阅读说明：本技术 用于后方交叉碰撞警告的方法和装置 (Method and apparatus for rear cross-collision warning ) 是由 姜恩奭 于 2021-05-21 设计创作，主要内容包括：公开了一种用于后方交叉碰撞警告的方法包括：将主车辆的周围区域划分成沿横向和纵向排列的多个单元格；创建网格地图,在所述多个单元格之中,在所述网格地图上与所述主车辆周围观测到的静止物体的位置相对应的单元格被分类为已占用的单元格；基于所述网格地图上所述已占用的单元格之间的位置关系,确定反射雷达信号的反射结构的位置；以及基于所确定的反射结构的位置以及由所述雷达观测到的追踪目标的位置和所述追踪目标的移动方向中的任意一项,确定所述追踪目标是否是幽灵追踪目标。(A method for rear cross-collision warning is disclosed comprising: dividing a surrounding area of a host vehicle into a plurality of cells arranged in a lateral direction and a longitudinal direction; creating a grid map on which cells corresponding to positions of stationary objects observed around the host vehicle are classified as occupied cells, among the plurality of cells; determining a position of a reflecting structure that reflects radar signals based on a positional relationship between the occupied cells on the grid map; and determining whether the tracking target is a ghost tracking target based on the determined position of the reflecting structure and any one of a position of the tracking target observed by the radar and a moving direction of the tracking target.)

1. A method of alerting for a rear cross-collision alert, comprising:

dividing a surrounding area of a host vehicle into a plurality of cells arranged in a lateral direction and a longitudinal direction;

creating a grid map on which cells corresponding to positions of stationary objects observed around the host vehicle are classified as occupied cells, among the plurality of cells;

determining a position of a reflecting structure that reflects radar signals based on a positional relationship between the occupied cells on the grid map; and

determining whether the tracking target is a ghost tracking target based on the determined position of the reflecting structure and any one of a position of the tracking target observed by the radar and a moving direction of the tracking target.

2. The method of claim 1, wherein the creating a grid map comprises: classifying cells corresponding to points of the stationary object observed by the radar as the occupied cells.

3. The method of claim 1, wherein the creating a grid map comprises: classifying the cell corresponding to the observed position of a stationary object as the occupied cell in response to the radar maintaining an observation rate equal to or higher than a predetermined reference observation rate for a predetermined reference observation period or in response to the radar receiving a signal amplitude equal to or greater than a predetermined threshold.

4. The method of claim 1, wherein the determining the position of the reflective structure comprises: in response to a distance between the occupied cells in a column of the grid map being within a predetermined threshold distance, determining that the occupied cells represent a reflective structure, and concluding: the cells determined to represent both end points of one reflection structure among the occupied cells are the start occupied cell and the end occupied cell of the one reflection structure, respectively.

5. The method of claim 1, wherein the determining whether the tracking target is the ghost tracking target comprises: determining that the tracking target is the ghost tracking target in response to the tracking target moving to the position of the reflective structure.

6. The method of claim 1, wherein the determining whether the tracking target is the ghost tracking target comprises: determining that the tracking target is the ghost tracking target in response to the lateral position of the tracking target being farther from the host vehicle than the lateral position of the reflective structure, the magnitude of the change in the lateral position of the tracking target being directed in the direction of the host vehicle, and the longitudinal position of the tracking target falling between the start point and the end point of the reflective structure.

7. The method of claim 1, wherein the determining whether the tracking target is the ghost tracking target comprises: determining that the tracking target is the ghost tracking target in response to a lateral position of the tracking target being farther from the host vehicle than a lateral position of the reflecting structure, a magnitude of a lateral position change of the tracking target being directed in a direction of the host vehicle, and a straight line representing a moving path of the tracking target intersecting a position of the reflecting structure.

8. The method of claim 1, wherein the determining whether the tracking target is the ghost tracking target comprises: in response to the lateral position of the tracking target falling between the position of the reflecting structure and the position of the host vehicle, the lateral position of the tracking target changes in a direction toward the host vehicle, and under the condition that the tracking target starts moving from the position of the reflecting structure, the lateral acceleration of the tracking target is physically calculated to be greater than a reference acceleration, determining that the tracking target is the ghost tracking target.

9. An apparatus for rear cross-collision warning, comprising:

a radar configured to observe an object of a surrounding area of a host vehicle; and

a controller configured to:

dividing a surrounding area around the host vehicle into a plurality of cells in a lateral direction and a longitudinal direction, and creating a grid map in which cells corresponding to positions of stationary objects observed around the host vehicle on the grid map are classified as occupied cells;

determining a position of a reflecting structure that reflects a radar signal of the radar based on a positional relationship between the occupied cells on the grid map; and

determining whether the tracking target is a ghost tracking target based on the determined position of the reflecting structure and any one of a position of the tracking target observed by the radar and a moving direction of the tracking target.

10. The apparatus of claim 9, wherein the controller comprises:

a grid map creator configured to divide a surrounding area of the host vehicle into the plurality of cells in a lateral direction and a longitudinal direction, and create the grid map on which the cells corresponding to the position of the stationary object observed around the host vehicle are classified as the occupied cells;

a reflection structure determiner configured to determine a position of the reflection structure reflecting the radar signal based on a positional relationship between the occupied cells on the grid map; and

a ghost-tracking-target determiner configured to determine whether the tracking target is the ghost tracking target based on the determined position of the reflecting structure and any one of the position of the tracking target and the moving direction of the tracking target.

11. The apparatus of claim 10, wherein the grid map creator is further configured to classify cells corresponding to points of the stationary object observed by the radar as occupied cells.

12. The apparatus of claim 10, wherein the grid map creator is further configured to classify the cell corresponding to the observed location of the stationary object as the occupied cell in response to the radar maintaining an observation rate equal to or higher than a predetermined reference observation rate for a predetermined reference observation period, or in response to the radar receiving a signal amplitude equal to or greater than a predetermined threshold.

13. The apparatus of claim 10, wherein the reflection structure determiner is further configured to determine that an occupied cell represents a reflection structure in response to a distance between occupied cells in a column of the grid map being within a predetermined threshold distance, and conclude: the cells determined to represent both end points of the one reflection structure among the occupied cells are the start occupied cell and the end occupied cell of the one reflection structure, respectively.

14. The apparatus according to claim 10, wherein the ghost tracking target determiner is further configured to determine that the tracking target is the ghost tracking target in response to a positional movement of the tracking target to the reflective structure.

15. The apparatus according to claim 10, wherein the ghost tracking target determiner is further configured to determine that the tracking target is the ghost tracking target in response to a lateral position of the tracking target being farther from the host vehicle than a lateral position of the reflective structure, a magnitude of a change in the lateral position of the tracking target being directed in a direction of the host vehicle, and a longitudinal position of the tracking target falling between a start point and an end point of the position of the reflective structure.

16. The apparatus according to claim 10, wherein the ghost tracking target determiner is further configured to determine that the tracking target is the ghost tracking target in response to a lateral position of the tracking target being farther from the host vehicle than a lateral position of the reflective structure, a magnitude of a change in the lateral position of the tracking target being directed in a direction of the host vehicle, and a straight line representing a movement path of the tracking target intersecting the position of the reflective structure.

17. The apparatus according to claim 10, wherein the ghost-tracking-target determiner is further configured to determine that the tracking target is the ghost tracking target in response to a lateral position of the tracking target falling between the position of the reflecting structure and a position of the host vehicle, the lateral position of the tracking target changing in a direction toward the host vehicle, and on a condition that the tracking target starts moving from the position of the reflecting structure, physically calculating that a lateral acceleration of the tracking target is greater than a reference acceleration.

Technical Field

The present invention relates to a method and apparatus for rear cross-collision warning, and more particularly, to a method and apparatus for rear cross-collision warning capable of preventing false warning generated by detecting a radar signal as a ghost (ghost) tracking target reflected by a reflecting structure.

Background

Recently, a system for observing and warning an obstacle or an object by a radar module mounted on a rear side portion of a vehicle is employed.

Particularly, a Rear Cross Collision Warning (RCCW) system tracks an object moving behind a vehicle by a radar module installed at a rear side portion of the vehicle when the vehicle backs up, and issues a warning when the tracked object approaches the vehicle within a certain range.

The rear cross-collision warning system developed in the conventional art has a problem in that a false warning is generated for an object laterally close to the vehicle. Such false alarms may be generated when the radar module detects a ghost tracking target by sensing radar signals reflected back from structures present around the vehicle.

In particular, in recent years, as the frequency of the radar signal employed in the rear-side radar system is increasing to improve the sensing distance or speed resolution, so that the probability of the occurrence of the false target tracking is made greater, the probability of the false warning in the rear cross-collision warning system is also increasing.

The statements in this background are merely provided to enhance an understanding of the background of the present disclosure and are not to be construed as an admission that they correspond to prior art that is known to a person of ordinary skill in the art.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In one aspect, a method for rear cross-collision warning includes: dividing a surrounding area of a host vehicle into a plurality of cells arranged in a lateral direction and a longitudinal direction; creating a grid map on which cells corresponding to positions of stationary objects observed around the host vehicle are classified as occupied cells, among the plurality of cells; determining a position of a reflecting structure that reflects radar signals based on a positional relationship between the occupied cells on the grid map; and determining whether the tracking target is a ghost tracking target based on the determined position of the reflecting structure and any one of a position of the tracking target observed by the radar and a moving direction of the tracking target.

The creating of the grid map may include: classifying cells corresponding to points of the stationary object observed by the radar as the occupied cells.

The creating of the grid map may include: classifying the cell corresponding to the observed position of a stationary object as the occupied cell in response to the radar maintaining an observation rate equal to or higher than a predetermined reference observation rate for a predetermined reference observation period or in response to the radar receiving a signal amplitude equal to or greater than a predetermined threshold.

The determining the position of the reflective structure may comprise: in response to a distance between the occupied cells in a column of the grid map being within a predetermined threshold distance, determining that the occupied cells represent a reflective structure, and concluding: the cells determined to represent both end points of one reflection structure among the occupied cells are the start occupied cell and the end occupied cell of the one reflection structure, respectively.

The determining whether the tracking target is the ghost tracking target may include: determining that the tracking target is the ghost tracking target in response to the tracking target moving to the position of the reflective structure.

The determining whether the tracking target is the ghost tracking target may include: determining that the tracking target is the ghost tracking target in response to the lateral position of the tracking target being farther from the host vehicle than the lateral position of the reflective structure, the magnitude of the change in the lateral position of the tracking target being directed in the direction of the host vehicle, and the longitudinal position of the tracking target falling between the start point and the end point of the reflective structure.

The determining whether the tracking target is the ghost tracking target may include: determining that the tracking target is the ghost tracking target in response to a lateral position of the tracking target being farther from the host vehicle than a lateral position of the reflecting structure, a magnitude of a lateral position change of the tracking target being directed in a direction of the host vehicle, and a straight line representing a moving path of the tracking target intersecting a position of the reflecting structure.

The determining whether the tracking target is the ghost tracking target may include: in response to the lateral position of the tracking target falling between the position of the reflecting structure and the position of the host vehicle, the lateral position of the tracking target changes in a direction toward the host vehicle, and under the condition that the tracking target starts moving from the position of the reflecting structure, the lateral acceleration of the tracking target is physically calculated to be greater than a reference acceleration, determining that the tracking target is the ghost tracking target.

In another aspect, an apparatus for rear cross-collision warning includes: a radar configured to observe an object of a surrounding area of a host vehicle; and a controller. The controller is configured to: dividing a surrounding area around the host vehicle into a plurality of cells in a lateral direction and a longitudinal direction, and creating a grid map in which cells corresponding to positions of stationary objects observed around the host vehicle on the grid map are classified as occupied cells; determining a position of a reflecting structure that reflects a radar signal of the radar based on a positional relationship between the occupied cells on the grid map; and determining whether the tracking target is a ghost tracking target based on the determined position of the reflecting structure and any one of a position of the tracking target observed by the radar and a moving direction of the tracking target.

The controller may include: a grid map creator configured to divide a surrounding area of the host vehicle into the plurality of cells in a lateral direction and a longitudinal direction, and create the grid map on which the cells corresponding to the position of the stationary object observed around the host vehicle are classified as the occupied cells; a reflection structure determiner configured to determine a position of the reflection structure reflecting the radar signal based on a positional relationship between the occupied cells on the grid map; and a ghost-tracking target determiner configured to determine whether the tracking target is the ghost-tracking target based on the determined position of the reflecting structure and any one of the position of the tracking target and the moving direction of the tracking target.

The grid map creator may be further configured to classify cells corresponding to points of the stationary object observed by the radar as occupied cells.

The grid map creator may be further configured to classify the cell corresponding to the observed position of the stationary object as the occupied cell in response to an observation rate of the radar remaining equal to or higher than a predetermined reference observation rate for a predetermined reference observation period or in response to a signal amplitude received by the radar being equal to or greater than a predetermined threshold.

The reflection structure determiner may be further configured to determine that an occupied cell in a column of the grid map represents a reflection structure in response to a distance between the occupied cells being within a predetermined threshold distance, and conclude: the cells determined to represent both end points of the one reflection structure among the occupied cells are the start occupied cell and the end occupied cell of the one reflection structure, respectively.

The ghost-tracking-target determiner may be further configured to determine that the tracking target is the ghost tracking target in response to a positional movement of the tracking target to the reflecting structure.

The ghost-tracking-target determiner may be further configured to determine that the tracking target is the ghost tracking target in response to a lateral position of the tracking target being farther from the host vehicle than a lateral position of the reflecting structure, a magnitude of a lateral position change of the tracking target being directed in a direction of the host vehicle, and a longitudinal position of the tracking target falling between a start point and an end point of the position of the reflecting structure.

The ghost-tracking-target determiner may be further configured to determine that the tracking target is the ghost tracking target in response to a lateral position of the tracking target being farther from the host vehicle than a lateral position of the reflecting structure, a magnitude of a lateral position variation of the tracking target being directed in a direction of the host vehicle, and a straight line representing a moving path of the tracking target intersecting the position of the reflecting structure, the ghost-tracking-target determiner may be further configured to determine that the tracking target is the ghost tracking target in response to the lateral position of the tracking target falling between the position of the reflecting structure and the position of the host vehicle, the lateral position variation of the tracking target being directed in the direction of the host vehicle, and physically calculate that a lateral acceleration of the tracking target is larger than a reference acceleration on a condition that the tracking target moves from the position of the reflecting structure, determining that the tracking target is the ghost tracking target.

Other features and aspects will become apparent from the following detailed description, the accompanying drawings, and the claims.

Drawings

Fig. 1 is a block diagram illustrating a rear cross-collision warning apparatus according to an embodiment of the present invention.

Fig. 2 is a flowchart illustrating a rear cross-collision warning method according to an embodiment of the present invention.

Fig. 3 is a diagram illustrating a first example of a possible occurrence of ghost tracking targets by the rear cross-collision warning apparatus and method.

Fig. 4 is a diagram showing a positional relationship between an observation point and a vehicle observed by a radar module in the example shown in fig. 3.

Fig. 5 is a schematic diagram showing an example of a grid map created from the diagram shown in fig. 4.

Fig. 6 is an exemplary view describing a process of determining a position of a reflecting structure by using a grid map in the rear cross-collision warning method and apparatus according to the embodiment of the present invention.

Fig. 7 is a diagram illustrating the position of the reflection structure obtained from the grid map shown in fig. 5.

Fig. 8 is a diagram showing an example in which a ghost tracking target appears in the example shown in fig. 3.

Fig. 9 is a diagram showing a moving path of the ghost-tracing target appearing in the case shown in fig. 8.

Fig. 10 is a diagram showing a second example in which ghost tracking targets may occur by the rear cross-collision warning apparatus and method.

Fig. 11 is a diagram showing a positional relationship between an observation point and a vehicle observed by a radar module in the example shown in fig. 10.

Fig. 12 is a schematic diagram showing an example of a grid map created by the diagram shown in fig. 11.

Fig. 13 is a diagram illustrating the position of the reflection structure obtained from the grid map shown in fig. 12.

Fig. 14 is a schematic diagram showing the occurrence of a ghost-tracking target in the example shown in fig. 10.

Fig. 15 is a schematic diagram showing a moving path diagram of the ghost-tracing target appearing in the case shown in fig. 14.

Fig. 16 is a diagram showing another example in which a ghost-tracking target appears in the example shown in fig. 10.

Fig. 17 is a schematic diagram showing a moving path diagram of the ghost-tracking target appearing in the case shown in fig. 16.

Detailed Description

A method and apparatus for rear cross-collision warning according to various embodiments will be described in detail below with reference to the accompanying drawings.

Fig. 1 is a block diagram illustrating a rear cross-collision warning apparatus according to an embodiment of the present invention.

Fig. 1 shows a rear cross-collision warning device 12, which may be configured to include a grid map creation unit 121, a reflection structure determination unit 122, and a ghost-tracking target determination unit 123. The grid map creating unit 121 divides an area around the vehicle into a plurality of cells arranged in the lateral and longitudinal directions, and makes the cells correspond to positions where stationary objects are located based on radar observation information; the reflection structure determination unit 122 determines the position of the reflection structure based on the marked cells on the grid map, the marked cells corresponding to the positions where the stationary objects are located; and the ghost tracking target determination unit 123 determines whether the tracking target is a ghost tracking target based on the determined position of the reflecting structure and the moving direction or moving speed of the tracking target observed through the radar module 11.

As known in the related art, the rear cross-collision warning device may monitor the movement of a tracking target observed by the radar module 11 and warn by the warning module 13 when the tracking target approaches the vehicle within a predetermined distance.

The grid map creation unit 121, the reflection structure determination unit 122, and the ghost tracking target determination unit 123 described above may be provided in the control unit 12 for controlling the operation of the rear cross-collision warning apparatus, or may be implemented in the form of an algorithm that performs a corresponding function. Of course, the control unit 12 may also include algorithms for performing operations for processing and calculating routine radar observed signals and determining whether to warn.

Furthermore, the storage unit 14 provided in the rear cross-collision warning device may be used to store the processed data into a program implementing an algorithm executed in the control unit 12 or a corresponding algorithm.

Fig. 2 is a flowchart illustrating a rear cross-collision warning method according to an embodiment of the present invention.

The rear cross-collision warning method according to an embodiment of the present invention may be implemented by the above-described rear cross-collision warning device, and may be performed by the grid map creating unit 121, the reflection structure determining unit 122, and the ghost tracking target determining unit 123 operating sequentially.

As shown in fig. 2, the rear cross-collision warning method according to the embodiment of the invention may be configured to include step S11 in which the grid map creating unit 121 represents the area around the host vehicle in a plurality of cells divided laterally and longitudinally, and classifies the cells corresponding to the positions where the stationary objects are observed by the radar module 11 as occupied cells; a step S12 in which the reflection structure determination unit 122 determines the position of the reflection structure that reflects the radar signal based on the positional relationship between occupied cells marked on the grid map; step S13, in which it is determined whether the tracking target is a ghost tracking target based on the position of the reflection structure and the moving direction and moving speed of the tracking target observed by the radar module 11.

The specific operation of the rear cross-collision warning apparatus and method according to the embodiment of the present invention shown in fig. 1 and 2 will be described below by way of examples of different environments in which ghost-tracking targets may occur.

Fig. 3 is a diagram illustrating a first example of a possible occurrence of ghost tracking targets by the rear cross-collision warning apparatus and method.

Fig. 3 shows an example of a case where the vehicle 200 moves laterally on the rear side of the vehicle parked behind the host vehicle 100 in a parking lot, where the vehicle is parked on both the right and left sides and the rear side of the host vehicle 100.

In the example shown in fig. 3, the radar signal is reflected between the vehicle parked behind the host vehicle 100 and the rear side of the host vehicle 100, so the rear cross-collision warning system erroneously senses that there is a vehicle moving behind the host vehicle even if there is actually no moving vehicle behind the host vehicle 100.

First, a rear cross-collision warning system provided in the host vehicle 100 observes other parked vehicles through the rear-side radar module 11. Reference character "P" in fig. 3 denotes an observation point at which other parked vehicles are observed in the vicinity of the radar module 11 on the rear side of the host vehicle.

Fig. 4 is a diagram showing a positional relationship between the host vehicle and an observation point observed by the radar module in the example shown in fig. 3.

As shown in fig. 4, the position 100 'of the host vehicle 100 and the position P' of the observation point may be marked in the illustration. In the illustration shown in fig. 4, the position P 'of the observation point is marked with respect to passing through the longitudinal axis and the lateral axis through the origin with the center behind the host vehicle 100' as the origin.

Fig. 5 is a schematic diagram showing an example of a grid map created from the diagram shown in fig. 4.

As shown in fig. 5, a grid map is created in step S11, and the grid map creating unit 121 represents the area around the host vehicle in a plurality of cells C1 and C2 into which the lateral direction and the longitudinal direction of the host vehicle are divided.

In step S11, a grid map is created, the grid map creating unit 121 represents the area around the host vehicle in a plurality of cells divided in the lateral and longitudinal directions, and then marks a position corresponding to a point where the stationary object observed by the radar module 11 is represented as P or P 'as an occupied cell C1, and marks other positions not corresponding to the point P or P' as unoccupied cells C2.

In the marking of the occupied cell C1, the grid map creating unit 121 may mark the cell as an occupied cell only as long as the observation rate remains equal to or higher than the predetermined reference observation rate when the predetermined reference observation period or the signal amplitude received by the radar module is equal to or greater than the predetermined threshold value.

This is to further improve the mapping performance of the label occupied cell C1. In general, since radar signal characteristics (bandwidth, dwell time, center frequency, etc.) of the radar vary for each observation period, the observation tendency (range resolution and velocity resolution) may also vary. For this reason, the stationary object information observed in each observation period may vary in the same environment. Therefore, the observation rate remaining equal to or higher than a certain observation rate within a certain period means that there is a high possibility that a stationary object exists at the corresponding position.

Furthermore, since the beam width with respect to the installation position and the vertical angle of the radar module 11 may cause the ground (floor) to be observed as a stationary object, the corresponding cell may be marked only as an occupied cell as long as the amplitude of the signal received by the radar module is equal to or greater than a predetermined threshold value, so as to filter out the ground observation information with a relatively small value.

Fig. 6 is an exemplary view describing a process of determining a position of a reflecting structure by using a grid map in the rear cross-collision warning method and apparatus according to the embodiment of the present invention.

In step S12, the position of the reflection structure is determined, and the reflection structure determination unit 122 may identify the positions of occupied cells in the longitudinal direction for each column of the grid map and determine the reflection structure based on the distance between the occupied cells.

More specifically, as shown in fig. 6, when the longitudinal distance between the k-th occupied cell (BIN (i, k)) and the k + 1-th occupied cell (BIN (i, k +1)) in the i-th column is equal to or smaller than a predetermined threshold value, the reflective structure determining unit 122 may determine that the two occupied cells represent one structure.

That is, when the distance between occupied cells in each column of the grid map is within the predetermined threshold, the reflection structure determination unit 122 may determine that the occupied cell corresponds to one reflection structure, and draw a conclusion that both ends of the occupied cell determined to correspond to one reflection structure are the initial occupied cell and the last occupied cell of the corresponding reflection structure.

Such a reflection structure determination may be performed for each column of the grid map.

Fig. 7 is a diagram illustrating the position of the reflection structure obtained from the grid map shown in fig. 5.

As shown in fig. 7, the reflection structure determination unit 122 may determine the position 500 of the reflection structure based on the positional relationship between occupied cells in each column (parallel to the longitudinal direction) on the grid map shown in fig. 5. It is confirmed that the straight line identified as the position 500 of the reflecting structure (determined by the same process as that shown in fig. 3, 4, 5, and 7) corresponds to the side of the parked vehicle around the host vehicle 100.

Fig. 8 is a diagram showing an example in which a ghost tracking target appears in the example shown in fig. 3.

In the situation shown in fig. 8, the other vehicle 200 is actually moving in the lateral direction, creating no risk to the host vehicle actually moving in the backward direction. However, radar signals reflected back from other parked vehicles may cause a radar module installed in the host vehicle to erroneously sense that the vehicle 200 is very close to the rear side of the host vehicle. Here, reference numeral 200' denotes a position of the sensed ghost tracking target generated by the reflection.

Fig. 9 is a diagram showing a moving path of the ghost-tracing target appearing in the case shown in fig. 8.

In step 13 a ghost tracking target is determined. The ghost tracking target determination unit 123 may determine whether the tracking target observed by the radar module is a ghost tracking target based on the position 500 of the reflection structure and the moving direction of the tracking target.

In the example shown in fig. 8 and 9, the tracking targets 200' and 200 "move towards the reflecting structure 500. In fact, there is little target movement toward a particular structure, and even if the target moves toward a particular structure, the host vehicle cannot be reached. Thus, when the tracking targets 200' and 200 ″ move toward the reflective structure 500, the tracking targets may be determined as ghost tracking targets.

In step S12 a reflective structure is determined. Since the coordinates of the start point and the end point of the reflecting structure have been determined and the position information of the tracking target can be observed by the radar module 11, it can be determined whether the tracking target moves toward the reflecting structure by a simple calculation.

For example, in the examples shown in fig. 8 and 9, when the lateral position of the tracking target is farther from the host vehicle than the lateral position of the reflection structure, the lateral position change (lateral speed) of the tracking target points in the direction of the host vehicle, and the longitudinal position of the tracking target falls between the start point and the end point of the reflection structure, the tracking target may be determined as the ghost tracking target.

More specifically, when the lateral position of the tracking target is farther from the host vehicle than the lateral position of the reflection structure, and the lateral position change (lateral speed) of the tracking target is directed in the direction of the host vehicle, it may be determined that the tracking target is the ghost tracking target based on the determination of whether or not a straight line representing the moving path of the tracking target (obtained from the slope and the intercept of the first-order formula representing the moving path of the tracking target) and a straight line representing the reflection structure intersect with each other.

Fig. 10 is a diagram showing a second example of occurrence of a ghost-tracked object by the rear cross-collision warning apparatus and method.

In the example of fig. 10, the vehicle is parked on the rear side, the right side, and the right rear side of the host vehicle, and a wall is spaced apart from the host vehicle, which is located on the left side of the host vehicle. Also, in fig. 10, reference sign "P" denotes an observation point at which the vehicle is observed by the rear side radar module 11.

Fig. 11 is a diagram showing a positional relationship between the observation point observed by the radar module shown in fig. 10 and the host vehicle in the diagram.

The position 100 'of the host vehicle and the position P' of the detection point may be marked on the illustration as shown in fig. 11. In the diagram shown in fig. 11, the position P' of the observation point is marked by the origin on the basis of passing through the longitudinal axis and the lateral axis, with the center of the rear of the host vehicle as the origin.

Fig. 12 is a schematic diagram showing an example of a grid map created by the diagram shown in fig. 11.

As shown in fig. 12, a grid map is created in step S11, and the grid map creating unit 121 represents the surrounding area of the host vehicle in a plurality of cells C1 and C2 into which the lateral direction and the longitudinal direction of the host vehicle are divided. The size of each cell on the grid map can be appropriately determined as necessary. Preferably, the unit cell may be a square, and the length of one side of the square may be set in advance to a length suitable for the positional relationship calculation in consideration of the resolution of the radar module 11 or the like.

The grid map is created in step S11, and the grid map creation unit 121 may mark the cell corresponding to the observation point P of the radar module 11 as the occupied cell C1.

Fig. 13 is a diagram illustrating the position of the reflection structure obtained from the grid map shown in fig. 12.

As shown in fig. 13, the reflection structure determination unit 122 may determine the position 500 of the reflection structure based on the positional relationship between occupied cells in each column (parallel to the vertical axis) on the grid map shown in fig. 12. The detailed method of determining the position of the reflecting structure is the same as the method described in fig. 6.

Fig. 14 is a diagram showing an example in which a ghost-tracing target appears in the example shown in fig. 10.

In the case shown in fig. 14, as shown in fig. 8 and 9, the vehicle 200 actually moves in the lateral direction, creating no danger to the host vehicle actually moving in the backward direction. But reflection of the radar signal by the reflective structure 500 (e.g., a wall) may cause a radar module mounted on the host vehicle to erroneously sense that the vehicle 200 is very close to the rear side of the host vehicle in the lateral direction. Here, reference numeral 200' denotes a position of the sensed ghost tracking target generated by the reflection.

Fig. 15 is a schematic diagram showing a moving path diagram of the ghost tracking target appearing in the case shown in fig. 14.

In step S13, a ghost tracking target is determined. The ghost tracking target determination unit 123 may determine whether the tracking target observed by the radar module is a ghost tracking target based on the position 500 of the reflection structure and the moving direction of the tracking target.

As with the examples shown in fig. 8 and 9, the tracking targets 200' and 200 "can be observed to move toward the reflective structure 500 in the examples shown in fig. 14 and 15.

Even in this case, when the lateral position of the tracking target is farther from the host vehicle than the lateral position of the reflection structure, the magnitude of the lateral position change (lateral speed) points in the direction of the host vehicle, and the longitudinal position of the tracking target falls between the start point and the end point of the reflection structure, the corresponding tracking target can be determined as the ghost tracking target.

More specifically, when the lateral position of the tracking target is farther from the host vehicle than the lateral position of the reflection structure, and the lateral position change (lateral speed) of the tracking target is directed in the direction of the host vehicle, it may be determined that the tracking target is the ghost tracking target based on the determination of whether or not a straight line representing the moving path of the tracking target (obtained from the slope and the intercept of the first-order formula representing the moving path of the tracking target) and a straight line representing the reflection structure intersect with each other.

Fig. 16 is a diagram showing another example in which a ghost-tracking target appears in the example shown in fig. 10. Fig. 17 is a schematic diagram showing a moving path diagram of the ghost-tracking target appearing in the case shown in fig. 16.

In the case shown in fig. 16 and 17, the radar module 11 can capture a tracking target that moves from a position very close to the reflecting structure.

This is determined to be the case where the ghost tracking target occurs because it is practically impossible for the vehicle to approach the host vehicle at a constant speed without driving force when there is a structure immediately behind the host vehicle.

In this case, it is determined whether the tracking target is a ghost tracking target in step S13. When the lateral position of the tracking target 200 "falls between the reflecting structure 500 and the host vehicle, the lateral position change (lateral velocity) of the tracking target 200" points in the direction of the host vehicle, and if the tracking target moves from the position of the reflecting structure in a stationary state, the lateral acceleration of the tracking target can be physically calculated to be larger than the reference acceleration, the ghost tracking target determination unit 123 can determine the corresponding tracking target as the ghost tracking target.

The lateral acceleration of the tracked target 200 "can be easily obtained from the calculation of the lateral velocity variation amplitude of the tracked target. Also, the reference acceleration may be obtained from known travel distance, velocity, and acceleration equations. When the initial velocity is set to zero, the reference velocity may be calculated by dividing the value of the squared velocity of the target 200 "by the value of 2 times the longitudinal distance between the reflecting structure 500 and the tracking target 200".

When the ghost tracking target determining unit 123 determines that the tracking target is the ghost tracking target, the control unit 12 can prevent the occurrence of a false alarm in the rear cross-collision warning system by not generating a warning by the warning module 13.

As described above, according to the rear cross-collision warning method and apparatus of various embodiments of the present invention, it is possible to prevent false sensing of a tracking target caused by a radar signal reflected by a reflection structure around a host vehicle, and to ensure the robustness of the rear cross-collision warning. In particular, by preventing the occurrence of an erroneous warning to the driver against a rear cross collision, it is possible to alleviate the anxiety of the driver and improve the marketability of the vehicle.

While the specific embodiments of the present invention have been illustrated and described, it is needless to say that those skilled in the relevant art can make improvements and modifications to the present invention in various ways within the scope not departing from the technical spirit of the present invention provided by the patent claims.