KR100504446B1 - Map-matching method considering road connection and road width in navigation system - Google Patents

Abstract

In the navigation system, in the map matching process, by detecting a starting point link corresponding to the current position of the moving object, by reading only the candidate link connected to the starting link among the candidate links within the set search range from the detected starting point link The candidate link to map matching is accurately selected by increasing the map matching speed and calculating the distance between the read candidate link and the current position of the moving object in consideration of the road width of the candidate link.

Description

Map-matching method considering road connection and road width in navigation system in navigation system

The present invention increases the map matching speed by reading only the candidate link connected to the link corresponding to the current position of the vehicle during the map matching process of the navigation system, and increases the map matching speed and calculates the distance between the read candidate link and the current position of the vehicle. The present invention relates to a map matching method considering road connectivity and road width in a navigation system that can accurately select candidate links for map matching by calculating the road width.

In recent years, the traffic has increased with the continuous increase of vehicles, and the problem is that the increase rate of vehicles is very fast compared to the speed of expanding roads and other transportation facilities.

As a solution to this, a navigation system is attracting attention, and a typical navigation system includes a distance to a GPS communication satellite, a current moving speed of a moving object, a route set before a driver, an optimal route to a destination, etc. on a map displayed on a screen. It is a system that provides the driver with various information necessary for driving, such as displaying the information, so that the given road network can be efficiently used.

The navigation system obtains the driving trajectory of the vehicle using the orientation sensor and the distance sensor mounted on the vehicle to obtain the current position of the vehicle, and then compares the driving trajectory of the vehicle with the shape of the road on the digital numerical map and determines the passing road. It is a system that maps the location of vehicles on a map and displays the location of the map-matched vehicles on a screen such as a monitor.

In particular, in the navigation system, the map matching process is a necessary process for displaying the route to be performed on the digital numerical map based on the current position of the vehicle. FIG. 1 is a diagram illustrating a general map matching process.

As shown in the drawing, the XY coordinates of the current position of the vehicle are calculated using GPS data received from the GPS satellites and values measured from the direction or distance sensor of the vehicle, and within the set range based on the calculated XY coordinates. After searching the candidate link, the candidate link having the highest similarity among the searched candidate links is selected, and the map matching is performed. The similarity becomes higher as the shortest distance from the XY coordinate to the candidate link with respect to the current position of the vehicle.

However, in this general map matching process, all the candidate links within the set range are simply searched without considering the connectivity between the currently matched road and the matching candidate road, and then the XY coordinates of the searched candidate links and the current vehicle position are determined. By sequentially comparing the distances of all of them, a problem of unnecessarily increasing the map matching time and significantly reducing the processing speed is generated. This problem will be briefly described with reference to FIGS. 2A and 2B.

First, as shown in FIG. 2A, the data required for map matching includes a link Lij, which is a minimum unit representing a road, and a node Pi, which represents an intersection or branch point, which is a connection point of each link, and the node is a two-dimensional plane. It consists of XY coordinate data, and in each XY coordinate data, attribute information, such as a unique value of a node, a type code, or a road type, is recorded.

Referring to FIG. 2B, the above-described problem is described. First, when the link corresponding to the current vehicle position is L1 and the candidate links searched within the setting range based on the current vehicle position are L2 and L3, the vehicle may be in any case. Since there is no choice but to move along L3, which is connected to L1, which is the road matching the current location, calculating the distance from the current location of the vehicle by searching for the candidate link L2 increases the map matching time unnecessarily. Will slow down.

In addition, if a candidate link is detected in addition to these problems, the general map matching process simply compares the distance from the XY coordinate to the candidate link with respect to the current position of the vehicle, ignoring the road width of the candidate link. There is also the problem of matching with the wrong link.

Accordingly, the present invention was developed to solve the above problems, and has a first object to increase the map matching speed by reading only the candidate link connected to the link corresponding to the current position of the vehicle during the map matching process. .

The second objective is to accurately select candidate links for map matching by calculating the distance between the candidate links read out and the current position of the vehicle. have.

Hereinafter, the present invention will be described with reference to the accompanying drawings.

First, as shown in FIG. 3, the present invention calculates an X-Y position coordinate value corresponding to a current point of a moving object, for example, a vehicle (S30).

In this case, the XY position coordinate value of the current vehicle location using the data collected from the distance sensor attached to the vehicle, the direction sensor such as a gyro or an electronic compass, and the GPS data received from the satellites included in the GPS system. To calculate.

That is, in order to correct the position error of the GPS and match the link on the digital numerical map, the distance between the link input as the XY coordinate data on the digital numerical map is close, and the input angle and the numerical road input from the sensor are input. A coordinate that best matches the slope of the road is calculated, and the calculated coordinate is estimated as the current position of the vehicle, which is a prior art and detailed description is omitted here.

Next, when the XY position coordinate value for the current position of the vehicle is calculated, the starting point link corresponding to the calculated coordinate value is detected and map matching is performed (S31). Map matching to the highest link, i.e., the road on which the vehicle is currently located.

In this case, the position matching degree is calculated by using a separation distance indicating a distance away from the link, and the link having the highest position matching degree has the shortest calculated distance, and the separation distance is closest to the current vehicle position. The straight line distance to the link, the length of the line that meets vertically from the current position of the vehicle to the link.

Next, when the starting point link corresponding to the current vehicle position is detected and the map matching is finished, it is determined whether there is another link within the search range based on the XY position coordinates for the current vehicle position (S32). The predetermined range is set in advance for.

For example, the setting range sets the area corresponding to the radius distance r or less based on the X-Y coordinate value corresponding to the current vehicle position as the search range.

The range that can be displayed on the display screen of the highest detailed scale map can be set as the search range, the range of the currently displayed screen can be set as the search range, or the operator can set the search range by operating the input device.

In addition, this setting range can be changed according to a specific condition. For example, the range of the search is reduced in areas with a large number of nodes, such as downtown areas, and the search range is expanded in areas with few nodes such as mountainous areas. It is desirable to be able to set it variably according to a density.

Subsequently, the determination of the presence or absence of the link within the set search range first reads adjacent x and y coordinate values according to the address order based on the x and y coordinate values corresponding to the current position of the vehicle. The distance from the current position of the vehicle is calculated using the x coordinate value and the y coordinate value, and the reading and calculating operations are repeatedly performed sequentially until the calculated distance is less than or equal to the radius distance r.

At this time, by inserting link information between the XY coordinate data to be read when the read and calculate operation is repeated, it is possible to determine the presence or absence of the link within a set radius around the position coordinate. The XY position coordinate data or link information is stored in a recording storage device such as an SRAM or a CD-ROM.

On the other hand, if it is determined that there is another candidate link in addition to the starting point link corresponding to the current vehicle position, it is determined whether the candidate link is connected to the starting point link (S34), and the candidate link according to the determination result. Is recorded in the matching candidate link list (S35).

At this time, the determination of the candidate link and the recording of the candidate link list, for example, first read sequentially the nearest node connected to the starting link in the order of addresses, and then write to the address immediately after the read nearest neighbor address. Preferably, the detected candidate link information is detected and the detected candidate links are recorded in the matching candidate link list, and the matching candidate link list is tabulated to be automatically recorded and updated according to the position of the vehicle.

Next, by calculating a straight line distance between the candidate link recorded in the candidate link list and the coordinate value corresponding to the current position, the candidate link having the shortest distance, that is, the candidate link having the highest similarity, is selected to match the map with the selected candidate link. (S36).

In this case, in order to select a candidate link more accurately, it is preferable to subtract the road width of the candidate link from the calculated distance to select a candidate link corresponding to the shortest distance as a result of the subtraction. For example, when the X coordinate data is 16 bits, the road width information records the X position coordinates in the lower 11 bits and the road width related information in the upper 5 bits.

4 is a view for explaining an example of determining whether there is another link within a search range based on an X-Y position coordinate corresponding to a current vehicle position after detecting a starting point link.

As shown in FIG. 2, when the starting point link corresponding to the current position P0 of the vehicle is detected and the map matching is completed, another link within the search range based on the XY position coordinate corresponding to the current position P0 of the current vehicle is detected. To determine whether there is, a predetermined range is set in advance for the search range.

For example, the setting range sets the area corresponding to the radius distance r or less on the basis of the X-Y coordinate corresponding to the current position P0 of the vehicle as the search range.

Subsequently, to determine whether there is a link within the search range set as described above, first, adjacent xy position coordinates are read in an address order based on the XY position coordinates corresponding to the current position P0 of the vehicle, and the read xy position coordinates are read. The distance from the current position of the vehicle is calculated, and the reading and calculating operations are repeatedly performed sequentially until the calculated distance is equal to or less than the radius distance r.

At this time, by reading out the link information inserted between the XY position coordinate data representing the node one by one, it is determined whether there is a link within the set radius r, where L1, L2, L3, L4, L5 within the set radius. It is determined that there are 5 links of.

FIG. 5 is a diagram illustrating a format of the XY position coordinate data as an example. As shown in FIG. 5, position coordinate data from X 1 to Y 1 position coordinate data to X 6 to Y 6 are sequentially recorded from the head address, and the link is performed. Number 21 (L21), 22 (L22) and 23 (L23) are respectively located at the rear end of a node consisting of X1-Y1 position coordinate data, a node consisting of X4-Y4 position coordinate data, and a node consisting of X6-Y6 position coordinate data. The L21 links and L22 links, and the L22 links and L23 links are respectively arranged in the order of addresses, so that when reading sequentially in the order of the head address, another link connected to the link can be detected.

FIG. 6 is a diagram illustrating an example of detecting a candidate link connected to a starting point link corresponding to a current vehicle position using the node and link information shown in FIG. 5.

Detecting a candidate link, for example, first sequentially reads the nearest nodes connected to the starting link in the order of addresses, and then detects the candidate links written at the next address next to the read nearest node address. It is preferable that one candidate link is recorded in a matching candidate link list, and the matching candidate link list is tabulated so that the candidate links are automatically recorded and updated according to the position of the vehicle.

Here, when the link corresponding to the current vehicle position is L1 and the candidate links searched within the set range based on the current vehicle position are L2, L3, L4, and L5, the L1 link and the L2 link are not connected, and the L1 link is not connected. When the vehicle moves along the L3 link through the L1 link when the L3 link and the L3 link are connected, the matching candidate link list because the current position of the vehicle is closer to the L2 link than the L3 link, but the L2 link is not connected to the L1 link. Does not include the L2 link.

Next, another map matching method considering the road width according to the present invention will be described.

7 is a flowchart illustrating a map matching method in consideration of the road width according to the present invention. As shown therein, a step (S70) of calculating a current position coordinate value of a moving object such as a vehicle and a dog matching the calculated coordinate value are shown. Detecting a viewpoint link (S71), searching for a candidate link within a set search range based on the calculated coordinate value (S72), recording the found candidate link in a candidate link list (S73), Calculating a distance between the candidate link and the current position coordinate value (S74), subtracting the road width from the calculated distance (S75), and selecting a candidate link corresponding to the shortest distance as a result of the subtraction, and selecting the current position of the vehicle. Is matched to (S76).

Thus, the map matching method of the present invention first calculates a position coordinate value corresponding to the current point of the vehicle (S70). For example, data collected from a distance sensor attached to the vehicle and a direction sensor such as a gyro or an electronic compass, etc. Using the GPS data received from satellites belonging to the GPS system, the coordinates of the current vehicle location are calculated.

Next, when the current position coordinate value of the vehicle is calculated, a starting point link corresponding to the calculated coordinate value is detected (S71). The detection is, for example, a link having the highest position matching degree based on the calculated coordinate, that is, the vehicle is The map matching is performed on a road estimated to be located at present, and the position matching degree is calculated using a distance indicating the distance from the link, and the link having the highest position matching is the shortest calculated distance. The separation distance is a straight line distance from the current position of the vehicle to the nearest link, and is a length of a line segment vertically meeting from the current position of the vehicle to the link.

Subsequently, when a starting point link matching the current position coordinate value of the vehicle is detected, a candidate link within a set search range is searched and read based on the calculated coordinate value (S72).

For example, the set search range sets an area corresponding to a radius distance r or less based on the x coordinate value and the y coordinate value corresponding to the current vehicle position as the search range.

The range that can be displayed on the display screen of the highest detailed scale map can be set as the search range, the range of the currently displayed screen can be set as the search range, or the operator can set the search range by operating the input device.

In addition, this setting range can be changed according to a specific condition. For example, the surrounding nodes are reduced in areas where there are many nodes such as downtown areas and the search ranges in areas where there are few nodes such as mountains. It is desirable to be able to set it variably according to a density.

On the other hand, when the candidate link is read, the read candidate link is recorded in the matching candidate link list (S73), and the matching candidate link list is tabled so that the candidate link related data recorded according to the position of the vehicle is automatically recorded and updated. It is desirable to.

Next, the distance between the candidate link recorded in the matching candidate link list and the XY coordinate corresponding to the current position is calculated (S74), and the distance corresponding to the road width of the candidate link is subtracted from the calculated distance (S74). In operation S75, the candidate link having the shortest distance is selected and matched with the map in operation S76.

8 is a view illustrating a format of XY coordinate data of a node to be applied to the present invention as an example. As shown in FIG. 8, attribute information recorded in a header of X coordinate data of a node is, for example, used to read data in a reverse direction. Offset information and the like.

Road width related data is recorded in the attribute information of the Y coordinate data of the node, where the length of the coordinate data is 16 bits (2 bytes = 1 word), the Y position coordinate is recorded in the lower 10 bits, and the upper 6 bits. Store road width information in.

9 is a diagram showing an example in which such road width information is displayed by a combination of binary bits. As shown in FIG. 9, for example, a road less than 5.5 m is a binary bit 00000, and 5.5 m to 13 m (1 to 2). Lanes are binary bits 000010, and roads longer than 13m (three to four lanes) are recorded as binary bits 000011. This embodiment is only one example, and the binary bits are spaced at 1m intervals from the minimum setting width to the maximum setting width. Various modifications are possible, such as recording.

As described in detail above, in the navigation system of the present invention, the map matching method considering the road connectivity and the road width, map matching by reading only the candidate link connected to the link corresponding to the current position of the vehicle during the map matching process. The speed can be increased, and the distance between the read candidate link and the current position of the vehicle is calculated in consideration of the road width of the candidate link, thereby accurately selecting the candidate link for map matching.

Although the invention has been described in detail only with respect to the specific examples described, it will be apparent to those skilled in the art that various modifications and variations are possible within the spirit of the invention, and such modifications and variations belong to the appended claims.

1 is a diagram illustrating a map matching method in a general navigation system,

2A is a diagram for explaining nodes and links used in map matching in a general navigation system.

FIG. 2B is a diagram for explaining a problem occurring when matching a map in a general navigation system.

3 is a view showing a map matching method in consideration of the connectivity of the road in the inventor navigation system,

4 is a view for explaining an example of determining whether there is another link within a search range based on an X-Y position coordinate corresponding to a current vehicle position.

5 is a view showing an example of the format of the X-Y position coordinate data applied to the present invention,

FIG. 6 is a diagram illustrating an example of detecting a candidate link connected to a starting point link corresponding to a location of a current vehicle by using node and link information shown in FIG. 5.

7 is a view showing a map matching method in consideration of the width of the road in another navigation system according to the present invention,

8 is a view for explaining the format of the X-Y coordinate data of the node to be applied to the present invention,

9 is a diagram illustrating an example in which the road width information shown in FIG. 8 is displayed by a combination of binary bits.

Claims (4)

Calculating a current position coordinate value of the moving object; A second step of detecting a starting point link matching the coordinate value calculated in the first step; A third step of searching for a candidate link within a set search range based on the coordinate value calculated in the first step, and determining whether the searched candidate link is connected to the starting point link; A fourth step of recording a candidate connected to the starting point link among the candidate links searched in the third step in a matching candidate link list; And And a fifth step of calculating a distance between the candidate link recorded in the matching candidate link list of the fourth step and the coordinate value corresponding to the current position of the moving object and selecting and matching the shortest distance to the map. Map matching method considering road connectivity in system. The method of claim 1, wherein the fifth step; After calculating the distance between the candidate link recorded in the matching candidate link list of the fourth step and the coordinate value corresponding to the current position of the moving object, the road width of the candidate link is subtracted and the candidate corresponding to the shortest distance as a result of the subtraction. A map matching method considering road connectivity in a navigation system comprising selecting a link and matching a map. 3. The method of claim 1 or 2, wherein the matching candidate link list; Map matching method considering road connectivity in navigation system characterized by lookup table Calculating a current position coordinate value of the vehicle; A second step of detecting a starting point link matching the coordinate value calculated in the first step; A third step of searching for a candidate link within a set search range based on the coordinate value calculated in the first step; A fourth step of recording the candidate link retrieved in the third step into a candidate link list; A fifth step of calculating a distance between the candidate link recorded in the matching candidate link list of the fourth step and the current position coordinate value; A sixth step of subtracting the road width from the distance calculated in the fifth step; And And a seventh step of selecting and matching a candidate link corresponding to the shortest distance as a result of the subtraction in the sixth step.