Sea Surface Imaging Simulation for 3D Interferometric Imaging Radar Altimeter

The interferometric imaging radar altimeter (InIRA) is a new generation radar altimeter, which can provide two-dimensional images of the sea surface topography at high resolution along a wide swath. This article proposes a method for the simulation of sea surface images measured by InIRA. First, the Pierson-Moskowitz wave spectrum and two-scale model are used to simulate the sea surface from which elevation data is to be acquired. This simulated sea surface is then divided into small triangular facets using Delaunay triangulation. Second, the backscattering cross sections of these small facets are calculated via application of quasi-mirror scattering theory, and the backscattering coefficient of the simulated region derived via coherent superposition. Third, system parameters are set, consistent with the basic principle of InIRA. Assuming that the signal transmitted is a linear frequency modulation pulse signal, the simulation images are then derived using the range Doppler and back projection algorithms. By inverting the interferometric phase diagram, elevation estimates can be derived, and compared with original simulated sea levels. This demonstrated accuracy within the centimeter range, verifying the correctness and feasibility of the proposed method.