Tethered probe system
The IMK-TRO operates two tethersonde systems to explore the lower atmosphere. The tethersondes are an in-house development of IMK-TRO. The probes are attached to a tethered balloon with a volume of 5m³ and can be released up to a peak height of 1000 m.
Fig. 1: Tethered balloon with tethersonde during an experiment in the Namib Desert in Namibia | Fig. 2: Measurements of wind speed and relative humidity performed with a tethersonde in the Namib Desert in Namibia. The color coding shows the horizontal wind speed, the arrows the horizontal wind vector and the black contour lines the relative humidity. After 0000 UTC, there was saturation indicating with fog formation in the lower 300-400 m a.g.l. |
Technical specifications
Groundstation | |
Type: | Self-construction |
Frequency: | 433,0625 .. 434.7875 MHz |
Tuning steps: | 12.5 kHz |
Connections | |
Probe antenna: | 1 |
RS232 connection to PC: | 1 |
Power Supply | |
AC: | 100 V/AC to 240 V/AC |
Dimensions | |
Size: | 230 mm x 210 mm x 90 mm |
Weight: | Ca. 500 g |
Sonde | |
Weight: | Ca. 1 kg |
Size: | 240 mm x 150 mm x 55 mm |
Battery: | LiIon/Alkali |
Transmission-rate: | 4.8 kbps |
Modulation: | Narrow band - FM |
Error correction telemetry: | 4 bit Forward Error Correction / CRC |
Parameter
Parameter | IMK-Tethered probe |
Temperature Area Accuracy Measuring interval |
HC-2 (Rotronic) -40...60 °C ± 0,1 K 1s |
Relative humidity Area Accuracy Measuring interval |
HC-2 (Rotronic) 0...100 %rF ± 0,8 %rF 1s |
Air pressure Area Accuracy Resolution |
Barometer MS5611 (Amsys) 10...1200 mbar ± 1.5 mbar 0.012 mbar |
Wind speed Area Resolution |
3 bowls-Anemometer (Kroneis Typ 260/LP) > 0.3 m/s – 0.4 m/s < 0.1 m/s |
Wind direction Area Accuracy Resolution |
Elektron. compass (Jenoptik JOK60) 0 ° .. 360 ° ca. 1 ° 0.1 ° |
Telemetry Frequency processing Frequency Modulation Modulation frequency / data rate Transmission power Reach Antenna / polarization |
139 Kanal PLL-Synthesizer 433.0625 .. 434.7875 MHz GMSK, BT=0,3 4,8 kBps 10 mW 2 km Rodantenne λ/4, linear, vert. |
RS232 interface -Occupation rules -Plug connectur -Baud rate -Format |
DCE, without Handshake SubD 9 polig 19200 ASCII–Sign |
General Construction Power supply Voltage Generation Uptime Weight |
Milled Styrodur housing, several assemblies LiIon 10,8V / 2,15 Ah Downward switching regulator 10 h 700 g |
Battery Pack Technology Manufacturer Type Rated capacity Nominal voltage Maximum charging voltage Maximum charge / discharge current Recommended charge current Range discharging Minimum temperature for charging |
Lithium - Ionen BMZ GmbH 3S1P CGR18650C, make Panasonic 2,15 Ah 10,8 V 12,6 V 2,15 A 1,1 A -20 .. +60 °C 0 °C |