Along-Track Dual-Satellite D-InSAR for Multidimensional Deformation and Troposphere Joint Measurement: Configuration Optimization and Performance Analysis

Differential synthetic aperture radar interferometry (D-InSAR) has been extensively applied to deformation monitoring. When deformation can be negligible, the differential interferometric phase mainly reflects tropospheric refractivity variations, enabling tropospheric parameters retrieval. However, conventional single-satellite D-InSAR provides only line-of-sight (LOS) deformation and integrated differential tropospheric refractivity (DTR). Multiangle observations can overcome this limitation, allowing multidimensional deformation and DTR measurement. Nevertheless, observation geometry involves inherent tradeoffs among imaging resolution, deformation retrieval accuracy, and DTR tomography performance, making the system configuration optimization essential. This article investigates an along-track dual-satellite D-InSAR (ATDS-DInSAR) system as a simple yet efficient multiangle configuration for 2-D deformation and 3-D DTR joint measurement. The configuration constraints from imaging, deformation retrieval, and DTR tomography are analyzed, and a configuration optimization method for multidimensional deformation and DTR joint measurement is proposed. Simulations show that the optimized configuration improves both deformation retrieval and DTR tomography accuracy by more than 50%. In-orbit experiments with SuperView Neo-2 further validate the method, achieving millimeter-scale cross-track and centimeter-scale along-track deformation retrieval accuracy, with the 3-D DTR tomography consistent with radiosonde, Global Forecast System (GFS), and European Centre for Medium-Range Weather Forecasts (ECMWF).