Adaptive Doppler filtering applied to modern air traffic control radars

Abstract

This paper presents an analysis of the Doppler processing technology currently in use in the USA's terminal airport surveillance radars, and examines possibilities for performance improvement, particularly in the presence of moving clutter. The research focuses on five- and eight-pulse waveform methodologies and their respective detection capabilities given clearly defined rain clutter scenarios. Performance with fixed coefficient filters similar to those used in the existing radars is calculated, followed by performance using an adaptive Doppler filtering technique. Performance is quantified in terms of signal-to-interference ratio at the output of the Doppler filters and resultant probability of detection given a specified probability of false alarm. The results show that a substantial improvement in detection in the vicinity of rain clutter is realized for both the five- and eight-pulse waveforms when using the adaptive coefficient Doppler filters as compared to the performance observed with the fixed coefficient filters. For constant filter weights, the eight-pulse Doppler filters give significantly better performance in most diverse rain clutter than the five-pulse Doppler filters.