Aggressive lighting [security]

A review of glare lighting systems installed on UK Government sites has identified that there were inconsistencies between installations. This prompted the study on which the paper is based. The idea of using bright light shining outwards from a secure perimeter as an aid to security is not new. The lighting is intended to provide a glare field which inhibits persons approaching the site from perceiving details within the site. An intruder will suffer a sense of uncertainty, providing the site with a measure of deterrence. The method of defining performance related specifications and their associated functional test methodologies has been limited by the requirement that measurements should be capable of being taken by non-technical staff using commercially available measuring equipment. To this end, measurements of vertical illumination are specified along a defined line outside the defended perimeter. Unfortunately, the performance parameters are more complex and depend on the relative spatial location of the observer with respect to the light source(s), together with the intensity of the sources. Both of these parameters can be difficult to measure in the field. The problem was investigated in two distinct stages. The first involved development of a mathematical model based on a theoretical analysis of the underlying science. The second stage of the work considered the implementation of such systems and included practical measurements to demonstrate the proposals