A conceptual design for simultaneous measurements of 3D surface wave field and ocean surface current vector using the InSAR technology

The radial velocity measured by a conventional along-track interferometric synthetic aperture radar (ATI) is contributed by all three orthogonal velocity components of the ocean surface current, of which the oscillatory orbital velocity of surface waves is frequently a dominant term. Mathematically, three simultaneous radial velocity measurements from different incident or azimuthal angles are needed to yield the unique solution of the ocean surface current. The 3D solution for sidelooking ATI is presented. If only two measurements are available, the error of the two horizontal velocity components caused by assuming zero vertical velocity is quantified. A conceptual design of integrating cross-track (XT) and along- track (AT) interferometry is presented. The XTI phase data give the surface wave topography, from which the 3D wave-induced current field can be calculated. The wave contribution in the ATI phase data can then be removed to recover the mean component of the ocean surface current while maintaining the SAR resolution. By taking a zigzag path, both horizontal components of the surface current and the 3D wave field can be resolved from a single sensor on a single platform.