The application of security-in-depth is affected
not only by the cost of equipment, installation,
and maintenance, but also by the more important
aspects of effectiveness and functionality. Certainly,
the highest consideration in an effective security
methodology is its ability to prevent unauthorized
penetration. Thus, any points of access through the
perimeter boundary should be capable of preventing
unauthorized access and be equipped to differentiate
between an authorized and unauthorized user while
reducing nuisance alarms. Access through perimeter
boundary lines can be frequent and should be efficient
to prevent unacceptable delays. Furthermore, if
a perimeter access point is not user-friendly, it may
be abused, disregarded, or subverted, thereby posing
a security risk.
Electronic sensors include motion detectors, infrared
or microwave sensors, vibration detection infrared
cameras, laser detectors, and ground-based radars. When
applying the detection principle as part of the 5D
methodology, it is important to note that all of these
sensors serve essentially the same security functions.
Although these technologies are similar to those normally
deployed for interior protection systems, they usually
come with somewhat higher installation and maintenance
costs due to the extensive outdoor distances.
PERIMETER INTRUSION DETECTION
SYSTEMS (PIDS) AND CONNECTIVITY
Perimeter intrusion detection systems (PIDS) are
designed to monitor and detect vehicle and personnel
incursions at the facility’s perimeter boundary. These
26 I ICT TODAY
systems employ either a single detection technology
that is highly optimized or a combination of separate
technologies, each providing its own unique detection
methodology that is integrated into a seamless operational
platform. In general, single-technology systems
achieve a lower probability of detecting incursion when
compared to multi-technology systems; these multitechnology
systems also achieve lower false alarm rates
(FAR) and nuisance alarm rates (NAR) by leveraging
the strengths of multiple detection modes. False
and nuisance alarms are typically caused by uncontrollable
factors, such as wind, rain, ice, standing water,
blowing debris, and wildlife and human activity
in proximity to the perimeter. There are other sources
including electronic interference, poor perimeter fence
conditions or lack of preventive maintenance.
When evaluating any technology for perimeter applications,
the FAR and NAR performance criteria provided
by the manufacturer should be part of the decision
process. When FAR and NAR performance factors are
included in the design, the recommendations typically
dictate that two or more disparate technologies should be
deployed to ensure the most effective intrusion detection
screen. These recommendations are based on the fact that
any legitimate incursion is likely to be detected by all
detection technologies. However, nuisance causes are
unlikely to trigger an alarm across all detection methods
and can be easily filtered. For example, the triggering
of vibration alarms on a fence caused by wind or rain can
be filtered out by verifying that video surveillance of that
fence section did not detect a human in the area.
What differentiates the systems deployed as part
of PIDS is the application of a broad concept called data
fusion or physical security information management
(PSIM) that offers real-time situational awareness. This
data fusion or PSIM platform leverages a wide array
of sensors, surveillance techniques, data analyses,
and communications capabilities and procedures;
outputs and findings are brought together to enhance
the ability of airport security response teams to monitor
and respond to a wide range of alarms.
New technologies are continually being developed
and introduced into the marketplace. The following
list represents the current state of technology and the
When evaluating any technology
for perimeter applications, the
FAR and NAR performance criteria
provided by the manufacturer should
be part of the decision process.