Joint Estimation of Satellite Attitude and Observation Area Using Interferometric Phase in ISAR Imagery

Parabolic reflector antennas are widely employed in synthetic aperture radar (SAR) satellites for Earth observation due to their high gain and low sidelobe characteristics. Accurate estimation of antenna attitude is critical for space situational awareness (SSA) and strategic intelligence collection. This article proposes a joint estimation framework for the satellite-borne parabolic antenna attitude and the corresponding ground observation area by leveraging interferometric phase information extracted from inverse synthetic aperture radar (ISAR) imagery. The core innovation lies in exploiting the coplanarity of antenna edge scatterers to derive an explicit analytical relationship between interferometric phase differences and the antenna attitude parameters. This enables attitude estimation through a phase-based optimization model that eliminates the need for interferometric phase unwrapping. Building on this, a closed-form expression is derived that maps the attitude parameters directly to the geographic coordinates of the ground observation area. Furthermore, the impact of baseline configurations in bistatic ISAR systems on attitude estimation accuracy is analyzed, providing practical guidelines for optimal baseline deployment. Extensive simulations demonstrate the proposed method's high accuracy and robustness under challenging imaging conditions.