A Three-Stage Inter-Channel Calibration Approach for Passive Radar on Moving Platforms Exploiting the Minimum...

Area of Science:

• * Passive radar systems
• * Moving platform applications
• * Synthetic aperture radar (SAR) imaging

Background:

• * Recent research focuses on passive radar for moving platforms, driven by hardware miniaturization for applications like moving target indication and SAR ground imaging.
• * Very High Frequency (VHF) and Ultra High Frequency (UHF) bands used by illuminators of opportunity pose antenna size constraints on small platforms, including unmanned aerial vehicles.
• * Displaced Phase Center Antenna (DPCA) and Space-Time Adaptive Processing are common clutter suppression techniques, but require precise channel calibration for effectiveness.

Purpose of the Study:

• * To develop and validate a robust three-stage calibration technique for passive radar systems with two receiving channels.
• * To enhance the effectiveness of clutter suppression methods, specifically DPCA, on moving platforms.
• * To improve the performance of moving target indication and ground imaging in challenging environments.

Main Methods:

• * A novel three-stage calibration process is proposed, utilizing the direct signal, data-adaptive amplitude calibration, and data-adaptive phase mismatch calibration via Minimum Variance Power Spectrum estimation.
• * The calibration technique specifically addresses phase and amplitude mismatches between the two receiving channels.
• * Validation was performed using both simulated data and real-world data acquired from a fast-moving ground platform.

Main Results:

• * The proposed three-stage calibration technique effectively calibrates the two receiving channels of a passive radar system.
• * Demonstrated significant improvements in clutter cancellation capabilities compared to uncalibrated systems.
• * Successful application on real data from a fast ground moving platform confirms the method's practical utility.

Conclusions:

• * The developed three-stage calibration method is crucial for effective clutter suppression in passive radar systems on moving platforms.
• * Accurate channel calibration significantly enhances the performance of DPCA for moving target indication and SAR imaging.
• * This research provides a practical solution for improving passive radar performance in dynamic environments.