Lessons learned from HUT-2D L-band airborne demonstrator

This paper discusses the development of the airborne synthetic aperture radiometer HUT-2D of Aalto University. We present the life cycle of the project starting from its initiation, highlighting the main milestones and achievements in hardware development, interferometric algorithm validation, and finally in airborne campaigns. We point out the most important lessons learned from especially the hardware development history and discuss the overall performance and usability of the instrument. With these lessons learned we sketch an easy-to-implement, cost-effective redesign of the HUT-2D instrument. This redesign focuses on issues that would produce improvements, which are the most beneficiary in terms of the instrument's ability to make scientific measurements.