Intercepted Signals for Ionospheric Science Array (ISIS)

The ISIS Array (Intercepted Signals for Ionospheric Science) is an instrumentation project currently funded by the DoD DURIP program via AFOSR and the National Science Foundation. This project is constructing a coherent software radio network capable of operating as a flexible multi-role distributed radio science instrument. In particular operational modes involving active and passive multistatic radar imaging, satellite beacon observation of TEC and scintillation, and radio intercept and time difference of arrival applications will be supported over a wide range of operating frequencies (0.5 to 2000 MHz). The system will be constructed of a series of MIDAS-Mobile Nodes which can coherently capture wide bandwidths of RF signals from a variety of antennas. The array will be capable of applying high performance supercomputing to the real time and batch processing requirements of a variety of experiments. Different operational modes may require the array to be configured with different antennas, however the underlying software radar technology will allow a unified data, signal processing, and instrument control system. The system will also be used to evaluate a wide variety of configurations and techniques for applications involving scientific and defense applications of intercepted signals. Currently seven ISIS array nodes have been constructed for the initial deployment with an additional equivalent capability located at the MIT Haystack Observatory. Long term plans include additional highly integrated receivers, a significantly expanded array, and experiments with the capabilities provided by much higher antenna apertures using antennas located at the NSF supported NRAO Green Bank facility.