Data Processing and Calibration for an Airborne Scatterometer

The ERASME radar system has been designed to be easily mounted on small helicopters or aircraft. As it is used for research investigations on radar remote-sensing applications, it has to be well calibrated in every configuration, both absolutely and relatively for comparisons at different points of the swath. The data processing is described, which allows for antenna pattern correction and for flight parameters correction (pitch, roll, altitude), as an introduction for the calibration procedures: internal calibration, external calibration on corner reflectors for absolute calibration (within 1 dB), and a statistical approach, which uses experimental data itself and analyzes the correlation between processed data and recorded flight parameters. This method provides a way to check or adjust calibration for specific flight configurations, and allows a relative accuracy of better than 0.5 dB for data comparison within the radar swath. Such a method could be used to calibrate any airborne or spaceborne scatterometer when accurate antenna measurement is not feasible.