BISPECTRUM OF RADAR SIGNATURES AND APPLICATION TO TARGET CLASSIFICATION

The scattering characteristics of a radar target can be specified by its impulse response. The impulse response can be computed using Fourier spectral estimation techniques on samples of the radar scattering obtained at a number of equally spaced frequencies. Usually, there is a clear relationship between the location of specific scattering mechanisms and the time such mechanisms appear in the impulse response. One of the difficulties in this type of analysis, however, is that complex targets often have multiple scattering interactions. Many of the terms in the impulse response are due to these interactions rather than specular subcomponent scattering. The bispectrum displays the specifics of the interactions of both single‐ and multiple‐reflection mechanisms. In addition, the suppression of Gaussian noise makes the bispectrum a source of robust features for classification of radar targets. Identification of multiple interaction terms as well as noise suppression are demonstrated in this paper. Finally, classification of scale models of commercial aircraft based on their bispectral signatures is performed. Copyright 1990 by the American Geophysical Union.