Radar Direction Estimation via Selective Correlation Matrix
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Solution Overview
Problem
Conventional radar apparatuses face challenges in accurately estimating the direction of radar reflected waves due to degraded signal-to-noise ratio (SNR) and increased circuit scale when trying to improve frequency resolution, leading to reduced accuracy in direction estimation.
Innovation Solution
A radar apparatus that generates a correlation matrix using signal components highly correlated with reflected wave signals and having good SNR, extracting correlation vectors corresponding to Doppler frequencies and adjacent times to improve direction estimation accuracy without increasing circuit scale.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frequency resolution is increased by increasing the FFT size, then the accuracy in estimating direction is improved, but the circuit scale is increased
Solution Approach 1:
The patent extracts only the necessary signal components (those with high correlation coefficients) from the frequency spectrum, rather than processing all frequency components. This selective extraction allows achieving accurate direction estimation without requiring high FFT size, thus avoiding increased circuit scale while maintaining measurement precision.
Solution Approach 2:
The patent applies different processing quality to different frequency components: high-correlation components are processed with high accuracy (included in correlation matrix generation), while low-correlation components are processed with lower accuracy (excluded from correlation matrix). This local quality differentiation achieves accurate direction estimation without uniformly increasing circuit scale across all processing paths.
2Quantity of substance
If individual correlation matrixes of frequencies in the vicinity of peak beat frequency are used, then the number of snapshots is increased, but the signal to noise ratio of each component is degraded
Solution Approach 1:
The patent changes the selection parameter from fixed frequency range (vicinity of peak) to dynamic selection based on correlation coefficient threshold. This parameter change allows selecting only those frequency components that meet the SNR requirement (high correlation coefficient), thus increasing the number of usable snapshots without degrading the signal to noise ratio of each component.
3Quantity of substance
If individual correlation matrixes of frequencies in the vicinity of peak beat frequency are used, then the number of snapshots is increased, but the accuracy in estimating direction is degraded
Solution Approach 1:
The patent changes the selection criterion from fixed geographic proximity (frequency vicinity) to quality-based selection (correlation coefficient threshold). This ensures that only high-quality signal components contributing to accurate direction estimation are included in the correlation matrix, while still increasing the number of snapshots through selective inclusion of multiple frequency components.
Data Source
AI summary
A radar receiver (Rx) receives a reflected wave signal corresponding to a radar transmitting signal having been reflected on a target by using a plurality of antenna system processors (D1 to D4), and estimates an arrival direction of the reflected wave signal. A peak frequency selector (21) selects a peak value of a correlation vector. An adjacent time-frequency component extractor (22) extracts correlation vectors in number of (NE×NT−1) corresponding to NE Doppler frequencies and NT times respectively adjacent to a Doppler frequency and a time giving a peak value. A correlation matrix generating adder (23) generates a correlation matrix corresponding to correlation of the reflected wave signal received by a plurality of receiver antennas on the basis of the (NE×NT) extracted correlation vectors.