Lightning strikes detection methods

Mostly used lightning detection method in the past was Magnetic Direction Finding (MDF) method. Method was based on detection of  lightning strike electromagnetic wave direction. Later, Time Of Arrival (TOA) method was developed. TOA method measures time difference from lightning strike hit to lightning strike detection by sensor. Based on that time, distance of lightning strike form sensor to lightning strike hit point is determined. Modern sensors nowadays uses combined method for lightning strike detection. With combined method time and location of lightning strike is accurately determined.

Magnetic Direction Finding (MDF) method

To determine lightning strike location with MDF method at least two sensors are needed. Sensors detect azimuth (angle between north and direction towards lightning strike) between the sensor and lightning strike hit. That is the way to determine line through the sensor and lightning strike hit point. With at least two lines (from two or more sensors) intersection of those lines is calculated. Intersection represents the exact logacion of lightning strike hit.With the use of several sensors we reduce the lighting strike position ofset.

In the above picture is shown how we determine the direction toward lightning strike. Elecric field caused by lightning strike, causes the magnetic field (vector marked with B). The magnetic field is always perpendicular to electric field, so with the determination of magnetic field, lightning strike direction is determined. With two or more sensors the exact location of lightning strike can be calculated.

in some cases, when lightning strike hits somewheare on line between two sensors, location can not be determine only with two sensors. In that case at least three sensors are needed.

Time Of Arrival (TOA) method

Combined method

New generation of sensors uses TOA and MDF method. This method is also named Combined method. Those sensor provides azimuth between sensor ang lightning strike hit point and exact UTC time. With those sensors exact time and location of lightning strike is determined.

This method has no problems that are specific to a particular method. With using Combined method only two sensors are enough to determine lightning strike position. More sensors contributes to accuracy of lightning strike time and position.

First dirrection vectors are used for ligtning strike position evaluation, then with the time differences the exact lightning strike location is determined.