Advanced Concepts for Multifunction Phased Array Radar

NOAA and FAA are performing concept development and risk reduction for a next-generation Multifunction Phased Array Radar. MPAR could subsume current national operational radar functions including surveillance for civil aviation, airport wind shear detection, severe weather observation and warning, quantitative precipitation monitoring and air-domain security. MPAR would exploit highly digital, active electronically scanned array technology to perform these missions.

Technical performance capabilities for MPAR are articulated in two documents: “Notional Functional Requirements” generated by the MPAR project team and NWS-generated “Radar Functional Requirements”. To a significant extent, both documents repurpose engineering specifications (e.g. maximum antenna sidelobe levels) that may not align with concepts of use for a next generation, multi-function active array radar.

In this paper, we describe and analyze four novel MPAR “use cases” that exploit MPAR's architecture to realize potential performance enhancements, but require reassessment of the appropriateness of the legacy radar specifications. These advanced concepts are:

1. a hybrid-multistatic MPAR configuration where, instead of a single, outward-looking aperture (multi-faced or cylindrical), multiple apertures would be deployed around the perimeter of the airport facing inwards. Inside this network, high duty-cycle waveforms returns would be processed multi-statically in order to significantly increase radar sensitivity to low-cross section meteorology phenomena such as dry microbursts and gust front fine lines;

2. a “staring” or “imaging” mode where near-continuous sampling (5 seconds or less) of the full cloud volume would be achieved using a “spoiled” transmit beam and multiple, digitally formed receive beams. This mode could be valuable in monitoring signatures in polarimetric variables that reflect ice crystal alignment as electric fields build rapidly in a thunderstorm updraft and then collapse following lightning;

3. a “multiple-input, multiple output (MIMO)” MPAR aperture configuration that might enhance weather angular resolution for a given number of active elements, thereby improving angular resolution and/or allowing the size/cost of the antenna to be reduced;

4. integration of high-precision 3-D aircraft locations provided by cooperative ATC surveillance systems (e.g. beacon radar). These data could be used to correct weather radar mode measurements for atmospheric refraction, and to reduce the amount of the available radar timeline required for aircraft surveillance.

The paper will describe each of these concepts in more detail, assess potential capability enhancements and the implications relative to MPAR “requirements” as articulated in the above referenced documents. We will show that a higher-level, more end-user focused view of system-level requirements may be beneficial in developing the future architecture for MPAR.

This abstract was prepared with funding provided by NOAA/Office of Oceanic and Atmospheric Research under NOAA-University of Oklahoma Cooperative Agreement #NA11OAR4320072, U.S. Department of Commerce. The statements, findings, conclusions, and recommendations are those of the author(s) and do not necessarily reflect the views of NOAA or the U.S. Department of Commerce.