Frequency Diverse Array and Spotlight Synthetic Aperture Radar 2D Imaging Based on Multiple Repeated Subpulses.

Area of Science:

• Radar Systems Engineering
• Signal Processing
• Electromagnetics

Background:

• Frequency Diverse Array (FDA) beams exhibit an 'S' shape, preventing direct combination with spotlight Synthetic Aperture Radar (SSAR) for spot beam formation.
• Traditional methods struggle to achieve high resolution in both distance-direction and azimuth-direction simultaneously when combining FDA and SSAR.

Purpose of the Study:

• To propose and validate a novel 2D imaging system, Multiple Repeated Subpulses-Frequency Diverse Array-Spotlight Synthetic Aperture Radar (MRS-FDA-SSAR), for improved target imaging.
• To address the limitations of FDA beams in forming spot beams and their incompatibility with SSAR.
• To enhance the clarity of 2D imaging results by reducing high target sidelobes that can mask weak targets.

Main Methods:

• Development of an MRS-FDA-SSAR system on an airborne platform.
• Utilizing the frequency difference between FDA elements to synthesize broadband signals for distance-direction resolution.
• Employing synthetic aperture techniques for azimuth-direction resolution.
• Applying the Backprojection (BP) algorithm for initial 2D imaging.
• Implementing a deconvolution algorithm to mitigate high sidelobes in BP imaging results.

Main Results:

• Successful synthesis of broadband signals for distance-direction resolution using FDA.
• Achieved azimuth-direction resolution through synthetic aperture techniques.
• Generated 2D imaging results using the BP algorithm.
• Demonstrated significant reduction in target sidelobes via the deconvolution algorithm, improving weak target visibility.
• Experimental simulations verified the effectiveness of the MRS-FDA-SSAR model.

Conclusions:

• The proposed MRS-FDA-SSAR system effectively overcomes the limitations of traditional FDA beams for SSAR integration.
• The implemented deconvolution algorithm successfully reduces sidelobes, enhancing the detection of weak targets in 2D radar imaging.
• The MRS-FDA-SSAR model shows significant promise for advanced 2D radar imaging applications.