Use of crosspolar returns to enhance target detectability

An instrumented X-band radar has been used to measure the relative magnitudes of copolar and crosspolar returns from targets and clutter for linear and circular transmit polarisations. The data was analysed to see if the inclusion of a second receiver to make use of crosspolar information can be justified. It is shown that, if linear polarisation is transmitted, there is little extra information in the crosspolar signal. However, when circular polarisation is transmitted, the inclusion of a second channel can enhance detections by 1-4 dB. The spectral returns of clutter were also measured, and it is shown that the spectra of copolar and crosspolar returns are identical.