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