Communications: directive radio wave systems and devices (e.g. – Return signal controls external device – Radar mounted on and controls land vehicle
Reexamination Certificate
1999-12-09
2001-06-19
Sotomayor, John B. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Return signal controls external device
Radar mounted on and controls land vehicle
C342S090000, C342S108000, C342S109000, C342S115000, C342S145000, C342S196000
Reexamination Certificate
active
06249243
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a radar apparatus for use on a vehicle and for detecting an object (a target) present in a scan range by scanning the scan range with a radar beam.
2. Related Background Art
A known example of the technology concerning the radar apparatus of this type is one described in Japanese Patent Application Laid-Open No. 9-145883. In this conventional technology, grouping is carried out under a judgment that data with distances close to each other belongs to a single object.
There are, however, cases wherein several data with an equal distance originates in actual objects different from each other, depending upon their directions, and, conversely, there are also cases wherein several data with different distances originates in a single, actual object. Therefore, wrong recognition was sometimes resulted by the above-stated conventional technology of simply grouping data with nearly equal distances.
SUMMARY OF THE INVENTION
The present invention has been accomplished in order to solve the above problem and a radar apparatus according to the present invention is a radar apparatus for use on a vehicle and for detecting a target or two or more targets present in a scan range by scanning the scan range with a radar beam, the radar apparatus comprising means for obtaining prior target data by the scanning with the radar beam, grouping means for carrying out grouping of the prior target data according to a predetermined condition to obtain group data, and target recognition means for identifying the group data and the prior target data remaining without being grouped, as detection data corresponding to respective targets and carrying out recognition of each target corresponding to each detection data, wherein the grouping means makes provision of a plurality of predetermined conditions, selects a condition or two or more conditions according to position information of prior target data to be grouped, and carries out the grouping based on the condition or conditions thus selected.
Principal targets of the radar apparatus are vehicles running ahead and a plurality of target data is sometimes obtained corresponding to a single vehicle running ahead. In such a sense that one-to-one correspondence is not always achieved to the targets as described, the target data herein will be called prior target data.
The “grouping” means putting a plurality of such prior target data together, and how the plurality of prior target data against one preceding vehicle is distributed differs depending upon the position of the preceding vehicle.
In the radar apparatus of the present invention, the optimum grouping condition(s) of the prior target data can be selected according to the position information of the prior target data, whereby correspondence can be made accurate between the group data as the grouping result and an actual target.
When a plurality of prior target data is obtained from a certain preceding car present in the front direction or in a range of a lane on which the vehicle with the radar apparatus is running currently, there is a very high probability that each data results from the rear end of the preceding car. Thus the prior target data based on such a single target can be grouped into a group, using a necessary condition that their distances and relative speeds are approximately equal.
On the other hand, when a plurality of prior target data is obtained from a preceding car present obliquely ahead or outside the range of the currently running lane, the data is a mixture of data originating in the rear end of the preceding car and data originating in the side face of the preceding car. Since the rear end and the side face of the vehicle present obliquely ahead have different distances but a small difference between their angles of directions, the prior target data based on such a single target can be grouped into a group, using a necessary condition that their directional angles and relative speeds are approximately equal. The range of the currently running lane may be assumed to be a fixed range or may be acquired by lane shape acquiring means.
If a target width based on the group data is not less than a predetermined value and if at least a part thereof is off the width of the currently running lane obtained by the lane shape acquiring means, it is desirable to divide the pertinent group data into two new group data inside and outside the currently running lane.
The present invention will be more fully understood from the detailed description given hereinbelow and the accompanying drawings, which are given by way of illustration only and are not to be considered as limiting the present invention.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will be apparent to those skilled in the art from this detailed description.
REFERENCES:
patent: 5745070 (1998-04-01), Yamada
patent: 6072422 (2000-06-01), Yamada
patent: 02000180540 (2000-06-01), None
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Sotomayor John B.
Toyota Jidosha & Kabushiki Kaisha
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