Radar Doppler Frequency Correction via Signal Segmentation
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Solution Overview
Problem
Conventional radar systems face challenges in correcting Doppler frequency folding without increasing transmission duration and in efficiently processing pairing of FFT spectrum peaks, particularly when detecting targets with high relative velocities.
Innovation Solution
A radar apparatus that includes a transmitter and receiver with pulse-compression codes, performing discrete sampling and correlation calculations, followed by distinct additions and Doppler frequency analyses using FFT, with correction circuitry to determine and correct Doppler frequency folding based on amplitude or phase differences between spectral peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the staggered scheme is used to correct Doppler frequency folding, then the folding correction capability is improved, but the transmission duration is doubled
Solution Approach 1:
The patent segments the correlation values into multiple groups and performs FFT processing on each group separately. This segmentation allows the system to detect and correct Doppler frequency folding without requiring the staggered transmission scheme, thereby maintaining accurate velocity measurement while avoiding the doubling of transmission duration.
Solution Approach 2:
The patent performs partial FFT processing on segmented correlation values rather than processing all correlation values in a single FFT operation. This partial action approach enables the detection of spectrum peak pairing issues and correction of Doppler folding without requiring the complete staggered transmission sequence, thus reducing the transmission duration requirement.
2Measurement precision
If multiple FFT spectrum peaks are paired to correct Doppler frequency folding, then the measurement accuracy is improved, but the processing complexity increases
Solution Approach 1:
The patent segments correlation values into multiple groups and performs separate FFT processing on each segment. This segmentation simplifies the overall processing by breaking down the complex task of analyzing all correlation values at once into manageable segments, making the spectrum peak pairing and Doppler folding correction more tractable.
Solution Approach 2:
The patent performs preliminary FFT processing on segmented correlation values before attempting to pair spectrum peaks. This preliminary action prepares the data in a form that facilitates easier identification and pairing of corresponding spectrum peaks across different FFT results, thereby reducing the complexity of the subsequent peak pairing operation.
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 accurate correction of Doppler frequency folding without extending transmission duration and simplifies the pairing of FFT spectrum peaks, enhancing the radar's ability to detect relative velocities of targets.
Implementation Method 1
When a target or a radar apparatus moves, a reflected radar wave experiences a Doppler frequency shift that is proportional in amount to the relative velocity between the target and the radar apparatus.
Data Source
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AI summary
A radar apparatus includes a radar transmitter and a radar receiver. The radar receiver includes sampling circuitry, correlation calculation circuitry, a plurality of adder circuitry, a plurality of Doppler frequency analysis circuitry and Doppler frequency correction circuitry. The Doppler frequency correction circuitry, which in operation, (i) determines whether or not a folding in a Doppler frequency included in a reflected wave signal is present according to an amplitude difference or phase difference between two of peak spectra of results of analyses performed by the plurality of Doppler frequency analysis circuitry, and (ii) makes a correction to the Doppler frequency included in a reflected wave signal on the basis of the results of the analyses in a case it is determined that the folding is present.