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Hawk Measurement Praetorian Fiber Optic Sensing Pipeline Monitoring and Leak Detection

The Praetorian Fiber Optic Sensing System can be installed on a buried or unburied pipeline and can immediately detect pipeline leakage, ground disturbances, manual and machine excavation, theft, hot tapping and vehicle movement. The Fiber Optic System continually monitors large spans of pipeline, looking for vibration and temperature changes. Once a detection occurs, the system alerts the operator or security personal to the exact location of disturbance in the pipeline. This type of real-time intelligent monitoring is critical to operating efficiently and protecting valuable assets.

Principle of Operation:

The Praetorian emits a laser pulse down a fibre optic cable to measure vibration and temperature as well as the position of that vibration and temperature. Using a combination of Rayleigh backscatter, Brillouin Backscatter* and time of flight, Praetorian determines the presence, location, intensity and frequency of vibrations and temperature changes along an optical fibre in real time. Rayleigh Backscatter responds to physical vibration imparted on the fibre 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 erroneous signals to maintenance personnel of potential issues with the pipeline. Brillouin Backscatter* responds to shifts in environmental temperatures and is used to detect the temperature drop associated with the reduction in fluid pressure caused by the leak taking advantage of the Joule-Thomson effect.

How does it work?

Distributed Acoustic Sensing (DAS) continuously monitors Vibration, Sound and Acoustic Energy along the fiber using a process called Rayleigh Backscatter along the entire length of an optical fiber. Using a “time of flight” calculation on the laser pulse the position of any incoming signal can be determined to within a meter on up to 80 kilometres (50 miles) of fiber.

Distributed Temperature Sensing (DTS) and Distributed Strain Sensing (DSS) work in a similar way, but use a looped fiber within the sensing cable to detect both Temperature and Strain. The laser is sent down both sides of this loop and the interference pattern allows for Brillouin Backscattering to be measured revealing changes to Strain and Temperature within the fiber.

Praetorian has a built-in Field Programmable Gate Array (FPGA) which quickly records, processes and analyses the data collected by the system and detects and reports signals generated by problematic events within the environment.


  • Praetorian can function on applications where either the product is invisible (gas) or the pipeline cannot be visually inspected (buried).
  • Immune to the effects of a broken or cut fiber
  • Fiber optic sensing detects not only the presence of the leak but its specific location.
  • Self-diagnostics monitor the unitÍs condition and maintain optimum performance
  • No maintenance or calibration require after commissioning
  • Monitor up at 80km (50mi) at the same time.
  • 24/7 real-time monitoring

What does Praetorian tell me?

Praetorian has a built in Human Machine Interface (HMI) and can be operated directly or connected to existing Control Systems (such as SCADA) via a digital communications protocol (Typically TCP/IP) and report:

  • The location of the alarm
  • The classification of the alarm
  • The alarms longitude and latitude
  • The intensity of the alarm
  • A time and date stamp of the alarm
  • And other detected conditions depending on the specific application

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