Donated by Peter Saglietti - commissioned 2008
http://blitzortung.org is a lightning detection network for locating electromagnetic discharges in the atmosphere (lightning discharges) with VLF receivers based on the time of arrival (TOA) and time of group arrival (TOGA) method. We are a community of station operators who send their data to the computing servers, programmers who develop and/or implement algorithms for locating and visualizing of sferic positions, and people who assist in any way to keep the system running. There is no restriction on membership. All people who keep the network in operation are volunteers. There are no fees, terms and conditions, and no contracts. If a station stops pooling its data, the server stops providing the access to the raw data for the user of that station.
The network consists of more than 500 lightning receivers and some central processing servers. The sources of the signals we locate are in general lightning discharges. The abbreviation VLF (Very Low Frequency) refers to the frequency range of 3 to 30 kHz. The receiving stations approximately record one millisecond of each signal with a sampling rate of more than 500 kHz. With the help of GPS receivers, the arrival times of the signals are registered with microsecond precision and sent over the Internet to our central processing servers. Every data sentence contains the precise time of arrival of the received lightning discharge impulse ("sferic") and the exact geographic position of the receiver. With this information from several stations the exact positions of the discharges are computed.A community project with free lightning maps