All important functions of the radiosonde (initializing before take-off, processing of measured data, control of telemetry transmitter) are controlled by a micro-processor installed in the radiosonde. The calibration data for the individual sensors are stored in a non-volatile memory on the radiosonde. These are transferred shortly before take-off into the computer of the GK-90C ground station by means of the RS232 communication cable.

Sensors

The standard DFM-90 is equipped with sensors for temperature, pressure and humidity. Ozone sensors are available at special request.

Data acquisition

Besides the inputs for the standard sensors, the radiosonde is equipped with 15 additional inputs for supplementary sensors (multi-channel)

The concept of the freely prommable PLL systhesiser is of interest in particular for large-scale users with many ascent stations. By connecting the radiosonde to the ground station via an RS 232 interface, it is possible to automatically set the desired transmitting frequency immediately before take-off. This involves storing the frequency information in a non-volatile memory on the radiosonde. This affords substantial streamlining of inventories and logistics for the user because only one radiosonde type has to be stocked in a central store for all ascent stations.

As an option, the DFM-90 can be equipped with a differential GPS receiver for wind finding.

Lithium batteries

The DFM-90 is equipped with high-power lithium batteries. These batteries work without any special preparations (e.g. water activation), and thus allow very easy handling of the complete radiosonde.