Ultrasonic Water Level Detection Using Time Offset Filtering
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Solution Overview
Problem
Existing methods for determining the water level around a motor vehicle face challenges due to multiple reflections and interference from vehicle attachments, leading to inaccurate water level detection.
Innovation Solution
A method using a driver assistance device that calculates a time offset between transmitted and received ultrasonic signals to differentiate between water level reflections and reflections from vehicle attachments, allowing for reliable water level determination by ignoring echoes from attachments and using the first echo outside a specified range to determine the water level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic sensors are used to detect water level, then water level detection capability is provided, but multiple reflections and attachments cause inaccurate detection
Solution Approach 1:
The patent segments the received echo signals by analyzing time offsets and grouping them into different categories (attachment echoes vs. water surface echoes). By dividing the echo analysis into discrete time intervals and identifying patterns, the system can distinguish between reflections from vehicle attachments and reflections from the water surface, thereby improving measurement accuracy despite the presence of multiple reflections.
Solution Approach 2:
The patent applies partial action by selectively processing only those echo signals that meet specific criteria (time offset within specified range, intensity thresholds). Rather than attempting to process all echoes equally, the system focuses on identifying and utilizing the relevant water surface echoes while filtering out attachment-related echoes, thus achieving accurate water level detection without being overwhelmed by spurious reflections.
2Measurement precision
If additional sensors are added to detect water level, then detection capability is improved, but device complexity increases
Solution Approach 1:
The patent makes existing ultrasonic sensors (originally designed for parking assistance) multi-functional by programming them to perform both parking distance detection and water level detection. The same sensor hardware and processing unit are utilized for multiple purposes, eliminating the need for additional dedicated water level sensors and thereby avoiding increased device complexity while maintaining detection accuracy.
Solution Approach 2:
The system uses its own existing sensor infrastructure and processing capabilities to perform water level detection without requiring external specialized equipment. The driver assistance device's existing ultrasonic sensors and evaluation unit serve the dual purpose of parking assistance and water level monitoring, making the system self-sufficient and avoiding additional hardware complexity.
3Loss of information
If sensor evaluates all received echoes, then comprehensive data is obtained, but incorrect water level estimation occurs due to attachment echoes
Solution Approach 1:
The patent extracts and separates attachment echo signals from the total received echo signals by analyzing time offsets and signal characteristics. Identification of echoes within specified time offset ranges allows the system to isolate and exclude attachment-related reflections from the water level calculation, preventing incorrect estimations while retaining comprehensive analysis of all received signals.
Solution Approach 2:
The system employs feedback mechanisms by continuously monitoring echo patterns, time offsets, and signal intensities to dynamically adjust its interpretation of received signals. By comparing expected echo patterns with actual received signals and using feedback from previous measurements, the system can identify and correct for attachment echoes, thereby maintaining accurate water level estimation despite the presence of multiple reflections.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the accuracy and reliability of water level detection, avoiding misjudgment caused by vehicle attachments and allowing for robust detection of water levels above, below, or at the same height as attachments, while adapting to the vehicle's geometric design.
Implementation Method 1
A signal component of the transmission signal reflected in the surrounding area is then received as a reception signal
Implementation Method 2
A next step is to determine a time offset, ie a time interval, between the transmission signal and a reception echo of the reception signal
Data Source
AI summary
The invention relates to a method for determining a water level in the vicinity of a motor vehicle by transmitting a signal (30) into the vicinity by means of a sensor, by receiving a signal component of the signal (30) reflected in the vicinity as a received signal (37), wherein the received signal (37) comprises several received echoes (31 to 36), by determining a time offset between the signal (30) and a received echo (31 to 36) of the received signal (37), and by checking whether the time offset lies within a predetermined value range (39) by an offset value (40) which corresponds to the distance of an attachment of the motor vehicle to the sensor. If the time offset lies outside the predetermined value range (39), the water level is determined based on the time offset.If the time offset is within the specified range (39), a time offset between the transmit signal (30) and at least one further received echo (31 to 36) of the received signal (37) is determined for determining the water level (10).