Ultrasonic Sensor Signal Origin Determination via Code Word Extraction
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Solution Overview
Problem
Current methods for determining the origin of a received signal from an ultrasonic sensor in a motor vehicle are inaccurate when the vehicle is moving relative to an obstacle, due to frequency shifts caused by the Doppler effect, which can lead to incorrect correlation results and misidentification of signals.
Innovation Solution
The method involves modulating the transmission signal with a specific code word and comparing it with the received signal to determine its origin, by extracting and matching the code word from the received signal, even in the presence of frequency shifts, using the ratio of time lengths of signal components to extract the code word from frequency-shifted signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correlation method is used to determine signal origin, then signal identification is possible, but accuracy deteriorates when vehicle moves relative to obstacle due to Doppler effect
Solution Approach 1:
The patent extracts the code word from the received signal and compares it with the transmitted code word, separating the identification function from the correlation process. This extraction method isolates the essential identifying feature (code word) from the affected signal characteristics, enabling reliable origin determination even when Doppler effect alters signal frequency and timing
Solution Approach 2:
The patent changes the approach from comparing entire signals (which are affected by Doppler-induced frequency and timing changes) to comparing extracted code words. By focusing on the code word parameter specifically, the system achieves parameter-invariant comparison that remains accurate despite changes in other signal parameters caused by relative motion
2Measurement precision
If code word extraction is used, then signal origin determination accuracy improves, but device complexity increases
Solution Approach 1:
The code word is embedded in the transmitted signal before transmission, preparing the signal in advance for easy extraction and identification. This preliminary encoding simplifies the receiving end's task, as the code word structure is predetermined and can be extracted using known patterns, reducing the complexity of real-time processing
Solution Approach 2:
The transmitted code word serves as a reference copy that is stored and used for comparison with the extracted code word from the received signal. This copying approach enables direct comparison without complex analysis, as the reference code word preserves the original identifying information for straightforward matching
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 allows for accurate determination of the signal origin independently of frequency shifts, enabling reliable distinction between the ultrasonic sensor's signal and interference signals, even during relative movement between the vehicle and the obstacle.
Implementation Method 1
The ultrasonic sensor transmits a transmission signal—ultrasound—and receives a reception signal—likewise a sound signal—which is the transmission signal reflected by an object external to the vehicle
Implementation Method 2
The distance between the object and the motor vehicle is then determined as a function of the measured propagation time of the ultrasonic wave
Implementation Method 3
the received signal is frequency-shifted compared to the transmitted signal due to the Doppler effect
Data Source
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AI summary
The invention relates to a method for checking the origin of a received signal (UE) received by an ultrasonic sensor (3, 5) of a motor vehicle (1), wherein a transmitted signal (US) of the ultrasonic sensor (3, 5) is modulated and a predetermined codeword (CS) is imprinted on the transmitted signal (US) by this modulation, the received received signal (UE) is compared with the transmitted signal (US) and the origin of the received signal (UE) is determined depending on a result of the comparison, wherein, as part of the comparison of the received signal (UE) with the transmitted signal (US), a codeword (CE) is extracted from the received signal (UE) and compared with the codeword (CS) of the transmitted signal (US).