Airborne SAR for Calibration of P-Band Tower Radar

BorealScat is a tower-based radar which measures multipolarization and tomographic backscatter time series data at a forest site in Southern Sweden. In this paper, we describe a methodology for absolute radiometric calibration of BorealScat and apply it to a set of backscatter measurements at P-band (420–450 MHz). We present radiometric calibration corrections which take into account antenna gain and range variations over the tomographic resolution cell. We also use data acquired by the LORA airborne UHF-band SAR over the BorealScat site to determine the absolute radiometric calibration factor for P-band and HH- polarization. It is shown that the methodology produces consistent results for multiple SAR images.