Data processing: vehicles – navigation – and relative location – Relative location – Collision avoidance
Reexamination Certificate
1999-09-15
2001-09-11
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Relative location
Collision avoidance
C701S300000, C701S096000, C340S398100, C340S398100, C342S455000
Reexamination Certificate
active
06289282
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the field of electronic devices. More specifically, the present invention is directed to a device and method for determining the distance between an object and a device of varying location, such as a motor vehicle.
2. Description of the Related Art
In order to facilitate reversing and to prevent collisions with parked vehicles, or other objects in the way, it is known to provide on the rear of the motor vehicle sensors which, for example, transmit ultrasonic or radar signals and which receive radiation reflected by the obstacle. In this case, the distance between the sensor arranged on the motor vehicle and the obstacle is determined from the propagation time of the signal from the sensor to the obstacle and back again.
DE 40 23 538 A1 discloses a method of generic type in which the distance between an obstacle and a motor vehicle is measured in a contactless fashion. In this case, two ultrasonic sensors are arranged at a prescribed spacing, and a device is provided for evaluating the propagation times between the transmission of in each case one ultrasonic signal and the reception of a reflected ultrasonic signal of respectively the same and the other ultrasonic sensor. The distance is determined in this case using the triangulation principle.
From 197 11 467.9, the measured data obtained from the direct measurement (the sensor transmitting the signal receives the reflected signal) and the measured data obtained by an indirect measurement (a second sensor receives the reflected signal) are compared, and the distance is calculated for the position which was determined by the two measuring methods.
This method has the disadvantage that results of different accuracy are also obtained due to the use of different measuring methods, since measured data which cannot be evaluated are generated with each measuring operation.
It is therefore one object of the present invention to specify a method for determining the perpendicular distance of the object from a motor vehicle, which permits an accurate result of the distance measurement in conjunction with a minimum evaluation time.
Other objects and advantages of the present invention will be apparent from the following summary and detailed description of the preferred embodiments.
SUMMARY OF THE INVENTION
In accordance with the invention distance measurement is achieved by virtue of the fact that in a first, very accurate evaluation method the evaluation device determines corresponding positions from the measured data and, subsequently, in a second, less accurate evaluation method further corresponding positions are determined from the remaining unverified measured data.
The advantage of the invention consists in that very exact measured results are obtained by the measured data generated in a single measuring operation, as a consequence of multiple evaluation. In the process, complicated multiple measurement for the purpose of increasing the accuracy of only one measuring method is eliminated.
In an alternate embodiment, in a first evaluation step the evaluation device determines the positions of the object, determined by at least three propagation time measurements, from the measured data. The distance being determined for the positions of the object which have been measured correspondingly by all three propagation time measurements. Subsequently, in a second evaluation step, the positions of the object determined by at least two propagation time measurements are determined from all the measured data ignored in the first evaluation step and the distance is determined from the position measured by the two propagation time measurements. The distance being determined, from a position determined by a single propagation time measurement, in a third evaluation step from the measured data ignored in the second evaluation step.
This method renders it possible for the measured data obtained to be evaluated not only simply and more accurately, but also more quickly. Such an evaluation method is favorable, in particular, for the near region of the motor vehicle, since because of overlap gaps of the sensor lobes there is less information available here in this region. The selected sequence of the different evaluation methods leads to filtering of the measured data, with the result that each measured value is reliably evaluated only once.
It is advantageous for the evaluation device to monitor the corresponding positions determined in the three evaluation steps with regard to the frequency of their occurrence, and to determine the distance between the object and motor vehicle only for the positions whose frequency exceeds a prescribed limit value. This method step is based on the finding that even different evaluation steps can come to the same result, the evaluation device recording that a position is occupied more than once. This multiple occupation is therefore a statement of the reliability of the evaluation. Moreover, random measured data which occur only once and have been recorded because of dispersion in the environment of the motor vehicle are filtered out.
The distance perpendicular to the vehicle contour is determined from the corresponding positions which have been multiply recorded.
In order to segregate environmental influences, the distance between the object and the device of varying location is determined only when the object is located in a sensor corridor which is defined between the first and the second sensor.
In another embodiment, given the presence of a plurality of sensors, the sensor corridor is defined between the sensors executing the current measurements. This ensures that the direct and indirect measurement is always carried out by two sensors.
Since the sensors have mutually differing distances, sensor corridors of different width are defined in the case of pairwise measurement of the sensors. It is thereby possible for objects or obstacles of different size to be located.
The object with the minimum distance is measured in the case of measurement of a plurality of objects with different distances from the device of varying location, and the minimum perpendicular distance is calculated and stored.
REFERENCES:
patent: 5004997 (1991-04-01), Shisgal
Fleischhauer Norbert
Hassler Gregor
Cuchlinski Jr. William A.
Depke Robert J.
Donnelly Arthur D.
Mannesmann VDO AG
Mayer Brown & Platt
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