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Calibration of Vector Network Analyzer for Measurements in Radio Frequency Propagation Channels
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Inter-Channel Error Calibration Method for Real-Time DBF-SAR System Based on FPGA.
Yao Meng1,2, Jinsong Qiu1,2, Pei Wang1,2
1Department of Space Microwave Remote Sensing System, Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100190, China.
Sensors (Basel, Switzerland)
|December 31, 2025
Summary
This study introduces a novel real-time calibration method for Digital Beamforming Synthetic Aperture Radar (DBF-SAR) systems. The approach significantly improves signal-to-noise ratio (SNR) and enhances data processing with low hardware resource usage.
Area of Science:
- Spaceborne Synthetic Aperture Radar (SAR) systems
- Digital Beamforming (DBF) technology
Background:
- High-resolution wide-swath (HRWS) imaging in SAR requires DBF.
- Multi-channel DBF-SAR systems face challenges in real-time calibration due to hardware limitations.
Purpose of the Study:
- To propose a real-time channel error calibration method for DBF-SAR systems.
- To address the conflict between real-time calibration needs and limited on-board hardware resources.
Main Methods:
- A real-time channel error calibration method based on Fast Fourier Transform (FFT) pulse compression.
- A "calibration-operation" dual-mode control with a parameter-persistence architecture.
- Decoupling high-complexity computations to the system initialization phase for low resource overhead.
Main Results:
- High-precision compensation for inter-channel amplitude, phase, and time-delay errors.
- Achieved a 5.93 dB improvement in synthesized signal-to-noise ratio (SNR) in a 4-channel system validation, reaching 44.26 dB.
- Performance approaches theoretical ideal gain, enhancing coherent integration gain.
Conclusions:
- Validated the feasibility of on-board, real-time calibration with low resource consumption for DBF-SAR systems.
- Provides key technical support for the engineering robustness and efficient data processing of next-generation SAR systems.
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