How the Lightning Networks Work

The USPLN, NAPLN, and GLN use Time Difference of Arrival (TOA) technology that employs high resolution internal timing devices and GPS timing as a reference. This design provides for a more stable accurate timing source and subsequently improved data resolution and more accurate location reports.

When lightning occurs, the lightning detection sensors triangulate to time-stamp the signal and send raw data to the TOA Systems Central Analyzer (ASP) where the data is quickly analyzed, solutions are produced, and then transformed to be sent to the user's display.

The Time Difference of Arrival technique is applied to the transmission from a radio signal source, in this case a stroke of lightning. It is based on the time differences between the receptions of a radio signal at three remote receivers at known points from a single source at an unknown point. Each signal, traveling at the speed of light, or approximately 186,000 miles per second, is time-stamped by the receivers at the three known points. The time-stamp differences are then used in highly complex hyperbolic curve generation calculations to locate the source of the unknown radio signal. In general, this method defines hyperbolic curves by their arrival time differences at the known receivers, (R1, R2, R3 below). The point of intersection of two hyperbolic curves defines the location of the source of the radio transmission (the location of the lightning stroke).

Only three receivers are needed for the hyperbolic calculations, but more than three receivers may intercept the same signal. With additional sensors, redundant information is available to improve accuracy calculations and verify the performance. Furthermore, the TOA Systems Network Monitoring Program can also use the redundant reception to automatically monitor receiver performance. The system monitoring function can evaluate if a redundant receiver that should have received, processed, and transmitted a signal’s data to the Central Analyzer did receive the data.

Lightning Detection Technology

An Overview of the United States Precision Lightning Network (USPLN)
Dr. Peter Neilley's presentation at the American Meteorological Society, Fourth Conference on the Meteorological Applications of Lightning Data, January 2009