Electricity: measuring and testing – Testing potential in specific environment
Reexamination Certificate
2001-02-13
2002-07-16
Le, N. (Department: 2858)
Electricity: measuring and testing
Testing potential in specific environment
Reexamination Certificate
active
06420862
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to identifying locations of lightning strikes.
Electronic equipment is susceptible to damage caused by nearby lightning strikes. The accurate knowledge of a lightning striking point is important to determine which equipment or system needs to be tested following a lightning strike. Existing lightning location systems can provide coverage of a wide area. For example, a lightning location system can provide coverage of an area having a 30 km radius. This system, however, has a 50% confidence region of about 500 meters. That is, the system has a 50% confidence that a lighting strike is within 500 meters of an identified location. As such, present lightning location systems cannot be used to determine whether a lightning strike occurred inside or outside of a parameter of an area of concern. One such application of a lightning location system is a space shuttle launch pad for the National Aeronautics and Space Administration (NASA). By accurately determining lightning strike locations, electronic equipment located within the launch pad area can be tested and/or reset to avoid erroneous operation.
One method of determining the location of lightning strikes uses a set of video cameras that are pointed in different directions within the area of concern. If a lightning strike occurs within the field of view of three or more cameras, the location of the strike can be determined. However, if the cameras are not pointed in the correct direction, or either an object or a heavy rain downpour obscures their field of view, it is difficult or impossible to accurately determine a striking point of the lightning. Further, this method has a relatively large uncertainty and does not facilitate an accurate location of the exact point of contact to the ground.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for the system and method to accurately locate locations of lightning strikes.
SUMMARY OF THE INVENTION
The above-mentioned problems with lightning strike location and other problems are addressed by the present invention and will be understood by reading and studying the following specification.
In one embodiment, a system to determine a location of lighting strikes comprises a processor, and a plurality of receivers coupled to the processor. Each of the receivers comprises an electric field sensor, an acoustic sensor, and a processor to provide a receiver output indicating a calculated time differential between an electric field pulse and a sound wave (thunder). The processor determines the location of lighting strikes in response to the output from the plurality of receivers.
A method is provided for determining a location of lightning strikes. The method comprises locating a network of at least three electric field sensors and at least three sonic sensors in an area of interest, and collecting lightning strike information, including a difference of the time of arrival of an electric field pulse and an associated sound wave from a lightning strike. The method processes lightning strike information recorded by the at least three electric field sensors and at least three sonic sensors, including measuring a time difference between the arrival of the electric field pulse and the sound wave at each electric field and sonic sensor. The processor uses the time differentials to produce estimates of the range between the receiver and the lightning strike. The processed information is used to determine the location of the lightning strike.
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Medelius Pedro J.
Starr Stanley O.
Borda Gary G.
Le N.
LeRoux Etienne P.
Mannix John G.
The United States of America as represented by the Administrator
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