Radar Arrival Direction Estimation Using Two-Stage FFT Filtering
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Solution Overview
Problem
Current radar technologies face challenges in accurately measuring the arrival direction of reflected waves, particularly in environments with multiple objects at the same distance and relative speed, leading to increased estimation errors and noise interference.
Innovation Solution
An electronic device equipped with a transmitting antenna and a receiving antenna that employs a two-stage Fast Fourier Transform (FFT) process to generate samples based on beat signals, where peaks exceeding threshold values are selected to estimate the arrival direction of reflected waves, improving accuracy by filtering out interference and accurately determining the arrival angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional radar techniques are used to measure arrival direction, then the system can detect reflected waves, but estimation errors increase and measurement precision deteriorates in environments with multiple objects at the same distance and speed
Solution Approach 1:
The patent segments the signal processing into two distinct FFT stages: first FFT processes beat signals to generate distance information and intermediate samples, then second FFT processes these intermediate samples to generate final arrival direction samples. This segmentation allows selective threshold application at different processing stages to filter interference while preserving useful signal components.
Solution Approach 2:
The patent applies preliminary threshold-based filtering in the first FFT stage before the second FFT processing. By selecting only beat signals with peaks exceeding the first threshold value, the system pre-filters interference and noise before they can propagate through the complete processing chain, thereby improving final measurement reliability.
2Quantity of substance
If all beat signals are processed to estimate arrival direction, then more data is available for estimation, but noise interference and estimation errors increase
Solution Approach 1:
The patent applies different quality criteria (threshold values) to different stages of signal processing. The first threshold is applied to beat signals in the first FFT stage, and a second threshold is applied to intermediate samples before second FFT processing. This local quality control ensures that only high-quality signal components proceed to subsequent processing stages.
Solution Approach 2:
The patent changes the threshold parameter at different processing stages to optimize sample selection. By adjusting the first threshold for initial beat signal filtering and the second threshold for intermediate sample filtering, the system dynamically controls the quantity and quality of samples entering each processing stage, balancing data quantity with measurement precision.
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
The proposed solution enhances the accuracy of arrival direction measurement by reducing estimation errors and noise interference, effectively distinguishing between reflections from multiple objects at the same distance and speed, and improves the robustness of radar systems in noisy conditions.
Implementation Method 1
a transmitting antenna 25 that transmits a transmitted wave
Implementation Method 2
a receiving antenna 31 that receives a reflected wave obtained by reflection of the transmitted wave
Implementation Method 3
a beat signal generated based on a transmitted signal based on the transmitted wave and a received signal based on the reflected wave
Implementation Method 4
generates a first sample based on a result obtained by subjecting a beat signal to a first fast Fourier transform process
Data Source
AI summary
An electronic device comprises a transmitting antenna that transmits a transmitted wave, a receiving antenna that receives a reflected wave obtained by reflection of the transmitted wave, and a controller. The controller generates a first sample based on a result obtained by subjecting a beat signal generated based on a transmitted signal based on the transmitted wave and a received signal based on the reflected wave to a first fast Fourier transform process. The controller generates a second sample based on a result obtained by subjecting the first sample to a second fast Fourier transform process, and estimates an arrival direction of the reflected wave based on the second sample. The controller sets the first sample from the beat signals in which the peak in the result obtained by performing the first fast Fourier transform process is equal to or higher than a first threshold value.