NOAA's Spectrum Efficient National Surveillance Radar (SENSR) Research Program

In 2016, the FAA, NOAA, Department of Defense (DoD) and Department of Homeland Security (DHS) initiated a feasibility study for a Spectrum Efficient National Surveillance Radar (SENSR). This study assesses approaches for vacating the 1.3 to 1.35 GHz radio frequency band currently allocated to FAA/DoD/DHS “Long Range Radars (LRR)”, so that this band could be auctioned for commercial use. One approach to accomplishing this is the use of phased array radar (PAR) to consolidate the LRR mission with that of near-airport aircraft detection and tracking radars, and weather surveillance radars which operate in the 2.7 to 3.0 GHz band. The participating agencies have developed SENSR “Preliminary Performance Requirements (PPR)” to communicate consolidated technical requirements to the aerospace industry. These assume as a minimum the capabilities of legacy operational radars, with several significant enhancements. For example, volumetric scan rate goals for both weather and aircraft surveillance are higher than current operational radars, height-finding capability for aircraft is required, and sensitivity requirements are more stringent. The PPR facilitates objective evaluation of proposed approaches to achieving SENSR goals.

This paper discusses NOAA-led research activities that address National Weather Service (NWS) mission benefits potentially realizable through the SENSR program, and associated technical challenges. Improved warning and forecasting services may result from PAR capabilities for more rapid, adaptive volume scanning and expanded coverage, particularly at low altitudes. Technical challenges being addressed include compensation for polarimetric variable estimate errors associated with PAR, simulation and analysis to assess strategies for managing the SENSR scanning timeline, mission-impacts and mitigations for PAR characteristics such as scan-dependent beam broadening and elevated range- or angle-sidelobes, and assessment of an all-digital PAR architecture. These research activities encompass measurements, analysis and modeling using scaled, active array radar testbeds, data driven simulators and storm observations.

The aim of this research is to refine and justify – in terms of National Weather Service mission benefit – technical requirements for the SENSR “high resolution weather” mission. Follow-on engagement with industry and the other stakeholder Government agencies will determine how best to realize these capabilities in the deployed SENSR network.