DPCA-Based Doppler Radar Measurements from Space: Impact of Antenna Beamwidths and Baseline Tilting

Since 1997, Earth’s atmosphere has been continuously monitored by a number of spaceborne atmospheric radars. Only the EarthCARE cloud profiling radar has had Doppler capability; others measured only reflectivity due to challenges resulting from platform motion. One concept for achieving high-accuracy Doppler measurements uses the Displaced Phased Center Antenna (DPCA) method, in which two antennas are appropriately spaced so that platform motion is cancelled for pulse pairs using the two antennas. Our previous work initially looked at ideal DPCA performance and, most recently, effects of antenna pointing and position errors. This work completes the investigation of plausible antenna configurations’ error sources for the Doppler velocity estimation by considering the effects of antenna beamwidth differences and tilting of the DPCA baseline in the vertical plane.