A Methodology for Calibrating the Pointing Angles of an Airborne Doppler Radar

The Imaging Wind and Rain Airborne Profiler (IWRAP) is a system of two airborne Doppler radars, operating at C- and Ku-band, that observe below the aircraft. Each radar transmits two conically-scanned pencil beams at approximately 30° and 50° Earth-incidence angle. The antennas make a complete rotation once every second and sample at approximately
30
m range gates. Since the 2021 hurricane season, the Ocean Surface Winds Team (OSWT) at NOAA/NESDIS/STAR have been retrieving and transmitting three-dimensional atmospheric wind vectors to the ground for near-real-time use. Small biases in the horizontal wind speed and direction were observed first in the downwind legs of the hurricane flight pattern. After more investigation, these errors were apparent throughout all storms as a function of aircraft drift angle. This paper describes a methodology the OSWT use for eliminating these drift-dependent errors.