An Ionospheric Scintillation Mitigation Method Based on Contrast Optimization Using PSO for P-band SAR Imaging

The spaceborne synthetic aperture radar (SAR) working at P-band is seriously affected by the ionospheric scintillation. The ionospheric scintillation introduces random perturbations of the phase and the amplitude of SAR signals and thus deteriorates the SAR imaging performance, which is extensively reported in equatorial regions. In recent years, a number of autofocusing methods have been developed, including the contrast optimization methods. Most of the existing methods utilize classical optimization algorithms without the global searching ability. As a consequence, these methods are unable to implement the global optimization. This paper proposes a novel scintillation mitigation method based on the contrast optimization criterion. The particle swarm optimization (PSO) algorithm is utilized for the global optimization. Furthermore, the gradient descent (GD) is applied to improve the convergence of the PSO algorithm. The proposed method has good autofocusing performance due to its global optimization capabilities. The simulation results of the point and the area targets validate the effectiveness of this method.