Costas DFC-Based Random Stepped Wideband Waveform for Interference Countermeasure in SAR Imagery.

Area of Science:

• Electrical Engineering
• Signal Processing
• Radar Systems

Background:

• Interference in Synthetic Aperture Radar (SAR) imagery degrades scene assessment by creating false targets or masking areas.
• Existing anti-jamming techniques, such as waveform agility, necessitate a compromise between anti-jamming capabilities and image resolution.
• A need exists for advanced SAR electronic counter-countermeasures (ECCM) that maintain high imaging quality while effectively mitigating interference.

Purpose of the Study:

• To propose a novel SAR ECCM scheme.
• To develop a Costas DFC-based random stepped wideband waveform and its associated imaging processing method.
• To demonstrate the effectiveness of the proposed scheme against forwarding interference without sacrificing imaging quality.

Main Methods:

• A Costas discrete frequency encoding (DFC) based random stepped wideband waveform was designed.
• The wideband signal was decomposed into multiple pulses with varying Costas DFC, carrier frequency, and phase modulation.
• A complementary imaging processing method was developed, integrating Frequency-dependent Chirp-Dependent (FCDC) processing to address Doppler sensitivity.

Main Results:

• The proposed waveform demonstrated high flexibility against forwarding interference by decomposing wideband signals.
• The combined FCDC and imaging processing successfully mitigated the Doppler sensitivity inherent in the waveform.
• Extensive simulations validated the superiority of the proposed waveform and processing technique under diverse interference scenarios.

Conclusions:

• The developed SAR ECCM scheme, featuring a Costas DFC-based random stepped wideband waveform and advanced imaging processing, offers a robust solution to interference.
• This approach effectively overcomes the limitations of traditional methods by maintaining imaging quality while enhancing anti-jamming performance.
• The findings confirm the proposed method's effectiveness and superiority in complex interference environments, paving the way for more reliable SAR systems.