Photo-electric lightning detector apparatus

Abstract

The apparatus is used primarily to monitor the occurrence of lightning diarges in the vicinity of a known objective such, for example, as a large rocket launch tower or other object which might be detrimentally affected by the lightning. A continuous, linear single-axis, position-sensing photodiode is deployed a predetermined distance from the objective and an optical objective lens focuses a relatively narrow field of view, such as a 40.degree. field on the photodiode. The arrangement is such that the image of a lightning discharge occurring within the field of view is in the form of a focussed narrow-line channel bisecting the length of the photodiode at varying locations dependent upon the actual location of the lightning discharges itself. In a conventional manner, the photodiode produces two signal outputs each corresponding in magnitude to the particular location of the bisecting channel image of the lightning. Using the fractional distribution of these signal outputs, the angle to discharge (.psi.) readily can be computed using a simple analog circuits or other desired means. This angle to discharge determines the proximity of the discharge to the object to be monitored. By use of an array of photodiodes spaced one from the other at a known distance, the vertical speed of propagation of the lightning can be determined, this speed being a function of the time lag or delay in the outputs produced by each of the spaced photodiodes.

Dependencies are inferred from the claim text.