Jamming recognition method based on the full polarisation scattering matrix of chaff clouds

This article studies the probability density function (PDF) of the polarisation-radar cross-section (RCS) ratio based on the polarisation rotation transformation, of chaff cloud with all possible rotation angles. The PDF of this ratio is different between chaff cloud and a single dipole, even when the chaff cloud is sparse. The results indicate that the PDF of the chaff cloud polarisation-RCS ratio is different from that of other radar targets such as aircraft and missiles, which provides a key to discriminate chaff jamming among other targets. An analytical formula of the PDF of the polarisation-RCS ratio for chaff cloud with arbitrary orientation distribution is presented and validated by numerical electromagnetic simulation results for sparse and dense chaff clouds, respectively. In addition, three typical orientation distributions are analysed in detail. Based on this formula of the PDF, a pilot study is also carried out to compare the chaff cloud radar signature of this ratio with other targets, which confirms the feasibility of chaff-jamming recognition by computing the posterior probabilities.