Since 1983 the radar research group (previous part of the Institute of Communications and Wave Propagation) is engaged in the detection and measurement of snow avalanches using radar. The original design has been changed and improved a few times since then. The avalanche radar operates in the C-band at about 5830 MHz with a bandwidth of 6 MHz at the maximum. This frequency allows sufficient reflections caused by snow cover and therefore echo strength while at the same time the attenuation due to water and water vapour in the atmosphere (rain, snowfall and fog) is neglectible. This makes the radar an ideal instrument to observe avalanches also in those occasions where optical observation is impossible.
The avalanche radar is a Pulsed-Doppler radar system, a design which allows both the measurement of range and radial velocity.
The Doppler-frequency-shift or velocity spectra are calculated simultaneously in different (up to 100) range section - so-called range-gates. In this way the avalanche's velocity of flow can be determined and spatialized to positions along the avalanche track with an resolution of typically 50 m (if necessary 25 m is also possible but with reduced echo intensity).
The radar consists of several RF modules which - together with a PC - are mounted in a rack. In case of a transportable version this is all installed in a portable box.
At the moment 6 avalanche radars are installed in Austria of which one is used mainly at a test and research site of the Swiss Institute for Snow and Avalanche Research (SLF) in Valais. Another radar is owned by the Norwegian Geotechnical Institute which has been developed as part of an European Framework project.