Radar Apparatus Signal Processing for Distance Detection
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Solution Overview
Problem
Conventional radar apparatuses face challenges in accurately determining the reception time of laser light due to signal saturation and waveform deformation, especially when detecting objects with high reflectivity or in close proximity, which affects detection sensitivity and accuracy.
Innovation Solution
The radar apparatus employs a differential signal processing method by integrating multiple light reception signals, generating a phase-shifted signal, and calculating a differential signal to detect the peak waveform of the reflection signal, allowing for accurate detection even in saturated conditions and eliminating background noise through a simpler process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple light reception signals are integrated to improve detection sensitivity, then detection sensitivity is improved, but signal saturation and waveform deformation occur for high-intensity reflection signals
Solution Approach 1:
The patent applies dynamic signal processing by introducing a variable threshold value that adapts to the signal intensity. The threshold is dynamically adjusted based on the maximum value in the integrated signal, allowing the system to handle both weak and strong reflection signals without saturation effects, thus maintaining measurement precision across varying signal intensities
Solution Approach 2:
The patent changes the parameter of threshold value from a fixed predetermined value to a dynamically calculated value based on the integrated signal's maximum. This parameter change allows the detection system to adapt to different signal intensities, preventing waveform deformation while maintaining detection sensitivity for weak signals
2Ease of operation
If a predetermined threshold is used to determine reception time, then the determination process is simple, but the reception time varies depending on the intensity of the received laser light
Solution Approach 1:
The patent changes the threshold parameter from a fixed predetermined value to a dynamically calculated value. The new threshold is determined by adding a fixed offset to the maximum value of the integrated signal, ensuring that the threshold adapts to signal intensity while maintaining a consistent detection criterion, thus improving reception time accuracy
Solution Approach 2:
The patent implements feedback by using the maximum value of the integrated signal to determine the threshold for subsequent detection. This feedback mechanism ensures that the threshold automatically adjusts to the actual signal conditions, maintaining determination simplicity while improving reception time accuracy across different signal intensities
3Measurement precision
If background noise is eliminated by calculating it during polygon mirror switching periods, then detection sensitivity is improved, but the CPU load increases due to periodic noise calculation
Solution Approach 1:
The patent applies preliminary action by pre-calculating the background noise characteristics during polygon mirror switching periods and storing them for subsequent use. This preliminary calculation is performed only once per scanning cycle, and the results are reused for multiple detection operations, thereby improving detection sensitivity while minimizing CPU load during actual detection
Solution Approach 2:
The patent uses periodic action by calculating background noise only during specific periodic intervals when the polygon mirror is switching, rather than continuously. This periodic calculation approach reduces CPU load while still providing accurate noise compensation for detection sensitivity improvement
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 enables accurate determination of the peak reflection signal corresponding to the object's distance, improving detection sensitivity and reducing the load on the CPU by simplifying noise elimination, while maintaining detection resolution.
Implementation Method 1
a laser light emitting section emitting laser lights; a reflection light detecting section receiving, as reflection lights, the laser lights emitted by the laser light emitting section and reflected from an object
Data Source
AI summary
The radar apparatus includes a laser light emitting section successively emitting laser lights, a reflection light detecting section receiving, as reflection lights, the laser lights reflected from an object, and generating light reception signals containing reflection signals respectively derived from the reflection lights and having signal levels depending on intensities of the reflection lights, an integrating section generating an integrated signal by integrating the light reception signals, the integrated signal containing the reflection signals being integrated, a phase shifted signal generating section generating a phase shifted signal by delaying the integrated signal by a predetermined time, a differential signal calculating section calculating, as a differential signal, a difference between the integrated signal and the phase-shifted signal, and a detector section detecting the object on the basis of a peak waveform of the differential signal caused by a rising edge of the reflection signals being integrated.