Radar I/Q Error Correction via Phase Rotation
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Solution Overview
Problem
Existing radar systems face performance degradation in detecting Doppler estimation results due to errors in in-phase (I) and quadrature (Q) components, and struggle to detect multiple targets when frequency domains with inverted signs include correct frequency components of reflected wave signals from different targets.
Innovation Solution
A radar apparatus that includes a phase rotator for both transmission and reception signal processing systems, applying phase rotation to cancel errors in I and Q components, and utilizing a correction parameter calculator to correct these errors, thereby preventing sidelobe performance degradation and enabling detection of all targets even with inverted frequency components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If phase rotation is applied to cancel I and Q component errors, then Doppler estimation performance is improved, but sidelobe performance degradation occurs
Solution Approach 1:
The patent applies preliminary phase rotation to the transmission pulse signal before transmission to pre-compensate for anticipated I and Q component errors. This preliminary action allows the system to counteract errors before they affect the received signal, thereby improving Doppler estimation performance while maintaining sidelobe characteristics through proper phase rotation angle selection.
Solution Approach 2:
The patent implements feedback by calculating correlation values between transmitted and received signals, estimating I and Q component errors from these correlation values, and using this estimation to determine appropriate phase rotation angles for correction. This closed-loop feedback mechanism enables dynamic adjustment of phase rotation to optimize both Doppler estimation and sidelobe performance.
2Measurement precision
If error correction is applied to I and Q components, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent integrates multiple functions into existing radar components: the phase rotator simultaneously performs phase rotation for error correction and signal modulation, while the correlation calculator serves both for target detection and for estimating I/Q errors. This multi-functionality approach enables error correction without adding separate dedicated hardware blocks, thus limiting the increase in device complexity.
Solution Approach 2:
The radar system performs self-diagnosis and self-correction by using its own transmitted signal as a reference to calculate correlation values, estimate its own I/Q component errors, and automatically apply phase rotation corrections. This self-service capability eliminates the need for external calibration equipment or complex separate error measurement systems, thereby controlling device complexity while improving detection accuracy.
Data Source
AI summary
A radar apparatus includes a correlator which, in operation, calculates a correlation value between the digital transmission pulse signals and the digital reception pulse signals, an error estimator which, in operation, estimates, on the basis of the correlation value, an I component error and a Q component error included in the digital reception pulse signals, a correction parameter calculator which, in operation, calculates a correction parameter for correcting the I component error and the Q component error, and an error corrector which, in operation, corrects, on the basis of the correction parameter, the I component error and the Q component error included in at least one of the digital transmission pulse signals and the digital reception pulse signals.