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The development and characteristics of high-resolution optical/SAR satellites are introduced. Geometric radiometric calibration is an important means to improve the image quality. The basic principles of optical/SAR geometric radiometric calibration are summarized, and the research progress of geometric radiometric calibration is summarized. Finally, the frontier issues of satellite geometric radiometric calibration are summarized.

TiCN films were deposited on AISI 304 stainless steel substrate by combining multi-arc ion plating and magnetron sputtering technique with ionizing titanium and graphite targets in an Ar+N2 mixture gas. The effect of duty ratio on the microstructure and corrosion resistance of TiCN films in a NaCl 3.5 wt% solution was investigated. The results show that the as-deposited films exhibit smooth, uniform and dense morphologies, mainly forming a fcc-TiN type structure with Ti-(C, N) bond as well a as few α-CNx, and present (111) preferred orientation with the increase of duty ratio. TiCN films display a better resistance to corrosion than the bare substrate; as the duty ratio increases, the corrosion resistance is enhanced gradually. When the duty ratio is 40%, the TiCN film shows the optimal corrosion resistance with a corrosion current density (icorr) of 3.262×10−7 A·cm−2 and a polarization resistance (Rp) of 238.4 kΩ·cm2. Electrochemical impedance spectroscopy (EIS) of the films also indicates that the penetration behavior of corrosive ions and the local corrosion process are two key factors affecting the electrode corrosion reaction kinetics process, which is consistent with the polarization curves analyses.

A new approach was adopted to integrate the promising performances of TiAlN and TiCN ternary films for applications in extreme environments. In this study, Al,C-co-doped δ-TiN films, that is, TiAlCN quaternary films, were fabricated using a novel multi-arc ion plating and direct current (DC) magnetron sputtering (MIP&DCMS) integrated technique. The sandwich-like gradient architecture of the TiAlCN quaternary films altered the columnar crystal nature of the δ-TiN matrix and yielded fine grains, finally producing a heterophase composite structure. This structure contributed to its high microhardness (36.8 ± 1.6 GPa) and elastic modulus (410 ± 22 GPa) while maintaining superior tribological characteristics, with a friction coefficient of 0.26 ± 0.03. The TiAlCN quaternary films provided excellent corrosion resistance to SS304 with a corrosion current density of 0.129 ± 0.116 μA cm−2 and a polarization resistance of 430.5 ± 10.56 kΩ cm2, which are comparable to those of emerging TiAlN and TiCN ternary films.