Adaptive polarimetric target detection with coherent radar

Abstract

A CFAR adaptive polarimetric generalized likelihood ratio test (GLRT) detector is proposed for the coherent detection of radar targets against a Gaussian background and its performance is fully characterized. A model based version of such a detector is also derived by applying a similar GLRT approach to a structured covariance matrix. This latter detector is shown to reduce the adaptivity losses and thus to reduce the homogeneous region, which is required to estimate the clutter covariance matrix. The application to live radar data demonstrates the performance improvement achievable in practice by exploiting the polarimetric information. In particular adding the HV channel to the two co-polarized channels can provide a sensible performance increase with respect to the HH and VV only. This is especially true for man-made targets having cross-polarized response higher than the clutter. When the target has a lower cross-polarized return than the clutter, a much lower improvement is available but there is not a sensible adaptivity loss and the CFAR characteristic is always enforced against the Gaussian background.