SRI CubeSat Imaging Radar for Earth Science (SRI-CIRES): Initial UAS Integration and Flight Demonstrations
Presenting Author: Lauren Wye
Organization: SRI International
Co-Author(s): Simon Lee, Patrick Rennich
Ground deformation measurements obtained with space-based interferometric synthetic aperture radar (InSAR) technologies have the potential to improve short-term forecasting of natural hazards and enable more effective management of natural resources. For maximum impact, InSAR measurements must be precise (sub-cm level) and timely. Frequent acquisitions are needed to achieve both requirements. More observations per unit time provide enhanced deformation precision through averaging, and also ensure that an event is properly captured and characterized. Yet, single-platform sensors cannot simultaneously achieve frequency and wide-area coverage, and traditional InSAR sensors are too expensive to replicate. SRI is working to provide high-precision ground deformation measurement capabilities in an affordable package that can be used to form a LEO constellation of InSAR sensors capable of rapid-repeat (daily) coverage of science targets. Such achievements are made possible through developments in nanosatellite technology, specifically the emergence of the CubeSat standard. Under a 2015-2016 ESTO ACT and 2017-2019 ESTO IIP grant, we have designed, developed, and tested an S-band radar instrument capable of moderate-resolution (5-25 m), high-fidelity InSAR performance (sub-cm deformation precision, SNR > 14 dB). We have advanced the RF and digital electronic subassemblies to achieve a functional flight-ready prototype (TRL 6). The complete radar instrument fits within a 16U CubeSat and satisfies the power and thermal requirements of the CubeSat environment. We call this subsystem the SRI CubeSat Imaging Radar for Earth Science (SRI-CIRES). The modular nature of CIRES lends itself to other small resource-constrained platforms, like UAVs. On our IIP grant, we have integrated and tested CIRES on various small airborne platforms. In this presentation, we review the initial UAS flight test results of SRI-CIRES, showing that the instrument can meet the science objectives and performance requirements of an operational mission.