Utility Survey Corp.

EM Profiling - Technology

Electromagnetic Induction Profiling (EM) - The Technology

GSSI Profiler EMP-400 and the Trimble Geo-7X mobile GPS units - Working Together!


 Primary Technology: The primary instrument to be used for this survey will be the GSSI Profiler EMP-400. This is a powerful new generation Electromagnetic Induction Instrument with georeferencing GPS capability.                                                        

The Profiler has the benefit of GSSI’s proprietary source cancellation and calibration technology to create the greatest signal stability available over any comparable instrumen  The Profiler’s system structure, electronics and coils are designed for maximum structural and thermal stability. These key features minimize signal drift thereby maintaining an accurate zero level and system null across its full bandwidth range. The major advantage of this design is to overcome the signal drift problem that is common with other previous generation EM instruments.

Older EM type instruments do not incorporate the advanced electronics and software controls employed in the Profiler. The Profiler can therefore be relied upon to produce superior data quality, which means more accurate results.

To obtain the highest level of georeferencing accuracy, Utility Survey Corp’s Profiler is driven by a Trimble Geo-7X mobile GPS unit with 1 cm accuracy (i.e. plus or minus half-inch corrected*).


*Corrected means that the collected GPS field data must be exported to an external satellite base-station data correction service for positional adjustment, or correction. The reason for this is that raw satellite data can be affected by potential errors such as shielding; i.e. tree canopies, high buildings etc. The Geo-7X accesses the highest number of satellites to record multiple date and time-stamped longitude and latitude coordinates. The correcting process correlates and adjusts the data to ensure our data files have the highest available level of accuracy.  

The procedure is to scan the target area with the Profiler in an x-y grid pattern. Data will be collected by the Trimble Geo-7X GPS. The survey data will then be downloaded into data processing software to generate georeferenced color contour maps.  

Typical Uses for The Profiler EMP-400 include:

  • Environmental Remediation

  • Utility/UST (underground storage tanks) detection – metallic and non-metallic

  • Archaeology

  • Cemetery/Gravesite Mapping
  • Geological Investigation

  • Site Assessment

  • Ground Water Investigation

  • Septic Field Mapping

  • Agricultural Research