Bistatic InISAR Baseline Optimization for Joint Antenna Attitude and Observation Area Estimation in Stripmap SAR

Accurate geolocation of ground areas observed by spaceborne synthetic aperture radar (SAR) operating in stripmap mode is critical for active defense applications. This article proposes a joint estimation framework for antenna attitude and ground observation areas in spaceborne stripmap SAR, utilizing baseline-optimized ground-based bistatic interferometric SAR (InISAR). First, the time-varying geolocation problem of ground observation areas is reformulated as a fixed antenna attitude estimation task using a stripmap SAR observation geometry model. Following this, a robust adaptive weighted normal estimation (AWNE) algorithm is developed to suppress outlier interference by adaptively weighting scatterers located at the parabolic antenna’s outer edge. Recognizing that height estimation accuracy fundamentally constrains both attitude estimation and ground-area geolocation precision, we further propose baseline-optimized deployment strategies for mobile receivers within the bistatic InISAR system to maximize height estimation accuracy. An InISAR baseline geometric model is established to quantify height estimation performance across baseline configurations, deriving optimal interferometric baseline vectors. The northward deviation angle parameter is then introduced to characterize mobile receiver positioning, enabling efficient deployment in practical scenarios. Experimental results demonstrate the effectiveness and robustness of the proposed algorithms in enhancing the accuracy of both antenna attitude estimation and observed-area geolocation.