Vehicle Radar Signal Distortion Analysis
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Solution Overview
Problem
Conventional radar apparatuses struggle to distinguish between frequency peaks caused by multiple reflections and those due to signal saturation in the amplifier circuit, leading to inaccurate target detection.
Innovation Solution
The radar apparatus employs complex frequency analysis of I and Q signals to differentiate between multiple reflection and saturation distortions by comparing intensity ratios in positive and negative frequency domains, using phase shifts to suppress harmonic wave components in multiple reflections but not in saturated signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amplifier circuit amplifies the incoming wave to improve signal strength, then the detection sensitivity is improved, but the incoming wave may be saturated and cause waveform distortion when the distance to the target is small
Solution Approach 1:
The system performs preliminary frequency analysis on the beat signal to detect harmonic wave components before they cause saturation distortion. By identifying the presence of harmonic waves at frequencies that are integer multiples of the fundamental frequency, the system can adjust amplification levels in advance to prevent saturation, thus maintaining both detection sensitivity and waveform accuracy.
Solution Approach 2:
The system uses feedback by analyzing the frequency spectrum of the beat signal and detecting harmonic wave components. When harmonic waves are detected, the system feeds this information back to adjust the amplification level of the amplifier circuit, preventing saturation while maintaining optimal detection sensitivity. This closed-loop control ensures waveform accuracy is preserved.
2Measurement precision
If the radar apparatus detects frequency peaks to identify targets, then the target detection capability is improved, but harmonic wave components from multiple reflections or saturation cannot be distinguished from actual targets
Solution Approach 1:
The system applies local quality analysis by examining specific frequency regions in the power spectrum. It identifies harmonic wave components by checking for frequency peaks at integer multiple frequencies of the fundamental frequency. This localized frequency analysis allows the system to distinguish between actual targets and harmonic distortions, preventing misidentification while maintaining accurate target detection capability.
Solution Approach 2:
The system performs partial frequency analysis by focusing specifically on detecting harmonic wave components at integer multiple frequencies rather than analyzing the entire spectrum. This selective approach allows the system to identify distortion sources without compromising overall target detection accuracy, effectively filtering out false positives while maintaining sensitivity to real targets.
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 detection accuracy by correctly identifying saturation distortions and preventing them from being misinterpreted as target reflections, thereby improving the reliability of target detection.
Implementation Method 1
transmitting means for transmitting a radar wave which is frequency-modulated along a time axis
Implementation Method 2
receiving means for receiving an incoming wave which is a reflected wave of the radar wave transmitted by the transmitting means and amplifies it in an amplifier
Implementation Method 3
I signal generating means for generating an I signal which is a real number component of a beat signal by mixing the incoming wave received and amplified by the receiving means with the radar wave transmitted by the transmitting means; Q signal generating means for generating a Q signal which is an imaginary number component of a beat signal
Implementation Method 4
peak detecting means for performing complex frequency analysis on the I signal generated by the I signal generating means and the Q signal generated by the Q signal generating means and, as a result of the complex frequency analysis, detecting a frequency which becomes maximum as a frequency peak
Data Source
AI summary
A radar apparatus which includes a transmitting unit, a receiving unit, an I signal generating circuit, a Q signal generating circuit, a peak detecting circuit, a target detecting unit, and a distortion judging unit. The transmitting unit transmits a radar wave which is frequency-modulated along a time axis in a specified cycle, and the receiving unit receives an incoming wave which is a reflected wave of the radar wave transmitted by the transmitting means and amplifies it in an amplifier. The I signal generating circuit generates an I signal which is a real number component of a beat signal by mixing the incoming wave received and amplified by the receiving means with the radar wave transmitted by the transmitting unit. The Q signal generating circuit generates a Q signal which is an imaginary number component of a beat signal by mixing the incoming wave received and amplified by the receiving unit with the radar wave transmitted by the transmitting unit with a phase being shifted by π/2 [rad].