Temporal Statistics Of Low Angle Ground Clutter

Detailed knowledge of the temporal statistics of ground clutter is essential to determine the detection threshold settings so as to maximize the probability of target detection while maintaining an acceptable probability of false alarm. The performance of existing false alarm control schemes is often limited due to a lack of detailed knowledge of the ground clutter temporal statistics. In this study we analyze experimental data to characterize the temporal statistics of low-angle ground clutter in terms of the clutter's linear amplitude distribution. Effects of radar frequency, polarization, waveform resolution, land covers and wind speed on the statistics are examined. Results show that the Ricean distribution and its limiting case, the Rayleigh distribution, are appropriate models for ground clutter in steady-state wind conditions. This implies that the diffuse clutter components, which give rise to the random properties of ground clutter may be modeled as a complex Gaussian process. We found, however, that at any given time there is a fraction of the resolution cells with clutter data having nonstationary temporal statistics not well modelled by the Ricean or Rayleigh distribution. The frequency of occurrence of nonstationary clutter statistics depends on radar frequency, land cover and wind speed. Forested land cover represents the worst case scenario. Application of the results of this study to determine optimal detection threshold settings is discussed. Radar clutter; Phased array radar; S band; Canada. (edc).