Radar-based target type vehicle detection

Abstract

This invention is used to detect the presence of other vehicles of a specific type traveling near a primary vehicle. The invention provides a method executed by a radar-based blind spot warning system of a primary vehicle, characterized in that the method includes: detecting a first radar reflection point reflected by an object outside the blind spot warning zone of the blind spot warning system; defining a target area based on the distribution of a group of the first radar reflection points; inferring that the object is another vehicle based on the positional relationship between the target area and the blind spot warning zone; detecting a second radar reflection point inside the blind spot warning zone; and determining that the other vehicle is a target type vehicle if a second radar reflection point satisfying a first predetermined condition is present.

Description

Technical Field

[0001] This disclosure relates to techniques for using radar devices to detect the approach of specific types of vehicles in motion. These specific types of vehicles include, in particular, large trailers or buses. Background Technology

[0002] In existing technology, vehicles can use radar-based blind spot warning (BSW) systems to detect adjacent vehicles entering the blind spot of the rearview mirror, thereby providing warnings for maneuvers such as lane changes. However, such radar-based BSW systems do not yet have the ability to accurately identify large trailers traveling near the main vehicle. (Reference) Figure 2 When a large trailer is traveling in the adjacent lane to the main vehicle, its chassis is higher than the main vehicle, so its reflection of radar signals may be different from that of a regular vehicle, which may cause the BSW system to fail to recognize the large trailer in the vicinity.

[0003] Patent document US20160274228A1 describes a system for distinguishing a trailer towing a main vehicle from other vehicles present in the vicinity of the main vehicle. This prevents the erroneous detection of other vehicles when only a trailer is actually present near the main vehicle. In the system described in US20160274228A1, a signal indicating an object approaching the main vehicle is detected using radar signals emitted from a radar device. Based on this signal, the time of connection between the trailer and the main vehicle is determined, and the area obscured by the trailer towing the main vehicle is defined. Therefore, targets detected within this area can be ignored. However, this type of technology does not solve the problems mentioned above. Summary of the Invention

[0004] The technical problem that the invention aims to solve

[0005] The present invention was made in view of the above aspects, and one of its objects is to enable the BSW system to use onboard radar devices to detect the approach of other vehicles of a specific type, such as trailers.

[0006] According to one aspect of the present invention, a method is provided for execution by a radar-based blind spot warning (BSW) system of a primary vehicle, characterized in that the method includes: detecting a first radar reflection point reflected by an object outside the blind spot warning zone of the blind spot warning system; defining a target area based on the distribution of a group of the first radar reflection points; inferring that the object is another vehicle based on the positional relationship between the target area and the blind spot warning zone; detecting a second radar reflection point inside the blind spot warning zone; and determining that the other vehicle is a target type vehicle if a second radar reflection point satisfying a first predetermined condition exists.

[0007] According to another aspect of the present invention, a driver assistance system is provided, comprising: a radar-based blind spot warning (BSW) system installed on a vehicle, the system including a processing unit for: detecting a first radar reflection point reflected by an object outside the blind spot warning zone of the radar object detection system; defining an object area based on the distribution of a group of the first radar reflection points; inferring that the object is another vehicle based on the positional relationship between the object area and the blind spot warning zone; detecting a second radar reflection point inside the blind spot warning zone; and determining that the other vehicle is a target type vehicle if the second radar reflection point satisfies a first predetermined condition; the driver assistance system further includes a driver assistance ECU, the driver assistance ECU being configured to receive a signal from the blind spot warning system and, based on the signal, notify the driver that the object is a target type vehicle. Attached Figure Description

[0008] Figure 1 This is a top view showing the state of a main vehicle and other vehicles traveling near the main vehicle in a traffic lane according to one embodiment of this disclosure.

[0009] Figure 2 Viewed from the left side Figure 1 The side view is obtained by taking the top view shown.

[0010] Figure 3 This is a block diagram illustrating the structure of an in-vehicle system according to one embodiment of the present disclosure.

[0011] Figure 4 This illustrates an embodiment of the present disclosure involving... Figure 3 The diagram shows a block diagram of the functional structure of the processing unit 300 of the vehicle-mounted radar device 14.

[0012] Figure 5 An example of a process performed in a vehicle system according to one embodiment of this disclosure is shown.

[0013] Figure 6 This is a diagram illustrating the positional relationship between the object area and the blind spot warning area according to one embodiment of this disclosure.

[0014] Figure 7A This is a diagram illustrating the positional relationship between a second radar reflection point and a target area in the longitudinal direction according to one embodiment of this disclosure.

[0015] Figure 7B This is a diagram illustrating the left-right positional relationship between a second radar reflection point and a target area according to one embodiment of this disclosure.

[0016] 6…Blind Spot Warning Zone

[0017] 10… Main vehicle

[0018] 12…car body

[0019] 14…Vehicle-mounted radar device

[0020] 18… Spread Area

[0021] 20…other vehicles

[0022] 22…Zero plane

[0023] 24…Bottom

[0024] 26…Target type vehicles

[0025] 100…in-vehicle system

[0026] 300… processing units. Detailed Implementation

[0027] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a top view showing the state of a vehicle 10 equipped with an on-board system 100 and other vehicles 20 traveling near the vehicle 10 traveling on a traffic lane, according to one embodiment of this disclosure. Figure 1 The vehicle system 100 shown detects objects around the vehicle 10 using the vehicle radar device 14, identifies the detected objects as other vehicles 20, and determines that the other vehicle 20 is a specific type of vehicle. The vehicle system 100 should be understood in the broadest sense; it can be a specific driver assistance system, a blind spot warning system (BSW system), or, more broadly, a vehicle computer / ECU.

[0028] Figure 1 This diagram is obtained from an overhead view of vehicle 10 traveling in lane L1 and other vehicles 20 traveling in lane L2 adjacent to lane L1. A blind spot warning zone 6R exists to the right rear of vehicle 10, and a blind spot warning zone 6L exists to the left rear. For each vehicle 10, the BSW system can pre-set the blind spot warning zones 6R and 6L based on factors such as the field of view of the rearview mirror, the position of the onboard radar device 14 mounted on the vehicle 10, and the direction of travel of the vehicle 10. The blind spot warning zones 6L and 6R are not limited to... Figure 1 The rectangle shape and size shown can be any shape and size.

[0029] Reference Figure 1The vehicle 10 includes at least a body 12 and an onboard radar device 14 (onboard radar device 14R and onboard radar device 14L) mounted on the body 12. The vehicle 10 is a moving body, such as a four-wheeled ordinary automobile, but is not limited to this; for example, it could be a small truck with six or more wheels, a two-wheeled automobile, etc. Furthermore, for ease of explanation, the concepts of "front," "rear," "left," and "right" in the vehicle 10 are defined as shown by the arrows in the figure. This concept of direction is based on the driver in the moving vehicle 10.

[0030] like Figure 1 As illustrated, the vehicle-mounted radar device 14R is mounted near the right rear corner of the vehicle body 12, and the vehicle-mounted radar device 14L is mounted near the left rear corner of the vehicle body 12. Hereinafter, without needing to distinguish between the vehicle-mounted radar device 14L and the vehicle-mounted radar device 14R, it will simply be referred to as "vehicle-mounted radar device 14". Furthermore, the vehicle 10 equipped with the vehicle-mounted radar device 14 will be referred to as the main vehicle.

[0031] The vehicle-mounted radar device 14 is mounted on the main vehicle 10 and configured to detect objects with a high probability of collision with the main vehicle 10 by transmitting and receiving electromagnetic waves. Specifically, the vehicle-mounted radar device 14 transmits radar signals as electromagnetic waves and receives the reflected waves of the radar signals reflected by the objects. Therefore, the distance between the objects can be determined based on the time difference between the transmitted radar signal and the radar signal reflected by the objects. The vehicle-mounted radar device 14 can be a millimeter-wave radar, microwave radar, etc.

[0032] The vehicle-mounted radar device 14 is configured such that the angular range centered on the approximate lateral direction of the main vehicle 10 (approximately ±120° in the example, if the straight-ahead direction is set to 0°) (approximately -70° to +70° in the example) forms the radar signal propagation area 18. The vehicle-mounted radar device 14 is capable of emitting radar signals into the propagation area 18 and detecting the position and relative speed of the reflecting points located within the propagation area 18 based on the received signals from the reflecting points that reflect the radar signals. Hereinafter, without needing to distinguish between the right-hand propagation area 18R and the left-hand propagation area 18L, it will simply be referred to as "propagation area 18".

[0033] The vehicle-mounted radar device 14 receives reflected waves emitted in the horizontal direction to detect objects present in the propagation area 18. Furthermore, if a radar signal with a height angle deviating from the horizontal direction is also emitted by the radar and reflected by an object, the vehicle-mounted radar device 14 will also receive a radar signal arriving from the height direction. As an example, but not a limitation, radar signals with a height angle can be transmitted and reflected intermittently. The radar reflection signal with the height angle sometimes appears and sometimes disappears, thus causing the corresponding reflection point to be detected intermittently.

[0034] The main vehicle 10 may also be equipped with a driver assistance ECU (Electronic Control Unit) 16 (not shown) as a driver assistance device. The driver assistance ECU 16 is communicatively connected to the vehicle-mounted radar device 14 and configured to transmit and receive signals with it. The driver assistance ECU 16 is configured to control driver assistance actions such as collision avoidance based on the detection results obtained from the vehicle-mounted radar device 14. This driver assistance ECU 16 has a Blind Spot Warning (BSW) function, used to detect and notify the driver when another vehicle 20 traveling parallel to the rear side is in the blind spot warning zone. As an example, the driver assistance ECU 16 is configured to notify the driver of the main vehicle 10, based on signals received from the vehicle-mounted radar device 14, that an object near the main vehicle 10 is a specific type of other vehicle 20. Furthermore, the function of determining that another vehicle 20 traveling parallel to the side of the main vehicle 10 is a specific type of other vehicle (hereinafter referred to as a target type vehicle) can also be provided by the vehicle-mounted radar device 14 itself as part of the radar object detection system of the main vehicle 10. Hereinafter, it is assumed that the vehicle-mounted radar device 14 itself includes this function.

[0035] Figure 2 Viewed from the left side Figure 1 The side view is obtained from the top view shown. For ease of explanation, the concepts of "front," "rear," "left," and "right" in vehicle 10 are defined as shown by the arrows in the figure. In addition, the vertical direction can be referred to as the "vehicle height direction." Figure 1 and Figure 2 Examples of other vehicles 20 that are target type vehicles 26 are shown. For example... Figure 2 As shown, the height of the bottom surface of the vehicle body 12 defined by the front wheels 28 and rear wheels 29 of the target type vehicle 26 (the bottom surface 24 of the base in the example figure) is higher than the height of the vehicle-mounted radar device 14 of the main vehicle 10 in the vehicle height direction. Furthermore, the front wheels 28 and rear wheels 29 of the target type vehicle 26 are separated, and the area of ​​the bottom surface 24 defined by the front wheels 28 and rear wheels 29 is wider than the blind spot warning zone 6. Additionally, the target type vehicle 26 is located on the height plane of the vehicle-mounted radar device 14 (… Figure 2 There is no obstruction (such as a metal plate) between the front wheels 28 and the rear wheels 29 on the zero plane 22 shown. The target type vehicle 26 is, for example, a large vehicle such as a trailer or passenger car.

[0036] Figure 3 It means Figure 1 The diagram shows a structural example of the vehicle system 100. The vehicle system 100 includes a vehicle radar device 14 ( Figure 1The vehicle system 100 is mounted on a main vehicle 10 equipped with a vehicle radar device 14, as well as a driver assistance ECU 16.

[0037] The vehicle-mounted radar device 14 is used to determine whether the object approaching the main vehicle 10 is a vehicle, and can further determine whether the object approaching the main vehicle 10 is a specific type of target vehicle 26.

[0038] The vehicle-mounted radar device 14 includes at least: a transmitting antenna 302 that transmits radar signals; a distributor 304 that distributes the power of a high-frequency signal input from a transmitting circuit 306; a transmitting circuit 306 that supplies a transmitting signal to the transmitting antenna 302; a receiving antenna 308 that receives reflected radar signals, i.e., reflected waves; a receiving circuit 316 that processes the received signal input from the antenna element and generates a bit signal; a processing unit 300 that performs object detection processing; and an output unit 318 that outputs a signal to a driver assistance ECU 16 indicating the presence of an approaching object, which is a target type vehicle 26. Figure 3 The vehicle-mounted radar device 14 shown omits descriptions of typical radar structures such as amplifiers and filters. Figure 3 The structure of the vehicle-mounted radar device 14 shown is an example, and multiple transmitting antennas 302 and receiving antennas 308 may also exist.

[0039] The processing unit 300 includes at least a processor 312 and a memory such as RAM (Random Access Memory) or ROM (Read Only Memory) (hereinafter referred to as memory 314) as hardware elements. The processor 312 is configured to read a program stored in the memory 314 and perform processing according to the program.

[0040] The driver assistance ECU 16 performs various processes for the driver to operate the main vehicle 10 based on various information input from the vehicle radar device 14 (such as signals indicating the approach of a target type vehicle 26). These driver assistance processes include, for example, issuing an alert to the driver to inform them of the approach of the target type vehicle 26.

[0041] The driver assistance ECU 16 includes at least a processor 162 and a memory 164 as hardware elements. The processor 162 is configured to read a program stored in the memory 164 and execute processing according to the program.

[0042] Figure 4 This illustrates an embodiment of the present disclosure relating to... Figure 3The diagram shows a block diagram of the functional structure of the processing unit 300 of the vehicle-mounted radar device 14. The processing unit 300 includes a control unit 410 and a storage unit 430. The control unit 410 includes a first detection unit 412, a target area setting unit 414, a vehicle estimation unit 416, a second detection unit 418, and a target vehicle determination unit 420. The storage unit 430 corresponds to... Figure 3 The memory 314 shown. The control unit 410 and the various parts 412 to 420 included in the control unit 410 indicate that... Figure 3 The processor 312 shown in the diagram reads and executes the program stored in the memory 314 to perform processing functions.

[0043] The first detection unit 412 detects the first radar reflection point of the reflected radar signal, and detects the position of the first radar reflection point and the relative speed of the first radar reflection point with respect to the main vehicle 10. The first radar reflection point is in the blind spot warning zone 6 ( Figure 1 The first radar reflection point is detected outside the blind spot warning zone 6. The target area setting unit 414 sets the target area 602 indicating the presence of the target based on the positional distribution of the detected first radar reflection point. The vehicle estimation unit 416 estimates that the target is another vehicle 20 based on the positional relationship of the target area 602 relative to the blind spot warning zone 6. The second detection unit 418 detects the second radar reflection point of the reflected radar signal. The second radar reflection point is located outside the blind spot warning zone 6. Figure 1 The reflection point detected inside the second radar reflection point. If the target vehicle determination unit 420 determines that other vehicles 20 are target type vehicles 26 when the second radar reflection point meets the prescribed conditions.

[0044] Figure 5 An example of a process 500 executed in a vehicle system 100 according to an embodiment of the present disclosure is shown. Process 500 represents an example processing flow as follows: the control unit 410, based on information about the reflection point obtained from the vehicle radar device 14, infers that the object approaching the vehicle 10 is another vehicle 20, and further determines whether the other vehicle 20 is a target type vehicle 26.

[0045] In step S2, the first detection unit 412 emits radar signals within the propagation area 18 defined by the predetermined angle range of the vehicle-mounted radar device 14 in each preset measurement cycle. Furthermore, the first detection unit 412 detects the position of each reflection point and the relative velocity of each reflection point based on the received signals corresponding to the reflected waves reflected by the object.

[0046] Next, in step S4, the object region setting unit 414 sets one or more object regions 602 based on the distribution of groups of reflection points located outside the blind spot warning zone 6. As an example, the region setting unit (e.g., the object region setting unit 414) sets object regions 602 indicating the presence of an object at locations where multiple reflection points are concentrated. When multiple reflection point groups are distributed separately, object regions 602 can be set separately for each reflection point group.

[0047] Next, in step S6, the vehicle estimation unit 416 determines whether the object area 602 has a specific positional relationship with the blind spot warning zone 6. If the object area 602 has a specific positional relationship with the blind spot warning zone 6, the process proceeds to step S8. In one example, in step S6, the vehicle estimation unit 416 determines whether the positional relationship between the object area 602 and the blind spot warning zone 6 is... Figure 6 Any of the first to fifth positional relationships shown. On the other hand, if there is no specific positional relationship between the object area 602 and the blind spot warning area 6, the process proceeds to step S18.

[0048] In step S18, the target vehicle determination unit 420 does not set a target vehicle model mark to indicate the presence of a target type vehicle 26 that is close to the main vehicle 10, and the process ends.

[0049] Figure 6 Examples illustrate the first to fifth positional relationships between the object area 602 and the blind spot warning zone 6R associated with step S6. When the direction of travel of the main vehicle 10 is in front of the driver, in the first positional relationship, the object area 602 is behind the blind spot warning zone 6R of the main vehicle 10. In the second positional relationship, the object area 602 is in front of the blind spot warning zone 6R of the main vehicle 10. In the third positional relationship, the object area 602 is on the opposite side of the main vehicle 10 across the blind spot warning zone 6R, and to the side of the blind spot warning zone 6R. In the fourth positional relationship, the object area 602 is on the opposite side of the main vehicle 10 across the blind spot warning zone 6R, and diagonally in front of the blind spot warning zone 6R. In the fifth positional relationship, the object area 602 is on the opposite side of the main vehicle 10 across the blind spot warning zone 6R, and diagonally behind the blind spot warning zone 6R. Additionally, Figure 6 In this context, the object region 602 is defined as rectangular, but it can also be set to other shapes depending on the extent of the distribution of the reflection point group.

[0050] In the first positional relationship, for example, when other vehicle 20 is the target type vehicle 26, the rear wheel 29 on the main vehicle 10 side of the target type vehicle 26 (in) Figure 6 The left rear wheel in the middle corresponds to object area 602.

[0051] In the second positional relationship, for example, when other vehicles 20 are target type vehicles 26, the front wheel 28 on the main vehicle 10 side of the target type vehicle 26 (in) Figure 6 The left front wheel (in the middle) corresponds to object area 602.

[0052] In the third positional relationship, for example, when other vehicles 20 are target type vehicles 26, the wheels of target type vehicles 26 on the side furthest from the main vehicle 10 (in) Figure 6 The middle wheel (either the right front wheel or the right rear wheel) corresponds to object area 602.

[0053] In the fourth positional relationship, for example, when other vehicles 20 are target type vehicles 26, the front wheel 28 of the target type vehicle 26 on the side furthest from the main vehicle 10 (in) Figure 6 The middle one is the right front wheel, which corresponds to object area 602.

[0054] In the fifth positional relationship, for example, when other vehicles 20 are target type vehicles 26, the rear wheel 29 of the target type vehicle 26 on the side furthest from the main vehicle 10 (in) Figure 6 The middle one is the right rear wheel, which corresponds to object area 602.

[0055] Return to Figure 5 In step S8, the vehicle estimation unit 416 estimates that the object corresponding to the first radar reflection point of the reflected radar signal is another vehicle 20 approaching the main vehicle 10. If there is no obstruction in the blind spot warning zone 6, for example, if the space of the blind spot warning zone overlaps with the space between the front wheels 28 and the rear wheels 29 of another vehicle 20, then there is no reflection point of the reflected radar signal in the space of the blind spot warning zone 6, and therefore no reflected wave is generated. Accordingly, the object area 602 is not within the blind spot warning zone 6. Even in such a case, in step S8, if the positional relationship between the object area 602 and the blind spot warning zone 6 is the specific positional relationship involved in S6, the object is estimated to be another vehicle 20.

[0056] Furthermore, when multiple object regions 602 are defined, in step S6, the vehicle estimation unit 416 determines whether each object region 602 corresponds to one of the first to fifth positional relationships based on their positional relationships. When multiple object regions 602 are defined, the first to fifth positional relationships may occur concurrently. In this case, in step S8, the vehicle estimation unit 416 also estimates that the object corresponding to the first radar reflection point of the reflected radar signal is another vehicle 20 approaching the main vehicle 10.

[0057] Furthermore, in other aspects, in step S6, the vehicle estimation unit 416 may also determine whether the positional relationship of the object area 602 relative to the blind spot warning zone 6 corresponds to any two or more of the first to fifth positional relationships, such as the first, third, and fifth positional relationships. If the first, third, and fifth positional relationships are all satisfied, the process proceeds to step S8. On the other hand, if the first, third, and fifth positional relationships are not all satisfied, in step S8, the vehicle estimation unit 416 determines that the object is not another vehicle 20 approaching the main vehicle 10, and proceeds to step S18.

[0058] Alternatively, in a further aspect, in step S6, the vehicle estimation unit 416 may also determine the positional relationship between the target area 602 and the blind spot warning zone 6 in stages. The vehicle estimation unit 416 may first determine whether it is in a first positional relationship, and if not, further determine whether it is in a third or fifth positional relationship. If it is not in any of the first, third, or fifth positional relationships, then in step S8, the vehicle estimation unit 416 determines that the target is not another vehicle 20, and proceeds to step S18. On the other hand, if it corresponds to both the first and third positional relationships and the fifth positional relationship, the process proceeds to step S8.

[0059] As an alternative to or supplement to the aforementioned implementation, in a further aspect, in step S6, the vehicle estimation unit 416 may also determine whether the relative speed of the first radar reflection point detected in step S2 relative to the moving speed of the main vehicle 10 is within a threshold. If the relative speed of the first radar reflection point relative to the moving speed of the main vehicle 10 is within the threshold, the process proceeds to step S8, whereby it is estimated that the object corresponding to the first radar reflection point reflecting the radar signal is another vehicle 20 approaching the main vehicle 10. Thus, the vehicle estimation unit 416 can estimate an object traveling to the side of the main vehicle 10 at approximately the same speed as the main vehicle 10 as another vehicle 20. On the other hand, if in step S6 it is determined that the relative speed of the first radar reflection point is greater than the threshold for the vehicle side, the process proceeds to step S18.

[0060] Return to Figure 5 In step S10, the second detection unit 418 detects a second radar reflection point inside the blind spot warning zone 6. If a second radar reflection point is detected inside the blind spot warning zone 6, the process proceeds to step S12. On the other hand, if no second radar reflection point is detected inside the blind spot warning zone 6, the process proceeds to step S18.

[0061] In step S10, it can be determined that the second radar reflection point has radar reflection wave characteristics reflected by the vehicle chassis located at a height higher than the main vehicle radar installation height, which can be achieved by at least one of the following methods.

[0062] There are two types of second radar reflection points: one is a reflection point caused by the target type vehicle 26; the other is a reflection point detected even when the target type vehicle 26 is not actually within the blind spot warning zone 6 (hereinafter referred to as a special interference point). Therefore, in step S10, if there is a special interference point in the group of second radar reflection points that meets the prescribed conditions, the second detection unit 418 can remove the determined special interference point from the group of second radar reflection points. Thus, after removing the special interference point from the group of second radar reflection points detected inside the blind spot warning zone 6, if the target type vehicle 26 is not actually within the blind spot warning zone 6, the target vehicle model mark is not set.

[0063] The specific interference point is a second radar reflection point that is detected even if the target type vehicle 26 is not actually present in the blind spot warning zone 6. When the target type vehicle 26 is not present in the blind spot warning zone 6, no reflection point is generated in the blind spot warning zone 6, and reflected waves from the target type vehicle are not detected. In this situation, false detection of the second radar reflection point may occur, for example, due to unwanted reflected waves from guardrails or other objects present near the main vehicle 10.

[0064] On the other hand, even when the target vehicle 26 is actually present in the blind spot warning zone 6, the second detection unit 418 also detects a second radar reflection point within the blind spot warning zone 6. This second radar reflection point can be caused by the underside 24 between the front wheels 28 and rear wheels 29 of the target vehicle 26. The height of the underside 24 of the target vehicle 26 is higher than the position of the vehicle-mounted radar device 14. Therefore, when the underside 24 of the target vehicle 26, which is parallel to the main vehicle 10, is located within the blind spot warning zone 6, the radar signal from the vehicle-mounted radar device 14 toward the underside 24 is referenced to the horizontal direction on which the vehicle-mounted radar device 14 is mounted, and has an elevation angle. ( Figure 2 Angle of elevation. This refers to the angle formed by the horizontal plane at the height where the vehicle-mounted radar device 14 is mounted and the line connecting the vehicle-mounted radar device 14 and the bottom surface 24 (near the end of the main vehicle 10). That is, the elevation angle. The elevation angle is determined by the height of the vehicle-mounted radar device 14, the height of the bottom surface 24 of the target type vehicle 26, and the vector pointing from the vehicle-mounted radar device 14 to the bottom surface 24 of the target type vehicle 26 (near the end of the main vehicle 10). The reflected waves can be detected intermittently. The reflection point (second radar reflection point) detected based on such reflected waves may appear and disappear at times, thus being detected intermittently.

[0065] Table 1 below summarizes the characteristics of the reflected waves obtained from actual measurements of the reflected waves from the second radar reflection point. The left side of Table 1 indicates the situation when the target area 602 is within the blind spot warning zone 6 or has… Figure 6 The table shows the characteristics of reflected waves from the bottom surface 24 of the target type vehicle 26 when the target type vehicle 26, which is parallel to the main vehicle 10, is present within the blind spot warning zone 6, according to the specific positional relationship shown. The right side of Table 1 shows the characteristics of reflected waves caused by objects other than the target type vehicle 26 when the target type vehicle 26 is not present within the blind spot warning zone 6.

[0066] [Table 1]

[0067]

[0068] Table 1 shows the electromagnetic wave intensity, distance change rate, and angular accuracy indicators of the reflected wave from the second radar reflection point. As shown in Table 1, the reflected wave from the target type vehicle 26 is different from the reflected wave obtained when the target type vehicle 26 is not within the blind spot warning zone 6.

[0069] The distance change rate represents the relative velocity of the reflecting point with respect to the velocity of the host vehicle 10. Taking the straight-ahead direction of the host vehicle 10 as a reference (0°), when the incident angle of the reflected wave is constant (e.g., 90°), the relative velocity with respect to the host vehicle 10 is 0, and the distance change rate is approximately zero. Therefore, the distance change rate of undesirable reflected waves from guardrails, etc., is approximately zero. On the other hand, the distance change rate of reflected waves from the target type vehicle 26 is not a constant value but varies with time. This is because when the relative velocity of the target type vehicle 26 relative to the moving host vehicle 10 changes, the position (front-to-back direction, vehicle height direction) of the reflecting point of the target type vehicle 26 also changes, and the relative velocity of the reflecting point with respect to the host vehicle 10 changes accordingly.

[0070] Furthermore, the index associated with angular accuracy is an index representing the goodness of the angular accuracy of the reflection point detected by the vehicle-mounted radar device 14, and is expressed in multiple levels. In this aspect, the angular accuracy index has four levels from 0 to 3, with 0 being the best and 3 being the worst. The angular accuracy index is 0 to 3 when the detected object is the target type vehicle 26, and the angular accuracy index is 3 when the detected object is a guardrail or other object other than the target type vehicle 26.

[0071] Additionally, it is possible to target a single transmitting antenna 302 ( Figure 3 ) using multiple receiving antennas 308 ( Figure 3 The phase difference of the reflected wave between each receiving antenna 308 is detected, thereby detecting the angle of the reflected wave from the reflection point. For example, when using receiving antenna 308 (1) and other receiving antennas 308 (2) in separate positions, the distances at which the reflected wave from the reflection point reaches the positions of these receiving antennas 308 (1) and 308 (2) differ. The phase difference between the signals (reflected waves) received by each receiving antenna can be calculated based on this distance difference, and the incident angle of the received signal can be detected based on this phase difference. The incident angle is the azimuth angle of the reflection point relative to the vehicle-mounted radar device 14. Ideally, the phase difference between each receiving antenna receiving the signal is determined by the distance between the receiving antennas and the wavelength of the reflected wave. However, if the signal strength of the received signal is weak or a high-intensity signal exists near the reflected wave, the phase difference between each receiving antenna will deviate due to mutual interference. The larger the deviation of the phase difference between each receiving antenna, the worse the angle accuracy index, and the smaller the deviation, the better the angle accuracy index. The deviation of the phase difference is divided into multiple levels, and the angle accuracy index is allocated according to each level of the phase difference deviation.

[0072] Return to Figure 5 As described above, in step S10, the second detection unit 418 determines specific interference points that meet predetermined conditions from the group of second radar reflection points, and removes the determined specific interference points from the group of second radar reflection points. Here, as shown on the right side of Table 1, the predetermined conditions for specific interference points include at least one of the following: electromagnetic wave intensity is less than a first predetermined threshold (e.g., less than -7 dBSM), the distance change rate of the reflected wave is approximately zero, and the angle accuracy index is 3. For example, two or more of the electromagnetic wave intensity, distance change rate, and angle accuracy index can be combined to remove reflection points associated with reflected waves reflected from sources other than the target type vehicle 26. By combining multiple conditions, specific interference points can be determined more accurately.

[0073] In step S10, the second detection unit 418 can also determine a second radar reflection point corresponding to the characteristics of the reflected wave reflected from the target type vehicle 26 in the second radar reflection point. That is, in step S10, the second detection unit 418 can also use the electromagnetic wave intensity and distance change rate of the reflected wave to determine a reflection point with the characteristics of the reflected wave reflected from the target type vehicle 26 in the second radar reflection point. In one example, as shown on the left side of Table 1, a second radar reflection point corresponding to a reflected wave that satisfies at least one of the following conditions: the electromagnetic wave intensity is less than a second predetermined threshold (e.g., less than 2 dBSM); and the distance change rate is not constant. The second predetermined threshold is larger than the first predetermined threshold. Alternatively or supplementarily, in step S10, the second detection unit 418 can also determine a reflection point corresponding to a reflected wave that is detected intermittently in the second radar reflection point. By determining and extracting reflection points with the characteristics of the reflected wave from the target type vehicle 26 in the second radar reflection point, the target type vehicle 26 can be determined more accurately.

[0074] Next, in step S12, if the target vehicle determination unit 420 meets the predetermined conditions at the second radar reflection point, it proceeds to step S14. On the other hand, if the predetermined conditions are not met at the second radar reflection point, it proceeds to step S18.

[0075] The predetermined condition in step S12 may refer to the distance between the second radar reflection point and the center of the rectangle when the object area 602 is set as a rectangle being longer than a specific distance. If the distance between the second radar reflection point and the center of the object area 602 is longer than the specific distance, proceed to step S14. On the other hand, if the predetermined condition is not met in step S12, proceed to step S18.

[0076] When other vehicles 20 are target type vehicles 26, the target area 602, defined based on the position of the first radar reflection point (reflection point caused by the wheels) that reflects radar signals emitted in the generally horizontal direction, should be separated from the second radar reflection point (reflection point caused by the bottom surface 24) that reflects radar signals emitted in the vertical direction. Therefore, the second radar reflection point detected at the same or close position as the first radar reflection point is likely to be a falsely detected reflection point.

[0077] Therefore, as one of the operational contents that S12 may include, this disclosure excludes the second radar reflection point that is close to the target area 602. Figure 7A and Figure 7B The positional relationship between multiple second radar reflection points located inside the blind spot warning zone 6 and the target area 602 is shown. Figure 7A The longitudinal direction between the second radar reflection point and the target area 602 is shown (in Figure 7A The positional relationship in the long side direction (in []) Figure 7B shows the left - right direction of the second radar reflection point and the object area 602 (in []) Figure 7A The positional relationship in the short side direction (in [])

[0078] In [] Figure 7A One second radar reflection point 702 is located inside the blind spot warning area 6 and also inside the object area 602. Another second radar reflection point 704 is located inside the blind spot warning area 6 and is separated from the object area 602 by a distance greater than a specific distance. lt is the length of the object area 602 in the front - rear direction, that is, the length from the front end to the rear end of the object area 602, and lx is the length in the front - rear direction from the second radar reflection point to the center of the object area 602.

[0079] In [] Figure 7B One second radar reflection point 706 is located inside the blind spot warning area 6 and also inside the object area 602. Another second radar reflection point 708 is located inside the blind spot warning area 6 and is separated from the object area 602 by a distance greater than a specific distance. wt is the length of the object area 602 in the left - right direction, that is, the length from the left end to the right end of the object area 602, and ly is the length in the left - right direction from the second radar reflection point to the center of the object area 602.

[0080] Return to [] Figure 5 If it is determined in step S12 that the distance between the second radar reflection point and the object area 602 is longer than a specific distance, the process proceeds to step S14. The specific distance is, for example, lt / 2 or wt / 2. When the specific distance is lt / 2 and wt / 2, when the relationship between the second radar reflection point and the distance to the center of the object area 602 satisfies at least one of |lx|>lt / 2 or |ly|>Wt / 2, the process proceeds to step S14.

[0081] In addition, the specific distances lt / 2 and wt / 2 are examples and are not limited to this. For example, when the relationship between the second radar reflection point and the distance to the center of the object area 602 satisfies at least one of |lx|(lt / 2)>1 + n / 100 or |ly|(Wt / 2)>1 + n / 100 (0 < n < 100), the process can also proceed to step S14.

[0082] Next, in step S14, the target vehicle determination unit 420 determines that the other vehicle 20 associated with the second radar reflection point is a target - type vehicle 26, and the process proceeds to step S16. On the other hand, if it is determined in step S12 that the distance between the second radar reflection point and the object area 602 is less than a specific distance, the process proceeds to step S18.

[0083] In step S16, the target vehicle determination unit 420 sets a target vehicle model indicator, which indicates that the detected object is the target type vehicle 26. Additionally, the target vehicle determination unit 420 sends the target vehicle model indicator to the driver assistance ECU 16. In step S16, upon receiving the target vehicle model indicator, the driver assistance ECU 16 can further alert the driver that a target type vehicle 26 is present alongside the main vehicle 10.

[0084] According to this disclosure, even if the target vehicle 26 is driving near the main vehicle 10, and the radar signal sent by the vehicle-mounted radar device 14 is emitted to the null plane 22 of the space between the front wheel 28 and the rear wheel 29 of the target vehicle 26 without being reflected, the presence of the target vehicle 26 can be detected based on the information from the vehicle-mounted radar device 14.

[0085] The embodiments of the present invention have been described above. However, the above-described embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. Modifications and improvements can be made to the present invention without departing from its spirit, and equivalents are also included in the present invention. Furthermore, any combination of embodiments and variations is possible within the scope of solving at least a portion of the above-described problems or achieving at least a portion of the effects, and any combination or omission of the structural elements described in the claims and specification is possible.

[0086] This invention should also cover the implementations corresponding to the following clauses:

[0087] (Item 1) A method performed by a radar object detection system of a main vehicle, wherein the method comprises:

[0088] The step of detecting the first radar reflection point of an object reflecting radar signals outside the blind spot warning zone;

[0089] The step of defining the target area based on the distribution of the group of the first radar reflection points;

[0090] The step of inferring that the object is another vehicle based on the positional relationship between the object area and the blind spot warning zone;

[0091] The step of detecting the second radar reflection point inside the blind spot warning zone; and

[0092] The step of determining the other vehicles as target type vehicles when the second radar reflection point meets the specified first condition.

[0093] (Item 2) The method described in Item 1, wherein the blind spot warning zone is preset based on the location of the radar device mounted on the main vehicle and the direction of travel of the main vehicle.

[0094] (Item 3) The method described in Item 1 or Item 2, wherein the height of the bottom surface between the front and rear wheels of the target type vehicle is higher than the height of the radar device mounted on the main vehicle.

[0095] (Item 4) The method described in any one of items 1 to 3, wherein the area of ​​the underside of the target type vehicle, defined based on the front and rear wheels of the target type vehicle, is wider than the blind spot warning zone.

[0096] (Item 5) The method described in any one of items 1 through 4, wherein the target type vehicle is a trailer.

[0097] (Item 6) The method described in any one of items 1 to 5, wherein the positional relationship includes any one of a first positional relationship, a second positional relationship, a third positional relationship, a fourth positional relationship, and a fifth positional relationship, wherein in the first positional relationship, the object area is located behind the blind spot warning zone relative to the direction of travel of the host vehicle; in the second positional relationship, the object area is located in front of the blind spot warning zone; in the third positional relationship, the object area is located to the side of the blind spot warning zone opposite to the host vehicle; in the fourth positional relationship, the object area is located diagonally in front of the blind spot warning zone opposite to the host vehicle; and in the fifth positional relationship, the object area is located diagonally behind the blind spot warning zone opposite to the host vehicle.

[0098] (Item 7) The method described in any one of items 1 to 6, wherein the step of inferring that the object is another vehicle further includes the step of inferring that the object is another vehicle based on the relative speed of the first radar reflection point relative to the moving speed of the main vehicle.

[0099] (Item 8) The method described in any one of items 1 to 7, wherein the step of detecting the second radar reflection point comprises: determining a specific interference point among the reflection points detected inside the blind spot warning zone that satisfies a predetermined second condition; and removing the determined specific interference point from the second radar reflection point.

[0100] (Item 9) The method described in Item 8, wherein the second condition is that the electromagnetic wave intensity of the reflected wave from the second radar reflection point is less than a first specified threshold.

[0101] (Item 10) The method described in Item 8 or 9, wherein the second condition specified therein is that the rate of change of distance of the reflected wave from the second radar reflection point is approximately zero.

[0102] (Item 11) The method described in any one of items 8 to 10, wherein the second condition specified therein is the worst index representing the goodness of the angular accuracy of the second radar reflection point.

[0103] (Item 12) The method described in Item 9, wherein the step of detecting the second radar reflection point comprises: detecting a reflection point in the second radar reflection point that satisfies at least one of the following conditions: the electromagnetic wave intensity of the reflected wave from the second radar reflection point is less than a second predetermined threshold, and the reflected wave from the second radar reflection point does not have a constant rate of change of distance, wherein the second predetermined threshold is greater than the first predetermined threshold.

[0104] (Item 13) The method described in any one of items 1 through 12, wherein the first condition specified therein includes a distance between the second radar reflection point and the target area that is longer than a specific distance.

[0105] (Item 14) The method described in Item 13, wherein the specific distance is lt / 2 in the long side direction or wt / 2 in the short side direction relative to the direction of travel of the main vehicle, where lt is the length of the object region in the long side direction and wt is the length of the object region in the short side direction.

[0106] (Item 15) A computer-readable medium storing a program that causes a radar object detection system to perform the methods described in any one of items 1 to 14.

[0107] (Item 16) A radar object detection system for a main vehicle, the radar object detection system comprising: a first detection unit that detects a first radar reflection point of an object reflecting a radar signal outside a blind spot warning zone; an object area setting unit that sets an object area based on the distribution of a group of the first radar reflection points; a vehicle estimation unit that estimates the object to be another vehicle based on the positional relationship between the object area and the blind spot warning zone; a second detection unit that detects a second radar reflection point inside the blind spot warning zone; and a target determination unit that determines the other vehicle to be a target type vehicle if the second radar reflection point meets a predetermined first condition.

[0108] (Item 17) The radar object detection system described in Item 16, wherein the blind spot warning zone is preset based on the location of the radar device and the direction of travel of the main vehicle.

[0109] (Item 18) A vehicle identification system comprising: a radar object detection system as described in Item 16 or Item 17; and a driving assistance device configured to receive a signal from the radar object detection system and, based on the signal, notify the driver of the main vehicle equipped with the radar device that the object is a vehicle of the target type.

Claims

1. A method executed by a radar-based blind spot warning system of a main vehicle, characterized in that, The method includes: Detect a first radar reflection point reflected by the object, the first radar reflection point being outside the blind spot warning zone of the blind spot warning system; Based on the distribution of the group of the first radar reflection points, the target area is defined; Based on the positional relationship between the object area and the blind spot warning zone, it is inferred that the object is another vehicle; In response to the assumption that the object is another vehicle, it is further determined whether at least one second radar reflection point is detected inside the blind spot warning zone; and If a second radar reflection point that meets the first predetermined condition exists, the other vehicles are determined to be vehicles of the target type.

2. The method as described in claim 1, characterized in that, The first predetermined condition is that the second radar reflection point is outside the target area.

3. The method of claim 1, wherein the first predetermined condition includes that the distance between the second radar reflection point and the target area is longer than a specific distance, wherein the specific distance is lt / 2 in the long side direction or wt / 2 in the short side direction relative to the travel direction of the main vehicle, where lt is the length of the target area in the long side direction and wt is the length of the target area in the short side direction.

4. The method as described in claim 1, characterized in that, The height of the bottom surface between the front and rear wheels of the target type vehicle is higher than the height of the radar device of the blind spot warning system mounted on the main vehicle.

5. The method as described in claim 4, characterized in that, The area under the vehicle, defined by the front and rear wheels of the target type vehicle, is wider than the blind spot warning zone.

6. The method as described in claim 5, characterized in that, The target type of vehicle is a trailer or a bus.

7. The method as described in claim 1, characterized in that, The steps to deduce that the object is another vehicle include: Based on the fact that the positional relationship between the object area and the blind spot warning zone meets specific positional conditions, it is inferred that the object is another vehicle. The specific positional condition must satisfy at least one of the following: a first positional relationship, a second positional relationship, a third positional relationship, a fourth positional relationship, and a fifth positional relationship. In the first positional relationship, the object area is located behind the blind spot warning zone relative to the direction of travel of the main vehicle. In the second positional relationship, the object area is located in front of the blind spot warning zone. In the third positional relationship, the object area is located to the side of the blind spot warning zone opposite to the main vehicle. In the fourth positional relationship, the object area is located diagonally in front of the blind spot warning zone on the opposite side from the main vehicle. In the fifth positional relationship, the object area is located diagonally behind the main vehicle on the opposite side of the blind spot warning zone.

8. The method as described in claim 7, characterized in that, The specific positional condition must satisfy at least two of the first positional relationship and the fifth positional relationship.

9. The method as described in claim 7, characterized in that, The specific location condition is: If the first positional relationship is satisfied, then the third positional relationship or the fifth positional relationship is further satisfied.

10. The method as described in claim 1, characterized in that, The step of inferring that the object is another vehicle further includes: inferring that the object is another vehicle based on the relative movement speed of the first radar reflection point relative to the main vehicle.

11. The method as described in claim 1, characterized in that, The steps for detecting the second radar reflection point include: Identify a specific interference point among the reflection points detected inside the blind spot warning zone that meets a second predetermined condition. The second predetermined condition is at least one of the following: the electromagnetic wave intensity of the reflected wave from the second radar reflection point is less than a first threshold; the distance variation rate of the reflected wave from the second radar reflection point is zero; the index representing the goodness of the angular accuracy of the reflected wave from the second radar reflection point is the worst; and... Remove the identified specific interference points from the second radar reflection point.

12. The method as described in claim 10, characterized in that, The step of detecting the second radar reflection point includes: determining the reflection point corresponding to the reflection waves that are detected intermittently.

13. The method as described in claim 1, characterized in that, The step of detecting the second radar reflection point includes: determining that the second radar reflection point has radar reflection wave characteristics reflected by the vehicle chassis located at a height higher than the main vehicle radar mounting height.

14. A driver assistance system, comprising: A radar-based blind spot warning system installed on a vehicle includes a processing unit for: detecting a first radar reflection point reflected by an object, the first radar reflection point being outside the blind spot warning zone of the blind spot warning system; defining an object area based on the distribution of a group of the first radar reflection points; and inferring that the object is another vehicle based on the positional relationship between the object area and the blind spot warning zone. In response to the assumption that the object is another vehicle, it is further determined whether at least one second radar reflection point is detected inside the blind spot warning zone; and if there is a second radar reflection point that meets the first predetermined condition, it is determined that the other vehicle is the target type vehicle. The driver assistance ECU is used to receive signals from the blind spot warning system and, based on the signals, notify the driver that the object is a target type vehicle.

15. The driver assistance system as described in claim 14, characterized in that, The first predetermined condition is that the second radar reflection point is outside the target area.

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