Improved GNSS-Based Bistatic SAR Using Multi-Satellites Fusion: Analysis and Experimental Demonstration

Area of Science:

• Remote Sensing
• Geospatial Technology
• Signal Processing

Background:

• Global Navigation Satellite System (GNSS)-based Bistatic Synthetic Aperture Radar (SAR) offers all-weather, real-time global observation.
• Limited signal bandwidth restricts the range resolution of current GNSS-based Bistatic SAR systems.
• Multi-satellite fusion presents a solution to improve resolution by leveraging different satellite configurations, but faces challenges in efficiency and computation.

Purpose of the Study:

• To effectively improve the resolution of multi-satellite fusion systems in GNSS-based Bistatic SAR.
• To analyze the Point Spread Function (PSF) and its relationship with geometric configuration and satellite number for resolution enhancement.
• To develop an optimized dual-satellite fusion imaging method for higher resolution and efficiency.

Main Methods:

• Analysis of the Point Spread Function (PSF) for multi-satellite fusion systems.
• Comparative analysis of multi-satellite vs. dual-satellite fusion efficiency.
• Development of a greedy algorithm for optimized dual-satellite selection based on geometric configuration and azimuthal vectors.
• Image fusion through non-coherent addition of images from selected reference and auxiliary satellites.
• Validation through GPS L1 real orbit multi-target simulations and experimental imaging.

Main Results:

• Dual-satellite fusion demonstrates higher resolution enhancement efficiency compared to general multi-satellite fusion.
• The proposed optimized dual-satellite selection method achieved globally optimal 2-D resolution in 15 out of 24 datasets.
• Experimental results showed a 70.1% reduction in resolution unit area compared to single-satellite images.
• The proposed method's processing time was 66.6% of the traversal method in experiments with three navigation satellites.

Conclusions:

• The developed dual-satellite fusion imaging method effectively improves resolution in GNSS-based Bistatic SAR.
• Optimized satellite selection significantly enhances resolution and processing efficiency.
• The method is feasible and demonstrates practical advantages for remote sensing applications.