FMCW Radar Beat Signal Pole Estimation for Accurate Distance Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional FMCW radars face challenges in accurately estimating the distance to a target object and the intensity of the reflected signal due to limitations in frequency bandwidth and pseudo power spectrum issues.
Innovation Solution
A radar apparatus and method that utilize eigenvalue decomposition of an autocorrelation matrix and least squares method to calculate the pole of a beat signal, enabling accurate estimation of distance and reflected signal intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Fourier transform method is used to analyze received signal, then distance can be measured, but distance resolution is limited by frequency bandwidth
Solution Approach 1:
The patent applies parameter changes by transitioning from conventional Fourier transform methods to eigenvalue decomposition of the autocorrelation matrix. This mathematical transformation changes the analysis parameters, enabling distance estimation that is no longer constrained by the original frequency bandwidth limitations. The eigenvalue decomposition extracts spectral information in a transformed domain, effectively resolving the contradiction between measurement precision and bandwidth constraints.
2Measurement precision
If MUSIC method is used to calculate frequency with high accuracy, then distance estimation improves, but reflected signal intensity becomes pseudo power spectrum and cannot be estimated accurately
Solution Approach 1:
The patent segments the signal analysis process into distinct components: eigenvalue decomposition for frequency estimation and separate intensity calculation through correlation operations. By dividing the analysis into independent stages, the system can optimize each component separately - using MUSIC for accurate frequency/distance estimation while recovering true signal intensity through subsequent correlation-based processing, thus preventing information loss.
Solution Approach 2:
The patent introduces an intermediary process between frequency estimation and intensity measurement. The autocorrelation matrix and its eigenvalue decomposition serve as an intermediary that enables accurate frequency extraction without directly determining the final intensity values. This intermediary step allows the system to separate frequency analysis from intensity measurement, ultimately recovering accurate intensity information through correlation operations.
3Measurement precision
If conventional FMCW radar methods are used, then both distance and reflected signal intensity can be measured, but neither can be estimated with high accuracy simultaneously
Solution Approach 1:
The patent performs preliminary actions by first constructing the autocorrelation matrix and performing eigenvalue decomposition to obtain accurate frequency and pole information before proceeding to intensity calculation. This preliminary spectral analysis establishes accurate distance estimates and signal parameters that are then used as foundations for subsequent intensity recovery, ensuring both measurements are performed from an optimized starting point rather than simultaneously from constrained conventional methods.
Data Source
AI summary
A radar apparatus includes: a transmission unit that transmits a chirp signal; a reception unit that receives a reflected signal that is the chirp signal reflected by a scatterer; and a pole calculation unit that calculates a beat signal based on the chirp signal and the reflected signal and calculates a pole of the beat signal by eigenvalue decomposition of an autocorrelation matrix of the beat signal. The radar apparatus further includes: a complex amplitude calculation unit that calculates a complex amplitude corresponding to the pole by using a least squares method between a basis waveform corresponding to the pole and the beat signal; a distance calculation unit that calculates a distance to the scatterer based on the beat signal; and an intensity calculation unit that calculates an intensity of the reflected signal based on the complex amplitude.