A Low-Fuel Consumption Method for Non-Uniform Space-Based Tomographic Baseline Planning Based on Active Utilization of Atmospheric Drag

Tomographic SAR imaging technology is widely applied in various civil and military domains, such as urban 3D/4D information extraction, forest vertical structure and biomass estimation, glacier thickness measurement and concealed object detection. A multi-baseline revisit scheme based on single-satellite active drift offers significant cost advantages. However, traditional uniform baseline imaging schemes consume substantial fuel for active drift, reducing satellite lifespan. To address this issue, this paper proposes a low-fuel consumption non-uniform baseline planning scheme that actively utilizes atmospheric drag. This approach allows satellites to actively exploit the orbit-lowering effect of atmospheric drag during active drift to form observation baselines. Within the constraints of adjacent baseline distances, a rational non-uniform baseline planning scheme is proposed to minimize satellite fuel consumption and reduce control frequency. First, an analytical model relating semi-major axis drift to ground longitude drift is established. Next, we invert the variation in the semi-major axis based on the analytical model based on the distance range of adjacent baselines. Then, by constructing an approximate atmospheric model, the orbit-lowering effect of atmospheric drag perturbations within each orbital period is evaluate. In the final step, within each revisit period, the reference orbit of adjacent non-uniform baselines is dynamically updated. The next adjacent non-uniform baseline is determined by evaluating the orbital decay caused by atmospheric drag. When the next baseline exceeds the range constraint of adjacent baselines, an orbit control strategy is implemented to raise the orbit. The numerical simulation validates the superiority of this approach in terms of fuel conservation and reducing control frequency.