Oceanic Vertical Deflections Derived from Observation Data by Tiangong-2 Interferometric Imaging Radar Altimeter

Vertical deflections are essential data in the marine gravity field inversion and submarine topography reconstruction. The accuracy and resolution of vertical deflection derived from satellite altimeter mainly depend on the range precision and spatial distribution. Due to the limitation that the conventional altimeter can only measure the sea surface height (SSH) along track with a footprint of about 2–7 km in diameter, the accuracy of the east component of vertical deflection is not as good as that of the north. The Tiangong-2 interferometric imaging radar altimeter (InIRA) has a wide swath because of its interferometric measurement mechanism. The purpose of this paper is to verify that the wide swath characteristics of InIRA can guarantee that the same accuracy in both north and east components can be achieved. In this paper, we collected Tiangong-2 InIRA data in the interest region. The preprocessing process includes resampling, outliers editing, and low-pass filtering. Then the north and east components were calculated through the along-track least squares method. The results show that the interferometric imaging altimeter can really achieve balanced accuracy in both the north and east components of vertical deflection, and the east component is slightly better than the north component. Further correction of errors is needed for further improving the accuracy.