VLF Lightning Location System

The use of both time-of-arrival and direction finder techniques to locate the sources of VLF radiation from distant lightning is well established. The accuracy of the locations, especially for distances beyond several hundred kilometers, has been limited by error sources such as polarization errors, instrumental errors, and errors due to interference between flashes. The last is believed to be the predominant source of error at distances greater than 1000 km. In this context, Nova Technology Systems is proposing a Phase 1 study to design a system for measuring, recording, and locating VLF radiation from distant lightning, as well as developing the algorithms required to discriminate among multiple overlapping, although spatially separated, VLF radiation sources. The innovation is based on the use of time-of-arrival techniques to determine the direction of arrival of the VLF waveform, the use of digital signal processing techniques to extract nanosecond-scale information from the VLF signatures, and the combination of results obtained by several receiving stations to accurately determine the location of the lightning strike. Innovative DSP algorithms will be developed for the identification and location of simultaneous sources while minimizing the effect of polarization and instrumental errors.