Sound Wave Sensor Control for Pedestrian Detection in Noise
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Solution Overview
Problem
Conventional sound wave sensors struggle to detect pedestrians and objects with low reflectivity due to weak echo signals, especially in noisy conditions like rain or tire noise, as background noise interferes with echo detection.
Innovation Solution
A driving support apparatus that employs a sound wave sensor control unit capable of selecting between pulse and spread spectrum modulation schemes, using spread spectrum modulation to enhance echo detection by increasing the energy of transmitted sound waves and suppressing background noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensitivity of object detection is increased to detect persons with low reflectivity, then detection capability is improved, but background noise becomes indistinguishable from echoes
Solution Approach 1:
The patent changes the temporal and spectral parameters of the transmitted sound wave from a simple pulse to a spread spectrum modulated signal. By spreading the signal energy across a wide frequency band and modulating it with a pseudo-random code, the system can distinguish the reflected signal from background noise through correlation detection, even when the echo amplitude is very weak.
Solution Approach 2:
The patent introduces a pseudo-random modulation code as an intermediary carrier that embeds unique identification information in the transmitted sound wave. This intermediary allows the receiver to distinguish the target echo from background noise through correlation matching, effectively filtering out unwanted signals while detecting weak reflections from low-reflectivity objects.
2Device complexity
If pulse scheme is used for sound wave transmission, then system simplicity is maintained, but detection reliability in noisy environments deteriorates
Solution Approach 1:
The patent transforms the transmitted signal from a simple time-domain pulse to a frequency-modulated spread spectrum signal. By spreading the signal energy across multiple frequencies and time periods using pseudo-random modulation, the system achieves better noise immunity and detection reliability while maintaining reasonable system complexity through software-based signal processing.
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 effectively detects pedestrians and objects even in noisy environments by increasing the energy of reflected signals and improving signal-to-noise ratio, allowing for reliable obstacle detection.
Implementation Method 1
detecting an obstacle on a route by using a sound wave sensor
Data Source
AI summary
A driving support apparatus according to the present disclosure includes a memory and a hardware processor coupled to the memory and a sound wave sensor. The hardware processor is configured to select, as a transmission and reception scheme, either a pulse scheme or a spread spectrum modulation scheme, and control the sound wave sensor with the selected transmission and reception scheme. When the spread spectrum modulation scheme is selected as the transmission and reception scheme, the hardware processor causes the sound wave sensor to successively transmit and receive sound waves by using the spread spectrum modulation scheme.