1. A method for detecting hidden explosives or weapons, comprising (a) transmitting a radar signal in different polarization channels towards an object; (b) collecting back scattered energy in different polarization channels from the object; (c) determining parameters that are dependent upon at least the transmitted signal polarization channels and the backscattered energy polarization channels, providing an indication if there are hidden explosives or weapons associated with the object based on said parameters, wherein said determination of parameters stipulated in (c) includes i) evaluating full polarization scattering matrices of range Doppler cells that belong to the object; ii) calculating correlation between elements of the polarization scattering matrices averaged over said range Doppler cells, giving rise to a covariance matrix; iii) analyzing polarimetric results for the covariance matrix; the polarimetric results include the largest eigenvalue and the eigenvector that corresponds to it; iv) evaluating the distributions of said eigenvalue and eigenvector over several detections of the object; v) determining whether the combined results of these distributions belong to an armed object and if so: vi) generating an indication that there are hidden explosives or weapons associated with the object.