Radar Self-Calibration Using Regression-Based Phase Correction
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Solution Overview
Problem
Existing radar systems face reduced accuracy and separation capability in angle estimation due to inhomogeneous temperature distribution and component aging, which affect phase errors, especially in large aperture systems used for vehicle automation, leading to increased side lobes and reduced dynamic range.
Innovation Solution
A self-calibration method for radar systems using two-dimensional linear regression to estimate intragroup and intergroup phase correction values, compensating amplitude and phase errors across multiple antenna groups, allowing for flexible antenna positioning and geometry, and enabling accurate angle estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If large aperture antenna groups are used to improve angle measurement accuracy and separation capability, then angle estimation performance is improved, but the circuit board size increases leading to inhomogeneous temperature distribution and phase error changes
Solution Approach 1:
The patent applies preliminary calibration action by measuring phase errors under controlled temperature conditions and storing calibration data before actual operation. The system performs temperature-dependent phase error calibration in advance, creating lookup tables that map temperature conditions to phase error corrections, thereby preventing temperature-induced performance degradation during operation.
Solution Approach 2:
The patent changes the parameter of phase error compensation by making it temperature-dependent. The system measures and compensates phase errors at different temperature conditions, adjusting the calibration parameters according to the actual temperature environment, thereby maintaining angle estimation accuracy despite temperature variations in large aperture systems.
2Measurement precision
If traditional one-time end-of-line calibration is used to establish control vectors, then initial calibration is achieved, but phase errors change due to temperature distribution and aging reducing calibration accuracy over time
Solution Approach 1:
The patent implements feedback by continuously monitoring temperature conditions and selecting appropriate calibration data from lookup tables based on measured temperature. The system provides feedback loops that adjust phase error compensation in real-time according to temperature changes, ensuring calibration accuracy is maintained throughout the operational lifetime despite temperature variations and aging effects.
Solution Approach 2:
The patent performs preliminary calibration measurements at multiple temperature conditions during manufacturing and stores these calibration data in lookup tables. This preliminary action creates a comprehensive set of calibration parameters that cover the full operating temperature range, enabling the system to maintain accuracy without requiring re-calibration during operation.
3Productivity
If control vectors are stored in non-volatile memory after one-time calibration, then calibration data is preserved, but phase errors change due to environmental factors reducing angle estimation performance
Solution Approach 1:
The patent adds another dimension to the calibration system by introducing temperature as a calibration parameter. Instead of storing a single set of control vectors, the system creates multi-dimensional lookup tables that include temperature as a dimension, allowing selection of appropriate calibration data based on actual operating conditions. This maintains calibration efficiency while adapting to environmental changes.
Solution Approach 2:
The patent changes the calibration parameters to be temperature-dependent, storing multiple sets of control vectors corresponding to different temperature conditions. The system dynamically selects and applies the appropriate calibration parameters based on measured temperature, thereby maintaining angle estimation accuracy without sacrificing calibration efficiency.
Data Source
AI summary
A method for self-calibration of a radar system which includes at least two antenna groups to which a transmission channel and a receiving channel are assigned. Targets are measured by the radar system. The range and Doppler information is processed for each antenna group, and the targets are detected to obtain reflection lists with complex amplitudes for each target. A compensation of the amplitude differences for the respective channels is performed. A two-dimensional linear regression is used to estimate a regression plane, and the difference between the measured phase value and the regression plane is calculated for each channel to obtain an intragroup phase correction value. A distance between two regression planes of different antenna groups is calculated with modulo 21 to obtain an intergroup phase correction value. The control vector of each channel is compensated with the intragroup phase correction value and the intergroup phase correction value.