FMCW Radar Signal Processing for Pseudo Target Removal
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Solution Overview
Problem
FMCW radar systems face challenges in distinguishing pseudo targets due to electromagnetic noise, as Doppler frequencies of peak signal components may not match for transmission waves with different frequency change rates, making it difficult to determine the presence of pseudo targets.
Innovation Solution
A radar device that processes frequency modulation signals with different chirp slopes and periods to identify and remove pseudo targets by matching beat and Doppler frequencies across multiple signal modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic shielding hardware is used to suppress electromagnetic noise, then the reliability of radar detection is improved, but the cost, weight, and volume of the radar device increase
Solution Approach 1:
The patent replaces electromagnetic shielding hardware (mechanical/physical system) with signal processing methods (electronic/software system). Specifically, it uses FFT-based frequency analysis to detect and remove pseudo targets caused by electromagnetic noise, substituting physical shielding with computational filtering to achieve the same reliability improvement without increasing device complexity
Solution Approach 2:
The radar device performs self-diagnosis and self-cleanup by automatically detecting pseudo targets through frequency analysis and removing them from the target list. The system uses its own signal processing capabilities to identify and eliminate false detections caused by electromagnetic noise, without requiring external shielding hardware
2Measurement precision
If frequency matching method is used to identify pseudo targets, then the measurement precision is improved, but the reliability deteriorates in FCM system where Doppler frequencies do not match
Solution Approach 1:
The patent changes the identification parameter from Doppler frequency (which varies with chirp slope in FCM) to beat frequency (which remains consistent). By using beat frequency as the primary identification parameter for pseudo targets, the system maintains reliable detection across different chirp slopes and measurement modes, resolving the reliability issue in FCM systems
Solution Approach 2:
The patent introduces a new dimension for pseudo target identification by using the relationship between beat frequency and chirp slope. Instead of relying solely on Doppler frequency matching, it analyzes how beat frequency correlates with chirp slope changes across multiple measurement modes, creating an additional identification criterion that works reliably in FCM systems
3Productivity
If multiple measurement modes with different chirp slopes are used, then the productivity of target detection is improved, but the difficulty of detecting and measuring pseudo targets increases
Solution Approach 1:
The patent implements a feedback mechanism where the radar performs multiple measurements with different chirp slopes, compares the results, and uses the correlation between beat frequency and chirp slope to identify pseudo targets. The system feeds back the identification results to selectively remove pseudo targets while preserving true targets, maintaining high productivity while solving the detection difficulty
Solution Approach 2:
The patent uses periodic switching between multiple measurement modes with different chirp slopes. By periodically alternating between these modes and analyzing the periodic patterns in beat frequency responses, the system can reliably distinguish pseudo targets (which show inconsistent patterns) from true targets (which show consistent patterns), reducing detection difficulty while maintaining productivity
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
Enables the determination and removal of pseudo targets caused by electromagnetic noise through signal processing alone, without the need for electromagnetic shielding or additional hardware measures.
Implementation Method 1
a frequency modulation signal whose frequency changes with the lapse of time
Implementation Method 2
a Doppler frequency corresponding to a relative speed with respect to the target
Data Source
AI summary
A radar device includes a radar signal output unit outputs a first frequency modulation signal that changes in frequency with a first chirp slope and repeats in a first chirp period, and a second frequency modulation signal that changes in frequency with a second chirp slope different from the first chirp slope and repeats in a first chirp period; a signal processing unit determines the target in the first frequency modulation signal and the target in the second frequency modulation signal as pseudo targets in a case where a beat frequency of the target in the first frequency modulation signal matches a beat frequency of the target in the second frequency modulation signal, and a Doppler frequency of the target in the second frequency modulation signal matches a Doppler frequency of the target in the second frequency modulation signal.