Method for dynamic calculation of noise levels

A noise level, noise technology, applied in the field of ultrasonic sensors, can solve problems such as wrong behavior, and achieve the effect of improving reliability and reducing costs

Active Publication Date: 2010-01-13
ROBERT BOSCH GMBH
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  • Abstract
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  • Application Information

AI Technical Summary

Problems solved by technology

The disturbance creates non-existent "ghost objects" that are perceived by sensors, which are identified as objects and lead to erroneous behavior of the system

Method used

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  • Method for dynamic calculation of noise levels
  • Method for dynamic calculation of noise levels

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Embodiment Construction

[0025] Known echo signal detectors have two comparators, the threshold values ​​of which can be used to adjust the evaluation window for the amplitude of the received signal. In the present case, the threshold value of the comparator is symmetrical to the null of the received signal, so that the evaluation window is constantly changed by means of a digital-to-analog converter. Here, the function of the window comparator is to output a signal as soon as the input signal exceeds the edge of the window. In order to obtain an output signal independent of the zero crossing of the ultrasonic carrier signal, each individual signal is extended by at least half a period of the minimum frequency to be processed. Here, this is achieved by a monoflop with a switching time of approximately 17 microseconds.

[0026] figure 1 A measurement cycle 1 is shown in , which runs from a first transmission pulse 2 to a second transmission pulse 3 . The voltage change of the received signal in volt...

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Abstract

The invention relates to a method for the dynamic measurement of noise level, in the method, the threshold value (12) is adapted to a signal output of a sensor by means of an echo procedure, and particularly the distance measurement is carried out by means of an ultrasonic procedure, wherein, a transmission signal (2) of the radiated object is sent back to the sensor in form of an echo signal (5), wherein, the time distance between sending of the transmission signal and the reception of the echo signal is measured, wherein, between the time of the decay of the transmission signal and the time of the arrival of the first echo signal (5), a time interval (6) is measured, and a threshold value (13) in the time interval (6) is gradually changed, wherein, the input noise signal is monitored according to compare of current threshold value (13), wherein, the current threshold value (13) becomes lowered, so long the input noise signal is below the current threshold value, and wherein, the current threshold value (13) becomes increased, so long the input noise signal is above the current threshold value (13), wherein, the current threshold value (13) becomes registered within the time interval (6) and wherein from the registered threshold values (13) a threshold value line (12) is determined.

Description

technical field [0001] The invention relates to a method according to the preamble of claim 1 for dynamically adapting threshold values ​​to the signal input of a sensor for distance measurement using the echo method. The invention also relates to a sensor, in particular an ultrasonic sensor, as part of a driver assistance system for applying the method. Background technique [0002] Such driver assistance systems, in particular based on ultrasound, for detecting the environment are known to use a pulse-echo method for distance measurement, in which the signal propagation time between the moment of transmission and the moment of reception is determined. Calculate the distance between the sensor and the object causing the echo. Such measurements yield data that are used as the basis for systems for parking support, overall angle detection, vehicle tire protection in narrow streets, detection of a collision threat and / or longitudinal adjustment. [0003] DE 19645339 A1 discl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01S15/08G01H17/00G01S13/931
CPCG01S13/931G01S7/527
Inventor M·弗兰克W-C·李K-H·里希特
Owner ROBERT BOSCH GMBH
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