JP2009036651A - Navigation apparatus, navigation method and navigation program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately calculate a vehicle position, in comparison with a conventional apparatus, even if a branch has a small branch angle. <P>SOLUTION: The navigation apparatus is provided with a current position information calculating section 21, and a Y-shape branch determining section 22. The current position information calculating section 21 obtains a current position P, based on a wireless signal from a GPS satellite and identifies the vehicle position Q on map data, based on the predetermined map data and the current position P. The Y-shape branch determining section 22 determines whether there is the branch having a branch point, at which a branch road candidate is branched from a branch source road candidate within a predetermined range in the travelling direction, based on the obtained current position P, calculates a distance D2 between the current position P and a road link of the branch source road candidate, at which the vehicle position Q corresponding to the current position P exists, and a distance D3 between the current position P and a road link of the branch road candidate, at which a virtual vehicle position R corresponding to the current position P exists, if there is the branch, and determines whether a vehicle enters into the branch road candidate by comparing the distances D2, D3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a navigation device, a navigation method, and a navigation program, and more particularly to a navigation device, a navigation method, and a navigation program that measure a position based on a signal from a satellite positioning system such as GPS (Global Positioning System).

  The navigation device mounted on the vehicle calculates current position information such as the current position, moving speed, and direction of the vehicle using a signal from a GPS satellite, a detection signal from a self-supporting sensor, and the like, and stores the calculated current position information and storage By performing matching processing with road map information stored in advance in the medium, the vehicle position on the map data is specified. In such a navigation apparatus, conventionally, when the vehicle enters a Y-shaped branch having a small branch angle, the vehicle position may be displayed incorrectly. On the other hand, when deceleration of the vehicle is detected when passing near the branch point, it is determined that the vehicle is traveling on the branch road, and when vehicle deceleration is not detected, it is determined that the vehicle is traveling on the branch road. A conventional navigation apparatus is disclosed in, for example, Patent Document 1.

JP 2006-17644.

  However, in the navigation device according to the above conventional example, when the branch road is congested near the branch point, the vehicle may decelerate despite traveling on the branch road. There was a possibility of misjudging that you are driving. Further, when both the branch road and the branch road are highways, the road is not necessarily decelerated on the branch road. For this reason, the navigation device according to the conventional example has a problem in that the vehicle position cannot always be accurately determined.

  An object of the present invention is to provide a navigation device, a navigation method, and a navigation program that solve the above problems and that can calculate the position of the vehicle more accurately than in the past even at a branch having a small branch angle. is there.

  A navigation device according to a first aspect of the present invention measures a current position based on radio signals from each transmitting station of a predetermined positioning system, and based on predetermined map data and the current position, the vehicle on the map data Current position information calculating means for specifying a position, and determining whether or not there is a branch having a branch point where a branch road candidate branches from a branch source road candidate within a predetermined range of the traveling direction from the measured current position When a branch exists, (a) a first distance between the current position and a road link of a branch source road candidate where the own vehicle position corresponding to the current position exists; and (b) the current position The branch road candidate is calculated by calculating a second distance from the road link of the branch road candidate where the virtual vehicle position corresponding to the current position exists and comparing the first distance and the second distance. To determine whether or not Characterized in that a branch judgment means for performing branch judgment.

  In the navigation device, the branch determination unit calculates a third distance between the current position before passing the branch point and the road link where the vehicle position corresponding to the current position is present, and the third distance is the third distance. The distance of 1 is corrected.

  Instead, in the navigation device, the branch determination unit determines whether a branch exists within a predetermined range in the traveling direction from the current position and passes through the branch point every predetermined period or predetermined distance. A plurality of fourth distances are calculated, an average value of the calculated fourth distances is calculated as a third distance, and the first distance is corrected by the third distance. . Here, the branch determination means calculates a difference between the fourth distance calculated last time and the fourth distance calculated this time when the fourth distance is calculated for a predetermined period or every predetermined distance, and the difference is calculated as follows. When it is equal to or larger than the predetermined value, the use of at least one fourth distance calculated up to the previous time for the calculation of the average value is stopped.

  In the navigation device, when the branch determination unit is on the same side as the branch road candidate with respect to a road link where the current vehicle position corresponding to the current position is present before the branch point passes. After passing through the branch point, the distance between the virtual host vehicle position corresponding to the current position after passing through the branch point and the road link of the branch source road candidate where the host vehicle position corresponding to the current position exists is third. On the other hand, the current position before passing the branch point is different from the branch road candidate with respect to the road link where the vehicle position corresponding to the current position exists. When present, after passing through the branch point, the distance between the virtual vehicle position corresponding to the current position after passing through the branch point and the host vehicle position corresponding to the current position is third. To greater than the distance, characterized in that to stop performing the branch judgment.

  A navigation method according to a second aspect of the present invention measures a current position based on radio signals from each transmitting station of a predetermined positioning system, and based on predetermined map data and the current position, the vehicle on the map data Determining a position, and determining whether or not there is a branch having a branch point where the branch road candidate branches from the branch source road candidate within a predetermined range of the traveling direction from the measured current position. When present, (a) a first distance between the current position and a road link of a branch source road candidate where the own vehicle position corresponding to the current position exists; and (b) the current position and the current position. Whether the vehicle entered the branch road candidate by calculating the second distance from the road link of the branch road candidate where the virtual vehicle position corresponding to the vehicle exists and comparing the first distance and the second distance Branch decision to determine whether or not Characterized in that it comprises a Cormorant step.

  A navigation program according to a third aspect of the present invention measures a current position based on a radio signal from each transmitting station of a predetermined positioning system, and based on predetermined map data and the current position, the vehicle on the map data Determining a position, and determining whether or not there is a branch having a branch point where the branch road candidate branches from the branch source road candidate within a predetermined range of the traveling direction from the measured current position. When present, (a) a first distance between the current position and a road link of a branch source road candidate where the own vehicle position corresponding to the current position exists; and (b) the current position and the current position. Whether the vehicle entered the branch road candidate by calculating the second distance from the road link of the branch road candidate where the virtual vehicle position corresponding to the vehicle exists and comparing the first distance and the second distance Branch to determine whether or not Characterized in that it comprises a step of performing constant.

  According to the navigation device, the navigation method, and the navigation program according to the present invention, whether there is a branch having a branch point where the branch road candidate branches from the branch source road candidate within a predetermined range of the traveling direction from the measured current position. When a branch exists, (a) a first distance between the current position and a road link of a branch source road candidate where the vehicle position corresponding to the current position exists; A branch is calculated by calculating the second distance between the position and the road link of the branch road candidate where the virtual vehicle position corresponding to the current position is present, and comparing the first distance and the second distance. Since the branch determination for determining whether or not the vehicle has entered the road candidate is performed, the advantageous effect that the vehicle position can be calculated more accurately than in the past even at a branch having a small branch angle is obtained. To.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, in each following embodiment, the same code | symbol is attached | subjected about the same component.

Embodiment.
FIG. 1 is a block diagram showing a configuration of a navigation device according to an embodiment of the present invention. The navigation device according to the present embodiment is mounted on an electronic device such as a navigation system mounted on a vehicle such as an automobile. In FIG. 1, the navigation device includes a sensor circuit unit 1, a controller 2, a road map information database 6, and a display 7. The sensor circuit unit 1 includes a GPS receiving circuit 11, an angle sensor 12, a speed sensor 13, and a distance sensor 14, and the controller 2 includes a current position information calculation unit 21 and a Y-shaped branch determination unit 22. And is configured. The Y-shaped branch determination unit 22 includes a data memory 22m, and the data memory 22m includes branch source road candidate road link information 22a, branch road candidate road link information 22b, distance data 22c, and direction data 22d. And are stored.

  The GPS receiving circuit 11 calculates the absolute position of the vehicle including the latitude, longitude, and altitude on the earth by receiving radio waves from a plurality of GPS satellites, and the moving speed of the vehicle from the calculated Doppler shift of the absolute position. And the absolute position and moving speed of the vehicle are output to the controller 2. The angle sensor 12 is a gyro apparatus such as a vibration gyroscope or an optical fiber gyroscope, for example, an angle in the traveling direction of the vehicle (roll angle), an angle in the right direction with respect to the traveling direction of the vehicle (pitch angle), and the traveling of the vehicle. A relative angle of the vehicle including an angle (yaw angle) perpendicular to the direction is detected and output to the controller 2. The speed sensor 13 is an acceleration sensor, for example, and detects the relative speed of the vehicle by detecting acceleration in a predetermined coordinate system and outputs the detected relative speed to the controller 2. The distance sensor 14 is, for example, a vehicle speed pulse generator that generates and outputs a vehicle speed pulse whose pulse cycle changes according to the traveling speed of the vehicle, and detects the distance traveled by the vehicle and outputs it to the controller 2.

  The road map information database memory 6 is a storage medium such as a rewritable hard disk drive, for example, and includes map data, coordinates of a plurality of nodes set at predetermined intervals on the road, directions of road links connecting the nodes, and Road map information such as road width is stored in advance. The display 7 is a liquid crystal display, for example, and the controller 2 displays the specified vehicle position superimposed on the map data stored in the road map information database memory 6 by the controller 2.

  The controller 2 is, for example, a CPU, and the processes of the current position information calculation unit 21 and the Y-shaped branch determination unit 22 are stored in advance in a ROM (not shown) as a computer program and executed using a RAM (not shown). The current position information calculation unit 21 detects the absolute position and moving speed of the vehicle detected by the GPS receiving circuit 11, and the relative angle, relative speed, and movement of the vehicle detected by the angle sensor 12, the speed sensor 13, and the distance sensor 14, respectively. The current position of the vehicle is calculated by comprehensively using the position and speed of the vehicle calculated by dead reckoning using the distance (details will be described later). The current position of the vehicle calculated by the current position information calculating unit 21 is subjected to matching processing with map data stored in the road map information database memory 6 and is calculated as the own vehicle position. Hereinafter, the calculated position of the vehicle is referred to as “current position”, and the position of the vehicle specified by matching with map data is referred to as “own vehicle position”.

  The Y-shaped branch determination unit 22 is based on the current position and the vehicle position calculated and specified by the current position information calculation unit 21, respectively, and the road map information in the road map information database memory 6 through the current position information calculation unit 21. Is used to determine branching in Y-shaped branching (details will be described later).

  First, a method for calculating the current position of the vehicle by the current position information calculation unit 21 will be described. FIG. 2 is a perspective view showing a vehicle coordinate system based on the vehicle center O1 of the vehicle 30 for explaining a method of calculating the current position by the current position information calculation unit 21 of FIG. In FIG. 2, the traveling direction of the vehicle is the XB axis, the right direction of the vehicle is the YB axis, and the downward direction perpendicular to the XB-YB axis plane is the ZB axis. Note that “B” on the XB axis, the YB axis, and the ZB axis represents a vehicle coordinate system (Body frame). The angle sensor 12, the speed sensor 13, and the distance sensor 14 are directly installed on the vehicle, and detect output values along the vehicle coordinate system. For example, the angle sensor 12 detects the relative angles of the yaw angle, the pitch angle, and the roll angle around the ZB axis, YB axis, and XB axis, respectively, and the speed sensor 13 detects the relative speed having a component in each axis direction, The distance sensor 14 detects the movement distance in the XB axis direction.

FIG. 3 shows a navigation coordinate system (locally level frame) and an earth coordinate system used for dead reckoning, which explains the method of calculating the current position by the current position information calculation unit 21 of FIG. FIG. The output value of each sensor in the vehicle coordinate system of FIG. 2 is as shown in FIG. 3 in order to perform dead reckoning in the earth coordinate system based on the XC axis, the YC axis, and the ZC axis based on the mass center O2 of the earth. It is necessary to convert to a navigation coordinate system with an XL axis, a YL axis, and a ZL axis centered on the current position O3 of the vehicle. The yaw angle, pitch angle, and roll angle in the vehicle coordinate system obtained from the angle sensor 12 can be transformed into the navigation coordinate system by the coordinate transformation matrix T expressed by the following equation (1) after adding the initial angles. In the following equation (1), θ ₁ is the yaw angle after adding the initial angle, θ ₂ is the pitch angle θ ₂ after adding the initial angle, and θ ₃ is the roll angle after adding the initial angle.

Therefore, using the coordinate transformation matrix T, the relative speed v _B of the vehicle in the vehicle coordinate system obtained by the speed sensor 13 can be converted to the moving speed v _L in the navigation coordinate system by the following equation (2). Note that in the following equation _{(2), v B, x} represents the XB-axis component of the relative velocity _{v B, v B, y} represents a YB-axis component of the relative velocity _{v B, v B, z} is the relative velocity _{v B} V _{L, x} indicates the XL axis component of the relative velocity v _L , v _{L, y} indicates the YL axis component of the relative velocity v _L , and v _{L, z} indicates the ZL of the relative velocity v _L Indicates the axis component. The distance sensor 14 similarly moving distance R _B of the vehicle obtained by, it can be converted to the moving distance R _L in the navigation coordinate system by using the following equation (3). However, since the moving distance _{R B} of the vehicle obtained by the distance sensor 14 is only XB-axis component is the traveling _direction, represented by _{R B = (0,0, R B} , x). Note that in the following equation _{(3), R L, x} represents the XL axis component of the movement distance _{R L, R L, y} represents the YL axis component of the movement distance _{R L, R L, z} is the moving distance _{R L} The ZL axis component of is shown.

Based on the moving velocity v _L and the moving distance R _L of the vehicle in the navigation coordinate system obtained as described above, by considering the initial value of the absolute position of the vehicle obtained by the GPS receiving circuit 11, the map data The current position of the vehicle above can be calculated.

  However, dead-reckoning navigation cannot withstand long-time navigation because errors inherent to each sensor accumulate over time. In view of this, the current position information calculation unit 21 determines the difference between the absolute position and moving speed of the vehicle obtained from the GPS receiving circuit 11 and the current position and moving speed of the vehicle obtained by dead reckoning navigation, respectively, as position errors and speeds that are observation errors. The position error, speed error, and attitude angle error, which are navigation errors, are estimated and corrected by using the Kalman filter as an error, and the final current position, moving speed, and attitude angle of the vehicle are calculated. Thereafter, for example, road links stored in the road map information database 6 are extracted within a radius of 10 m centering on the current position of the vehicle, and the road links where the respective road link directions and the current position are the best are currently traveling. A matching process is performed to determine that the vehicle is on the road, and the vehicle position on the map data is specified. Once the vehicle position is determined, the position may be updated by advancing the distance on the road link from the vehicle position.

  Next, branch determination by the Y-shaped branch determination unit 22 will be described. FIG. 4 is a conceptual diagram showing a road link of a branch road candidate and a branch source road candidate in a Y-shaped branch having a branch angle θ, for explaining a branch determination method by the Y-shaped branch determination unit 22 of FIG. In FIG. 4, nodes N1 to N9 and links Pn + 1 to Pn + 8 between the nodes are shown. The branch road candidate is constituted by road links Pn + 1 to Pn + 5, and the branch road candidates are road links Pn + 1, Pn + 2, Pn + 6 to Pn + 8. Composed. The Y-shaped branch determination unit 22 searches for, for example, up to about five road links connected to nodes at both ends of the road link where the vehicle position exists, and determines whether there is a Y-shaped branch. . If there is a branch, the road map information in the road map information database memory 6 is read out via the current position information calculation unit 21, and the road link information 22a of the branch road candidate and the road link information 22b of the branch road candidate are obtained. It is generated and stored in the data memory 22m (see FIG. 5). At this time, the road link before branching, that is, the road link having a smaller difference among the difference between the direction of the road link Pn + 2 and the direction of the road link Pn + 3 and the difference between the direction of the road link Pn + 2 and the direction of the road link Pn + 6. The Pn + 3 side is set as a branch source road candidate, and the road link Pn + 6 side having a larger difference is set as a branch road candidate. Further, when the branch angle θ between the branch source road candidate and the branch road candidate is, for example, 60 degrees or less, it is determined that the branch is a Y-shaped branch.

  5A is a table showing the road link information 22a of the branch source road candidate stored in the data memory 22m of FIG. 1, and FIG. 5B is the branch road candidate stored in the data memory 22m of FIG. FIG. 5C is a table showing an example of data 23-1 regarding the road link Pn + 1 in each road link information. The road link information 22a of the branch source road candidates stores data 23-1 to 23-5 related to the road links Pn + 1 to Pn + 5 constituting the branch source road candidates in order. The road link information 22b of the branch road candidate stores data 23-1, 23-2, 23-6 to 23-8 related to each road link Pn + 1, Pn + 2, Pn + 6 to Pn + 8 constituting the branch road candidate in order. For example, as shown in FIG. 5C, the data regarding each road link includes the presence / absence of the vehicle position, the link number, the link length, the node numbers of the nodes at both ends of the link, the latitude and longitude of each node, Includes adjacent node information.

  FIG. 6 is a conceptual diagram illustrating a branch determination method by the Y-shaped branch determination unit 22 in FIG. 1 and showing a relationship between the current position P of the vehicle before passing the branch point and the own vehicle position Q on the road link. . FIG. 7 illustrates a branch determination method performed by the Y-shaped branch determination unit 22 of FIG. 1. The current position P of the vehicle after passing the branch point, the own vehicle position Q on the road link, and the virtual own vehicle position R It is a conceptual diagram which shows the relationship. 6 and 7, when the Y-shaped branch determination unit 22 confirms the Y-shaped branch in the traveling direction of the vehicle, the branch where the current position P and the own vehicle position Q corresponding thereto exist before the branch point is passed. The distance D2 from the road link of the former road candidate and the distance between the current position P and the road link D3 of the branch road candidate corresponding to the virtual own vehicle position R are measured. While the host vehicle position Q is actually displayed on the display 7, the virtual host vehicle position R is not displayed on the display 7, but coincides with the host vehicle position Q before passing through the branch point, and passes through the branch point. Thereafter, the calculation is performed by advancing the position on the road link of the branch road candidate by the same distance as the distance of the own vehicle position Q on the road link of the branch source road candidate from the branch point. When the two measured distances are equal, that is, when D2 = D3 as shown in FIG. 6, it is determined that the vehicle is not passing the branch point, while the two measured distances are not equal, that is, As shown in FIG. 7, when D2 ≠ D3, it is determined that the vehicle has passed the branch point.

  FIG. 8 is a conceptual diagram illustrating a method of calculating the correction amount W used for branch determination of the Y-shaped branch determination unit 22 of FIG. In FIG. 8, the Y-shaped branch determination unit 22 starts at time t when it is determined that a Y-shaped branch exists ahead of the branch point, and at each predetermined time, the current position P0 to P5 and the vehicle corresponding to each The distances y (t) to y (t + 5) with the road links where the positions Q0 to Q5 exist are measured and stored in the data memory 22m as distance data 22c. The own vehicle positions Q0 to Q5 coincide with the virtual own vehicle positions R0 to R5. When it is determined that the vehicle has passed the branch point, the average value of the distances y (t) to y (t + 5) stored in the data memory 22m is calculated as the correction amount W using the following equation (4). . In the following equation (4), k is the number of measured distance data, and k = 6 in the example shown in FIG. At this time, the direction data 22d indicating whether or not the current positions P0 to P5 are present on the same side as the branch road candidate with respect to the traveling road link is stored in the data memory 22m. This is because the road link stored in the road map information database memory 6 represents the center line of the road, while the vehicle does not necessarily travel in the center of the road, and the GPS antenna included in the GPS receiving circuit 11 does not necessarily It is necessary to consider that it is not installed in the center.

  FIG. 9 is a conceptual diagram illustrating a branch determination method of the Y-shaped branch determination unit 22 of FIG. In FIG. 9, after the vehicle passes through the branch point, the distance D2 between the current position P6 to P10 and the branch road link where the own vehicle position Q6 to Q10 corresponding to each of the current positions P6 to P10 is corrected by the correction amount W. Calculated as the distance D2a. At this time, when the direction data 22d stored in the data memory 22m indicates that the current positions P0 to P5 before passing through the branch point are on the same side as the branch road candidate with respect to the traveling road link, the distance D2a Is calculated by the following equation (5), and when the current positions P0 to P5 before passing the branch point indicate that the current road link is on a different side from the branch road candidate, the distance D2a is expressed by the following equation (6 ).

[Equation 1]
D2a = D2-W (5)

[Equation 2]
D2a = D2 + W (6)

  Then, the corrected distance D2a between the current positions P6 to P10 and the road links of the branch source road candidates where the own vehicle positions Q6 to Q10 corresponding to the current positions P6 to P10 and the virtual positions corresponding to the current positions P6 to P10 and the respective Of the distances D3 to the road links of the branch road candidates where the own vehicle positions R6 to R10 exist, it is determined that the road candidate having a shorter distance is the road on which the vehicle is actually traveling, and the own vehicle position is determined. Update.

  FIG. 10 illustrates the branch determination method by the Y-shaped branch determination unit 22 of FIG. 1, when the current positions P0 to P5 before passing the branch point are on the same side as the branch road candidate with respect to the traveling road link It is a conceptual diagram explaining Y character branch determination of. In FIG. 10, when the current positions P0 to P5 before passing through the branch point are on the same side as the branch road candidate with respect to the road link being traveled, the vehicle is branched even though the vehicle is traveling on the branch source road. There is a possibility of misjudging that you are driving on the road. Therefore, after passing through the branch point, the current position P or the own vehicle position Q passes a position where the distance D4 between the virtual vehicle position R on the road link of the branch road candidate and the road link of the branch source road candidate exceeds the correction value W. Do not make a branch decision until Thereby, the erroneous determination immediately after passing through the branch point can be avoided.

  FIG. 11 illustrates the branch determination method by the Y-shaped branch determination unit 22 of FIG. 1, when the current positions P0 to P5 before passing the branch point are on the different side from the branch road candidate with respect to the road link that is running It is a conceptual diagram explaining Y character branch determination of. In FIG. 11, similarly, when the current positions P0 to P5 before passing through the branch point are on a different side from the branch road candidate with respect to the road link being traveled, the vehicle is traveling on the branch road. There is a possibility of misjudging that the vehicle is traveling on a branch road. Therefore, after passing through the branch point, branch determination is made until the current position P or the vehicle position Q passes a position where the distance D5 between the vehicle position and the virtual vehicle position R on the road link of the branch road candidate exceeds the correction amount W. Do not do.

  FIG. 12 is a flowchart showing a Y-shaped branch determination process executed by the controller 2 of FIG. First, in step S1 of FIG. 12, the current position P is calculated based on each output value of the sensor circuit unit 1. In step S2, the calculated current position P and the road map information in the road map information database memory 6 are calculated. The vehicle position Q is identified on the road link and displayed on the display 7, and then the process proceeds to step S3. In step S3, it is determined whether or not the road link where the vehicle position Q exists includes a Y-shaped branch within a predetermined number of road links in the traveling direction. If YES, the process proceeds to step S4. If NO, Ends the processing. In step S4, the value n is initialized to 0, and then the process proceeds to step S5. In step S5, based on the road map information in the road map information database memory 6, the road link information 22a of the branch source road candidate and the road link information 22b of the branch road candidate are created and stored in the data memory 22m. In step S7, the current position P is calculated based on the output values of the sensor circuit unit 1. In step S7, the current position P is calculated on the road link based on the calculated current position P and the road map information in the road map database memory 6. After the own vehicle position Q is specified and updated on the display 7, the process proceeds to step S8.

  In step S8, the distance D2 between the current position P and the road link of the branch source road candidate corresponding to the vehicle position Q corresponding thereto, and the branch road candidate including the current position P and the corresponding virtual vehicle position R corresponding thereto. After calculating the distance D3 to the road link, it is determined in step S9 whether or not the distance D2 and the distance D3 are equal. If YES, the process proceeds to step S10, and if NO, the process proceeds to step S12. In step S10, the distance y (t + n) and direction from the current position P to the road link where the vehicle position Q corresponding thereto is present are calculated and stored in the data memory 22m as distance data 22c and direction data 22d, respectively. In S11, after increasing the value n by 1, the process returns to Step S5 and is repeated.

  In step S12, the average value from the distance y (t) to y (t + (n-1)) stored as the distance data 22c is calculated as the correction value W. In step S13, the road link information of the branch road candidate In 22a, the own vehicle position Q is updated by the moving distance detected by the distance sensor 14, updated and displayed on the display 7, and in step S14, the virtual own vehicle position R is determined as the distance in the road link information 22b of the branch road candidate. After updating by updating the moving distance detected by the sensor 14, the process proceeds to step S15. In step S15, it is determined whether or not the direction data 22d indicates that the current position P before passing through the branch point is on the same side as the branch road candidate with respect to the running road link. While the process proceeds to S16, the process proceeds to Step S19 if NO. In step S16, the distance obtained by subtracting the correction value W from the distance D2 is calculated as the distance D2a. In step S17, the distance D4 between the virtual vehicle position R and the road link of the branch source road candidate is calculated. move on. In step S18, it is determined whether or not the distance D4 is larger than the correction value W. If YES, the process proceeds to step S22. If NO, the process returns to step S13 and the process is repeated. In step S19, the distance obtained by adding the correction value W to the distance D2 is calculated as the distance D2a. In step S20, the distance D5 between the vehicle position Q and the road link of the branch road candidate is calculated, and then the process proceeds to step S21. In step S21, it is determined whether or not the distance D5 is larger than the correction value W. If YES, the process proceeds to step S22. If NO, the process returns to step S13 and the process is repeated.

  In step S22, it is determined whether or not the distance D2a is smaller than the distance D3. If YES, the process proceeds to step S23. If NO, the process proceeds to step S24. In step S23, it is determined that the vehicle has entered the branch road, the virtual vehicle position R is updated and displayed as the vehicle position Q, and then the process ends. In step S24, it is determined that the vehicle has not entered the branch road, and the process ends without updating the vehicle position Q.

  As described above, according to the navigation device of the present embodiment, there is a branch having a branch point where the branch road candidate branches from the branch source road candidate within a predetermined range in the traveling direction from the current position P that is measured. When a branch exists, (a) a distance D2 between the current position P and a road link of a branch source road candidate where the own vehicle position Q corresponding to the current position P exists; b) The distance D3 between the current position P and the road link of the branch road candidate where the virtual vehicle position R corresponding to the current position P is present is calculated, and the distance D2 is compared with the distance D3 to branch. Since it is determined whether or not the vehicle has entered the road candidate, the vehicle position is calculated more accurately than in the past even at a branch having a small branch angle.

  In the present embodiment, the navigation device includes the road map information database memory 6 that stores map data, detailed information on roads, and the like. However, the present invention is not limited to this, and a wireless communication device such as a mobile phone or PHS is used. The road map information may be downloaded from the center facility each time.

  Further, the navigation device includes the display 7 and notifies the user of the vehicle position by displaying the map data and the vehicle position. However, the present invention is not limited to this, and notifies the user of the vehicle position by voice. It may be a configuration.

  Further, although the angle sensor 12 detects the roll angle, the pitch angle, and the yaw angle, the present invention is not limited to this, and the roll angle and the pitch angle may be detected by an acceleration sensor.

  Furthermore, although the Y-shaped branch determination unit 22 determines a Y-shaped branch that branches from one road to two roads, the present invention is not limited to this, and the controller 2 has three from one road. You may determine the branch branched to the above roads.

  In addition, the Y-shaped branch determination unit 22 calculates an average value W of the distance y from the time t when it is determined that the Y-shaped branch exists until the vehicle position passes the branch point. However, for example, when the vehicle changes lanes near the Y-shaped branch, the average value W may not be accurately calculated. Therefore, when the amount of change in the distance y from the previous measurement, that is, when the difference between the previously calculated distance y and the currently calculated distance y is, for example, 3 m or more, it is determined that the vehicle has changed lanes. The average value W may be calculated using only the distance y calculated after the lane change, ignoring the distance y calculated so far.

  Further, the Y-shaped branch determination unit 22 measures the distance y every predetermined time from the time t when it is determined that the Y-shaped branch exists. However, the present invention is not limited to this, and the distance y may be measured every predetermined moving distance (for example, 10 m) from the point where it is determined that a Y-shaped branch exists.

  Furthermore, the Y-shaped branch determination unit 22 measures the distance D2 between the current position P and the road link of the branch source road candidate and the distance D3 between the current position P and the road link of the branch road candidate, and the measured 2 Depending on whether the two distances are equal or not, it was determined whether or not the vehicle passed through the branch point. However, the present invention is not limited to this, and it may be determined whether or not the vehicle has passed the branch point depending on whether or not the vehicle position Q has passed the node N3 that is the branch point.

  In addition, the navigation device according to the present embodiment receives a signal from a GPS satellite and measures the current position of the vehicle. However, the present invention is not limited to this, and the GLONASS (Global Navigation Satellite System) operated by Russia and Europe. May receive a signal from a satellite positioning system other than GPS, such as the Galileo system planned.

  As described above, the navigation device, the navigation method, and the navigation program according to the present invention include a branch having a branch point at which a branch road candidate branches from a branch source road candidate within a predetermined range in the traveling direction from the current position that is measured. When a branch exists, (a) a first distance between the current position and a road link of a branch source road candidate where the own vehicle position corresponding to the current position exists; b) calculating the second distance between the current position and the road link of the branch road candidate where the virtual vehicle position corresponding to the current position exists, and comparing the first distance and the second distance; Thus, the branch determination for determining whether or not the vehicle has entered the branch road candidate is performed, so that the vehicle position is calculated more accurately than the conventional case even at a branch having a small branch angle.

  The navigation device, the navigation method, and the navigation program according to the present invention can be used as an in-vehicle navigation device that measures the position of a vehicle based on a signal from a GPS satellite, for example.

It is a block diagram which shows the structure of the navigation apparatus which concerns on one Embodiment of this invention. FIG. 2 is a perspective view showing a vehicle coordinate system based on a vehicle center O1 of a vehicle 30 for explaining a current position calculation method by a current position information calculation unit 21 in FIG. 1. It is a figure which shows the navigation coordinate system and earth coordinate system which perform the calculation of dead reckoning explaining the calculation method of the present position by the present position information calculation part 21 of FIG. It is a conceptual diagram which shows the road link of the branch road candidate and branch origin road candidate in the Y-shaped branch which has the branch angle (theta) explaining the branch determination method by the Y-shaped branch determination part 22 of FIG. (A) is a table showing the road link information 22b of the branch source road candidate stored in the data memory 22m of FIG. 1, and (b) is the road link information of the branch road candidate stored in the data memory 22m of FIG. 22c is a table showing an example of data 23-1 regarding the road link Pn + 1 in each road link information. It is a conceptual diagram which shows the relationship between the present position P of the vehicle before a branch point passage, and the own vehicle position Q on a road link explaining the branch determination method by the Y-shaped branch determination part 22 of FIG. 1 is a conceptual diagram illustrating a relationship between a current position P of a vehicle after passing through a branch point, a host vehicle position Q on a road link, and a virtual host vehicle position R, explaining a branch determination method by the Y-shaped branch determination unit 22 of FIG. It is. It is a conceptual diagram explaining the calculation method of the correction amount W used for the branch determination of the Y-shaped branch determination part 22 of FIG. It is a conceptual diagram explaining the branch determination method of the Y-shaped branch determination part 22 of FIG. FIG. 1 is a conceptual diagram illustrating a branch determination method performed by the Y-shaped branch determination unit 22 in FIG. 1 and illustrating a Y-shaped branch determination when the current positions P0 to P5 are on the same side as a branch road candidate with respect to a traveling road link. It is. 1 is a conceptual diagram illustrating a branch determination method performed by the Y-shaped branch determination unit 22 in FIG. 1 and illustrating a Y-shaped branch determination when the current positions P0 to P5 are on a different side from a branch road candidate with respect to a traveling road link. It is. It is a flowchart which shows the Y-shaped branch determination process performed by the controller 2 of FIG.

Explanation of symbols

1 ... Sensor circuit part,
2 ... Controller,
6 ... road map information database,
7 ... Display,
11 ... GPS receiver,
12 ... An angle sensor,
13 Speed sensor
14 ... Distance sensor,
21 ... Current position information calculation unit,
22 ... Y-shaped branch determination unit,
22a ... Former road candidate link information,
22b ... Branch road candidate link information,
22c Distance data,
22d ... direction data,
22m ... Data memory.

Claims (7)

Current position information calculating means for positioning the current position based on radio signals from each transmitting station of a predetermined positioning system and identifying the vehicle position on the map data based on predetermined map data and the current position; ,
When determining whether there is a branch having a branch point where the branch road candidate branches from the branch source road candidate within a predetermined range of the traveling direction from the current position measured, when a branch exists,
(A) a first distance between the current position and a road link of a branch source road candidate where the own vehicle position corresponding to the current position exists;
(B) calculating a second distance between the current position and a road link of a branch road candidate where a virtual vehicle position corresponding to the current position exists;
A navigation apparatus comprising branch determination means for performing branch determination for determining whether or not the vehicle has entered a branch road candidate by comparing the first distance and the second distance.   The branch determination means calculates a third distance between the current position before passing the branch point and the road link where the vehicle position corresponding to the current position exists, and corrects the first distance by the third distance. The navigation device according to claim 1, wherein:   The branch determination means calculates a plurality of fourth distances for a predetermined period or every predetermined distance from when it is determined that there is a branch within a predetermined range in the traveling direction from the current position until the branch point is passed. The navigation device according to claim 1, wherein an average value of the calculated fourth distances is calculated as a third distance, and the first distance is corrected by the third distance.   The branch determination means calculates a difference between the previously calculated fourth distance and the currently calculated fourth distance when the fourth distance is calculated for a predetermined period or every predetermined distance, and the difference is equal to or greater than a predetermined value. 4. The navigation device according to claim 3, wherein at least one fourth distance calculated up to the previous time is not used for the calculation of the average value.   When the branch determination means is present on the same side as the branch road candidate with respect to a road link where the current vehicle position corresponding to the current position is present before the branch point passes, after the branch point passes, Branch determination until the distance between the virtual vehicle position corresponding to the current position after passing through the branch point and the road link of the branch source road candidate where the vehicle position corresponding to the current position exceeds a third distance When the current position before passing through the branch point is on a different side from the branch road candidate with respect to the road link where the vehicle position corresponding to the current position exists, The branch determination is performed until the distance between the virtual vehicle position corresponding to the current position after passing through the branch point and the vehicle position corresponding to the current position exceeds a third distance. The navigation device according to any one of claims 2 to 4, characterized in that stop. Determining a current position based on a radio signal from each transmitting station of a predetermined positioning system, and identifying a vehicle position on map data based on predetermined map data and the current position;
When determining whether there is a branch having a branch point where a branch road candidate branches from a branch source road candidate within a predetermined range of the traveling direction from the measured current position, and when a branch exists,
(A) a first distance between the current position and a road link of a branch source road candidate where the own vehicle position corresponding to the current position exists;
(B) calculating a second distance between the current position and a road link of a branch road candidate where a virtual vehicle position corresponding to the current position exists;
A navigation method comprising a step of making a branch determination for determining whether or not the vehicle has entered a branch road candidate by comparing the first distance and the second distance. Determining a current position based on a radio signal from each transmitting station of a predetermined positioning system, and identifying a vehicle position on map data based on predetermined map data and the current position;
When determining whether there is a branch having a branch point where a branch road candidate branches from a branch source road candidate within a predetermined range of the traveling direction from the measured current position, and when a branch exists,
(A) a first distance between the current position and a road link of a branch source road candidate where the own vehicle position corresponding to the current position exists;
(B) calculating a second distance between the current position and a road link of a branch road candidate where a virtual vehicle position corresponding to the current position exists;
A navigation program comprising a step of making a branch determination for determining whether or not the vehicle has entered a branch road candidate by comparing the first distance and the second distance.

Images