Critical Infrastructure Protection Starts at the Perimeter
Critical infrastructure sites are constantly at risk of vandalism, theft and attack. There are also concerns for regulatory compliance and for liability associated with trespassing. By adding deterrence and detection measures at the perimeter, such as fence sensors, intelligent lighting, and video analytics, intruders can be stopped before they cause damage to property or hurt themselves.
Deployed on their own or in multi-layered combination, perimeter security solutions can protect critical infrastructure sites of all sizes.
Detect Intruders Before They Get Inside
Perimeter intrusion detection systems are a first line of defense against intrusions. While there are many types of sensor technologies that protect perimeters, some are more suitable for critical infrastructure protection than others. When looking at different systems, consider these factors:
• Coverage – Does the system protect the entire perimeter (e.g. no blind spots)?
• Probability of detection (Pd) – Does the system quickly and accurately detect attempts to breach the perimeter every time?
• Nuisance alarm rate (NAR) – Does the system only generate alarms for real or simulated intrusion attempts? If the system generates alarms during normal conditions or high winds, security may start to suffer because of responder complacency.
• Ease of installation and configuration – How easy is the system to install and configure? Can the system be configured remotely from an equipment room so maintenance staff can avoid travelling out to the perimeter whenever an adjustment is required?
• Integration with Security and Video Management Systems (SMS/VMS) – Can the information generated by the system be presented in a way that improves situational awareness? For example:
o Can the SMS/VMS display the precise location of intrusion attempts on a map?
o Can the alarms be integrated with the VMS for automated camera control?
o Is there full logging of activity so that incident reports can be generated?
• Cybersecurity concerns – Can the system be hardened to keep physical security systems safe against computer-based attacks?
Fence-mounted sensors turn existing fences into smart fences by detecting and locating attempts to cut, climb or lift the fence fabric. They are durable, cost-effective, field-proven, difficult to defeat, and work reliably in all weather conditions. When an intruder is detected, the generated alarm (which includes the intrusion zone or precise location) can be used to trigger other on-site security resources, including PTZ cameras, as well as deterrence devices like sirens, loudspeakers, and/or security lights. The system can be managed by security personnel at a centralized monitoring station, enabling them to assess the situation remotely and respond appropriately.
Fiber optic-based fence sensors are a popular choice for critical infrastructure sites, especially those with longer perimeters. These sensors are non-conducting, intrinsically safe in explosive atmospheres, and immune to lightning and EMI. Often with support for extended coverage distances, a single unit installed indoors in a safe location can protect a facility’s entire perimeter. Using advanced sensing techniques like Coherent Optical Time-Domain Reflectometry (C-OTDR), the systems offer high-value security features such as precision ranging, environmental compensation algorithms, and cut immunity.
Precision ranging, a major technology improvement over previous generation “block” sensors, provides many benefits. Not only can intrusion location information be used to direct surveillance cameras, but it also enables sensitivity levels to be adjusted for specific areas of the fence (for example, to accommodate for changes in fence construction). Ranging capabilities can also reduce nuisance alarms, as the system can distinguish between site/area-wide disturbances caused by high winds and a legitimate intrusion attempt. Finally, ranging reduces operational costs by enabling maintenance staff to quickly locate and resolve issues.
A common concern with fence-mounted sensors is what happens in the event of a cable cut. When this happens, either accidentally or in an attempt to defeat the sensor, the system immediately reports the incident, including its exact location. Moreover, systems based on time-domain reflectometry technology retain the ability to detect and localize intrusions up to the point of the cut. When installed in a redundant-loop configuration, the sensor becomes cut-immune and continues to provide detection on the full perimeter even after a cable cut.
Gates along a perimeter fence, typically equipped with electronic access control and closely monitored via surveillance cameras, can also be enhanced with perimeter sensors. Swing gates can use the same fence sensor protecting the perimeter by routing the cable onto each moving panel (the cable is trenched from one side to the other). For sliding gates other technologies are more effective. If the area can be viewed from a clear, overhead location, virtual detection zones can be monitored via outdoor people and vehicle tracking video analytics. Another solution is wireless gate sensors, where an embedded accelerometer analyzes gate movement in three-dimensions, enabling the sensor to distinguish between gate activity, intrusion attempts, and environmental conditions. The sensor communicates with a nearby processor over an encrypted and monitored wireless link. If a suspicious event occurs – intrusion attempt, communication link failure, or an attempt to remove the sensor from the gate – an alarm is immediately generated.
Intelligent, low-voltage lighting is a new trend in perimeter security. Installed on fences outside of designated hazardous areas, LED-based luminaires provide uniform, targeted wide-spectrum illumination along the fence line. This improves the quality of video feeds by avoiding hot spots while a high Color Rendering Index (CRI) value means colors are accurately shown, greatly assisting security personnel with identification. LED-based lighting also dramatically reduces electrical consumption while a 10-year-plus lifespan virtually eliminates maintenance.
These benefits are useful but how do they relate to perimeter sensors? This is where “intelligent” comes into play. Sensors embedded in the luminaires themselves detect the fence vibrations caused by someone attempting to cut, climb or lift the fence fabric. In addition to notifying the SMS/VMS, the luminaires in the immediate area can instantly switch to full power or strobe. Knowing they are detected, potential intruders may rethink their actions.
The effectiveness of video analytics has greatly improved over recent years, benefiting from today’s higher performance/lower cost computing resources, as well as HD cameras with impressive low-light, infrared and thermal capabilities. Advances in computer vision research have led to the development of sophisticated video analytic software optimized for outdoor/indoor people tracking, left/removed object detection, PTZ auto-tracking, face and license plate recognition, crowd detection, and more. These software modules may be included as part of a VMS or embedded on individual cameras.
Rather than being an alternative to traditional fence-mounted sensors, video analytics offer a new set of technologies that greatly enhance perimeter security at relatively low cost. For example, video analytics can leverage a facility’s existing camera infrastructure to detect and track people near both sides of perimeter fences, providing early warning of potential security events before they can occur.
Video surveillance footage showing a site protected by both an outdoor people tracking video analytic and an intelligent lighting system.
Cybersecurity of Physical Security Devices
Whenever physical security devices are deployed, they themselves have the potential to become cybersecurity targets, often with the intension to be used as a springboard for targeting other critical systems. To keep physical security devices from introducing new vulnerabilities, site owners and integrators should ensure:
• Security devices are physically protected against tampering, as well as being configured to generate alarms if tampering does occur
• Inter-device communications are separate from external network connectivity
• Software applications use encrypted communications
• Software vendors conduct Penetration Testing (PEN Testing) by reputable third parties
Increased Security, Increased Public Safety
Perimeter intrusion detection technology, including fence-mounted sensors, intelligent lighting, and integrated video analytics can help meet the goal of reliably detecting attempts to bypass perimeter fencing and gates. The key concerns when evaluating these systems for use at critical infrastructure facilities is to ensure they reliably detect intrusion attempts while avoiding false alarms, avoiding blind spots and other security gaps, are cost-effective for sites with long perimeters, and can be properly integrated to enhance overall security response capabilities while not exposing the organization to additional cybersecurity risks. Implementation of the appropriate physical technology along with security practices can help mitigate risks to environmental and public safety.
Senstar Product Manager Stewart Dewar discusses how fence sensors, intelligent lighting, and video analytics can provide early warning of potential security events before they occur.