iMet-54 Research Radiosonde

The iMet-54 Research is based on the synoptic iMet-54 radiosonde however comes with a communications port to the radiosonde allowing the connection of external sensors whose data can be transmitted along with the standard radiosonde data.

External sensor examples :

  • EN-SCI Ozonesone (link)
  • EN-SCI En-SCI Cryogenic Frost Point Hygrometer (link)

Download Brochure

System Overview

Operating Principle GPS or RDF Wind Finding
Nominal Frequencies 403MHz
Range >250km*
Altitude >30km*
Battery Lithium
Operating time > 3 hours
Weight 80 grams
Calibration Stabilioty 2 years
Power control WIreless or Push button


Tuning Range 400 – 406MHz
Output Power 200mW
Data rate 4800 bit/s
Frequency selection Wireless or push button (defaults, 402, 403, 404 & 405MHz)
Emission Bandwidth According to
EN 302 054
Sideband Radiation According to
EN 302 054
Frequency Stability ±2 kHz

GPS receiver

Type GNSS, 99 Channel
GNNS Systems GPS, GLONASS, Galileo, QZSS
Cold Start Acquisition Time 35 s (nominal)
Acquisition Time Reacquisition Time 1 s (nominal)
Horizontal Position Accuracy 3 m (CEP)


Type Bead Thermistor
Range -90°C to +60°C
Accuracy ±0.2°C
Resolution 0.01°C
Response time (still air)
Response time (6 m/s flow)
<2 s @ 1000hPa
0.7 s @ 1000hPa
Repeatability in Calibration 0.1°C
Uncertainty > 100 hPa
Uncertainty < 100 hPa
Reproducibility> 100 hPa
Reproducibility< 100 hPa


Type Thin Polymer Capacitive
Range 0% to 100% RH
Resolution 0.1% RH
Response Time
6 m/s, 1000 hPa, > 0°C
6 m/s, 1000 hPa, > -20°C
6 m/s, 1000 hPa, > -40°C
<1 s
3.2 s
20 s
Repeatability in Calibration 3% RH
Uncertainty 4% RH
Reproducibility 3% RH


Wind Speed Range GNSS derived
Wind Speed Resolution 0 to 150 m/s
Wind Speed Uncertainty 0.1 m/s
Wind Speed Reproducibility <0.5 m/s
Wind Direction Range 0 to 360°
Wind Direction Resolution 0.01°
Wind Direction Uncertainty
Wind Direction Reproducibility

Pressure (GNSS derived)

Type GNSS derived
Range 1080 to 3 hPa
Accuracy 0.5 hPa
Resolution <0.01 hPa
Response Time <1.0 seconds

Pressure (optional sensor)

Type Piezo-resistive sensor
Range 1200 to 10 hPa
Accuracy ±0.15hPa
Resolution <0.13 hPa
Response Time <8.22 milliseconds

Geopotential Height

Type GNSS derived or optional Piezoresistive
Range 0 to 50 km
Resolution 0.1m
Uncertainty 15m
Reproducibility 6m