The direction finders (DF) used in Austria have a mean detection range of about 400 km. Due to the high density of direction finders in the Austrian lightning detection system some redundant information about discharges in Austria is collected. A high number of flashes is located by four or even more DF. This network configuration allows to achieve a median location accuracy better than 500 meters.
All lightning data is stored on a UNIX-workstation by the software package CATS (Computer Aided Thunderstorm Surveillance System), which was developed by METEORAGE, the company that runs the French lightning detection system.
All sensors of the Austrian Lightning Detection & Information System ALDIS have been completely renewed in 2006. Today ALDIS employs the so called LS7002 sensor manufactured by VAISALA Inc. This type of sensor is comparable with the previously used IMPACT sensor measuring angle and time. Main changes are due to fully digital signal processing. The following figure shows the locations of the eight LS7002 sensors employed in the ALDIS network. ADSL communication is used for data transfer between sensors and central processor.
CATS permanently stores the flash data in a continuous database which allows to perform data analysis for short but also for long time periods (e.g. statistics over several years).
Besides data recording, the CATS workstation is also used as a server for online users of the lightning location system. The online display runs on a PC that is connected by different kinds of communication lines to the ALDIS server.