Designing a detection scan for adaptive weather sensing

Fast adaptive weather scanning was first demonstrated on the National Weather Radar Testbed (NWRT) Phased Array Radar (PAR) in 2009 with the implementation of the Adaptive Digital Signal Processing Algorithm for Phased-Array Radar Timely Scans (ADAPTS). The algorithm provides spatially focused weather observations to reduce volumetric scanning times and increase overall dwell times in regions of interest. Initially, in ADAPTS I, beams of a predefined volume coverage pattern (VCP) were turned “on” and “off” based on weather detections and the spatial proximity to those weather detections. The beams that are turned “on” by ADAPTS are referred to as weather beams. At start up and periodically thereafter (to capture developing weather), a complete weather scan (i.e. all beams of the VCP) is performed. In ADAPTS II, the need for periodic complete weather scans is eliminated by the introduction of a surveillance scan that is transmitted in regions where weather beams are “off.” Whereas, the weather beam provided sample sizes consistent with good quality estimates as part of the VCP design, the surveillance beam was intentionally limited to only 4 samples for faster volume coverage. To deal with ground clutter contamination, ground clutter power removed from previous weather beams were fed back into the surveillance beams. This created a dependency of the surveillance beams on previously scanned weather beams. In this paper, we present the design considerations for a detection beam in ADAPTS III that provides fast volume coverage and allows for the use of independent scanning strategies for both weather and detection beams.