ABSTRACT
Recognition that modern active EW engagement zones are becoming more complex and agile, it’s now essential that threat Radio Frequency Interference (RFI) emitters are quickly characterised and precisely geolocated. Recognising this new importance, late in 2020 Defence announced several new Sovereign Industry Capability Priorities (SICPS) with a heavy focus on advanced radar phased array technologies and weak signal spectrum processing.
The technologies required for precision RFI emitter geolocation although are similar to active or bistatic radar principles, are distinctly different by not relying upon threat RF active or passive illumination. By utilising a synchronised network surveillance monitoring stations, (GPS in reverse), normal navigation principles for signal “time of flight”, referred as Time Difference of Arrival (TDOA), plus Angle of Arrival (AOA) and Doppler Frequency Difference of Arrival (FDOA), can all be tightly coupled to deliver precision 3D RFI threat geolocation. With additional advanced of Spectrum Whitening (SW) and Track Before Detect (TBD) technologies, RFI threat detection sensitivities can also be substantially enhanced for weak/ very long range operations.
The underlying scientific principles and practical implementation examples of these technologies are presented. Also, through tightly combining/ fusing these technologies in statistical filters, (EKalman), substantial increases in geolocation accuracy and reliability can be achieved. An example is given for long range detection, spectral characterisation, and precision geolocation of problematic RFI in persisting in the GPS Bands. Emerging from this unique geospatial information, detailed regional Area of Influence Prediction (AOIP) maps can be generated.
BIOGRAPHY
Graeme established GPSat Systems in 1992 and is a Senior Engineer and company Managing Director. He has both 30years experience in GPS/GNSS and 10years in RF antenna engineering. He specialises in the application of these technologies to both Defence and aerospace industries.