JP2014002012A - Radar device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radar device capable of correctly acquiring information of another vehicle located diagonally behind its own vehicle.SOLUTION: A radar unit radiates a beam within a predetermined angle range diagonally behind its own vehicle and receives the reflection wave of a beam from another vehicle. Reflection point detection means repetitively detects the position of a reflection point of a beam in the other vehicle and a relative velocity on the basis of a reflection wave to be received by the radar unit (S100). Position estimation means estimates the movement position of a past reflection point detected by the reflection point detection means to a present time through the use of a relative velocity of the reflection point (S140). Size calculation means calculates the size of the other vehicle (S160). Other vehicle information acquisition means acquires information of the other vehicle on the basis of the movement position of a reflection point, that is estimated by the position estimation means (S180).

Description

  The present invention relates to a technique for detecting other vehicles around the host vehicle.

  Conventionally, there is a technique for detecting other vehicles around the host vehicle using a radar. For example, a technique is known in which other preceding vehicles are detected, an inter-vehicle distance is calculated, an alarm process is performed, or braking or steering is automated.

  Thus, when detecting another vehicle with a radar, the reflected wave from another vehicle is received. That is, the beam output so as to spread at a predetermined angle is reflected by a predetermined portion (hereinafter referred to as “reflection point”) of another vehicle and returns from the direction, so that the reflected wave of the beam is received.

  At this time, the distance to the other vehicle is measured based on the temporal deviation between the transmitted beam and the received reflected wave. Also, the speed of the other vehicle is measured by the Doppler effect generated in the reflected wave. Therefore, by repeatedly receiving the reflected wave from the reflection point in the other vehicle, the position and relative speed of the other vehicle with respect to the host vehicle can be obtained.

  However, since the reception of the reflected wave from the reflection point may become unstable, in recent years, an object detection device that groups reflected wave data into segments and detects other vehicles based on the data for each segment has been proposed. (For example, refer to Patent Document 1).

JP 2010-266225 A

  By the way, for example, when considering another vehicle approaching the host vehicle from the rear of the adjacent lane, if the distance to the other vehicle is relatively large, the reflected wave from the reflection point in front of the other vehicle will be received. On the other hand, when the distance to the other vehicle is relatively small, the reflected wave from the reflection point on the side surface of the other vehicle is received. That is, the reflection point described above changes depending on the positional relationship between the host vehicle and the other vehicle.

  However, the invention described in Patent Document 1 does not consider such movement of the reflection point. Therefore, the movement of the reflection point may affect the recognition of other vehicles. For example, if the reflection point moves in the direction approaching the host vehicle in the lateral direction in the other vehicle, an erroneous determination that the other vehicle is approaching the host vehicle is caused. Further, for example, if the reflection point moves in a direction away from the host vehicle in the front-rear direction in the other vehicle, an erroneous determination that the other vehicle is decelerating is caused. As a result, alarm processing due to erroneous determination may be performed.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a radar device that can more accurately acquire information on other vehicles located obliquely behind the host vehicle. .

  In the radar apparatus (1) of the present invention made to achieve the above object, the radar unit (20) irradiates a beam in a predetermined angle range obliquely behind the host vehicle, and reflects a reflected wave of the beam from another vehicle. Receive. The reason why the vehicle can be judged as another vehicle is that the relative speed can be detected by distance measurement based on the reflected wave.

  The reflection point detection means (11) repeatedly detects the position and relative velocity of the reflection point of the beam in the other vehicle based on the reflected wave received by the radar unit. Since the direction of the reflection point is known, the position of the reflection point can be measured by measuring the distance to the reflection point. In addition, the relative velocity of the reflection point can be measured by using the Doppler effect of the reflected wave.

  The position estimation means (12) estimates the movement position of the past reflection point detected by the reflection point detection means up to the present time using the relative speed of the reflection point. And the other vehicle information acquisition means (13) acquires the information of the other vehicle based on the movement position of the reflection point estimated by the position estimation means.

  In other words, in the present invention, by using the relative speed of the reflection point to estimate the movement position of the past reflection point up to the present time, it is not necessary to identify another vehicle as one reflection point. The information of the other vehicle is acquired assuming that the reflection point indicates the other vehicle. In this way, it is possible to more accurately obtain information on other vehicles located obliquely behind the host vehicle.

It is a block diagram which shows schematic structure of a radar apparatus. It is explanatory drawing which shows arrangement | positioning and the irradiation range of the radar part in a radar apparatus. It is a flowchart which shows a position estimation process. It is explanatory drawing which shows a position estimation process concretely. It is explanatory drawing which shows the malfunction by the conventional estimation method. It is explanatory drawing which shows the malfunction by the conventional estimation method.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
A radar apparatus 1 shown in FIG. 1 is used by being mounted on a vehicle, and is configured around a control unit 10. The control unit 10 is configured as a so-called computer system, and includes a CPU, a ROM, a RAM, an I / O, and a bus line connecting them. A radar unit 20 is connected to the control unit 10.

  As shown in FIG. 2, the radar unit 20 is mounted inside the bumper of the host vehicle 100. For example, a beam of several tens GHz (for example, 26 GHz) is irradiated obliquely behind the host vehicle 100, and the reflected wave is received. The beam is irradiated so as to spread at a predetermined angle. In FIG. 2, a region K sandwiched between solid lines is a detection range. Of course, it is only necessary to be able to irradiate obliquely rearward of the vehicle, and therefore, it is not limited to being mounted inside the bumper.

Next, the position estimation process will be described based on FIG. This process is repeatedly executed after the ignition switch of the vehicle is turned on.
In the first S100, a reflection point is detected. This process is to receive a reflected wave of a beam irradiated to a predetermined angle range by the radar unit 20 and detect a reflection point of another vehicle. Specifically, the distance to the reflection point and the relative speed are calculated. At this time, since the direction of the reflection point is known from the reception direction of the reflected wave, the position and relative velocity of the reflection point are detected.

  In subsequent S110, it is determined whether or not there is a reflection point this time. The current reflection point is a reflection point detected at the present time, and this process determines whether or not the reflection point is detected in S100. If it is determined that there is a reflection point this time (S110: YES), the process proceeds to S120. On the other hand, when it is determined that there is no reflection point this time (S110: NO), the process proceeds to S190.

  In S120, which is shifted when it is determined that there is a reflection point this time, it is determined whether or not there is a previous reflection point. The previous reflection point is the closest to the present time among the past reflection points. Since the reflection point is generally detected each time the beam is irradiated to the detection range, when the reflection point based on the latest reflected wave among the reflected waves received in the past is stored, An affirmative determination is made here. If it is determined that there is a reflection point last time (S120: YES), the process proceeds to S130. On the other hand, when it is determined that there is no previous reflection point (S120: NO), that is, when the reflection point is detected for the first time, the processing of S130 to S160 is not executed and the process proceeds to S170.

  In S130, information on the reflection point is acquired. Here, information on past reflection points is acquired. Information on past reflection points is updated and stored each time a new reflection point is detected, as will be described later. The information on the reflection point is the position and relative speed of each reflection point.

  In subsequent S140, position estimation calculation is performed. In this process, the relative position of the previous reflection point is used to estimate the movement position of the previous reflection point, and the movement position of the past reflection point whose position has already been estimated is estimated.

  In next S150, it is determined whether or not the current reflection point is at the same position as the previous reflection point. Here, the position of the previous reflection point is the one after the position estimation calculation in S140. Here, when it is determined that they are not at the same position (S150: NO), the vehicle size is calculated in S160, and thereafter, the process proceeds to S170. In S160, the size of the other vehicle is calculated from the movement position of the reflection point detected in the past to the current time and the position of the current reflection point. Specifically, the width of the other vehicle is calculated from the variation in the lateral direction of the reflection point, and the length of the other vehicle is calculated from the variation in the front-rear direction of the reflection point. The front-rear direction indicates the vehicle front-rear direction, and the lateral direction is a direction orthogonal to the vehicle front-rear direction. However, strictness is not required in these directions. The same applies to the following. On the other hand, if it is determined that they are at the same position (S150: YES), the process proceeds to S170 without executing the process of S160.

  In S170, the reflection point information is stored. In this process, information on the current reflection point is stored, and the movement position of the past reflection point up to the present time is stored. The information on the reflection point this time is the position and relative velocity detected in S100. The current reflection point is used as the previous reflection point when the position estimation process is executed next.

  In continuing S180, the information of another vehicle is acquired. This process acquires position information of other vehicles and size information of other vehicles. The position information of the other vehicle is exemplified as the distance from the head portion of the other vehicle to the portion closest to the host vehicle. Moreover, you may acquire the part nearest to the own vehicle in the head part of another vehicle as a point (X, Y) on the coordinate system on the basis of the own vehicle. The size information of the other vehicle is the size calculated in S160.

  If a negative determination is made in S110, that is, if the current reflection point is not detected, the process proceeds to S190 to determine whether there is a past reflection point. When it is determined that there is a past reflection point (S190: YES), reflection point information is acquired in S200, and the process proceeds to S210. The process of S200 is the same as the process of S130. On the other hand, if it is determined that there is no past reflection point (S190: NO), that is, if no reflection point has been detected yet, the subsequent processing is not executed and the position estimation process is terminated.

  In S210, it is determined whether or not to perform position estimation. This process is because even if there is a past reflection point, if the state in which the reflection point is not detected continues, the reliability of position estimation decreases. Therefore, specifically, it is conceivable that the number of negative determination processes in S110 is counted and an affirmative determination is made while the count value is below a predetermined value. Alternatively, the determination may be made based on the elapsed time since the last reflection point was detected. If it is determined that position estimation is to be performed (S210: YES), position estimation is performed in S220, and then the process proceeds to S170. The process of S220 is the same as the process of S140. On the other hand, when it is determined not to perform position estimation (S210: NO), information on other vehicles is cleared in S230, and then the position estimation process is terminated.

Next, the position estimation process will be described based on a specific example.
In FIG. 4, time elapses from the left side to the right side. That is, the other vehicle 101 that travels in the adjacent lane is approaching the host vehicle 100.

  At this time, it is assumed that the reflection point P (N) is detected as shown on the leftmost side in FIG. Here, N is a natural number and indicates the Nth detection of the reflection point P. In addition, in order not to make the description complicated, the description will be continued assuming that N = 1. In this case, the reflection point P (N) is detected (S100, S110: YES in FIG. 3), but since this is the first detection (S120: NO), the reflection point information is stored (S170), etc. Vehicle information is acquired (S180). Specifically, the position and relative speed of the current reflection point are stored as information on the current reflection point. At this time, the information of the other vehicle 101 is only information of the reflection point P (N).

  Subsequently, as shown second from the left side in FIG. 4, a reflection point P (N + 1) is detected (S100 in FIG. 3). Accordingly, it is determined that there is a reflection point this time (S110: YES), it is also determined that there is a previous reflection point P (N) (S120: YES), and information on the reflection point P (N) is acquired (S130). ). Then, a position estimation calculation is performed based on the relative speed of the previous reflection point P (N) (S140). As shown in FIG. 4, the previous reflection point P (N) is moved to Ps (N) by the relative speed Vr. At this time, since the reflection point Ps (N) and the current reflection point P (N + 1) are not at the same position (S150: NO in FIG. 3), the vehicle size of the other vehicle 101 is calculated (S160). In this case, the sizes in the horizontal direction and the front-rear direction (“0” in FIG. 4) are calculated based on the reflection point Ps (N) and the current reflection point P (N + 1). Subsequently, the position of the reflection point Ps (N), the position of the reflection point P (N + 1), and the relative speed are stored (S170 in FIG. 3), and the information of the other vehicle 101 is stored (S180).

  Subsequently, as shown third from the left side in FIG. 4, a reflection point P (N + 2) is detected (S100 in FIG. 3). Thereby, it is determined that there is a reflection point this time (S110: YES), it is also determined that there is a previous reflection point P (N + 1) (S120: YES), and reflection point information is acquired (S130). Then, a position estimation calculation is performed based on the relative speed of the previous reflection point P (N + 1) (S140). As shown in FIG. 4, the further moving position of the reflection point Ps (N) is estimated by the relative velocity of the previous reflection point P (N + 1), and the movement position of the reflection point P (N + 1) is estimated as Ps (N + 1). The At this time, since the reflection point Ps (N + 1) and the current reflection point P (N + 2) are not at the same position (S150: NO in FIG. 3), the vehicle size of the other vehicle 101 is calculated (S160). In this case, the sizes in the horizontal direction and the front-rear direction are calculated based on the reflection points Ps (N), Ps (N + 1) and the current reflection point P (N + 2). Subsequently, the positions of the reflection points Ps (N) and Ps (N + 1), the position of the reflection point P (N + 2) and the relative speed are stored (S170 in FIG. 3), and information on the other vehicle 101 is acquired (S180). ).

  Subsequently, as shown fourth from the left side in FIG. 4, a reflection point P (N + 3) is detected (S100 in FIG. 3). Thereby, it is determined that there is a reflection point this time (S110: YES), it is also determined that there is a previous reflection point P (N + 2) (S120: YES), and reflection point information is acquired (S130). Then, a position estimation calculation is performed based on the relative speed of the previous reflection point P (N + 2) (S140). As shown in FIG. 4, the further moving positions of the reflection points Ps (N) and Ps (N + 1) are estimated by the relative velocity of the previous reflection point P (N + 2), and the movement position of the reflection point P (N + 2) is Ps ( N + 2). At this time, since the reflection point Ps (N + 2) and the current reflection point P (N + 3) are not at the same position (S150: NO in FIG. 3), the vehicle size of the other vehicle 101 is calculated (S160). In this case, the sizes in the horizontal direction and the front-rear direction are calculated based on the reflection points Ps (N), Ps (N + 1), Ps (N + 2) and the current reflection point P (N + 3). Subsequently, the positions of the reflection points Ps (N), Ps (N + 1), Ps (N + 2), the position of the reflection point P (N + 3), and the relative speed are stored (S170 in FIG. 3), and information on the other vehicle 101 is stored. Is acquired (S180).

  Further, as shown on the rightmost side in FIG. 4, the reflection point is not detected (S100 in FIG. 3). Thus, it is determined that there is no reflection point this time (S110: NO), and it is determined whether there is a past reflection point (S190). Here, it is determined that there is a past reflection point (S190: YES), and reflection point information is acquired (S200). Specifically, the movement positions of the reflection points Ps (N), Ps (N + 1), and Ps (N + 2), and the position and relative speed of the previous reflection point P (N + 3) are acquired. When it is determined that position estimation is to be performed (S210: YES), position estimation calculation is performed based on the relative speed of the reflection point P (N + 3) (S220). Specifically, as shown in FIG. 4, further movement positions of the reflection points Ps (N), Ps (N + 1), and Ps (N + 2) are estimated based on the relative speed of the reflection point P (N + 3), and the reflection point P ( The movement position of (N + 3) is estimated as Ps (N + 3). Also in this case, the positions of the reflection points Ps (N), Ps (N + 1), Ps (N + 2), and Ps (N + 3) are stored (S170 in FIG. 3), and information on the other vehicle 101 is acquired (S180).

Thereafter, when it is determined not to perform position estimation due to the passage of time or the like (S210: NO in FIG. 3), the information of the other vehicle 101 is cleared (S230).
Next, the effect which the radar apparatus 1 of this embodiment exhibits is demonstrated. In order to facilitate understanding of the description here, the conventional problem will be described first.

Conventionally, since the movement of the reflection point has not been taken into account, the movement of the reflection point may affect the recognition of other vehicles.
For example, as shown in FIG. 5, it is assumed that the reflection point is detected in time series in the other vehicle 101 such as P (N) → P (N + 1) → P (N + 2) → P (N + 3). At this time, if the reflection point is not detected (the rightmost side in FIG. 5) when the reflection point is identified with the other vehicle 101 without considering the movement of the reflection point in the other vehicle 101, the reflection point is finally detected. The reflection point P (N + 4) estimated from P (N), P (N + 1), P (N + 2), and P (N + 3) is at the position shown by the broken line. That is, the other vehicle 101 appears to be stagnant. Further, the head position of the other vehicle 101 cannot be detected, and the length thereof is not known. Therefore, there is a possibility that the start / end timing of alarm processing for overtaking other vehicles 101 may be inappropriate.

  For example, as shown in FIG. 6, in the case similar to FIG. 5, when the reflection point is moved in the horizontal direction, if the reflection point is identified with the other vehicle 101, the reflection point is finally detected. When it disappears, the reflection point P (N + 4) estimated from the reflection points P (N), P (N + 1), P (N + 2), and P (N + 3) is at the position shown by the broken line. That is, it appears that the other vehicle 101 is changing the traveling direction toward the own vehicle 100. Therefore, there is a risk of performing an erroneous alarm process.

  In this regard, in the present embodiment, the radar unit 20 irradiates a beam in a predetermined angle range obliquely behind the host vehicle and receives a reflected wave of the beam from another vehicle. Then, the reflection point detection means 11 repeatedly detects the position and relative velocity of the beam reflection point in the other vehicle based on the reflected wave received by the radar unit 20 (S100 in FIG. 3). The position estimation unit 12 estimates the movement position of the past reflection point detected by the reflection point detection unit 11 up to the present time using the relative speed of the reflection point (S140, S220). And the other vehicle information acquisition means 13 acquires the information of another vehicle based on the movement position of the reflection point estimated by the position estimation means 12 (S160, S180). In other words, by using the relative speed of the reflection point to estimate the movement position of the past reflection point to the present time, it is not necessary to identify the other vehicle as the reflection point detected each time, but to detect a plurality of past reflections. Information on other vehicles is acquired assuming that the points indicate other vehicles. Thereby, the information of the other vehicle located diagonally behind the host vehicle can be acquired more accurately.

  Moreover, in this embodiment, the positional information on another vehicle is acquired as information on another vehicle (S180). As described above, the position information of the other vehicle is exemplified as the distance from the head portion of the other vehicle to the portion closest to the host vehicle. Moreover, you may acquire the part nearest to the own vehicle in the head part of another vehicle as a point (X, Y) on the coordinate system on the basis of the own vehicle. That is, the other vehicle information acquisition unit 13 acquires the position information of the other vehicle as the information on the other vehicle. Thereby, the positional relationship between the host vehicle and the other vehicle is acquired more accurately.

  Furthermore, in this embodiment, it is determined whether or not there is a previous reflection point (S120 in FIG. 3). If there is a previous reflection point (S120: YES), the reflection point information is acquired (S130). The movement position of the past reflection point is estimated using the relative speed of the reflection point (S140). That is, the position estimation means 12 estimates the movement position of the previous reflection point using the relative speed of the previous reflection point closest to the current time among the past reflection points, and the past where position estimation has been performed in the past. A further moving position of the reflection point is estimated. As described above, since the relative speed of the previous reflection point closest to the current time is used, the estimation result becomes close to reality, and more accurate position information of the other vehicle can be obtained.

  In the present embodiment, the size of the other vehicle is calculated from the movement position of the reflection point detected in the past to the current time and the position of the current reflection point (S160 in FIG. 3). And the size information of other vehicles is acquired as information on other vehicles (S180). That is, based on the movement position of the past reflection point estimated by the position estimation unit 12 up to the present time, the vehicle further includes a size calculation unit 14 that calculates the size of the other vehicle, and the other vehicle information acquisition unit 13 As information, the size information of other vehicles is acquired. Thereby, since the size of the other vehicle is known, it is useful for determining the execution timing of the alarm process. In particular, the start / end timing of alarm processing can be made appropriate.

  At this time, the size of the other vehicle is calculated using the position of the reflection point detected this time (S160 in FIG. 3). That is, the size calculation unit 14 determines the position of the past reflection point estimated by the position estimation unit 12 and the current position when the reflection point detection unit 11 detects the current reflection point, which is the current reflection point. The size of the other vehicle is calculated based on the position of the reflection point this time. As a result, the size of the other vehicle is calculated each time a reflection point is detected, and the execution determination of the alarm process can be performed quickly.

  Specifically, the width of the other vehicle is calculated from the variation in the lateral direction of the reflection point, and the length of the other vehicle is calculated from the variation in the front-rear direction of the reflection point. That is, the size calculation means 14 calculates the length of the other vehicle based on the variation in the front-rear direction, which is the vehicle front-rear direction, of the position of the reflection point. The size calculation means 14 calculates the width of the other vehicle based on the variation in the lateral direction orthogonal to the vehicle front-rear direction of the position of the reflection point. Thereby, the size of the other vehicle can be calculated relatively easily.

  Furthermore, in this embodiment, when the reflection point is no longer detected (S110: NO in FIG. 3), it is determined whether or not the reflection point position is estimated (S210), for example, detection of the last reflection point. If it is confirmed that the corresponding time has elapsed (S210: NO), the movement position of the reflection point is not calculated and the information of the other vehicle is cleared (S230). That is, the position estimation unit 12 does not perform estimation when the reflection point detection unit 11 continues to detect the current reflection point, which is the current reflection point. Thereby, the uncertain information of the other vehicle is cut.

As described above, the present invention is not limited to the embodiment described above, and can be implemented in various forms without departing from the technical scope thereof.
In the above embodiment, as the position information of the other vehicle, the distance to the portion closest to the host vehicle at the head portion of the other vehicle and the coordinates (X, Y) of the portion are used. On the other hand, the distance and coordinates to the center part of the other vehicle may be acquired as the position information of the other vehicle from the size information of the other vehicle.

  DESCRIPTION OF SYMBOLS 1 ... Radar apparatus, 10 ... Control part, 11 ... Reflection point detection means, 12 ... Position estimation means, 13 ... Other vehicle information acquisition means, 14 ... Size calculation means, 20 ... Radar part, 100 ... Own vehicle, 101 ... Others vehicle

Claims (9)

A radar unit (20) for irradiating a beam in a predetermined angle range obliquely behind the host vehicle and receiving a reflected wave of the beam from another vehicle;
Reflection point detection means (11) for repeatedly detecting the position and relative velocity of the reflection point of the beam in the other vehicle based on the reflected wave received by the radar unit;
Position estimation means (12) for estimating the movement position of the past reflection point detected by the reflection point detection means up to the present time using the relative speed of the reflection point;
Other vehicle information acquisition means (13) for acquiring information of the other vehicle based on the movement position of the reflection point estimated by the position estimation means;
A radar apparatus comprising: The radar apparatus according to claim 1, wherein
The other vehicle information acquisition means acquires position information of the other vehicle as information on the other vehicle (S180).
A radar device characterized by the above. The radar apparatus according to claim 1 or 2,
The position estimation means estimates the movement position of the previous reflection point using the relative speed of the previous reflection point closest to the current time among the past reflection points, and the past position estimated in the past. Estimating the further moving position of the reflection point (S140, S220)
A radar device characterized by the above. In the radar apparatus according to any one of claims 1 to 3,
Size calculation means (14) for calculating the size of the other vehicle based on the movement position of the past reflection point estimated by the position estimation means up to the present time;
The other vehicle information acquisition means acquires size information of the other vehicle as information on the other vehicle (S180).
A radar device characterized by the above. The radar apparatus according to claim 4, wherein
The size calculation means, when the current reflection point, which is the current reflection point, is detected by the reflection point detection means, and the movement position of the past reflection point estimated by the position estimation means to the current time Based on the position of the reflection point this time, the size of the other vehicle is calculated (S160).
A radar device characterized by the above. The radar device according to claim 4 or 5,
The radar apparatus according to claim 1, wherein the size calculating means calculates the length of the other vehicle based on a variation in a front-rear direction which is a vehicle front-rear direction of the position of the reflection point. The radar apparatus according to any one of claims 4 to 6,
The radar apparatus according to claim 1, wherein the size calculating means calculates a width of another vehicle based on a variation in a lateral direction orthogonal to the vehicle longitudinal direction of the position of the reflection point. The radar apparatus according to any one of claims 1 to 7,
The position estimation means does not perform the estimation if the current reflection point that is the current reflection point is not detected by the reflection point detection means (S210: NO).
A radar device characterized by the above.   The program which implement | achieves the function as each means of the radar apparatus as described in any one of Claims 1-8.