Research on the Signal-to-Noise Ratio in Sliding Spotlight Mode Down-Looking Synthetic Aperture Imaging Ladar

A measuring method of polarization aberration based on aerial image of alternating phase-shift mask is proposed.The polarization aberration is represented by Pauli-Zernike coefficients.The image placement error and best focus shift are measured by image sensor at multiple illumination settings,combined with X and Ylinearly polarized illuminating light.The Pauli-Zernike coefficients are retrieved using the calibrated sensitivity matrix of polarization aberration.The validity of this proposed method is verified by numerical simulations,and the results indicate that the measuring accuracy is less than 3.07 mlambda.