Microwave Radiometer Sensors for Economical Satellite Constellations

Passive microwave radiometers are one of the most valuable observational assets for meteorology, weather forecasting and climate observations from space. A cross track scanning (sounding) spaceborne radiometer on a Low Earth Orbit (LEO) can provide persistent observations of the Earth’s atmosphere and its surface under all atmospheric conditions, even vertical structures within and below a storm/clouds. These microwave sensors, such as the Advanced Technology Microwave Sensor (ATMS), provide two observations daily for a given location from a polar orbit. Conversely, a constellation of satellites with similar sensors, global coverage, and with hourly or half-hourly revisit time would be able to fully capture fast-evolving weather systems [Ma, Zou, & Weng, IEEE Journal of selected topics in applied Earth observations and remote sensing, 2017].

The recent progress of nano satellite technology, mostly focused on CubeSats, and advances in the integration of microwave radiometer receivers allow the design of a compact, low mass, high performing, and economical radiometer sensor for Earth Observations. Boulder Environmental Sciences and Technology is developing such a new class of radiometric receivers with a direct-detection architecture for airborne, ground based, and space borne applications. This architecture enables a higher level of integration, lowers the power consumption, and it is well suited for mass production. In addition, the receiver sensitivity, reliability, stability, and calibration accuracy are improved.

A constellation of microwave sounding satellites promises much better temporal resolution, enabling timely observations of severe storms and improving forecast capabilities of mesoscale and storm-scale weather systems. In addition to improved revisit times, such a constellation of small satellites will also be more cost effective, it will have a shorter development cycle, and it will eliminate the risk of a catastrophic failure during its launch or operation. A constellation can be also updated continuously, e.g. annually, as technology improvements allow, and new satellites are added.

To enable operation of such a constellation, multiple advanced but cost-effective sensors or radiometers, must be developed. Industry engagement in mass producing instruments for constellation is necessary. We estimate that for the cost of one ATMS sensor, ~$124 million, such a satellite constellation could be developed and built.

We will present a conceptual design of a microwave temperature and humidity sounder, a small and economical satellite with channels similar to the ATMS, spanning frequencies between 23 and 200 GHz and with improved spatial resolution.