| 摘要 |
PROBLEM TO BE SOLVED: To measure a water level without being influenced by a weather condition or by the state of a water surface. SOLUTION: A receiving antenna 1 is a directive antenna which receives milliwave-band electromagnetic waves radiated from a target. A drive control part 3 controls an antenna drive part 2, it periodically changes the receiving direction of the receiving antenna 1 to the direction of an angle of depression, and it outputs angle-of-depression data (θ). A polarizer 4 passes only the horizontally polarized wave component of the received electromagnetic waves. A noise- temperature detection part 5 detects the noise temperature of the electromagnetic waves to be output from the polarizer 4, and it outputs noise-temperature data (T). On the basis of the angle-of-depression data (θ) on the receiving antenna 1 and on the basis of the noise-temperature data (T), a water-level calculation part 6 detects an angle of depression at which the noise temperature is changed suddenly, it finds the water level, and it outputs water-level data (H). |
