Recent Data System and Antenna Upgrades to the CSU-CHILL Radar

To provide improved capabilities to the research community, the CSU-CHILL National Radar Facility has recently undergone several engineering improvements. This paper summarizes the upgrades that have been made to the radar's data and antenna systems.

Raw time series of the receiver in-phase (I) and quadrature (Q) signal voltage provide the most fundamental representation of the phenomenon observed by meteorological radar systems. As a result, time series records permit maximum flexibility in the application of various post-processing techniques. However, the volumes and rates associated with time series data streams can be formidable. Fortunately, the performance of off the shelf computer equipment has made the routine generation and recording of time series data feasible. The CSU CHILL engineering group has designed and built a digital receiver system that operates in parallel with the radar's existing commercial signal processing hardware. The parallel receiver equipment is based on an off the shelf digital receiver board hosted by a high performance PC. This equipment can generate and continuously record the I,Q data values from the radar's two receiver channels. The paper will provide detailed descriptions of the design and performance of the CSU-CHILL parallel receiver system.

Antenna side-lobes can introduce data artifacts when ground clutter targets or high reflectivity gradients are present. To significantly reduce the side-lobe levels, the CSU-CHILL radar will be obtaining a custom-designed, dual-offset feed antenna in August, 2005. This antenna design minimizes side-lobes by physically removing the feed assembly support structure from the main beam radiation pattern. The paper will present an overview of the new antenna's design features and a summary of its performance characteristics as measured at the manufacturer's test range.