A 180 GHz prototype for a geostationary microwave imager/sounder-GeoSTAR-III

GeoSTAR-III, a 180 GHz prototype for the Precipitation and All-weather Temperature and Humidity Sounder (PATH), is the culmination of a decade of technology development funding. The interferometric radiometer comprises 144 receivers operating from 165-183 GHz and utilizes a 192×192 input, ASIC based mixed signal correlator. The demonstration of this instrument raises the technology readiness of the radiometer subsystem to level 6 (TRL 6) and the correlator subsystem to TRL 5. We demonstrate the full functionality of this system with observations of the Sun and Moon as well as nearby thermally emissive objects. This represents the final milestones in the development effort of pre-mission technologies for this decadal survey mission.