"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.
The aim of the project is to establish a low budget lightning location network with a high number of stations. The price for the hardware currently is less than 300 Euro. The sferic positions are free accessible in raw format for all users that transmit their data to our servers. The station owners can use the raw data for all non-commercial purposes. The lightning activity is additionally displayed at our website on several public maps in real-time. The average delay is between 3 and 20 seconds depending on the load of our servers.
For the recording of the signals we have developed a special detector. This consists of several amplifiers and a digital part for processing and forwarding of data to our central processing server. To keep the cost of potential participants as low as possible, the participants should try to get as much as possible of the necessary electronic parts from local providers.
The community "Blitzortung.org" is primarily aimed to individuals with an interest in meteorology and competencies in electrical and computer engineering. For the construction and operation of a lightning detector a basic understanding of the used reception technique is necessary.