Techniques for Rapid Scanning Weather Surveillance using the MWR-05XP, a mobile, phased-array, X-band, Doppler radar

The Naval Post Graduate School's Center for Interdisciplinary Remotely Piloted Aircraft Studies (CIRPAS) in collaboration with ProSensing Inc, funded through a NAVY SBIR program, modified a phased array X-band tactical radar system to add a weather surveillance mode. The modified system named MWR-05XP was reconfigured for mobile operation and is the first mobile electronically scanned phased array radar developed for weather sensing applications.

The rapid scan capability of this radar presents new challenges with regards to calibration, clutter removal, radar control and data processing. As part of the modification, ProSensing developed a state-of-the-art PC-based weather radar processor (WRP), which provides radar control, data acquisition and signal processing for 3-D weather radar measurements. The radar's antenna is a hybrid, with pulse-to-pulse electronic elevation scanning and rapid mechanical azimuth scanning. The MWR-05XP also employs frequency hopping which used to generate independent samples well within the decorelation time of the weather targets. Frequency agility represents a key capability enabling MWR-05XP to obtain rapid scanning volume weather images with statistically significant reflectivity and velocity estimates. Transmitting at different frequencies also results in back scanning the antenna beam in the opposite direction of the mechanical scan. This back scanning allows the beam to dwell at a nearly fixed azimuth angle during the time required to gather independent samples and eliminates beam smearing which is common side effect in rapid scanning systems. In this presentation we will describe the different scanning techniques and algorithms implemented to maximize system performance and the in-depth analysis of the trade-off considerations.