Communications: directive radio wave systems and devices (e.g. – Testing or calibrating of radar system – By monitoring
Reexamination Certificate
2000-01-28
2002-07-02
Gregory, Bernarr E. (Department: 3662)
Communications: directive radio wave systems and devices (e.g.,
Testing or calibrating of radar system
By monitoring
C342S070000, C342S104000, C342S109000, C342S115000, C342S118000, C342S128000, C342S165000, C342S195000
Reexamination Certificate
active
06414628
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of detecting any fault of radar apparatus mounted on a vehicle using a movement distance of the vehicle, and a radar apparatus for the same.
2. Description of the Related Art
A radar apparatus mounted on a vehicle is conventionally made a practical use, to detect an obstacle in a relatively short distance. By using the radar apparatus, it is possible to avoid collision of the vehicle with obstacles such as an electric light pole and a block wall when the vehicle is put in a garage.
Also, in recent years, the study for coming to practical use is carried out of a radar apparatus to detect a detection object in relatively long distance in a high speed and in a high precision. By using the radar apparatus, it is possible to prevent the collision of the vehicle with a preceding vehicle. The radar apparatus detects a moving body running at high speed such as a vehicle running in front of the vehicle and a coming vehicle as a main target. Therefore, a detection area is generally set to a relatively narrow range in front of the vehicle.
Also, in such a radar apparatus, it is necessary to carry out a detecting process of a preceding vehicle at high speed in correspondence to the velocity of the vehicle. In this case, the distance measuring range must cover a range from the close distance of tens of centimeters to about hundreds of meters from the vehicle. Therefore, a radar apparatus is proposed in which transmitting means radiates a sharp directional radar beam to the preceding vehicle and receiving means receives a reflected beam from the preceding vehicle.
In U.S. Pat. No. RE 36,095, for example, a multi-beam radar apparatus is proposed which uses a high frequency radio wave beam of a millimeter band. In a radar apparatus of this technique, radar beams are radiated to overlap spatially using a plurality of transmitting and receiving sections, and the combinations of the transmitting and receiving sections are changed to improve the detection precision.
Also, in EP 840,140 A1, for example, a scan beam radar apparatus is proposed which uses a high frequency radio wave beam in the millimeter band as the radar wave. In this technique, the radio wave beam is radiated from a primary emitter and is scanned by a rotating reflector, and a reflection beam from the reflector is converged by a dielectric lens, to reduce an expansion angle. Thus, the radio wave beam is radiated to the front direction of the vehicle.
However, in the multi-beam radar apparatus having a plurality of transmitting sections and a plurality of receiving sections, a peculiar detection area is defined for every combination of the transmitting section and the receiving section. Also, the position of a detection object, i.e., an azimuth angle and a distance from the vehicle are calculated by synthesizing reception signals for the respective combinations of the transmitting section and the receiving section. For this reason, the calculated position of the detection object is different from the actual position of the detection object, when any of the plurality of receiving sections and the plurality of transmitting sections is degraded in sensitivity.
Also, in the scan beam radar apparatus, because a single transmission circuit and a single reception circuit are used, an azimuth angle error is difficult to be generated unlike the above multi-beam radar apparatus. However, the detection sensitivity reduces uniformly over all the azimuth angles due to the degradation of the transmitting circuit or the receiving circuit. Therefore, the distance measuring range for the detection object becomes narrow.
Also, in these conventional radar apparatus, the following matters are necessary to measure sensitivity of the radar apparatus for detection of the degradation of the transmitting or receiving circuit. First, the vehicle with the radar apparatus mounted must be carried to an examination environment in which a reference subject is installed. There, a radar beam is transmitted from an examination location to the stationary reference subject and the reflected signal is received. Thus, the sensitivity of the radar apparatus is detected based on the received signal. Therefore, the regular check is necessary in the conventional radar apparatus. This is inconvenient to the user.
SUMMARY OF THE INVENTION
Therefore, an object of the present invention is to provide a method of detecting a fault of a radar apparatus, in which any fault of the radar apparatus mounted on a vehicle can be detected in a usual running state of the vehicle, and a radar apparatus for the same.
Another object of the present invention is to provide a method of detecting a fault of a radar apparatus, in which erroneous detection of a position of a detection object can be avoided, and a radar apparatus for the same.
Still another object of the present invention is to provide a method of detecting a fault of a radar apparatus, in which a detecting operation of any fault of the radar apparatus can be selectively started or stopped, and a radar apparatus for the same.
Yet still another object of the present invention is to provide a method of detecting a fault of a radar apparatus, in which any fault of the radar apparatus can be informed to a passenger of the vehicle, and a radar apparatus for the same.
It is also an object of the present invention to provide a method of detecting a fault of a radar apparatus, in which a detecting operation of any fault of the radar apparatus can be executed to received signals of channels other than fault channels, and a radar apparatus for the same.
Another object of the present invention is to provide a method of detecting a fault of a radar apparatus, in which a detecting operation of any fault of the radar apparatus can be executed based on the detection of a detection object and the movement distance of the vehicle, and a radar apparatus for the same.
Still another object of the present invention is to provide a method of detecting a fault of a radar apparatus, in which a detecting criteria of any fault of the radar apparatus can be changed based on the peripheral circumstance of the running vehicle, and a radar apparatus for the same.
In order to achieve an aspect of the present invention, a radar apparatus mounted on a vehicle includes a detecting section and a fault determining section. The detecting section includes a radar unit and detects a detection object using radar wave radiated from a radar unit toward the detection object and reflected radar wave from the detection target to the radar unit. The fault determining section determines whether any fault has occurred in the radar unit, based on the detecting result of the detection object and a movement distance of the vehicle, and generates a fault detection signal, when it is determined that any fault has occurred in the radar unit.
Here, the radar apparatus mounted on a vehicle may further include a state setting switch operated by a passenger of the vehicle to start or stop the fault determining section.
Also, the radar apparatus mounted on a vehicle may further include an alarm section outputting an alarm in response to the fault detection signal.
Also, the fault determining section is always started when the vehicle is started.
Also, the fault determining section may include a counter and a determining section. The counter counts the movement distance of the vehicle, and the counter is reset in response to the detection of the detection object as the detecting result. The determining section checks whether the counter reaches a predetermined value, and determining that any fault has occurred in the radar unit, to generate the fault detection signal, when the counter reaches the predetermined value.
Also, the fault determining section may include a counter and a determining section. The counter counts the movement distance of the vehicle when a power spectrum of the reflected radar wave does not contain any component with an intensity value larger than a predetermined intensit
Blackman William D.
Carrier Joseph P.
Carrier Blackman & Associates P.C.
Gregory Bernarr E.
Honda Giken Kogyo Kabushiki Kaisha
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