Patent Publication Number: US-2023152425-A1

Title: Vehicle radar system and target detection

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit under 35 USC 119(a) of Korean Patent Application No. 10-2021-0157683 filed in the Korean Intellectual Property Office on Nov. 16, 2021, the entire disclosure of which is incorporated herein by reference for all purposes. 
     BACKGROUND 
     1. Field 
     This application relates to a vehicle radar system and a target detecting method thereof. 
     DESCRIPTION OF THE BACKGROUND 
     For safety of vehicles and pedestrians, vehicles are equipped with various sensors such as ultrasonic waves, cameras, radars, and lidar that recognize a surrounding environment. These sensors may detect people, vehicles, animals, moving objects, etc. within a line of sight (LOS) area. On the other hand, a front camera used in the vehicle can sense the surrounding environment at a long distance and a short distance by using a plurality of cameras having a field of view (FOV) of a narrow angle and a wide angle. 
     In vehicles equipped with the radar, a corner radar may be mounted on the front bumper of the vehicle to widen the detecting range. The corner radar mounted on the right side of the vehicle bumper mainly detects the target approaching from the right lane or the right side of the intersection, and the corner radar mounted on the left side of the vehicle bumper mainly detects the target approaching from the left lane or the left side of the intersection. 
     The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the disclosure. 
     SUMMARY OF THE 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 general aspect, a method for detecting a moving target through a vehicle radar system includes acquiring radar data from a radar sensor disposed with respect to a vehicle, using the radar data to detect at least one plane of at least one structure, setting at least one reference classification line based on the at least one plane of the at least one structure, and determining whether the moving target is in a line of sight (LOS) area or a non-line of sight (NLOS)) area based on the at least one reference classification line. 
     The determining may include determining that the moving target is in the NLOS area when the radar data for the moving target is positioned beyond a predetermined distance from the vehicle based on the at least one reference classification line. 
     The determining may include determining that the moving target is in the LOS area when the radar data for the moving target is positioned within a predetermined distance of the vehicle based on the at least one reference classification line. 
     The setting may include calculating at least one plane reference line based on the at least one plane. The setting may also include setting the at least one plane reference line to be parallel to the traveling direction of the vehicle among a plurality of plane reference lines as the at least one reference classification line. 
     The calculating may include calculating a first plane reference line corresponding to a plane of a first structure on the right of the vehicle, and calculating a second plane reference line corresponding to a plane of a second structure on the left of the vehicle. The setting of the at least one reference classification line may include setting the first plane reference line as a first reference classification line, and setting the second plane reference line as a second reference classification line. 
     The method may further include dividing the radar data into a right area and a left area based on the center of the vehicle. 
     The determining may include determining that the moving target is in the NLOS area when the radar data for the moving target indicates that the moving target is in the right area and the moving target is positioned beyond a predetermined distance from the vehicle based on the first reference classification line, and determining that the moving target is in the NLOS area when the radar data for the moving target is the left area and the moving target is positioned beyond a predetermined distance from the vehicle based on the second reference classification line. 
     The method may further include mirroring radar data positioned beyond a predetermined distance from the vehicle based on the plane reference line based on the plane reference line. 
     The acquiring may include converting a relative coordinate system corresponding to a position in which the radar sensor is installed into an absolute coordinate system to acquire the radar data. 
     The at least one plane of the at least one structure may be at least one of a wall surface of a building, a guard rail, a billboard, and a side of a parked or stopped vehicle. 
     According to another aspect, a vehicle radar system includes a radar sensor that is installed in a vehicle and acquires radar data, and a target determining device that detects at least one plane of at least one structure through the radar data to set at least one reference classification line, and determines whether a moving target is in a non-line of sight (NLOS) area based on the at least one reference classification line. 
     The target determining device may be configured to determine that the moving target is in the NLOS area when the radar data corresponding to the moving target indicates that the moving target is located beyond a predetermined distance away from the vehicle based on the at least one reference classification line. 
     The target determining device may be configured to determine that the moving target is in the line of sight (LOS) area when the radar data corresponding to the moving target indicates that the moving target is positioned within a predetermined distance of the vehicle based on the at least one reference classification line. 
     The target determining device may be configured to calculate at least one plane reference line by using the at least one plane, and to set at least one of the at least one plane reference line to be parallel to a direction in which the vehicle travels as at least one of the at least one reference classification line. 
     The plane reference line may include a first plane reference line corresponding to a plane of a first structure positioned on the right side of the vehicle and a second plane reference line corresponding to a plane of a second structure positioned on the left side of the vehicle, and the target determining device may set the first plane reference line as a first reference classification line and the second plane reference line as a second reference classification line. 
     The target determining device may determine that the moving target is in the NLOS area when the radar data corresponding to the moving target indicates that the moving target is in an area right of the center of the vehicle and is located beyond a predetermined distance from the vehicle based on the first reference classification line. The target determining device may also be configured to determine that the moving target is in the NLOS area when the radar data corresponding to the moving target indicates that the moving target is in an area left of the center of the vehicle and is positioned beyond a predetermined distance from the vehicle based on the second reference classification line. 
     The target determining device may mirror the radar data indicating that the moving target is positioned beyond a predetermined distance from the vehicle with respect to the at least one plane reference line. 
     The target determining device may convert the the relative coordinate system corresponding to the position where the radar sensor is installed into a predetermined absolute coordinate system to convert the radar data into radar data for the absolute coordinate system. 
     The at least one plane of the at least one structure may be at least one of a wall surface of a building, a guard rail, a billboard, and a side of a parked or stopped vehicle. 
     A method of detecting a moving target in a vehicle radar system is provided. The method includes acquiring radar data from a radar sensor disposed on a vehicle, detecting one or more planes of one or more structures from the radar data, setting one or more reference classification lines corresponding to the one or more planes, and determining whether the moving target is in a line of sight (LOS) area or a non-line of sight (NLOS) area based on the one or more reference classification lines. 
     Other features and aspects will be apparent from the following detailed description, the drawings, and the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a block diagram showing an example of a vehicle radar system. 
         FIG.  2    is a view illustrating an example of a mounting position of a radar sensor. 
         FIG.  3    is a view illustrating an example of a method for converting a relative coordinate system to an absolute coordinate system. 
         FIG.  4    is a flowchart showing a method of detecting a target, which may be implemented by a vehicle radar system according to an example. 
         FIG.  5    illustrates a scenario of calculating a plane reference line according to an example. 
         FIG.  6    is a view showing an example scenario of detecting a target by a vehicle radar system. 
         FIG.  7    is a table showing a classification result of a LOS area and an NLOS area for a case such as described with respect to  FIG.  6   . 
         FIG.  8    is a view illustrating a computer system according to an example. 
     
    
    
     Throughout the drawings and the detailed description, the same reference numerals refer to the same elements. The drawings may not be to scale, and the relative size, proportions, and depiction of elements in the drawings may be exaggerated for clarity, illustration, and convenience. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The following detailed description is provided to assist the reader in gaining a comprehensive understanding of the methods, apparatuses, and/or systems described herein. However, various changes, modifications, and equivalents of the methods, apparatuses, and/or systems described herein will be apparent after an understanding of the disclosure of this application. For example, the sequences of operations described herein are merely examples, and are not limited to those set forth herein, but may be changed as will be apparent after an understanding of the disclosure of this application, with the exception of operations necessarily occurring in a certain order. Also, descriptions of features that are known in the art may be omitted for increased clarity and conciseness. 
     The features described herein may be embodied in different forms, and are not to be construed as being limited to the examples described herein. Rather, the examples described herein have been provided merely to illustrate some of the many possible ways of implementing the methods, apparatuses, and/or systems described herein that will be apparent after an understanding of this disclosure. 
       FIG.  1    is a block diagram showing a vehicle radar system  1000  according to an example. 
     As shown in  FIG.  1   , a vehicle radar system  1000  according to an example may include a radar sensor  100  and a target determination device  200 . 
     In many instances, sensors may not be able to detect people or vehicles that are obscured by buildings, walls, and adjacent vehicles, which increases a likelihood of a crash. That is, the sensors mounted on the vehicles can detect a target within the line of sight (LOS) area, but cannot detect a target within a non-line of sight (NLOS) area. Additionally, corner radars cannot detect the targets that are hidden by buildings, fences, soundproof walls, or parked vehicles positioned on the left and right of the vehicle. Radar sensors  100  may be installed on a vehicle to reduce these potential problems. 
     The radar sensor  100  may be installed at a predetermined position of the vehicle (for example, on or within the vehicle, etc.). As an example, the radar sensor  100  may be installed near a front bumper and a front rearview mirror of the vehicle. The radar sensor  100  may include at least one radar sensor. The radar sensor  100  may emit a transmission beam to a predetermined range from the installed position and receive a reflected beam reflected by an object. The radar sensor  100  transmits radar data, which includes information on the transmission beam and the reflected beam, to the target determining device  200 . The radar sensor  100  may be configured to and operate in a manner to collect, determine, transform, and/or transmit, etc., the radar data in a compatible form to the target determining device  200 , and the detailed description is omitted. 
     The target determining device  200  receives the radar data from the radar sensor  100 , and may use the received radar data to determine whether the moving target is in the line of sight (LOS) area or the non-line of sight (NLOS) area. The moving target may be a moving object, such as a person, a bicycle, or a vehicle (for example, as illustrated with respect to  FIG.  5    and described with respect to  FIG.  5    herein below). First, the target determining device  200  may detect a plane of a fixed structure (e.g., a wall, guard rail, billboard, side of a parked or stopped vehicle, etc.) by using radar data and use the detected plane to determine a reference classification line. The target determining device  200  may determine whether the moving target is in the LOS area or the NLOS area based on the reference classification line. According to an example embodiment, the target determining device  200  may provide information determined on the moving target to an autonomous driving system installed in the vehicle. Alternatively, the vehicle radar system  1000  may be included in the autonomous driving system. The specific operation of the target determining device  200  is described in more detail below. 
       FIG.  2    is a view illustrating an example of a mounting position of a radar sensor  100 . 
     The radar sensor  100  may include multiple radar sensors, for example, four radar sensors  100   a  to  100   d , such as illustrated in  FIG.  2   . Alternatively, the radar sensor  100  may include more or fewer radar sensors  100 . The radar sensor  100   a  may be installed in the left corner of the vehicle  10 , and the radar sensor  100   d  may be installed in the right corner of the vehicle  10 . That is, the radar sensors  100   a  and  100   d  may be corner radar sensors. The radar sensor  100   b  may be installed on the front left (the left of the bumper) of the vehicle  10 , and the radar sensor  100   c  may be installed on the front right (the right of the bumper) of the vehicle  10 . In the following description, for convenience, it is assumed that there is a plurality of radar sensors  100  (e.g., four radar sensors), but the following description may be applied in instances in which there is a single radar sensor  100 . 
     The radar sensors  100   a  to  100   d  may have a relative coordinate (RC) area according to each install position. Referring to  FIG.  2   , each of the radar sensors  100   a  to  100   d  may respectively have a relative coordinate system (RCS) that determines a relative coordinate area, such as relative coordinate areas RC 1   205 - 1  to RC 4   205 - 4  based on (for example, determined relative to) an installed central position. The radar data obtained from each radar sensor  100   a  to  100   d  may be data based on each relative coordinate system, which may be converted, in some instances, into data compatible with an absolute coordinate system (ACS) (which may determine an absolute coordinate (AC)  210  area). Accordingly, the target determining device  200  may convert the radar data obtained from the radar sensors  100   a  to  100   d  into the absolute coordinate system and integrate them. As an example, the absolute coordinate system may be an absolute coordinate system AC based on the center point O  220  of the bumper of the vehicle  10 . As another example, the absolute coordinate system may be set to (for example, use as a reference) any one of the relative coordinate systems RC 1   205 - 1  to RC 4   205 - 4 . 
       FIG.  3    is a view illustrating an example of a radar sensor converting coordinates from a relative coordinate system to an absolute coordinate system. 
     As shown in  300   a  of  FIG.  3   , the radar sensor  100   a  may obtain radar data (for example, Cartesian coordinates, X ( 340 ), Y ( 350 ), relative angle ( 320 ), etc.) for the target  310  based on the relative coordinate system RC 1   205 - 1 . As shown in  300   b  of  FIG.  3   , the target determining device  200  may convert a relative angle (of the target  310 ) into an absolute angle ( 330 ). Also, as shown in  300   c  of  FIG.  3   , the target determining device  200  converts the relative coordinate into the absolute coordinate (for example, based on cartesian coordinates relative to the central point O  220  (not separately shown in  FIG.  3   ). The target determining device  200  may determine the position of each radar sensor  100   a  to  100   d  (for example, based on the install position provided in advance) and converts the data based on the relative coordinate system provided by each radar sensor  100  into data based on the absolute coordinate system by computing an offset, etc., thereby integrating the radar data. 
     Hereinafter, a method for detecting whether the moving target is positioned in the LOS area or the NLOS area by the vehicle radar system  1000  is described in detail. The method may allow a system to detect targets that are obscured by buildings, walls, vehicles, etc. 
       FIG.  4    is a flowchart showing a method of detecting a target, which may be implemented by vehicle radar system  1000 , according to an example. 
     The vehicle radar system  1000  may acquire the radar data through the radar sensor  100  (S 410 ). The radar sensors  100   a  to  100   d  each emit a transmission beam in a predetermined range and receive a reception beam to acquire the radar data. The radar sensors  100   a - 100   d  may transmit the radar data to the target determining device  200 . Here, the target determining device  200  may convert the radar data into data based on the absolute coordinate system. That is, the target determining device  200 , as shown in  FIG.  3   , may convert the radar data of the relative coordinate system acquired by each radar sensor  100   a  to  100   d  into the radar data of the absolute coordinate system. 
     The vehicle radar system  1000  may detect the plane of a fixed structure by using the radar data acquired in the step (S 410 ) and calculate a plane reference line by using the detected plane (S 420 ). For example, the plane of the fixed structure may be a wall surface of a building, a guard rail, a billboard, or a side of the parked or stopped vehicle. The method of detecting the plane of the fixed structure and calculating the plane reference line through the vehicle radar system  1000  is described with reference to  FIG.  5   .  FIG.  5    describes a case in which the plane of the fixed structure is the wall surface of the building, however the process described herein may also be applied to other fixed structure, such as a guard rail, a billboard, the side of a parked or stopped vehicle, etc. 
       FIG.  5    illustrates a scenario of calculating a plane reference line, according to an example. 
     In  FIG.  5   , it is assumed that a wall  1   505 - 1  is positioned on the right side in the traveling direction of the vehicle  10  and a wall  2   505 - 2  is positioned in the front side. 
     The radar sensor  100   d  may acquire the radar data reflected by the wall surface  1   505 - 1 , and this radar data has a constant distance  515  and a constant angle from the position of the vehicle  10 . Accordingly, the target determining device  200  may detect the wall surface  1   505 - 1  and calculate the plane reference line  510  formed along the wall surface  1   505 - 1 . The target determining device  200  may detect the wall surface and calculate the wall surface reference using any suitable process compatible with the features disclosed herein. 
     The radar sensor  100   b  may acquire the radar data reflected by the wall surface  2   500 - 2 , and this radar data also has a constant distance and a constant angle from the position of the vehicle  10 . Accordingly, the target determining device  200  may detect the wall surface  2   500 - 2  and calculate a plane reference line  520  formed along the wall surface  2   500 - 2 . 
     On the other hand, as shown in  FIG.  5   , when the moving target  540  approaches, the radar sensor  100   b  may acquire the radar data for the moving target  540  by the radar beam  530 . The radar data obtained by the radar sensor  100   b  is not data found by a direct radar beam, but data found by a reflected radar beam. That is, the radar data acquired by the radar sensor  100   b  is not data about the actual position of the moving target  540 , but data about the reflected moving target  545 . Accordingly, it is necessary to convert the data on the reflected moving target  545  into the data on the actual moving target  540 . The target determining device  200  determines the radar data positioned far from the vehicle  10  based on the plane reference line  520  as the data acquired by the reflected signal. Accordingly, the target determining device  200  may mirror the data on the reflected moving target with respect to the plane reference line  520  to be converted into the data for the actual moving target. 
     Referring to  FIG.  4   , the vehicle radar system  1000  may set the reference classification line among the plane reference lines calculated in the step S 420  (S 430 ). As in the case of  FIG.  5   , a plurality of plane reference lines may be calculated. The vehicle radar system  1000  may set the reference classification line according to a predetermined reference among a plurality of plane reference lines. As an example, the vehicle radar system  1000  may set the plane reference line parallel to the traveling direction of the vehicle among the plane reference lines as the reference classification line. As another example, the vehicle radar system  1000  may set the plane reference line that maintains a certain angle with the traveling direction of the vehicle among the plane reference lines as the reference classification line. That is, in the case of  FIG.  5   , the vehicle radar system  1000  may set the plane reference line  510  parallel to the traveling direction of the vehicle among the plane reference line  510  and the plane reference line  520  as the reference classification line. 
     Next, the vehicle radar system  1000  may set the LOS area  550  and the NLOS area  560  based on the reference classification line set in the step S 430  (S 440 ). The vehicle radar system  1000  may set an area close to the vehicle  10  as the LOS area  550  based on the reference classification line, and set an area far from the vehicle  10  as the NLOS area based on the reference classification line. Referring to  FIG.  5   , the vehicle radar system  1000  may set the left area of the reference classification line  510  as the LOS area  550  and the right area of the reference classification line  510  as the NLOS area. 
     The vehicle radar system  1000  may determine whether the moving target is in the LOS area  550  or the NLOS area  560  (S 450 ). The vehicle radar system  1000  may determine that the moving target is in the LOS area  550  when the radar data of the moving target  540  is in the LOS area  550 . Also, the vehicle radar system  1000  may determine that the moving target  540  is in the NLOS area  550  when the radar data of the moving target  540  is in the NLOS area. Referring to  FIG.  5   , the target determining device  200  may calculate the actual position of the moving target  540  from the radar data for the actual moving target. Also, since the actual position of the moving target  540  is located in the NLOS area  550 , the target determining device  200  may finally determine that the moving target is in the NLOS area  550 . 
     Next, implementation of target detecting by the vehicle radar system  1000  in instances in which four wall surfaces are disposed similarly to an environment of an intersection is described with reference to  FIG.  6   . 
       FIG.  6    is a view showing an example scenario of detecting a target by the vehicle radar system  1000 . 
     In  FIG.  6   , positions ( 605 ,  615 ) associated with the target are illustrated by circled numbers with numbers {circle around ( 1 )} to   indicating the actual positions  605  of the moving target, and circled numbers with an apostrophe, for example, {circle around ( 1 )}′, {circle around ( 2 )}′, {circle around ( 3 )}′, {circle around ( 8 )}′, {circle around ( 9 )}′, and  ′ indicating the reflected position  615  of the moving target. Corresponding numbers indicate a corresponding actual position  605  and reflected position  615 . For example, {circle around ( 1 )}′ indicates the reflected position  615  corresponding to the actual position  605  {circle around ( 1 )}. Also, in  FIG.  6   , It is assumed that the wall surface  1   505 - 1  is positioned on the right side, the wall surface  5   505 - 5  is positioned on the left side, and the wall surfaces  3   505 - 3  and  4   505 - 4  are positioned in the front side of the vehicle  10  in the moving direction of the vehicle  10 . 
     The vehicle radar system  1000 , in a similar manner as described with respect to  FIG.  4    and  FIG.  5   , may detect the plane reference line. That is, the vehicle radar system  1000  may detect the plane reference lines  610 _R,  610 _L,  620 _R, and  620 _L indicated in  FIG.  6   . The plane reference line  610 _R is the plane reference line for the wall surface  1   505 - 1  on the right side of the vehicle  10 , and the plane reference line  610 _L is the plane reference line for the wall surface  5   505 - 5  on the left side of the vehicle  10 . Also, the plane reference line  620 _R is the plane reference line for the wall surface  3   505 - 3 , and the plane reference line  620 _L is the plane reference line for the wall surface  4   505 - 4 . Here, since the radar sensor  100   d  may mainly detect the wall surface  1 , the radar sensor  100   d  may be used to detect the plane reference line  610 _R. Also, since the radar sensor  100   a  may mainly detect the wall surface  5   505 - 5 , the radar sensor  100   a  may be used to detect the plane reference line  610 _L. 
     The vehicle radar system  1000 , in a similar manner as described with respect to  FIG.  4    and  FIG.  5   , may set the reference classification line among a plurality of detected plane reference lines. Since the plane reference lines  610 _R and  610 _L are determined parallel to the traveling direction of the vehicle  10 , the vehicle radar system  1000  may set the plane reference lines  610 _R and  610 _L as the reference classification lines, respectively. Meanwhile, the vehicle radar system  1000  may be divided into a right area and a left area with respect to the center O  220  of the absolute coordinate system. In addition, the vehicle radar system  1000  may set the reference classification line  610 _R positioned in the right area as a reference classification line  610 _R on the right, which is the reference classification line for classifying the radar data in the right area. The vehicle radar system  1000  may set the reference classification line  610 _L positioned in the left area as a left reference classification line  610 _L, which may be the reference classification line for classifying the radar data in the left area. 
     The vehicle radar system  1000 , as described in  FIG.  5   , may mirror the signals for the reflected positions  615  {circle around ( 1 )}′, {circle around ( 2 )}′, {circle around ( 3 )}′, {circle around ( 8 )}′, {circle around ( 9 )}′, and  ′, which are determined based on data acquired by the reflected signal reflected by the wall surface. The vehicle radar system  1000  may mirror the signals based on the plane reference line to converted the data into data corresponding to the actual moving target  540 . The vehicle radar system  1000  mirrors the radar data corresponding to the reflected positions  605  {circle around ( 1 )}′, {circle around ( 2 )}′, and {circle around ( 3 )}′ based on the plane reference line  620 _R to be converted into the radar data for the actual moving target  540 . Further, the vehicle radar system  1000  mirrors the radar data corresponding to the reflected positions  605  {circle around ( 8 )}′, {circle around ( 9 )}′, and  ′ based on the plane reference line  620 _L to be converted into the radar data for the actual moving target  540 . 
     The vehicle radar system  1000 , in a similar manner as described with respect to  FIG.  4    and  FIG.  5   , may determine whether the moving target is in the LOS area  550  or the NLOS area  560  based on the reference classification line. 
     The vehicle radar system  1000  may determine that the moving target is positioned in the right area on the basis of the reference classification line  610 _R on the right. If the moving target  540  is in positions  605  {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )}, the moving target is located far from the vehicle  10  based on the reference classification line  610 _R on the right, so the vehicle radar system  1000  may determine that the moving target  540  is positioned in the NLOS area  560 . When the moving target  540  is in the positions  605  {circle around ( 4 )} and {circle around ( 5 )}, it is positioned close to the vehicle  10  based on the reference classification line  610 _R on the right, so the vehicle radar system  1000  may determine that the moving target  540  is positioned in the LOS area  550 . 
     The vehicle radar system  1000  may determine that the moving target is positioned in the left area on the basis of the reference classification line  610 _L on the left. When the moving target  540  is at the positions {circle around ( 8 )}, {circle around ( 9 )}, and   it is located far (for example, beyond a predetermined distance) from the vehicle  10  based on the reference classification line  610 _L on the left, so the vehicle radar system  1000  may determine that the moving target is located in the NLOS area  560 . When the moving target is at the positions  605  {circle around ( 6 )} and {circle around ( 7 )}, it is located close to (for example, within a predetermined distance of (e.g., a second that is the same or different to the predetermined distance used to determine whether the moving target is located in the NLOS area  560 )) the vehicle  10  based on the reference classification line  610 _L on the left, so the vehicle radar system  1000  may determine that the moving target  540  is located in the LOS area  550 . 
     According to at least one of exemplary embodiments, the reference classification line may be set using the detected wall surface, and it may be determined whether the moving target is in the NLOS area based on the set reference classification line. 
     Hereinafter, the method for determining whether the moving target is in the LOS area or the NLOS area is described with reference to  FIG.  7    in a different aspect from the above-described part. 
       FIG.  7    is a table  700  showing a classification result of a LOS area  550  and an NLOS area  560  for a case such as described with respect to  FIG.  6   . 
     In  FIG.  7   , Loc_x denotes a location of the moving target, with x denoting a position  605  of the moving target  540 . For example, Loc-1 means that the moving target  540  is in the position  605  {circle around ( 1 )}. The reflected signals are denoted by m_nR, where m denotes a position  605 , and n denotes a wall surface. For example, 1_3R means the signal detected by the reflection of the wall surface  3   505 - 3  when the moving target  540  is in the position  605  {circle around ( 1 )}. 2_2R means the signal detected by the reflection of the wall surface  2   505 - 2  when the moving target  540  is at the position  605  {circle around ( 2 )}. Further, detection of the moving target  540  from direct positions is denoted by a single number. For example, 5 means the signal detected directly when the moving target is at the position  605  {circle around ( 5 )}. 
     The vehicle radar system  1000  according to an example determines whether the moving target  540  is in the LOS area  550  or the NLOS area  560  by using a matrix such as illustrated and described with respect to  FIG.  7   . 
     According to an example embodiment, the vehicle radar system  1000  (particularly, the target determining device  200  of the vehicle radar system) may build a matrix such as illustrated in  FIG.  7    for the radar data acquired through each radar sensor  100   a  to  100   d . As shown in  FIG.  7   , the vehicle radar system  1000  may divide the areas associated with the vehicle  10  into a right area  705 -R and a left area  705 -L based on the origin O  220  of the absolute coordinate system. 
     The vehicle radar system  1000  may select a reference radar sensor from among the radar sensors  100   a  to  100   d . As an example, the vehicle radar system  1000  may select the radar sensor mainly used to detect the plane of the fixed structure corresponding to the reference classification line as the reference radar sensor  100 . In  FIG.  6   , the vehicle radar system  1000  may select the radar sensor  100   d  as the reference radar sensor for the right area  705 -R in the right area  705 -R. Also, the vehicle radar system  1000  may select the radar sensor  100   a  as the reference radar sensor for the left area  705 -L in the left area  705 -L. 
     The vehicle radar system  1000  may determine whether the moving target  540 , positioned in the right area  705 -R, is in the NLOS area  560  or the LOS area  550  based on the radar data of the reference radar sensor  100   d . The target determining device  200  identifies the radar data acquired by a direct radar signal among the radar data of the reference radar sensor  100   d . That is, the target determining device  200  may detect the radar data  710 . The target determining device  200  may determine the positions  605  {circle around ( 4 )} and {circle around ( 5 )} of the moving target  540  corresponding to the radar data  710  as the LOS area  550 . In addition, the target determining device  200  may determine the positions  605  {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )} of the moving target  540  as the NLOS area  560  and exclude the positions  605  {circle around ( 4 )} and {circle around ( 5 )} of the moving target  540 . 
     The vehicle radar system  1000  may determine whether the moving target  540 , positioned in the left area  705 -L, is in the NLOS area  560  or the LOS area  550  based on the radar data of the reference radar sensor  100   a . The target determining device  200  identifies (for example, detects, receives, etc.) the radar data acquired by the direct radar signal among the radar data of the reference radar sensor  100   a . That is, the target determining device  200  identifies the radar data  720 . The target determining device  200  may determine the positions  605  {circle around ( 6 )} and {circle around ( 7 )} of the moving target corresponding to the radar data  720  as the LOS area  550 . Also, the target determining device  200  may determine the positions  605  {circle around ( 8 )}, {circle around ( 9 )}, and   of the moving target  540  excluding the positions  605  {circle around ( 6 )} and {circle around ( 7 )} of the moving target  540  as the NLOS area  560 . 
     On the other hand, in  FIG.  7   , the reference classification line  610 _R on the right and the reference classification line  610 _L on the left may be displayed. In the right area  705 -R, moving target(s)  540  at positions  605  {circle around ( 4 )} and {circle around ( 5 )} positioned to the left of the reference classification line  610 _R on the right may be determined to be positioned in the LOS area  550 , and moving targets at positions {circle around ( 1 )}, {circle around ( 2 )}, and {circle around ( 3 )} positioned on the right of the reference classification line  610 _R on the right may be determined to be positioned in the NLOS area  560 . Also, in the left area  705 -L, the moving targets  540  at positions  605  {circle around ( 6 )} and {circle around ( 7 )} positioned on the right of the reference classification line  610 _L on the left may be determined to be positioned in the LOS area  550 , and the moving targets at positions  605  {circle around ( 8 )}, {circle around ( 9 )}, and   positioned on the left of the reference classification line  610 _L on the left may be determined to be positioned in the NLOS area  560 . 
     Although a scenario in which there are multiple radar sensors  100  has been described above, the above method may be applied in instances in which a single radar sensor is configured, and to determine whether the moving target is in the LOS area  550  or the NLOS area  560 . 
     As described above, the vehicle radar system  1000  according to the example can determine whether the moving target is in the NLOS area  560  or the LOS area  550  by setting the reference classification line using the plane of the fixed structure. Accordingly, the vehicle radar system  1000  may prevent accidents in advance by notifying the information about the moving target  540  in the NLOS area  560  to the driver in advance. 
       FIG.  8    is a view illustrating a computer system according to an example. 
     The vehicle radar system  1000  according to an example may be implemented into a computer system  800  such as illustrated in  FIG.  8   . Each constituent element of the vehicle radar system  1000 , that is, the target determining device  200  and the radar sensor  100 , may be implemented in the computer system  800  such as that in  FIG.  8   . 
     The computer system  800  may include at least one of a processor  810 , a memory  830 , a user interface input device  840 , a user interface output device  850 , and a storage device  860 , which communicate through a bus  820 . 
     The processor  810  may be a central processing unit (CPU) or a semiconductor device that executes instructions stored in the memory  830  or the storage device  860 . The processor  810  may be configured to implement the functions and methods described in  FIG.  1    to  FIG.  7   . 
     The memory  830  and the storage device  860  may include various types of volatile or non-volatile storage media. For example, the memory  830  may include a read only memory (ROM)  831  and a random-access memory (RAM)  832 . In one example, the memory  830  may be positioned inside or outside the processor  810 , and the memory  830  may be connected to the processor  810  through various known means. 
     While this disclosure includes specific examples, it will be apparent after an understanding of the disclosure of this application that various changes in form and details may be made in these examples without departing from the spirit and scope of the claims and their equivalents. The examples described herein are to be considered in a descriptive sense only, and not for purposes of limitation. Descriptions of features or aspects in each example are to be considered as being applicable to similar features or aspects in other examples. Suitable results may be achieved if the described techniques are performed in a different order, and/or if components in a described system, architecture, device, or circuit are combined in a different manner, and/or replaced or supplemented by other components or their equivalents. Therefore, the scope of the disclosure is defined not by the detailed description, but by the claims and their equivalents, and all variations within the scope of the claims and their equivalents are to be construed as being included in the disclosure.