A PROCEDURE TO CORRECT AIRBORNE DOPPLER RADAR DATA FOR NAVIGATION ERRORS USING THE ECHO RETURNED FROM THE EARTHS SURFACE

The development of airborne Doppler radars for atmospheric sciences re search has vastly improved the ability to measure atmospheric storms. This paper addresses a new technique for improving airborne Doppler ra dar data quality. Assuming the earth's surface is flat and still, the technique uses the airborne radar measurements of the earth's surface reflectivity and velocity to correct for errors in navigation and rada r pointing angles. The methodology makes use of the helical scanning a dopted in the existing systems onboard the two National Oceanic and At mospheric Administration P3 aircraft and on the National Center for At mospheric Research Electra aircraft (ELDORA/ASTRAIA radar). On the bas is of a scan-by-scan analysis, it is shown that this methodology has t he potential to retrieve most of the navigation errors, including erro rs in aircraft altitude, aircraft speed and drift, aircraft vertical v elocity, aircraft pitch and roll, radar ranging error, and error in an tenna spin angle. The methodology is demonstrated using a dataset obta ined from ELDORA/ASTRAIA during the Tropical Ocean Global Atmosphere C oupled Ocean-Atmosphere Response Experiment. Analysis of these data sh ows it is possible to systematically correct for the navigation errors from a large dataset using a single set of corrections to the data.