| 摘要 |
Two beams (I), (II) having directivities slightly deviated in the upper and lower directions are formed by an antenna (1) and the antenna axis at which the two beams (I), (II) meet is directed by a direction adjusting mechanism toward a middle point between a target and an image thereof. Phase differences ( beta ) between the received waves of the two beams (I), (II) are measured in regard to the two frequencies and the effects of indirect waves are removed through a predetermined processing based upon the phase differences between the direct waves and the indirect waves of the two beams by finding out an altitude of a target of a low wave angle with a means (15) which determines a true altitude from two sets of altitudes calculated based upon the phase differences. The two independent beams are transmitted by switching over into beams each having two frequencies that are slightly different to calculate a plurality of altitudes for comparison, and many false altitudes (ambiguities) are removed by the means (15) which determines a true altitude, to thereby highly precisely measure the wave angle of a low wave angle object on the relatively clam surface of the sea. |
