The CRS is a 94 GHz (W-band; 3 mm wavelength) Doppler radar developed for autonomous operation in the NASA ER-2 high-altitude aircraft and for ground-based operation. It provides high-resolution profiles of reflectivity and Doppler velocity in clouds and has important applications to atmospheric remote sensing studies. The CRS was designed to fly with the Cloud Lidar System (CLS) in the tail cone of an ER-2 superpod. It was upgraded from 2012 through 2014 to include a new solid-state transceiver with pulse compression, data system, digital receiver, antenna, and power supply.