Ultrasonic Blind Spot Sensor Using 2N Decimation for Noise Rejection
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Solution Overview
Problem
Ultrasonic sensors for blind spot detection face challenges in distinguishing between noise signals and signals reflected from opponent vehicles due to the Doppler effect, leading to false alarms and difficulty in differentiating ground signals from vehicle signals, especially at higher velocities.
Innovation Solution
An ultrasonic sensing device and method that employs a band pass filter with a 2N decimation operation to shift the frequency of input signals, allowing for the differentiation between noise and vehicle signals by using a low-order infinite impulse response (IIR) band pass filter and a calculation unit to perform decimation operations, effectively blocking ground noise and passing only the signal reflected from an opponent vehicle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a band pass filter with large bandwidth is used to pass Doppler-shifted signals from moving vehicles, then the sensor can detect opponent vehicles at higher velocities, but the filter cannot distinguish between ground noise and vehicle signals, leading to false alarms
Solution Approach 1:
The patent divides the filtering process into two sequential stages: first filtering the received signal through a band pass filter, then performing decimation operation to generate a down-sampled filtered signal. This segmentation allows each stage to handle specific aspects of signal processing, improving overall reliability while maintaining velocity adaptability
Solution Approach 2:
The decimation operation acts as an intermediary process between the band pass filter and the final detection stage. By down-sampling the filtered signal, it enhances the distinction between ground noise and vehicle signals, thereby improving signal differentiation accuracy without compromising the ability to detect vehicles at higher velocities
2Reliability
If a band pass filter with small bandwidth is used to be robust to acoustic noise, then the filter can reject external noise effectively, but it attenuates Doppler-shifted signals from moving vehicles, causing false negatives
Solution Approach 1:
The patent employs dynamic signal processing by applying decimation operation to the filtered signal. This dynamic approach allows the system to adapt to Doppler-shifted frequencies from moving vehicles while maintaining the noise rejection capabilities of the band pass filter, thus preserving both noise robustness and detection capability
3Measurement precision
If a high-order band pass filter is used to achieve good signal differentiation, then the filter can distinguish between noise and vehicle signals, but the implementation complexity increases significantly
Solution Approach 1:
The patent segments the signal processing into two simpler stages: a band pass filter followed by a decimation operation. This segmentation achieves good signal differentiation precision without requiring a complex high-order filter, thereby reducing implementation complexity while maintaining measurement precision
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
The solution enables accurate detection of opponent vehicles in a blind spot by reducing the complexity of the band pass filter and improving signal differentiation, achieving performance comparable to high-order filters while minimizing implementation complexity.
Implementation Method 1
Due to the Doppler effect, the frequency of the transmission signal is not equal to the frequency of the reception signal
Implementation Method 2
a transmission signal generator configured to generate a transmission signal, a ultrasonic converter configured to convert the transmission signal into an ultrasonic signal and convert a received signal from the ultrasonic signal into an electrical signal
Data Source
AI summary
Provided are an ultrasonic sensing device and method for a vehicle, which may block ground noise and pass a signal reflected from an opponent vehicle traveling in a blind spot. The ultrasonic sensing device for the vehicle includes a band pass filter configured to filter a first input signal reflected by an object according to a predetermined first bandwidth to output a first filtering signal or filter a second input signal on which a 2N decimation operation has been performed according to a predetermined second bandwidth to output a second filtering signal, and a calculation unit configured to perform the 2N decimation operation on the first filtering signal output from the band pass filter and deliver the first filtering signal on which the 2N decimation operation has been performed to the band pass filter as the second input signal.