Extended Multiple Aperture Mapdrift-Based Doppler Parameter Estimation and Compensation for Very-High-Squint Airborne...

Area of Science:

• Remote Sensing
• Synthetic Aperture Radar (SAR) Imaging
• Signal Processing

Background:

• Doppler parameter estimation and compensation (DPEC) is crucial for airborne SAR imaging due to trajectory disturbances.
• Traditional DPEC methods are limited to broadside, small-, or medium-squint geometries, considering only second-order Doppler phase variance.

Purpose of the Study:

• To propose an extended multiple aperture mapdrift (EMAM) method for accurate DPEC in very-high-squint airborne SAR geometries.
• To address the limitations of traditional DPEC methods in complex flight paths.

Main Methods:

• The extended multiple aperture mapdrift (EMAM) method is developed.
• It involves estimating and compensating for the spatial variation of the third-order Doppler phase (derivative of Doppler rate).
• Key procedures include sub-view image generation, sliding-window cross-correlation, and image-offset-based Doppler parameter estimation.

Main Results:

• The EMAM method demonstrates enhanced accuracy for DPEC in very-high-squint SAR imaging.
• Detailed derivation and performance analysis of the EMAM method are provided.
• The approach is validated through computer simulations and real airborne data.

Conclusions:

• The proposed EMAM method effectively extends DPEC capabilities to very-high-squint geometries.
• This advancement improves the accuracy and applicability of airborne SAR imaging under challenging conditions.