A new invisible volumetric sensor for solid wall applications

Even though, chain link fences are popular in North America for property delimitation, most European countries use solid walls, i.e., brick, stone or concrete. Solid walls are also very common in detention centres, for court yard delimitation. Other applications include sensors mounted on the external wall of a stone building, where detection of intrusions by wall climbing is needed. Until recently, the sensors used had to be mounted on the facade or the top of the wall using stand offs to perform properly. The sensor discussed in the article presents interesting characteristics that allow it to address the need for an invisible solid wall sensor. Indeed, ENCLOSURE uses a single cable concept that can be mounted directly on the wail. Using a local FM broadcast tower, the field surrounding the cable is not dense and distributes uniformly along the wail to prevent problems associated with rain or ice which are a problem to other sensors. For covert applications, the single leaky coaxial cable, can be embedded directly in the mortar of the wall during its construction, or grooved into an existing wall. Recently, ENCLOSURE has been successfully installed on different wall constructions. The latest results which include brick walls for detention centres, brick walls of an archaeological site and stone wall fences for a private VIP property are very encouraging. We present results of longer term beta testing for new wall mounted and fast deployable applications. Emphasis is placed on site particularities and the treatment of site impairments for those applications.