| 摘要 |
PROBLEM TO BE SOLVED: To allow measurement of a dielectric constant in snow fall without conducting any factitious work for the snow fall. SOLUTION: A measuring instrument calibration value (initial value) from which an influence of a coaxial cable portion is removed is found in a non-snow- fall condition, and stored. A calibration value of the coaxial cable portion is measured in the snow fall, and added to the stored measuring instrument calibration value (initial value) to serve as a new measuring instrument calibration value (calibration value in the snow fall). Then, a reflection characteristic in the snow fall is measured by a network analyzer, and the dielectric constant in the snow fall is calculated based on a reflection coefficient found based on the reflection characteristic. A measuring error caused by a direct wave component from a measuring transmission antenna onto a measuring reception antenna, and a calibration value error caused by fluctuation of the network analyzer by a temperature change in the measurement, extension and contraction of the coaxial cable portion, and the like are eliminated thereby, and an unstable factor is eliminated in a calibration system of spatially opened type comprising a reflection board and the measuring antennas.
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