5:15 PM - 6:30 PM
[PEM16-P03] Water vapor estimation using digital terrestrial broadcasting waves - Results using reflected waves -
Keywords:digital terrestrial broadcasting wave, water vapor
We are developing a real-time delay (phase of delay profiles) measurement system with software-defined radio technique. Each TV station has their own local oscillators. Out system is improved and it can measure phase fluctuations of radio waves from whatever TV station stably for a long time. We are planning a proving test for synchronization of local oscillators at different sites.
In this presentation we report a method and results of water vapor measurment without synchronization of local oscillators. We observe phase variations of digital terrestrial broadcasting waves at cartain site. If there is a reflector at the opposite side from the radio tower, we can observe direct waves and reflected waves simultaneously. Measurement is conducted using single local oscillator at the observing point. So we can measure a round trip propagation delay between the observing point and reflector without synchronization of local oscillators. NICT is located at about 29 km westward from the Skytree. A building is located at about 1 km westward from NICT. Both direct and reflected waves can be observed at NICT. We have a groundbase meteorological observatory equipment at NICT. Provagation delay can be calculated using these data on the assumption that these data are representative of the meteorological condition around there (within 1 km). Observed time vriations of propagation delay using digital terrestrial broadcasting waves correspond to the calculation.