Polarisation and sea echo

It is sometimes of interest to compare the radar cross-section for transmitting and receiving a given linear polarisation with that for another linear polarisation. Even if only average values are required, such an experiment may be difficult to implement because echoing characteristics might change within a time interval smaller than that required to change transmitted polarisation. Depending on target characteristics, desired results might be obtained by simultaneously receiving the two linear polarisations of interest and transmitting a circular polarisation. Applicable equations are developed and used as an aid in interpreting recently reported sea-echo data.