JP4497017B2 - Vehicle object detection device - Google Patents

Description

  The present invention generally relates to a vehicle object detection device that is mounted on a vehicle and detects an object around the host vehicle, and more particularly, to a vehicle object detection device in which an area where an object can be detected with high accuracy is expanded in an array antenna. .

  Conventionally, a radar device that is mounted on a vehicle and detects an object (for example, another vehicle) around the host vehicle is well known. Such an in-vehicle radar device can calculate a relative distance, a relative speed, and a direction between the own vehicle and a detection target object from detection data, an auto cruise control system that maintains a constant inter-vehicle distance with a preceding vehicle, It is used in pre-crash safety systems that minimize the impact during a collision.

  In such an on-vehicle radar device, an array antenna is often used. This is because the array antenna is advantageous in terms of mounting space because it can electronically scan an object without having to swing the antenna by a mechanical mechanism. Furthermore, there is an array antenna of a type called a flat type with a short depth, and if this type is used, mountability on a vehicle becomes more advantageous.

  However, in a radar apparatus using an array antenna, unnecessary antenna directivity called a grating lobe and a side lobe is inevitably generated in principle. For this reason, normally, only a region that is clearly detected by the main lobe is set as a detection region.

  In the area outside this detection area, there is a low-accuracy detection area where it is possible to detect the object, but it is uncertain whether it is detected by the main lobe or the grating lobe or side lobe. . Usually, the detection result in this low-accuracy region is not used because there is a high possibility of misdirection.

  If the detection area of one radar apparatus is narrowly limited in order to prevent an object from being erroneously detected due to the low precision area, a large number of radar apparatuses are required to cover a wide range as a detectable range.

In order to avoid such a situation, conventionally, a radar apparatus has been proposed in which a null is provided in the grating generation direction by the antenna directivity to suppress the grating lobe and the side lobe level (gain), thereby improving the accuracy in the low accuracy region. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 11-23310

  However, even with a conventional apparatus such as the above-mentioned Patent Document 1, in principle, the grating lobe and the side lobe level cannot be made zero. Therefore, the possibility that indefinite detection will be left remains. In particular, when the object to be detected is a very strong reflector, there is a possibility of erroneous detection (ghost detection) in the grating lobe or the side lobe even if the detection area is limited to be narrow.

  In addition, since scanning is necessary to detect the orientation of the object, if the main lobe for scanning is moved to the left or right, the position (azimuth) of the grating lobe and side lobe changes accordingly. Therefore, there is a possibility that an angle shift occurs between the set null point and the grating lobe or side lobe direction, and the gain of the grating lobe or side lobe may increase.

  Furthermore, it is conceivable to reduce the uncertainty region by narrowing the antenna element interval of the array antenna, but this method may not provide a sufficient gain.

  As described above, in the conventional apparatus, it is still necessary to limit the detection area to a narrow range, and there is a problem that many radar apparatuses are required to reliably cover a wide angle range. Yes.

  The present invention has been made to solve such problems, and a main object of the present invention is to provide a vehicle object detection device in which an area where an object can be detected with high accuracy using an array antenna is expanded.

One aspect of the present invention for achieving the above object is a vehicle object detection device that is mounted on a vehicle and detects an object around the host vehicle, wherein the object has a first accuracy in the first object detection region. It detects, in the above-described first object detection area object detecting means comprising one or more detectors to detect an object in a different second object detection region lower second accuracy than the first accuracy in the A trajectory estimating means for estimating a subsequent relative movement trajectory of the object based on a plurality of object relative positions respectively detected at a plurality of locations in the first object detection area by the object detecting means; and the object detection When the object relative position detected in the second object detection area by the means overlaps the estimated relative movement locus of the object estimated by the locus estimation means, the object is detected in the second object detection area. Relative object position Serial is a second object detection device for a vehicle having an accuracy correction means deemed to be detected at a higher third precision accuracy.

  In this aspect, the “object” that is the detection target is a concept including a moving body and a stopped object, such as another vehicle or a guardrail.

Further, in this aspect, each of the detectors typically includes an array antenna, and the first object detection area is an angular range in which an object is detected by a main lobe in the antenna gain of the array antenna. The second object detection area is an angle range in which an object is likely to be erroneously detected due to a grating lobe or a side lobe in the antenna gain of the array antenna.

According to this aspect, the plurality of object relative positions detected in the region with the relatively low detection accuracy (second object detection region) are detected in the region with the relatively high detection accuracy (first object detection region). If the object estimated on the basis of the relative position of the object is on the estimated relative movement trajectory that is predicted to pass thereafter, the accuracy of the object relative position detection result is relatively low even within the low detection accuracy region. Based on the insight that it can be considered high, it is possible to detect an object with relatively high accuracy in the low detection accuracy region using the estimated relative movement trajectory as described above. The area that can be detected can be expanded.

In this embodiment, when the object detection means has two detectors, the first and second detectors are interconnected so that information can be transmitted and received, and the trajectory estimation means is Estimating a subsequent relative movement trajectory of the object based on a plurality of object relative positions respectively detected at a plurality of locations in a first object detection region of the first detector by the first detector ; The accuracy correction means includes the object relative position detected by the second detector in the second object detection area of the second detector and the estimated relative movement locus of the object estimated by the locus estimation means. Can be regarded as having been detected with the above-mentioned third accuracy when the object relative position detected in the second object detection area of the second detector . Here, for example, the first detector is for vehicle rear or side, and the second detector is for vehicle front, for example.

In this aspect, when the object detection means has three detectors, the first, second, and third detectors are interconnected so that information can be transmitted and received, and the locus The estimation means includes at least one object relative position detected in the first object detection area of the first detector by the first detector and the second detector by the second detector. A subsequent relative movement trajectory of the object is estimated based on at least one object relative position detected in the first object detection region, and the accuracy correction means is configured to detect the third detector by the third detector. When the object relative position detected in the second object detection area of the detector overlaps the estimated relative movement trajectory of the object estimated by the trajectory estimation means, the second object of the third detector detected in the detection area the object relative position The deemed to have been detected by the third accuracy can be so. Here, for example, the first detector is for a vehicle rear, the second detector is for a vehicle side, and the third detector is for a vehicle front, for example.

  Furthermore, in this aspect, it is preferable that the third accuracy is equal to the first accuracy because detection results of both accuracy can be handled equally.

  ADVANTAGE OF THE INVENTION According to this invention, the object detection apparatus for vehicles by which the area | region which can detect an object with high precision in an array antenna was expanded can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. The basic concept of the radar itself using the array antenna, the main hardware configuration, the operating principle, the basic control method, and the like are known to those skilled in the art and will not be described in detail.

  First, the configuration of a vehicle object detection device according to an embodiment of the present invention will be described with reference to FIG. In the present embodiment, the “object” that is the detection target is a concept including a moving body and a stopped object, such as another vehicle or a guardrail.

  FIG. 1 is a schematic configuration diagram of a vehicle object detection device 100 according to the present embodiment. The vehicle object detection device 100 mounted on the vehicle V includes one or more arbitrary numbers of radars. Here, each radar is assumed to be a radar apparatus using an array antenna. Therefore, each radar has a high-precision detection area and a low-precision detection area (uncertain area) as described above.

  In the present embodiment, as an example, the vehicle object detection device 100 is mounted on the front radar 101 mounted on the front end of the vehicle V, the rear radar 102 mounted on the rear end of the vehicle V, and on the right side of the vehicle V. It is assumed that the right side radar 103 and the left side radar 104 mounted on the left side of the vehicle V are provided.

  The vehicle object detection device 100 further includes a management ECU 106 connected to these four radars via a communication line 105.

  In the vehicle object detection device 100 having such a configuration, each of the radar sensors 101 to 104 transmits data of the detected object (distance to the host vehicle, relative speed, direction, etc.) to the management ECU 106 via the communication line 105. At this time, each radar sensor transmits to the management ECU 106, for example, using a flag or the like whether the detection data is in the detection area or in the uncertain area.

  Hereinafter, the flow of the detection area expansion process performed by the management ECU 106 will be described with reference to FIG. FIG. 2 is a flowchart showing the flow of processing by the vehicle object detection device 100 according to the present embodiment.

  First, the management ECU 106 determines whether or not the same object has been detected at two or more locations in the detection area with high detection accuracy based on the detection data transmitted from each radar (S201). The detection area here may be a detection area of one radar, or may be a detection area of a plurality of radars. If two or more locations in the detection area are not detected (“NO” in S201), one routine of this flow is terminated without performing any special processing.

  When an object around the host vehicle is detected at two or more locations in the detection area (“YES” in S201), the management ECU 106 determines the relative movement trajectory (or vector) of the object from the detection data at these two or more locations. At the same time, the subsequent relative movement locus is estimated from the calculated relative movement locus (S202). For example, the estimated trajectory of the estimated object is stored and held in the management ECU 106 for a predetermined time after being estimated.

  Next, based on the detection data transmitted from each radar, the management ECU 106 determines whether any radar has detected again an object whose relative movement locus has been estimated (S203). For example, if the object is not detected again even after a predetermined time has elapsed (“NO” in S203), one routine of this flow is terminated.

  When the object is detected again (“YES” in S203), the management ECU 106 then determines from the detected information from the radar whether or not it is detected within a detection area with good detection accuracy. (S204).

  When the detection data is within the detection area (“YES” in S204), the detection data is determined to be accurate, that is, the data detected by the main lobe as usual, and the detected object is determined ( S207).

  On the other hand, if the detection is not within the detection region, that is, if the detection is within the indeterminate region (“NO” in S204), then the management ECU 106 determines that the detected object relative position is in S202. Whether or not the calculated object is on the estimated relative movement locus is determined based on detection data such as distance, relative speed, and direction (S205).

  As described above, detection in the indeterminate region is uncertain whether it is a main lobe, a grating lobe, or a side lobe. In this embodiment, therefore, the management ECU 106 determines that the object relative position detected in the uncertain area is highly correlated with the estimated relative movement trajectory calculated in advance for the object (“YES” in S205). Even in the detection in the area, it is determined that the probability of the detection result having high accuracy by the main lobe is high, and the detection result is treated as having the same accuracy (probability) as the detection result in the detection area (S207). .

  On the other hand, if it is determined that the relative position of the object detected in the indeterminate region deviates from the estimated relative movement trajectory of the object (“NO” in S205), the detection result is determined to be low in probability. Thus, the detection data is discarded as usual (S206).

  As described above, the management ECU 106 determines whether or not the relative position of the object detected in the uncertain area is reliable based on the previously estimated relative movement trajectory. This detection result can be partially used, and as a result, the detection range can be expanded.

  Hereinafter, three examples of detection object determination in the indeterminate region according to the present embodiment will be given using FIGS.

  FIG. 3 uses the relative movement trajectory estimated based on the detection result in the detection area of one radar (here, the forward radar as an example) to determine the relative position of the object in the uncertain area of the same radar. Shows when to do.

  In FIG. 3, assuming that an object is detected at points A and B in the detection area of the front radar, the vector between points A and B from the position data of these two points is the relative movement locus (solid line) of the object. An arrow) is calculated and a vector obtained by extending this to the right, which is the relative movement direction, is an estimated relative movement locus (dashed arrow).

  Therefore, when an object is detected at the point C (star) in the uncertain area of the forward radar, this is on the estimated relative movement locus, and therefore this detection accuracy is equivalent to that in the detection region. Can be considered.

  FIG. 4 shows another radar (front radar as an example here) using a relative movement trajectory estimated based on the detection result in the detection area of one radar (here a right side radar as an example). This shows a case where the relative position of the object is confirmed within the uncertain area.

  In FIG. 4, assuming that an object is detected at points A and B in the detection area of the right-side radar, a vector between point A and point B from the position data of these two points is a relative movement locus of the object ( A vector obtained by calculating as a solid arrow) and extending it forward as a relative movement direction becomes an estimated relative movement locus (dashed arrow).

  Therefore, when an object is detected at the point C (star) in the uncertain area of the forward radar, this is on the estimated relative movement locus, and therefore this detection accuracy is equivalent to that in the detection region. Can be considered.

  FIG. 5 shows another radar (here, forward as an example) using the relative movement trajectory estimated based on the detection results in the detection area of two radars (here, rear radar and right side radar as an example). In this example, the relative position of the object is determined within the uncertain area of the radar.

  In FIG. 5, if an object is detected at a point A in the detection area of the rear radar and a point B in the detection area of the right side radar, the vector between the points A and B is obtained from the position data of these two points. A relative movement trajectory (solid arrow) of the object is calculated, and a vector obtained by extending the relative movement direction forward is an estimated relative movement trajectory (broken arrow).

  Therefore, when an object is detected at the point C (star) in the uncertain area of the forward radar, this is on the estimated relative movement locus, and therefore this detection accuracy is equivalent to that in the detection region. Can be considered. That is, the object can be detected at an early stage before the object reaches the point D (x mark) in the forward radar detection area.

  As described above, according to the present embodiment, one of the detection results in the low-precision uncertain region is obtained by using the relative movement trajectory of the object estimated based on the detection result in the high-precision detection region. As a result, the detection range can be expanded.

  In the above embodiment, when the object relative position detected in the uncertain area overlaps with the estimated relative movement locus calculated in advance for the object, the object relative position is detected in the determined area. Although the accuracy equivalent to the relative position is assumed, this is only an example, and it may be handled as having a higher accuracy than the detection result in the uncertain region that does not overlap with the estimated relative movement locus. However, since it is convenient if an equivalent process becomes possible without requiring a weighting process or the like, it is preferable to regard it as having the same accuracy as the detection result in the definite region as in the above-described embodiment. I can say that.

  Further, in the above-described one embodiment, as an example, a case where a management ECU that comprehensively manages and controls the entire apparatus has been described, but as is apparent to those skilled in the art, the present invention is not limited thereto, Of course, it is possible to omit the management ECU and connect each radar so as to be able to communicate directly, so that all processing judgments are performed in each radar.

  It is also clear from the specific examples shown in FIGS. 3 to 5 that the detection range extension processing according to the present invention can be widely applied regardless of the number of mounted radars.

  The present invention is not limited to the array antenna exemplified in the above-described embodiment, and can be widely used for all antennas having a detection area with relatively high object detection accuracy and a detection area with relatively low object detection accuracy. The mounted object may be a moving object (for example, a vehicle, a ship, an aircraft, etc.) or a stationary object (fixed communication station).

It is a schematic block diagram of the vehicle object detection apparatus which concerns on one Example of this invention. It is a flowchart which shows the flow of the detection area expansion process by the object detection apparatus for vehicles which concerns on one Example of this invention. It is a figure which shows an example of the detection object determination in the indeterminate area | region by the vehicle object detection apparatus which concerns on one Example of this invention. It is a figure which shows another example of the detection object determination in the indeterminate area | region by the vehicle object detection apparatus which concerns on one Example of this invention. It is a figure which shows another example of the detection object determination in the indefinite area | region by the vehicle object detection apparatus which concerns on one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Vehicle object detection apparatus 101 Front radar 102 Rear radar 103 Right side radar 104 Left side radar 105 Communication line 106 Management ECU

Claims (5)

A vehicle object detection device that is mounted on a vehicle and detects an object around the host vehicle,
In the first object detection area to detect objects in the first accuracy, an object in a different in the second object detection region is lower than the first accuracy second accuracy with said first object detection area Object detection means comprising one or more detectors for detecting
Trajectory estimation means for estimating a subsequent relative movement trajectory of the object based on a plurality of object relative positions respectively detected at a plurality of locations in the first object detection area by the object detection means;
When the object relative position detected in the second object detection area by the object detection means and the estimated relative movement trajectory of the object estimated by the path estimation means overlap, the second object detection area And an accuracy correction unit that regards the relative position of the object detected in step 3 as being detected with a third accuracy higher than the second accuracy. The vehicle object detection device according to claim 1,
The object detection means has two detectors,
These first and second detectors are interconnected so that information can be transmitted and received,
The trajectory estimation means is configured to detect the relative position of the object based on a plurality of object relative positions respectively detected at a plurality of locations in a first object detection area of the first detector by the first detector. Estimate the movement trajectory,
The accuracy correcting means includes an object relative position detected by the second detector in a second object detection area of the second detector and an estimated relative movement locus of the object estimated by the locus estimating means. Is detected with the third accuracy, the object relative position detected in the second object detection area of the second detector apparatus. The vehicle object detection device according to claim 1,
The object detection means has three detectors,
These first, second, and third detectors are interconnected to allow transmission and reception of information,
The trajectory estimation means includes at least one object relative position detected in the first object detection area of the first detector by the first detector and the second detection by the second detector. Estimating a subsequent relative movement trajectory of the object based on at least one object relative position detected in the first object detection region of the vessel;
The accuracy correcting means includes an object relative position detected by the third detector in a second object detection area of the third detector and an estimated relative movement locus of the object estimated by the locus estimating means. Vehicle object detection, wherein the relative position of the object detected in the second object detection area of the third detector is regarded as having been detected with the third accuracy. apparatus. The vehicle object detection device according to any one of claims 1 to 3,
Each of the detectors includes an array antenna;
The first object detection area is an angle range in which an object is detected by a main lobe in an antenna gain of the array antenna,
The vehicle object detection device according to claim 2, wherein the second object detection region is an angle range in which an object is likely to be erroneously detected by a grating lobe or a side lobe in an antenna gain of the array antenna. The vehicle object detection device according to any one of claims 1 to 4,
The vehicle object detection device, wherein the third accuracy is equal to the first accuracy.

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