P-band SAR instrument for BIOMASS

BIOMASS mission was selected in 2013 as the next ESA Earth Explorer Core mission. BIOMASS mission will provide consistent maps at global scale of forest biomass, forest disturbances and recovery with time as well as a better understanding of forests evolution dynamics. The payload of the BIOMASS satellite consists of a P-band Synthetic Aperture Radar (SAR), operating at 435 MHz and implementing full-polarimetric and interferometric capabilities, using a large reflector antenna in a side-looking configuration. A System (mission, satellite, instrument and ground segment) Phase A study has been successfully performed while the Phase B1 is now on-going. In parallel, a plan of pre-development activities has been implemented by ESA to improve the technological maturity level of the technologies deemed to be critical for the project, thus mitigating the risks associated with the development of the instrument. In this paper, the architecture and design of the P-band SAR instrument proposed by Thales Alenia Space is described. The expected SAR performance is addressed taking into account the last results of the GaN-based high power transmit section breadboarding and of the feed array breadboarding proofing the improvement of cross-polarization ratio needed for ionospheric correction. Breadboarding activities include also test for discharge of power critical parts (multipactor & Corona).