JP2009222455A - Radar system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the erroneous detection that a vehicle exists in an intermediate point between two vehicles existing in front of the own vehicle, without using a camera. <P>SOLUTION: The radar system has a first radar system installed in the left front of the own vehicle, and a second radar system installed in the right front of the own vehicle. The first and second radar systems are installed with an interval of a resolution between necessary for detecting a plurality of objects existing in front while isolating them. It does not matter if the electric-wave irradiation ranges of the first and second radar devices are adjusted so as to overlap respectively on a traveling lane of the own vehicle, and in addition so as not to overlap on the right and left adjoining lanes. Moreover, it does not matter if the plurality of objects existing in front of the own vehicle are detected while being mutually isolated, based on the difference between a detection result acquired from the electric-wave irradiation range of the first radar system and a detection result acquired from the electric-wave irradiation range of the second radar device. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an automobile mounting configuration of a radar apparatus and a collision determination method.

  There is a need for a collision damage reducing device that reduces the damage of a collision by detecting the presence of an obstacle ahead using a radar device using radio waves and automatically operating a brake. Here, if the vehicle is traveling at the same distance from the vehicle, one vehicle at the left front of the vehicle and one at the right front of the vehicle, whether the vehicle exists at the midpoint between the two vehicles in front As a method for solving this problem, in addition to the radar device, the result of measuring the vehicle position by image recognition using a camera is collated to improve the accuracy of vehicle detection. A technique is known (see Patent Document 1).

JP-A-6-230115

  In Patent Document 1, a camera is used. However, the camera has a problem that the detection performance in rainy weather or night falls. Another problem is that the cost of the camera is higher than that of the radar.

  Therefore, an object of the present invention is to avoid a false detection that a vehicle is present at an intermediate point between two front vehicles without using a camera.

  In order to solve the above problems, one of the desirable embodiments of the present invention is as follows.

  The radar system includes a first radar device installed on the left front side of the host vehicle and a second radar device installed on the right front side of the host vehicle, wherein the first and second radar devices are respectively It is installed with a resolution interval for separating and detecting a plurality of objects existing in front.

  According to the present invention, it is possible to avoid erroneous detection that a vehicle is present at an intermediate point between the two vehicles ahead without using a camera.

  Embodiments will be described below with reference to the drawings.

  FIG. 1 is a diagram for explaining a mounting position of a radar apparatus. FIG. 1A shows a case where two vehicles 102 a and 102 b exist in front of the host vehicle 101.

  The distance resolution ΔR indicating the performance of the FMCW radar device can be calculated by the following equation when the modulation width Δf is 1 Ghz, and is 0.15 m. c indicates the speed of light.

  Here, in FIG. 1, when the radar device 103c is attached to the center of the own vehicle (conventional technology), and when the radar devices 103l and 103r are attached to the left and right positions at a distance of offset from the center of the own vehicle ( The present invention).

  In the case of the prior art, in order to separate and detect the preceding vehicle, the distance difference between the vehicles existing in front of the host vehicle is required to be 0.15 m or more in the front-rear direction. On the other hand, in the case of the present invention, the offset at which the distance difference from the preceding vehicle is 0.15 m or more is 1.07 m according to the following calculation formula. In the following calculation formula, the distance between the host vehicle and the preceding vehicle is 50 m, and the distance between the preceding vehicles is 7 m (lane width 3.5 m).

  That is, if two radar devices 103l and 103r are installed with an offset of 1.07m or more from the center of the own vehicle, even if the two forward vehicles arranged in parallel are at a distance of 50m from the own vehicle, The position can be detected. Further, as shown in FIG. 1B, when the received wave of the radar device is shown as a spectrum waveform, when the radar device 103c is mounted at the center, it is synthesized into one frequency as shown in FIG. As shown in (C), when the lens is attached to the left end, 103l can be detected by separating it into two frequencies like 112, and the angle can be calculated individually at each frequency.

  As described above, either one of the two radar devices can reliably detect and detect a plurality of forward vehicles.

  Next, the obstacle detection device that determines whether or not to perform the collision damage reduction brake combines the detection results of the two left and right radar devices to determine whether or not there is a possibility of a collision with the preceding vehicle. However, since the results of the two radar devices have some errors in the detected position of the preceding vehicle due to errors in the respective mounting positions and detection errors, it is necessary to perform combination processing within a certain range. Here, a processing method for combining the detection results of the two radar devices obtained in the first embodiment will be described with reference to FIG.

  As shown in FIG. 2A, the position detected by the left radar device is 202l and the right radar device detects the actual position 201 of the preceding vehicle in the radio wave irradiation range of the two radar devices. Assume that the result was 202r. At this time, the obstacle detection device searches for the presence / absence of the result 202r in the range of the vehicle width 203 that is half of the passenger car, for example, centering on 202l. If there is a result of 202r, it is determined that the vehicle is the same, and an intermediate position 204 is output. However, as shown in FIG. 2B, when the radar device on the right side has a small distance difference as in the forward vehicles 205a and 205b and is detected as a virtual image 205c, the result is obtained by the processing procedure shown in FIG. Output. Hereinafter, FIG. 3 will be described.

  The obstacle detection device performs the above combination processing centering on the result of the left radar device (STEP 1). Next, it is determined whether or not STEP1 has been performed for all the vehicles detected by the left radar device. If it is not completed, the process returns to STEP1 (STEP2). Then, it is determined whether or not the combination processing has been completed for all the vehicles detected by the left radar device, and if so, the result of the combination processing is output (STEP 3).

  In STEP3, when there are vehicles that cannot be combined, the determination methods are distinguished according to the radio wave irradiation range, and the combinations are performed (STEP4). First, if the position of the vehicle is within the radio wave irradiation range of only the left radar device, it is adopted as the detection result of the left radar device (STEP 5). Next, if it is the radio wave irradiation range of only the right radar device, it is similarly adopted as the detection result of the right radar device (STEP 6). Finally, if the radio wave irradiation ranges of the left and right radar devices overlap, the vehicle is searched for other vehicles that cannot be combined (STEP 7). A search is made as to whether a vehicle detected by the radar device is present (STEP 8). If it exists, it is determined that the virtual image is detected by the right radar device, and the position of the left radar device in STEP 5 is adopted. On the other hand, if there is no vehicle that can be combined between the vehicles in STEP 8, it is discarded as an unknown vehicle (STEP 9). In STEP 7, if there is only one vehicle that cannot be combined with the left radar device, the processing in the range a is performed on the right radar (STEP 10).

  Note that the above processing may be performed by switching the left and right radar devices.

  FIG. 4 is a diagram illustrating a state in which two radar devices are attached to both ends of the own vehicle. Here, two radar devices 901l and 901r are attached to the own vehicle 900 at both ends of the own vehicle, and the radio wave irradiation ranges of the respective radar devices are adjusted so as to overlap each other on the traveling path of the own vehicle. It is.

  In this example, the radar device 901l at the left end uses the traveling path of the own vehicle and the adjacent lane on the right side as the irradiation range 902l, and the radar device 901r at the right end sets the traveling path of the own vehicle and the adjacent lane on the left side as the irradiation range 902r. For example, when the radar apparatus receives a reflected wave from a preceding vehicle, the irradiation range referred to here is a range in which a sufficient radio wave intensity that can be determined as a reflected wave from the vehicle can be received (generally, a radio wave The intensity is calculated in a unit called Radar Cross Section normalized by the distance from the vehicle ahead, and the Radar Cross Section of the passenger car is set to 10 dBm).

  When this radar apparatus mounting method is employed, a method for measuring the exact position of the preceding vehicle from the detection results of the left and right radar apparatuses in the traveling scene shown in FIGS. 5 to 7 will be described below.

  In the case of FIG. 5, since the two radar devices 503l and 503r have a front vehicle in the radio wave irradiation range, the positions of the front vehicles can be measured by the respective radar devices, and the positions coincide with each other. Accordingly, when the detection results of the two radar devices match in the overlapping range of the radio wave irradiation ranges, it is determined that the actual vehicle position can be measured, and the result is adopted.

  In the case of FIG. 6, the detection results of the two radar devices 603l and 603r can be detected because 603l is within the irradiation range of the vehicle 602b, and 603r can detect 602a. As described above, when outputting a detection result in which the two radar apparatuses do not match in a region where the radio wave irradiation ranges do not overlap, it is determined that there is a vehicle ahead in the adjacent lane, and each detection result is adopted.

  In the case of FIG. 7, the radar devices 703l and 703r attached to both ends of the own vehicle can detect only the radio wave irradiation range 702a, and the 703r detects 702a and 702b. At this time, when the two forward vehicles are located at a distance difference that cannot be separately detected with respect to the radar device 703r, the angles of the two forward vehicles may be combined, and the combined result may be detected as a virtual image. is there. In that case, since there is a mismatch in the detection results in the overlapping area of the radio wave irradiation area, it is determined that the right radar device 703r that has not been able to detect the front vehicle in the overlapping area of the radio wave irradiation is detecting a virtual image, The detection result of the left radar device 703l is employed.

The figure for demonstrating the attachment position of a radar apparatus. FIG. 3 is a diagram for explaining a combination processing method according to the first embodiment. FIG. 5 is a diagram for explaining a combination processing order according to the first embodiment. The figure which shows the radar apparatus attachment of Example 2. FIG. The figure for demonstrating the determination method of the front vehicle position of Example 2. FIG. The figure for demonstrating the determination method of the front vehicle position of Example 2. FIG. The figure for demonstrating the determination method of the front vehicle position of Example 2. FIG.

Explanation of symbols

101 Vehicle 102 Front vehicle 103 Radar device

Claims (3)

A first radar device installed on the left front side of the vehicle;
A second radar device installed on the right front side of the host vehicle,
The first radar system and the second radar apparatus are each installed with a resolution interval for separating and detecting a plurality of objects existing in front.   2. The radar system according to claim 1, wherein the radio wave irradiation ranges of the first and second radar devices are adjusted so as to overlap each other on the traveling road of the own vehicle and not on adjacent left and right lanes. .   Based on the difference between the detection result obtained from the radio wave irradiation range of the first radar device and the detection result obtained from the radio wave irradiation range of the second radar device, a plurality of vehicles existing in front of the host vehicle The radar system according to claim 2, wherein the object is detected separately.

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