Complex Scattering Mechanisms at Power Lines in X-Band SAR Imagery

The analysis of complex scattering patterns in SAR images of high-voltage power lines is important to comprehend the multireflection effects of these cylindrical shape structures. Such insights are invaluable for applications related to inspection management, particularly in safety analysis and ongoing monitoring. This letter introduces a novel point scattering tracing method to dissect the intricate multireflection effects of power lines in high-resolution X-band SAR data. The paths of multireflection events at the power lines are delineated through a proposed model, which leverages LiDAR point cloud data and SAR system parameters with subpixel precision. Under the condition of a parallel tangent line to the azimuth direction, the proposed quadratic polynomial model is solvable to pinpoint the centers of the single- and triple-reflection point signatures of power lines in SAR coordinate. The analysis of time-series SAR images reveals the activation of the double- and triple-reflection effects induced by water ripples or swinging lines, which is challenging to quantify. The proposed mathematical model is validated through testing with TerraSAR-X (TSX) data in two distinct cases, and the results are highly consistent. The new insights of both visible and invisible components of the double and triple reflections of power lines introduce new challenges to SAR research.