Radar detection of Small Targets (low observables) and low RCS (Radar Cross section) targets (e.g small boats, periscope, drones etc) submerged in Sea clutter,has always been a challenge in modern times. But there is always a critical requirement to detect intruders (slow moving small boats) entering the territorial waters, UAVs (Unmanned Aviation Vehicles) over land and sea involved in EW assignments, detection of submarine periscopes exposed just above the water surface etc. Also, recently birds flying low at critical heights above the ground, have become potential aviation safety hazards too, during aircraft takeoff and landing periods. These targets (birds) have significantly low RCS with weak reflected/scattered power, masked by strong correlated sea clutter (at high sea states) /inherent ground clutter returns. Hence, extracting such weaker, unpredictable and unstable target returns amidst strong clutter background require efficient, reliable and robust Small Target detection methods and techniques.

The small moving targets exhibit low Doppler frequencies and conventional Doppler detection processes used in surveillance systems may not always be useful due to dwell length limitations to get sufficient Doppler information with sea returns exhibiting the same velocity range as that of the targets of interest. To alleviate such hurdles in doppler processing we have other options open to us like various Track- before-detect (TkBD) methods e.g Dynamic programming, Particle Filters, MHT (Multi-hypothesis Tracking) etc, pulse-to-pulse and scan-to-scan integration techniques coupled with distribution-free CFAR, Binary integration etc supported by various research outcomes of K-distributed clutter modelling.

In recent times, several research outcomes have shown significant improvements in the detectability of weak targets in strong sea clutter, by utilising netted (distributed) radars-based detection methods. This involves data capture, analysis and processing of the target returns of the same target at various aspect angles, thanks to the availability of low-cost surveillance radar systems in the market. Netted radar architecture improves system sensitivity multifold, as compared to single sensor detection and this tutorial will also discuss the sensitivity models of netted radars. In order to exploit further of the advantages of netted radar systems, coherent detection signal processing in multi-static/ multi-site radar systems as applicable to low observables, will also be presented briefly, covering the recent research and trials outcomes including the impact of phase (and time) synchronisation in multistatic/multi-node radar systems for efficient and optimal detection performance of small targets.

Optimal detection of small weak targets also relies on the noise performance at the RF front end amidst strong clutter returns. Hence modifications/tuning up of the RF front end circuitry such as Tracking STALO, helps to pre-process the target returns feeding into the subsequent stages of signal/data processing chain with enhanced SNR (Signal-to-Noise Ratio) of targets of interest, to optimize small target detection performance. This tutorial will provide an overview of the radar detection theory combined with various CFAR processing methods. It will elaborate the various algorithms/techniques employed for small target detection as referred above for ground based, seaborne and airborne systems, with illustrations, models and case studies with captured data, as much as possible.

It will also elaborate further studies and research work undertaken and potential applications that are envisaged by the radar community in this area. The delivery of the tutorial is aimed for 3 Hours (with tea break) through Power Point presentation and brief interactive sessions.