Test and evaluation of the AN/APS-145 radar surface detection and discrimination capability between small radar cross section surface targets and free floating objects

This study is a comprehensive analysis of the surface detection capability of the AN/APS-145 radar which is currently the weapon system configuration of the U.S. Navy's Airborne Early Warning (AEW) and control aircraft, the E-2C II Hawkeye. The major portion of this study concentrates on the primary objective of the test which was to exploit the full AN/APS-145's surface detection capabilities (overwater) in varying sea states. This included the demonstration that the weapon system could retrieve target attributes in the radar return signal (target radar signature) and use them to discriminate between small powered targets such as periscopes, and free floating surface targets such as large ships or buoys. The examination also concentrated on the scope and methodology of the flight test, the validation of a specialized radar In-Phase and Quadrature (I&Q) data collection device in collecting generic ultra-high frequency (UHF) radar data, and finally the development of analytic tools and processing algorithms for data reduction. The results of the evaluation are also presented in this thesis. It was concluded and strongly evident that presently with an off line detection system, small powered surface targets could be discriminated from free floating objects at significant tactical ranges with better that 90% detection rates, in agreement with earlier Naval Air Warfare Center, Aircraft Division studies. Overall, the results indicated that a viable E-2C surface detection mode for small radar cross section (RCS) targets could be designed and implemented with comparatively modest changes to the weapon system. Recommendations for improved surface detection in the ultra-high frequency (UHF) radar band were presented to the Office of Naval Research. Further study and evaluation of this topic is curently being conducted at the Naval Air Warfare Center Aircraft Division (NAWCAD).