Azimuth Full-Aperture Processing of Spaceborne Squint SAR Data with Block Varying PRF

Area of Science:

• Remote Sensing
• Signal Processing
• Aerospace Engineering

Background:

• Spaceborne squint sliding-spotlight SAR systems utilize block varying pulse repetition frequency (BV-PRF) schemes.
• BV-PRF schemes help resolve large-range cell migration and reduce azimuth signal non-uniformity.
• However, BV-PRF data suffer from different PRFs per block and insufficient sampling.

Purpose of the Study:

• To propose a novel azimuth full-aperture pre-processing method for SAR raw data generated by the BV-PRF scheme.
• To address the challenges of varying PRFs and insufficient azimuth sampling in BV-PRF data.
• To enable effective processing of BV-PRF SAR data using classical focusing algorithms.

Main Methods:

• The proposed method involves de-skewing, resampling, azimuth continuous combination, and Doppler history recovery.
• Raw data blocks with different PRFs are resampled to a uniform azimuth sampling interval.
• Azimuth time shifts are introduced for continuous splicing of azimuth signals.

Main Results:

• The pre-processing method results in sufficiently and uniformly sampled azimuth data.
• The processed data are compatible with classical SAR focusing algorithms.
• Simulation results on point targets validate the effectiveness of the proposed approach.

Conclusions:

• The novel azimuth pre-processing method effectively handles SAR raw data from BV-PRF schemes.
• The method ensures sufficient and uniform azimuth sampling, improving data processability.
• This approach is more effective than methods processing SAR data with continuous PRF.