Perimeter Security & Threat Detection

Using a combination of Rayleigh backscatter and time of flight, Praetorian determines the presence, location, intensity and frequency of vibrations along an optical fiber in real-time.
Rayleigh backscatter responds to physical vibrations imparted on the fiber by disturbances to the application. HAWK’S signal analysis software allows Praetorian to quickly determine the most likely origin of the vibration and report any nefarious signals to security personnel without notifying an intruder of their detection.
The location of vibration is determined using a “Time of Flight” calculation. When a laser pulse is emitted from the system a very fast clock is started. As backscattered light returns to the detector they are recorded for further analysis and time stamped. Due to the speed of light being constant within a fiber (approximately two thirds of normal light speed) this timestamp corresponds to a distance on the fiber.

Primary Areas of Application

Installation locations:

  • Army barracks
  • Airports
  • Prisons
  • Explosive storage areas (Magazines)
  • Country borders
  • Hazardous areas
  • Unmanned sites


  • Cyclone fence perimeter
  • Concrete, block or brick wall perimeters
  • Covert subsoil installation
  • Sterile zone monitoring
  • Gate traffic monitoring
  • Border protection
  • Barbed or concertina wire
  • Security patrol tracking

Perimeter Security & Threat Detection Function

Praetorian acts as an infinite series of microphones within the fiber recording in real-time. The system analyses an enormous amount of data using ultra fast FPGA architecture to give real-time feedback on the likely origin and type of the disturbance. Utilizing proprietary pattern recognition software Praetorian reduces the incidences of false positives normally associated with other Fiber Optic Sensors.
Praetorian uses a series of pattern-recognizing modes to detect, identify, and report nefarious movements at, on or around the perimeter being monitored.
Multiple outputs are available from simple Alarm/No-Alarm States to full digital integration such as Modbus over Ethernet and can be fed directly into existing DCS and SCADA control systems for high-speed integration. Alternatively, Praetorian can be operated directly with a keyboard and mouse through the units inbuilt Human Machine Interface (HMI).

Praetorian’s fast processing speed and pulse rate allow it to detect minute interferences that may otherwise go unnoticed. Some examples of detectable activities include:

  • Intruder movement along a perimeter
  • Intruder movements either side of a perimeter via covert sub terrain detection (Intruders cutting a fence)
  • Intruders climbing a fence
  • Vehicle movement along a perimeter
  • Digging, excavation, trenching and undermining

Unique Features

No Time Splicing
Praetorian has a number of unique features which make it a market-leading technology. Unlike other fiber sensing technologies, the field programmable gate array allows for ultra-fast parallel processing of the returned signals. Praetorian does not have to time splice or “skip” sections of time to keep up, potentially allowing a chance for an intruder to go unnoticed.
Broken/Cut Cable Immunity
One distinct advantage with the Praetorian system is that it is able to work such that it is immune to the effects of a broken or cut fiber. The unit is able to be attached as a loop to both channels on independent fibers and in the event of a cut will report the damage but continue to monitor the fiber on both sides up to the cut.
Extreme Laser Stability
Unlike systems restricted by Multimode LED light sources, Praetorian uses a highly stable laser controlled to within ±5pm allowing the system to handle two independent sensing channels of up to 40kms (25 miles) each without any loss of measurement in switching or time splicing.
No Signal Fading
In all distributed acoustic fiber sensors, the detected signal level has certain variations depending on the polarization state of the received signal which produces scattering of the signal. This scattering can be constructive interference or deconstructive interference and to date there has been no method to control this scattering which is commonly referred to as signal fading. HAWK has patented an effective solution to overcome signal fading where small signals can be detected without fading.
Fiber Condition Monitoring
Praetorian is also able to monitor cable condition whilst performing its normal duties. The condition of the return signal at commissioning is recorded and Praetorian regularly compares current signals to this commissioned state. Praetorian is able to determine that degradation is occurring to the cable due to age or other environmental conditions and warn the user well in advance of sensing or data transfer problems occurring.

Additional Features of Perimeter Security & Threat Detection

  • Standalone hardware capable of detecting and generating alarms
  • Multi-sensing capability - DAS (Acoustic) + DTS (Temperature) + DSS (Strain)
  • Multivariable analysis minimize false positives
  • Automatic signal calibration
  • System interlock - optional laser shutoff in case of cable break
  • End of fiber detection to ensure fiber length
  • Real time fiber + connector quality monitoring
  • Temperature compensation over full fiber length
  • Dynamic threshold in 250mm segments
  • Independent detection algorithms for static & motion tracking signals
  • 64 Bit high speed FPGA architecture
  • GIS integration capability
  • 48 point on-board multifunctional self-diagnostic feature
  • Adjustable pulse width from 10ns to 295ns
  • Very high extinction ration (more than 80dB)
  • Monitors gate open / close activities and vehicle movement

Technical Specifications of Perimeter Security & Threat Detection

Category Parameter Description
Sensing element Fiber Optic Sensing cable
Number of channels 1 or 2
Interrogator operating temperature 0 to -40ºC (32 to 104ºF)
Interrogator storage temperature -20 to -60ºC (-4 to 140ºF)
Interrogator operating humidity 10-85% @ 40°C (104°F) non-condensing
Dimensions (rack enclosure) 4RU, 19” Rack, 600mm minimum depth
Dimensions (physical) 430 x 177 x 479mm (16.93 x 5.9 x 18.85 inches)
Internal cooling 3 individually controlled fans
Weight 25kg (55 lbs)
Power supply 110-240VAC (50-60Hz), 24VDC
Power consumption <200W
Sensing range Up to 40kms (25 miles) per channel
Spatial resolution 250 or 500mm (10” or 20”)
Frequency response 1Hz-120kHz (range dependant)
Temperature sensing range (cable) -30°C to 200°C (-22°F to 392°F) (special options for temps up to 800°C (1472°F) and down to -200°C (-328°F) available)
Light source Laser (infra red) class 1M/td>
Laser wave length 1550.12nm (nanometers)
Laser stability ±5pm (picometers)
Acquisition rate 400MHz
Processor transfer rate 64Bit (ultra high speed)
Operating system Linux
Output Modbus over ethernet (standard) USB
Remote interfacing Ethernet, Wi-Fi and 3G/4G enabled
Processer architecture Field Programmable Gate Array (FPGA)
Data storage (removable) 2x 2TB HDD (removable)
Data storage (internal) 128GB solid state drive