Design and Implementation of an RF front end for the NeXtRAD radar system

This dissertation presents the design of the RF front end for use on the NeXtRAD radar system. The system is intended for research purposes to investigate potential target detection benefits to be derived from a multistatic, dual-band (X- and L-band), polarimetric radar architecture, particularly within dense clutter environments such as the maritime environment. By examining the high-level system requirements and objectives, requirement specifications for the RF front end were derived and a suitable architecture, making use of commercial off-the-shelf components, proposed. This architecture was modified in order to meet cost constraints - subsequently offering reduced levels of functionality but suitable for an initial build. Using this modified RF front end architecture, design verification and system analysis was conducted, both analytically and with the aid of SystemVue, in order to predict both the front end and overall radar detection performance. Once the front end design was found to be satisfactory, it was built and tested in a laboratory environment. Test results revealed a general improvement in performance when compared with the design predictions, yielding peak transmitter power levels in excess of 61dBm at L-band, and 54dBm at X-band. Some non-conformances were also identified, but these were as a result of component problems and not system design. Since the front end could not yet be integrated into the radar, performance modelling was repeated using the final lab test results. This indicated a negligible improvement in receiver single-pulse signal-to-noise ratio, but confirmed that the system performed as predicted. Based on the lab test results, it was concluded that the 'as-built' front end design closely matched the design goals and would be suitable for eventual integration into the first revision of the NeXtRAD system. It was, however, recommended that a concerted effort be made to secure funding to implement the original front end architecture in order to achieve the full system functionality originally desired

RF/microwave system high-fidelity modeling and simulation: Application to airborne multi-channel receiver system for angle of arrival estimation

In this paper, a high-fidelity RF modeling and simulation framework is demonstrated to model an airborne multi-channel receiver system that is used to estimate the angle of arrival (AoA) of received signals from a stationary emitter. The framework is based on System Tool Kit (STK®), Matlab and SystemVue®. The SystemVue-based multi-channel receiver estimates the AoA of incoming signals using adjacent channel amplitude and phase comparisons, and it estimates the Doppler frequency shift of the aircraft by processing the transmitted and received signals. The estimated AoA and Doppler frequency are compared with the ground-truth data provided by STK to validate the efficacy of the modeling process. Unlike other current RF electronic warfare simulation frameworks, the received signal described herein is formed using the received power, the propagation delay and the transmitted waveform, and does not require information such as Doppler frequency shift or radial velocity of the moving platform from the scenario; hence, the simulation is more computationally efficient. In addition, to further reduce the overall modeling and simulation time, since the high-fidelity model computation is costly, the high-fidelity electronic system model is evoked only when the received power is higher than a predetermined threshold