Modelling sea clutter: correlation, resolution and non-Gaussian statistics

The performance of maritime surveillance radar is inevitably limited by the presence of sea clutter, the unavoidable but unwanted radar returns from the sea surface. Realistic modelling of this clutter process is thus a prerequisite for any reliable assessment of systems of this type. It has been recognised for some time that a simple Rayleigh model cannot capture those features of sea clutter that degrade the performance of high resolution radar. The K distribution provides a much improved statistical clutter model and is now incorporated in many radar performance calculations. However, all but the simplest (`single hit´ detection) radar signal processing schemes are affected by the spatial and temporal correlation properties of the clutter. Thus far the modelling of these correlation properties and their influence on radar performance has been quite crude, although significant success has been achieved in the analysis of pulse to pulse integration. We describe our attempts to model the spatial correlation in the sea clutter more realistically and discuss the implications of our findings for radar system performance