Measurements of atmospheric phase delay using 22-GHz water vapor line emission comparison atmospheric brightness temperature with 'HALCA' round trip phase

摘要

Tropospheric phase fluctuation due to the water vapor content is one of difficult problems which degrades imaging performances of radio interferometry. One of the potential solutions is differential radiometry observations to measure the differential water vapor content along the line of sights. We developed a 22-GHz-line radiometer to be mounted on a ground data-link antenna which supplies the timing reference signal for a space VLBI satellite, HALGA. This system will allow us to compare directly the atmospheric phase fluctuation with the water vapor content along a single line of sight measured by the radiometer.