An Improved Imaging Algorithm for High-Resolution Spotlight SAR with Continuous PRI Variation Based on Modified Sinc...

Area of Science:

• Remote Sensing
• Signal Processing
• Electromagnetics

Background:

• Conventional synthetic aperture radar (SAR) systems face limitations in achieving both wide swath coverage and high azimuth resolution simultaneously.
• Pulse Repetition Frequency (PRF) variation offers a solution but introduces ambiguities due to nonuniform sampling.
• Existing reconstructive methods like Nonuniform Discrete Fourier Transform (NUDFT) are computationally intensive.

Purpose of the Study:

• To develop a computationally efficient and accurate imaging algorithm for spotlight SAR with continuous Pulse Repetition Interval (PRI) variation.
• To address the challenges of nonuniform sampling and ambiguities in high-resolution SAR imaging.
• To improve upon existing NUDFT-based reconstruction methods.

Main Methods:

• A modified sinc interpolation technique based on NUDFT is proposed for reconstructing uniformly sampled echo data.
• The modified sinc interpolation utilizes a shorter kernel for improved computational efficiency.
• A two-step processing approach is combined with the modified sinc interpolation for enhanced accuracy.

Main Results:

• The proposed modified sinc interpolation significantly improves computational efficiency compared to conventional NUDFT.
• The two-step processing approach combined with modified sinc interpolation demonstrates superior accuracy.
• Experimental validation using simulated and GF-3 satellite data confirms the approach's validity and accuracy.

Conclusions:

• The developed algorithm effectively overcomes the resolution-swath limitations of conventional SAR systems.
• The modified sinc interpolation offers a computationally efficient alternative for high-resolution SAR imaging.
• The proposed method provides a robust and accurate solution for spotlight SAR data processing.