Interference nulling of multipath signals in stacked beam pulse radar

XA4170WO 18 Improvements in and Relating to Radar Abstract A radar apparatus (5) for detecting multipath signal propagation when determining an elevation angle of an object, comprising an antenna array with which the radar apparatus is arranged to form at least three separate antenna beams (11, 12, 13) comprising a first antenna beam (11) having an angle of elevation above horizontal, and a separate second antenna beam (12) having an angle of elevation at or above horizontal which is less than that of the first antenna beam, and a separate third antenna beam (13) having an angle of elevation below horizontal. The apparatus is arranged to transmit radio pulses from the antenna array; to receive return radio signals within the first, second and third antenna beams; to calculate a measure of the magnitude of a return radio signal received within the third antenna beam using all of said received radio signals collectively; and, to detect multipath signal propagation using said measure. [Fig.2]