While a fence or wall of some sort is still the foundation for a perimeter solution, a simple barrier is not a sufficient defence against the continual criminal onslaught against estates (and everywhere else). And if one considers the expected further decline in the economy, the onslaught is only going to get worse.
Traditionally, a perimeter has been defined by a fence or wall of some sort, which was supplemented with electric fencing with zone alarms and eventually visual and/or thermal cameras. However, there is another option for perimeter security – fibre-optic cables that use acoustic (vibration) information to determine what is happening on your perimeter (of course, the cost of fibre is an issue and we have local companies who do the same task with copper cabling).
Using fibre cables attached to a fence or even underground can provide accurate information on a breach or potential breach, even to determining the number of people or vehicles near the fence. But how have these cable defences changed over the years? Are they reliable enough to use to ensure the safety of people or as another layer of perimeter security?
Reliable and effective, fibre or copper
Cliff Rose, managing director of AcoustAlert, says that fibre-based Perimeter Intrusion Detection Systems (PIDS) are available to complement security arrangements on the perimeter fence, which may already have an electrified fence element. “In fact, it is good practice to have more than one level of detection on a perimeter fence, especially if the only element is electrified fencing,” says Rose. “Other layers now more commonly used are CCTV cameras with analytics, which may include line crossing, human and/or vehicle detection as well as the so-called self-learning behaviour analytics.”
While most people assume PIDS means using fibre-optic cables, Rose says fibre and copper cables do a similar job and can be used with or without an electric fence. However, “neither fibre nor copper has the potential deterrent value of a high-voltage shock”.
These technologies are still versatile and can, for example, be used on mesh-type fences to detect tampering with the fence or as an early warning system for an impending intrusion. These PIDS are also adept at detecting digging under a fence, where electrified fencing cannot. For under-dig detection, either fibre or copper systems can be used.
Stuart Large, product line director and business development at the Fotech Group, adds, “Systems based on Distributed Acoustic Sensing (DAS) technology have been deployed to protect many assets around the world and thousands of kilometres in total. Fotech’s LiveDETECT solution is protecting military installations, civil airports, government buildings and other key infrastructure”.
In addition, LiveDETECT has been deployed to detect people or vehicles illegally crossing international borders, preventing people-trafficking or the smuggling of contraband. Whether it is for a perimeter or a border, fibre-optic cable is deployed strategically to detect intrusions. It can be mounted on a physical barrier, such as a fence or wall, where people are detected climbing the barrier or attempting to cut through it, or buried in the ground where footsteps, vehicular movements, digging and tunnelling activities are of concern.
“The DAS system converts the fibre-optic cable into a series of thousands of vibrational or acoustic sensors. The system is very sensitive and therefore detects small disturbances caused by the previously mentioned events,” explains Large. “Software algorithms process the data in real time to identify what events are really occurring and discriminate them from other disturbances, such as the wind or rain. This ensures confidence in the system by providing alarms to the security in a timely manner and minimising false alarms. Alarms are reported with an accuracy of a few meters and shown on a map to facilitate a direct and rapid response.”
The cost factor beyond the wire
Rose adds that the problem implementing a fibre solution is the high cost of the 'field processing unit', although the cost per meter becomes more palatable the longer the fence that needs protection is. Another issue with fibre is that a cut in the fibre can disable large lengths of fence from being protected until a specialised technician comes along to fix with a fibre splicing tool.
Therefore, he says that for shorter length fence protection, the cost for the fibre option is expensive and sometimes not justified. “On the other hand, copper based sensor cable systems (which can be more sensitive than fibre) have a much lower cost for the field processor and are cost effective for short, medium and long fence solutions. Coupled with this is the low cost to repair. which can be done quite simply requiring no special tools or skills.
“In any event shorter detection zones are preferred in order to ensure that large sections of protection are not taken out in event of cable damage.”
When it comes to the equipment required for back-office processing, Large says the Fotech LiveDETECT system comes in a standard 19-inch rack, which will reside in a suitable room. “One end of the fibre will need to be connected to the system and the other end, which may be up to 50 km away, will simply be terminated,” Large explains. “The LiveDETECT system is often integrated with another system, for example Genetec Security Center, where the alarms from the DAS-based system can be integrated with other inputs such as a camera system or radar to provide seamless management of security.”
The role of artificial intelligence
PIDS systems generally function by processing large amounts of data from which alerts are extracted and processed. This naturally leads to the question of whether and how AI can make a difference in this market as it does in the surveillance analytics market. Rose and Large approach this question from different angles.
“With PIDS, the analysis of the response from the cable (copper or fibre) as a result of vibration on the fence is the basis and ability of the field processor to analyse the frequency and amplitude emanating from the sensor cable,” explains Rose. “Certain analytics may be inherent in the field processor to disregard unwanted information and amplify wanted responses, and this is what makes a cable detection system what it is. It is unlike a CCTV camera made to reproduce the image in front of it and then using analytics or AI routines to determine ‘allowed or not allowed’ changes in the image based on direction, size, speed, contrast, colour, motion and so on.
“So unlike CCTV cameras with analytics or AI, cable sensor systems have a specific job and are not necessarily driven by AI in determining pending threats, direction, amount and so on, but will react to predetermined responses based on wanted and unwanted input from the sensor cable.”
The Fotech system employs AI and the use of machine learning is imminent. Large explains, “The DAS systems need to process a huge amount of data very quickly. A number of algorithms are used to process the data in real time and detect the unique signatures of the events we’re concerned about and report them to an alarm server, called Panoptes. Within Panoptes, events are accumulated and logic is applied to decide when to raise a green, amber or red level alarm. All of this takes place automatically, controlled by AI.
“Currently, the preferred way to optimise performance is to refine parameters within the algorithms by using real data recorded on site, so Fotech engineers will spend time on location simulating the events the system must detect and testing the performance. This culminates in a site acceptance test in front of the client. In the future, this will be further enhanced by a process of machine learning.”
AcoustAlert and the Site Manager
“As a general rule we rarely find applications for fibre solutions in the shorter to medium-length perimeter fence projects and this is primarily because of the high cost per metre for fibre solutions,” says Rose. “Coupled to this is the cost of repair and maintenance when fibre cables are damaged.
“We find our AcoustAlert system very functional and cost effective for most fence detection applications. The field units, although employing latest technology features, are easy to set up and are equally simple to maintain. AcoustAlert has simple relay interfaces to tie into any alarm or remote signalling system, or in bigger applications is simply managed over a LAN by a central PC workstation with the AcoustAlert software suite. The software has graphic capabilities for displaying your site map and alarm zoning, as well as managing other external devices through LAN based I/O controllers, which are all easily programmed to respond to input conditions and drive output responses.
“This software, Site Manager, can be used to remotely (from the guard room) open and close gates, switch lights or sirens on or off, pick up any alarms from other types of PIR and beam detectors as well as alarm conditions from electrified fences. All these alarms and responses are logged and available in a report form in order to do investigations after the event or for record.
“AcoustAlert and the Site Manager software are cost effective and made in South Africa.”
A complete solution
“Fotech can provide a complete solution comprising the LiveDETECT module which contains the DAS system and Panoptes alarm server, along with UPS, KVM and network switch along with fibre cable and the equipment necessary to install it, which might include splice boxes and cable ties,” states Large. “Fotech-trained engineers will make the installation and Fotech will be happy to provide warranty and ongoing support.
“Fotech’s system is versatile and can be configured to meet the specific requirements of each project. For example, a lower-cost solution is available for short-range installations and Fotech’s dual-channel technology can be configured to monitor the cable around a perimeter in both directions. This ensures that if the cable is cut, both sections of the perimeter loop are monitored without interruption to the perimeter monitoring solution.
“Fotech was recently acquired by BP Launchpad, a subsidiary of BP. This ensures that even in the current tough economic climate, Fotech will be able to continue to invest in continual technology development and commit to stand by our clients for the long term.”
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