Distributed Beams: A Technique to Reduce the Scan Time of an Active Rotating Phased Array Radar System

Important requirements for a future generation of weather surveillance radars include improvements in data quality, rapid-update volumetric data, and the ability to perform adaptive weather observations. Phased Array Radar (PAR) is a candidate system capable of providing the required functionality. The National Oceanic and Atmospheric Administration (NOAA) is considering an affordable rotating PAR architecture to improve the capabilities of the current parabolic-reflector-based Weather Surveillance Radar – 1988 Doppler (WSR-88D) operational network. To achieve the current and future needs to support the National Weather Service mission, a concept of operations for the rotating PAR architecture has to be developed. The distributed beams technique introduced in this paper provides a way to reduce the scan-update times by spoiling the transmit beam while receiving multiple digital beams as the radar rotates in the azimuth plane. Specifically, the azimuthal rotation rate of the platform is matched to the desired sampling (spatial and temporal) such that the coherent processing interval for a given beam position is distributed over several overlapping receive beams. That is, the scan time can be reduced by a factor equal to the transmit beam spoil factor. This exploits the use of spoiled transmit beams in azimuth and allows a faster rotation rate which leads to rapid updates. In this presentation, we will illustrate this technique and provide a trade-off analysis in the context of rotating PAR weather surveillance network.