A radar arrangement which is particularly useful for the terrain following radar of an aircraft avoids disturbances from rain echoes by utilizing an antenna arrangement with a transmitting/receving directional antenna which is circularly polarized. A supplementary receiving antenna of orthogonally-circularly polarized type is used in conjunction with the directional antenna. From a comparison of the signal level distinctions is made between a target and a rain echo. The rain echo can thus be suppressed to give a truer target signal.
