For the first time, validation of the Precipitable Water Vapor (PWV) at the continuous GPS stations (cGPS) of "Bako" is carried out in Indonesia, located in the Office of Bakosurtanal. The first Radiosonde balloon used for this measurement was launched by the Head of Bakosurtanal, Asep Karsidi, at the lawn of Bakosurtanal. This balloon is used to perform the measurements at the intervals of six hours during the five days since its launch (July 28 to August 1, 2010).
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Precipitable Water Vapor (PWV) is needed to know the accuracy of GPS data processing. In determining the precise geodetic position on earth by using the GPS satellite constellation, we often see the slowing GPS satellite signals in the layer of atmosphere (ionosphere and troposphere). This slowdown signals can be modeled to eliminate the refraction in the layer. The zenith total delay (ZTD) can be obtained through the model on the layer of the atmosphere toward the zenith. ZTD can be decomposed into a hydrostatic component and a slowing wet (precipitable water vapor (PWV)). PWV indicates that the presence of water vapor in the troposphere are very useful for data input of the parameters in the weather forecast.
Validation is required through measurements using the equipment that has been used by the meteorological community: the radiosonde balloon. The equipments used in the measurement of the radiosonde are radiosonde receiver + gps, sensor + transmitter + gps, and a hot air balloon that is used to launch the sensor + transmitter + gps it. Radiosonde sensor (consisting of pressure sensors, temperature and humidity) was launched from the earth's surface so that the journey to the layer of the atmosphere can transmit data at any particular time interval (eg. every interval of two seconds), which will be listed on the radiosonde receiver.
This event was conducted through the cooperation between Bakosurtanal and Lapan, the Department of Meteorology and the Department of Geodesy and Geomatics, the Faculty of Science and Earth Technology - ITB.
According to the Head of Bakosurtanal, Asep Karsidi, the utilization of GPS observations can be optimized not only to make the precise geodetic positioning, but also to determine the total particle electron content (TEC) in the layer of the ionosphere that is useful as supporting data on rocket launch, radio communications, and to determine the content of water vapor in the troposphere as supporting data in weather forecasting. In addition, the cGPS nets can be used for navigation safety systems and others.
The Head of Bakosurtanal expected that this activity can be utilized to increase the ability of human resources to pursue their higher study to the degree of magister or doctoral.
By Susilo
