border surveillance, data handling, foliage penetration, knowledge-aided adaption, Passive radar, situational awareness, symmetric and asymmetric threat mitigation
SET-108 demonstrated the relevance and extent of understanding of passive sensors for air surveillance applications. SET-164 has made a valuable contribution to addressing the critical unknown of bistatic clutter and has demonstrated the capability of passive radar in Maritime Situational Awareness (MSA) roles. The work of SET-164 has, however, shown the limitations of existing land-clutter models and indicated that VHF bistatic radar performance is strongly dependent on the propagation over the surface, to the extent that further study will be needed to find models which are suitable for general modelling of passive radars.
The objective of this new SET is to extend the valuable lessons learned from SET-164 by developing and validating a robust and inclusive model for passive radar. A robust model-based approach to radar design and procurement is in accord with the approach desired by the more sophisticated military sensor research and planning agencies. The proposed model will consist of: a comprehensive prediction of propagation effects and a characterisation of bistatic clutter, (both of which SET-164 has shown require more development), target modelling, characterisation of RFI, and development of agile mitigation techniques for clutter and interference.
One benefit of bistatic radars, particularly at VHF/UHF, is their ability to use forward-scatter techniques to detect low-observable targets. As the forward-scatter behaviour is only achieved over a limited set of directions, networking between multiple transmitter/receiver pairs is required to obtain complete coverage. For systems using omni-directional (broadcast) transmitters the poor angular accuracy which is obtainable from low-cost receivers means that practical systems will have to use multilateration, again between multiple transmitter/receiver pairs, to obtain adequate positional accuracy. Both of these considerations mean that the radar deployment will have to consist of a collection of sensors. The topic of passive radar sensor integration needs to be studied, adhering to the aforementioned methods, to accurately determine sensor performance and to enhance siting for strategic advantage in a net-centric domain. The group will research a robust infrastructure of sensors, which as well as exploiting spatial diversity and improving resolution will also yield greater detection ranges and exploit frequency and temporal diversity over what is obtainable by an individual sensor. Aspects of Dynamic Spectrum Access (DSA) and system covertness for network resilience will have to be researched to ensure the survivability and efficient operation of the network, even if individual nodes have been destroyed.
Countries are increasingly investing resources into border surveillance. UHF/VHF radar, due to its operating frequency has foliage penetration capabilities and would potentially make a viable border surveillance sensor, which could also complement battle-field surveillance radar. However, it would probably not be possible to obtain a transmission license for an active radar at these frequencies, so a Passive Bistatic Radar (PBR) would be the only way of exploiting such a capability. Since border surveillance radars typically recognise people by their Doppler signatures, this aspect will have to be studied. The effects of motion-induced interference on radar performance will also have to be mitigated for solutions that require the PBR receiver to be mounted on moving/unstable platforms. There is also increased interest in the use of satellite illuminators for border and perimeter surveillance, and for Maritime Situational Awareness. The clear benefit to NATO is an increased expertise in border surveillance and control and MSA, and an in-depth feasibility study of the suitability of passive radar for these, and similar, applications.
• Military relevant, situation-specific, modelling for strategic operation and deployment of PBRs.
• Investigation of PBR net-centric infrastructure of sensors.
• Extending harbour protection, MSA, and border security capabilities.
• Motion compensation techniques and satellite-based surveillance for aforementioned applications.