Conically-scanning radiometer design for satellite remote sensing applications

The heritage of TAS-I in conical scanning radiometers dates since 1991 with the study on multifrequency microwave imager (MIMR), in the frame of METOP program, that culminates with the manufacturing of an engineering demonstrator. In the years the original MIMR design evolved be mean of several studies (EGPM, and FLORAD) with the aim of improving both the performances and the budgets figure and ease the accommodation of that kind of instruments on a spaceborne platform. Specific attention will be devoted to the evolution of the concept that moved from lower part of the microwave spectrum to higher frequencies and that will tend, time by time, towards the combined imaging/sounding concept leading to the instrument concept represented by the FLORAD Millimeter-wave Imaging Radiometer (FLOMIR) instrument foreseen to be embarked on the FLORAD mission. FLORAD mission is based on a small-satellite FLOwer constellation deploying millimeter-wave scanning RADiometers devoted to tropospheric observations. The FLORAD mission is aimed at the retrieval of thermal and hydrological properties of the troposphere, specifically temperature profile, water vapour profile, cloud liquid content, rainfall and snowfall. The Flower Constellations (FCs) are built on compatible (resonant) elliptical orbits and can offer several degrees of freedom in their design. In this paper the previous studies results will be presented and compared to each other giving evidence of the technological progresses and improvements of the design.