Clock Scanning Microwave Interferometric Radiometer and Potential Application Analysis

Microwave (MW) radiometers at low-frequency bands play unreplaceable roles in Earth remote sensing, especially in the areas of numerical weather prediction (NWP) and climate research. All MW radiometers have been flown, so far, at low Earth orbit (LEO), which provide relatively narrow swath with long revisit time. There are increasing demands for applying MW radiometer at geostationary Earth orbit (GEO) for the purpose of having temporally continuous and spatially large coverage. Unfortunately, the required ground spatial resolution leads to a large-sized antenna that prevents MW radiometer applications, especially at low-frequency bands. The new concept of clock scanning microwave interferometric radiometer (CS-MIR) provides an opportunity to resolve this problem. By virtue of the simple and deployable array structure, it has the potential to work at GEO and produce hourly hemispheric imagery. This paper investigates the essential theory of CS-MIR and presents some approaches about its design principles in aspects of array configuration, sampling patterns, polarization corrections, and image reconstruction. The potential GEO applications of CS-MIR in frequencies lower than 50 GHz are investigated. Finally, a conceptual design of CS-MIR for SST measurement from GEO and the associated numerical simulations of image reconstruction are presented.