SAR System for UAV Operation with Motion Error Compensation beyond the Resolution Cell

Area of Science:

• Remote Sensing
• Radar Systems Engineering
• Signal Processing

Background:

• Synthetic Aperture Radar (SAR) systems are crucial for high-resolution imaging.
• Unmanned Aerial Vehicle (UAV) platforms introduce significant motion errors impacting SAR image quality.
• Existing motion compensation techniques often rely on Inertial Measuring Unit (IMU) data.

Purpose of the Study:

• To develop and validate a novel SAR image focusing method for UAVs that does not require IMU data.
• To address challenges posed by motion errors exceeding the resolution cell in UAV-based SAR.
• To demonstrate the efficacy of the proposed method through real-world experiments.

Main Methods:

• Development of an experimental millimeter-wave LFM-CW SAR system with a two-antenna configuration.
• Implementation of a novel focusing algorithm combining Phase Gradient Autofocus (PGA) and Inverse SAR (ISAR) translational motion compensation.
• Experimental validation using a car as a mobile platform for the radar system.

Main Results:

• Successful generation of high-resolution SAR images using the developed system and method.
• Demonstration of effective image focusing despite motion errors larger than the resolution cell.
• Validation of the proposed technique's ability to compensate for motion errors without IMU data.

Conclusions:

• The proposed SAR image focusing technique offers a viable alternative for UAV applications by eliminating the need for IMU data.
• The experimental results confirm the effectiveness of the combined PGA and ISAR approach for motion error compensation.
• This advancement has the potential to simplify UAV-based SAR system design and improve operational flexibility.