calculation based on the current position setting data Di input from the position setting data input unit 13 is performed by referring to the map data Dm read from the map data storage memory 14, and the estimation on the road map represented by the map data Dm is performed. The position Qi is estimated and calculated, and in step 44, it is confirmed that the number of estimated positions Qi estimated and calculated is n.

Then, in step 45, the reference position Ps is set based on the position data Dg obtained from the GPS signal processing unit 18,
Further, in step 46, the radius R according to the value of GDOP at that time is set based on the signal GPOP obtained from the GPS signal processing unit 18.

Then, after setting the flag i to 1 in step 47, in step 48, the estimated position Qi is calculated from the reference position Ps.
The distance Li to (one estimated position specified by the value of the flag i at that time) is calculated, and in step 49, it is determined whether or not the distance Li calculated in step 48 is larger than the radius R. To do. If the distance Li is larger than the radius R, the estimated position Qi is deleted from the subsequent calculation element in step 50, and then the process proceeds to step 51. If the distance Li is not larger than the radius R, directly. Go to step 51.

In step 51, the flag i is incremented by 1, and in the following step 52, it is determined whether the flag i is equal to n + 1. Then, as a result of the judgment in step 52, if the flag i is not equal to n + 1, that is, if the flag i is less than or equal to n, the process returns to step 48 and the subsequent steps are repeated to repeat the flag i.
Terminates the program when becomes equal to n + 1.

In the above example, in the estimated position selecting means 23 in the arithmetic processing unit 15, the radius R is the GPS signal processing unit 1
Based on the signal GPOS obtained from 8, it is set as changing according to the value of GDOP at that time, but it is not always necessary to do so. For example, in the estimated position selecting means 23, the radius R is always It may be set so as to take a fixed predetermined value.

(Effects of the Invention) As is clear from the above description, according to the vehicle navigation device of the present invention, the position of the traveling vehicle is calculated as the vehicle position on the road map represented by the map data, and the image is displayed together with the road map. In constructing a self-contained navigation system that displays, calculation based on the detection output of the vehicle speed sensor and the detection output of the geomagnetic sensor is performed by referring to the map data, and the estimated position on the road map represented by the map data is calculated. Along with the calculation, an evaluation value indicating the degree of possibility that the vehicle position is the candidate node point for each estimated position is calculated, and a specific one of the candidate node points is selected based on the evaluation value and selected. The estimated point corresponding to the selected candidate node point is selected as the display vehicle position to be shown on the road map. At this time, the estimated position that is involved in the calculation for selecting the display vehicle position is limited to the one whose distance from the reference position set based on the position data obtained from the satellite signal processing unit is within a predetermined value. To be Therefore, the number of candidate node points for which the evaluation value is calculated is limited, and the arithmetic processing for selecting the display vehicle position may impose an excessive burden on the arithmetic processing unit, and the arithmetic processing is compared. It is possible to reduce the situation that requires a long time, and the limit of the estimated position is
It is assumed that the reference position set based on the position data obtained from the satellite signal processing unit is used as a reference, so that the limitation of the estimated position does not adversely affect the calculation processing result by the calculation processing unit. be able to.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a vehicle navigation device according to the present invention, FIG. 2 is a diagram used for explaining the operation of an arithmetic processing unit in the example shown in FIG. 1, and FIG. 3 is FIG. 9 is a flowchart showing an example of a program executed by the microcomputer in the process of setting the vehicle position displayed by the image display means when the microcomputer is used as the arithmetic processing unit in the example shown in FIG. In the figure, 11 is a geomagnetic sensor, 12 is a vehicle speed sensor, 14 is a map data storage memory, 15 is an arithmetic processing unit, 17 is a GPS signal receiving unit, 18 is a GPS signal processing unit, 19 is an image display control unit, and 20 is an image. It is a display unit.

Front page continued (72) Inventor Yasuyuki Masaki 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Co., Ltd. (56) Reference JP-A-2-257013 (JP, A) JP-A-1-109278 (JP, A) JP-A-1-109276 (JP, A) JP-A-2-296172 (JP, A) JP-A-3-26913 (JP, A) JP-A-63-115004 (JP, A) Kaihei 2-17407 (JP, A) JP 64-53112 (JP, A) JP 64-41817 (JP, A) JP 2-275310 (JP, A) JP 1-140015 ( JP, A) JP 63-148115 (JP, A) JP 61-57982 (JP, A) JP 3-29815 (JP, A) JP 61-56910 (JP, A) JP Flat 2-257014 (JP, A) JP 63-198887 (JP, A) JP 64-88312 (JP, A) JP 1-276015 (JP, A) , U) Actual flat 2-33316 (JP, U) Actual flat 1-71611 (JP, U) Actual flat -71610 (JP, U)

Claims (2)

(57) [Claims] 1. A map data storage unit storing map data relating to a plurality of node points on a road network in a region where a vehicle travels and a traveling link between two adjacent node points, and a traveling state of the vehicle. A traveling state detecting means, a satellite signal processing section for receiving satellite signals in the satellite navigation system, and obtaining position data representing the position of the vehicle based on the received satellite signals, and a detection output from the traveling state detecting means. On the road map represented by the map data that can be the position of the vehicle, the calculation based on the data representing the running state of the vehicle obtained based on the map data retrieved from the map data storage unit is performed. Position estimation calculation means for obtaining an estimated position, and position data obtained from the satellite signal processing unit The distance from the reference position is within a predetermined value among the reference position setting means for obtaining both positions as the reference position on the road map represented by the map data and the estimated position obtained by the position estimation calculation means. For each of the estimated position selecting means for selecting an object as the selected estimated position and the selected estimated position, a node point for obtaining an evaluation value indicating the degree of possibility of being the position of the vehicle with respect to the node point closest to the selected estimated position. One of the evaluation value calculation means and the node point for each of the selected estimated positions is selected based on the evaluation value, and the node point selected from the selected estimated positions is the closest node to the destination. An arithmetic processing unit including a position selecting means for selecting a point as a display vehicle position, and a display vehicle position obtained from the position selecting means. The map and image display means for displaying together with the road map represented by the map data retrieved from the data storage unit, a vehicle navigation system, characterized in that it comprises a. 2. A map data storage unit that stores map data relating to a plurality of node points on a road network in a region where a vehicle travels and a traveling link between two adjacent node points, and a traveling speed of the vehicle. A vehicle speed sensor, a direction sensor that detects the direction of the vehicle, a satellite signal processing unit that receives a satellite signal in a satellite navigation system, and obtains position data representing the position of the vehicle based on the received satellite signal, From the map data storage unit, an operation based on the data representing the traveling distance of the vehicle obtained based on the detection output from the vehicle speed sensor and the data representing the direction of the vehicle obtained based on the detection output from the direction sensor is performed. The map data taken out is referred to, and the map data that can be the position of the vehicle is used to Position estimation calculation means for obtaining an estimated position on the road map represented, a reference position for obtaining the position of the vehicle represented by the position data obtained from the satellite signal processing unit as a reference position on the road map represented by the map data. Of the estimated positions obtained by the setting means, the position estimation calculation means, the estimated position selecting means for selecting a position whose distance from the reference position is within a predetermined value as a selected estimated position, and the selected estimated position, respectively. One of a node point evaluation value calculating means for obtaining an evaluation value indicating a degree of possibility of being the position of the vehicle with respect to the nearest node point on the other side, and a node point for each of the selected estimated positions. Is selected based on the evaluation value, and the selected node point among the selected estimated positions is the closest node point in the forward direction. An image that displays a calculation processing unit including a position selection unit that selects one as a display vehicle position and a display vehicle position obtained from the position selection unit together with a road map represented by the map data extracted from the map data storage unit. A vehicle navigation device comprising: a display unit.