The GNSS reflectometry station was designed for measurements of soil water content. Therefore the station was installed at a remote position with low vegetation and far from other obstacles. No electrical power supply was available and had to be designed autonomously.
GNSS messages are recorded using a tinyPC/3. All data is transferred on an hourly basis. Since power consumption is critical at this station, the UMTS router is controlled by the tinyPC and deactivated when not used.
Additional sensors for measuring meteorological and hydrological parameters are installed and their power supply is provided by the same sources.
Total power consumption is about 8-9 W. The primary power source is a 120 W solar panel, which is connected to a 105 Ah AGM battery. However, since provided energy is not sufficient in conditions with low solar radiation, a fuel cell is connected to the system and will charge the battery if needed. The fuel cell can be configured and controlled by the tinyPC/3.
Access to the station is possible via ssh.
The station was designed for validation of soil moisture measurements by GNSS reflectometry and comparison of different GNSS equipment for this purpose.
The station is connected to a 230 VAC power supply at the site und uses a UMTS router for wireless data transfer. Data is collected by a tinyPC and an additional computer.
The receivers deployed are currently two dual-frequency receivers: a JAVAD DELTA Quattro-G3D and a JAVAD DELTA, and two single-frequency receivers: an ublox in an evaluation kit, and a Novatel Smart.
Both single frequency antennas and an Antcom L1/L2 antenna are mounted on a mast.
For transmission measurements, an Antcom antenna is placed at ground level and three additional antennas of the same type are installed at 10, 50 and 90 cm below ground.
For reference measurements a TDR system is installed.