Frequency sensitivity of clutter scattering statistics

Development of radar systems which use digital signal processing requires the design of sophisticated constant false alarm rate (CFAR) circuitry to minimize processing of false reports. This CFAR circuitry must account for changes in clutter statistics as the grazing angle and clutter patch size change to optimize detection probability. The use of automated data collection systems by recent investigations has made data available on scattering statistics over a wide variety of surfaces at many operating frequencies. A scaling process has been developed to relate data from these systems. This process involves fitting a Weibull distribution to the data and deriving a skewness parameter. This skewness parameter is plotted with respect to such variables as polarization, terrain type, wind direction, wave height, operating frequency, and clutter patch size. An empirical fit has been made to the variation of the skewness parameter. This fit is a simple analytic function which can be used in modeling the performance of prospective CFAR designs.