Design and algorithms of the Tiangong-2 interferometric imaging radar altimeter processor

The Interferometric Imaging Radar Altimeter (InIRA) operating at Ku-band (13.58 GHz) was launched on Chinese Tiangong-2 space laboratory on September 15, 2016. The primary goal of Tiangong-2 InIRA is to measure wide-swath sea surface height, sea waves and sea winds. Winds and waves in the observed sea area are retrieved by processing the synthetic aperture radar (SAR) images. The ocean surface topography and the digital elevation models of land areas are determined using the interferometric SAR (InSAR) technique. The scope of this paper is to present the processing algorithms for the generation of the Tiangong-2 InIRA images from the raw data. The focusing algorithm for generating the single look complex (SLC) image products and the interferometric processing algorithm for generating the surface topography are briefly introduced.