Capabilities of BIOMASS Three-Baseline PolInSAR Mode for the Characterization of Tropical Forests

Abstract:
As the 7th Earth Explorer Mission within the ESA Earth Observation Program, the BIOMASS will be the first spaceborne P-band polarimetric interferometric SAR (PolInSAR) mission, dedicated to global forest remote sensing. BIOMASS’s main mission will be split into two phases, the seven-pass tomographic phase and the three-pass interferometric phase. The objective of this paper is to propose a three-baseline PolInSAR method for robust forest parameter retrieval and analyze its feasibility and efficiency under the observation configuration of the BIOMASS mission. Focused on the low bandwidth of 6 MHz and the repeat-pass acquisition mode, multi-baseline coherence optimization is introduced to derive a more robust estimation of forest structural parameters. The proposed method was validated by the airborne P-band datasets acquired above the tropical forests in Paracou (French Guiana) and Mondah (Gabon), as well as the simulated BIOMASS data. This study demonstrates that the limited bandwidth of BIOMASS spaceborne data has a certain impact on refined forest structure parameter retrieval, and the proposed method still works effectively under the three-baseline PolInSAR mode and the accuracy meets the requirements of the BIOMASS mission.