Comparative Study of Sentinel-1-Focused and Simulated SAR Images Using LiDAR Point Cloud Modeling for Coastal Areas

Abstract

Aiming at SAR imaging for large coastal scenes, a comprehensive comparative study is performed based on Sentinel-1 raw data, SAR imaging simulation, and Google Maps. A parallel Range-Doppler (RD) algorithm is developed and applied to focus Sentinel-1 raw data for large coastal scenes, and the focused SAR image is compared with the multi-look-processed SAR image using SNAP 9.0.0 software, as well as the corresponding areas of Google Maps. A scheme is proposed to convert the LiDAR point cloud data of the coast into a 3D coastal area digital elevation model (DEM), and a tailored 3D model suitable for RaySAR simulator is obtained after statistical outlier removal (SOR) denoising and down-sampling processing. Comparison results show good agreements, which verify the effectiveness of the parallel RD algorithm as well as the backward ray-tracing-based RaySAR simulator, which serves as a powerful SAR imaging tool due to its high efficiency and flexibility. The cosine similarity between the RaySAR-simulated SAR image and Google Maps achieves 0.93, while cosine similarity reaches 0.85 between Sentinel-1 SAR-focused images with our parallel RD algorithm and multi-look SAR image processed using SNAP software. This article can provide valuable assistance for SAR system performance evaluation, SAR imaging algorithm improvement, and remote sensing applications.