Maritime surveillance radar. Part 1: Radar scattering from the ocean surface

The successful optimisation of the detection performance of maritime surveillance radars requires a detailed knowledge and understanding of both forward- and backscattering from the ocean surface. Such an understanding enables the development of suitable signal-processing techniques. The paper is therefore divided into two parts, the first being concerned with radar scattering from an ocean environment and the second with target detection. In the first part it is shown, through the analysis of full-scale measurements, how the amplitude and correlation properties of high-resolution radar backscatter (sea clutter) can be accurately represented by the compound K-distribution model which has the unique characteristic of providing realistic performance predictions for a wide range of signal-processing techniques. Although the model has been presented before, the paper gives the first detailed account of the evidence and statistical analysis which have led to the model. In addition to modelling noncoherent clutter it is shown how the spectral and polarisation characteristics of coherently detected sea clutter relate to those observed in the noncoherent case. Results are also presented of forward-scattering and multipath propagation. This includes a consideration of the importance of the spatial and temporal coherence of the forward-scattered wavefront.