On The Site Error of Wide Band Magnetic Direction Finder

Abstract

A wide band magnetic direction finder is an element of the magnetic direction finding system, which is now widely used for lightning location. A magnetic direction finder exhibits systematic errors in the measurement of the bearing and the intensity of the incoming electromagnetic wave, and they are often called “site errors”. Two magnetic direction finding systems, having three direction finders each, were installed in Niigata area. The differences between two direction finders installed within several tens of meters, in the observed bearings and the amplitudes of electromagnetic waves associated with lightning return strokes, were measured. The results are explained by the theory of the quadrantal error, which is caused by nearby objects which scatter electromagnetic fields. A method to estimate site errors is proposed, and its application to the observed data draws the same conclusion, regarding the causes of the site errors at all of the three sites, as that based on the direct measurement of the differences of site errors.