Evaluation of the ASR-9 weather reflectivity product
The ASR-9 is a modern airport surveillance radar (ASR) under procurement by the United States Federal Aviation Agency. The radar operates at S-band, providing range-azimuth position information on aircraft targets within a 111-km radius. A fully-coherent klystron amplifier, large dynamic range and digital signal processing enable high integrity target processing and display under condition of ground clutter, weather, angel clutter, RF interference and ground vehicular traffic. To aid controllers in the identification of hazardous weather conditions, the processor will also generate two- or six-level weather reflectivity contours for display at the terminal radar control center and (potentially) remote sites. In this paper, we present an overview of the ASR-9 and its weather processor, emphasizing those features that raise issues with respect to the utility of the weather reflectivity product in an air-traffic control environment. We then describe a simulation procedure that utilizes pencil-beam Doppler weather radar data and ground clutter measurements to preview the ASR-9 product and assess the effects of the radar's configuration on the weather intensity reports. Examples of the simulated weather reports are used to illustrate" (a) partial beamfilling die to the fan-shaped surveillance antenna pattern; (b) attenuation of low velocity weather by the clutter filters' (c) the effects of the spatial filters used in weather processing.