An Advanced Ku-Band Fine-Resolution and High-Sensitivity Wind Scatterometer.

An advanced Ku-band pencil-beam scatterometer has been developed having a scanning 1.4 m diameter Cassegrain antenna, for providing 3 x 20 km [for horizontal-transmit and horizontal-receive (HH) beam] and 3 x 23 km (for VV beam) fundamental range-slice resolution, a marked improvement over its predecessor Scatsat-1, which provided 6 x 46 km (for HH beam) and 6 x 70 km [for vertical-transmit and vertical-receive (VV) beam]. This instrument will carry forward the legacy of data services from the Indian Space Research Organization's OScat (Oceansat-2 Scatterometer, which operated in orbit from 2009 to 2014) and Scatsat-1, which operated from September 2016 to April 2021, with improved spatial resolution, noise-equivalent normalized radar cross section (NE sigma(0)), and the sensitivity parameter K-p. The improvement in NE sigma(0) and the signal-to-noise ratio (SNR) is of the order of 4.5 dB, and of K-p by 2.5 dB over a Scatsat-1 equivalent resolution cell. Equivalently, over its own range-slice resolution, the new sensor will match Scatsat's measurement sensitivity. This article elaborates on the system design of the instrument, the performance improvements over Scatsat-1 and the payload characterization methods.