Principles of tracing buried utilities

An extensive underground utility network feeding energy and data to ever expanding cities, lie just below the ground. This invisible transport hub delivers electricity, gas, water, telecoms and fibre-optics powering our modern day lives.

Utility providers are investing significant amounts to improve their utility records. Digital technology allows asset owners to understand their networks, reduce risk and improve operational efficiencies. If a utility is recorded incorrectly, excavation teams may cause damage to this utility or nearby utilities due to inaccurate records. For this reason utility companies and their associated contractors are increasingly requesting cable locators to be precise, flexible and familiar.


A simple non-intrusive utility tracing survey undertaken prior to the commencement of site work can provide clear and accurate results on the amount and location of buried services and other possible sub-surface hazards. This can:

  • significantly reduce the health and safety risk
  • allow informed planning for future work
  • help avoid damaging the buried apparatus thereby reducing downtime and costly repairs
  • ensure that best practice and regulations are followed
  • accurately target intrusive investigations
  • minimise disruption to the site work and also to members of the public

State-of-the-art Digital Signal Processing (DSP)

Sensing the smallest signals from buried utilities in congested areas is a technical challenge. Cable location instruments need to detect, process and alert operators about the presence of a signal without over complicating the detection process.

Leica has developed Digicat XF-series with a powerful state-of-the-art digital platform, removing the reliance of analogue dials to control the signal sensitivity, which requires constant adjustment throughout the detection process.

Leica’s Digital Signal Processing (DSP) electronically analyses the signals from utilities, processing through powerful algorithms to filter out noise and distortion. The results deliver a clearer, cleaner signal output.

Large intuitive display

All Leica Digicat models benefit from a large screen detailing both a graphical and numerical Signal Strength Indicator (SSI). This combination provides greater pinpointing accuracy allowing the operator to find a peak reading over a utility irrespective of the signal strength.

Mode Lock

Mode lock allows the user to set the locators default start up setting to either the last mode used for scan continuity or power mode for safety.

Measuring signal current

The transmitter is used to apply a signal to the target line, the signal will reduce gradually in strength as the surveyor moves away from the transmitter and also couple on to other utilities.

When tracing a utility in congested environments, the locator may detect signals from an adjacent utility. The line with the highest current measurement (mA) will be the target utility.

Measure the signal current from a Leica Digitex xf signal transmitter with a Leica Digicat xf locator.

Increased Depth Readings

All Digicat XF models provide increased depth readings allowing operators to trace the location and path of deep sewer drains to a depth of 9.9 meters when using a sonde.

When tracing underground CCTV sewer cameras, the Digicat XF-series provides greater flexibility with 8kHz, 33kHz, 512Hz and 640Hz trace options.


Download your white paper – “Principles of tracing buried utilities” here.

Written by Anabela Ferreira Fernandes, Marketing Communications Manager at Leica Geosystems

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