Advanced inspection of photovoltaic installations by aerial triangulation and terrestrial georeferencing of thermal/visual imagery


We introduce aerial IR/visual image triangulation for inspection/diagnosis of PV plants.

We introduce terrestrial IR/visual image georeferencing for inspection/diagnosis of PV plants.

Several defective modules in two PV systems were successfully detected and diagnosed.

Additional IR, I-V and electroluminescence measurements validated the results.

Complete fault diagnosis for PV plants, based only on IR imaging, is the following step.


Towards tackling the evident practical challenges of fault detection and diagnosis for PV modules, especially in large-scale installations, this paper proposes two different techniques for advanced inspection mapping of PV plants; aerial triangulation and terrestrial georeferencing. The former uses data of aerial thermal/visual imagery of operating PV modules, obtained by an unmanned aerial vehicle (UAV), to generate static “inspection maps”, in the form of true orthophoto mosaics. On the other hand, georeferencing is used to associate terrestrial thermal/visual imagery, obtained at distinct positions in a PV plant, with geographic data. By such way, inspection is based on a dynamic virtual map of the installation. Both mapping techniques were tested in two grid-connected PV systems, of a total installed power of 70.2 KWp. Several defective modules were easily and accurately detected, typically as abnormal temperature profiles, in the infrared (IR) spectrum. In addition, specific thermal image patterns of operating modules, were validated and quantified by additional diagnostic measurements, and were assigned to possible fault types. On the basis of the experience feedback, the potential of the proposed techniques and their limitations, for further application to PV plants of larger scale, are also discussed.


  • PV plant;
  • Inspection;
  • Fault diagnosis;
  • Thermal imaging;
  • Triangulation;
  • Georeferencing

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