General¶

The lightning location network Blitzortung.org consists of several VLF lightning receiver sites and one central processing server for each larger region. The receiver sites transmit their data in short time intervals over the Internet to our server. Every data sentence contains the precise time of arrival of the received lightning strike impulse ("sferic") and the geographic position of the receiver site. With this information from all receiver sites the exact positions of the discharges are computed. The sferic positions are made available in raw format to all users that transmit their data to our server. The users can use the raw data for all non-commercial purposes. The lightning activities of the last two hours are displayed at Blitzortung.org on several public maps recomputed every minute.

The Project¶

The aim of this project is to accomplish a low budget highly accurate world-wide lightning location network based on a high number of receiver sites spaced close to each other, typically separated by 50 km - 250 km. The stations transmit their data to a central computing server, where the strike locations are computed by the arrival times of the signals.

The station operators are volunteers who bought and assembled the hardware by themselves. There are also volunteer programmers who develop and/or implement algorithms for the location or visualization of sferic positions, and people who assist to keep the system running. There is no restriction on membership. There is no fee and no contract. If a receiver site stops pooling its data for a longer time period, the server stops providing the access to the archive of sferic positions for the corresponding user.

Blitzortung.org is completely different to other data collection platforms as for example marinetraffic.com or flightradar24.com. Ships and airplanes already know their exact position. They send their positions by radio. The information can be received with simple receivers and transferred over the Internet to a data server. Receiving and sending the received position is not time-critical and on their data server nothing needs to be calculated. The data is only collected and visualized. To receive the position of a ship or aircraft, one receiving station is sufficient.

Lightning location, on the other hand, is much more complicated. The waveforms of the signals must be sampled with high frequency (512 values at ≥500 KHz) and assigned with an accurate absolute time stamp (+/- 1 usec). The exact location of the detector is extremely important. An absolute microsecond accurate time stamp and an accurate position of the receiving detector can only be obtained by a GPS module. On computing server the signals from different detectors are adjusted and compared with each other. Each pair of signals from different detectors defines a hyperbolic curve. The intersection point of several hyperbolic curves determines the location. This is calculated on our server in a few seconds, that even professional systems do not always achieve.

Example video¶