Compact GPR for mapping of underground utilities

 

State of the art

 

The development of automatic detection algorithms for extracting underground assets position from Ground Penetrating Radar (GPR) data is one of the most active fields of research for this technology. The ambition is to “democratize” this market by making underground utility detection accessible to the broad market of non-expert professionals including surveyors and geospatial professionals. So far, this has led to interesting results but has not fulfilled this very ambitious objective; on this respect, the progress beyond the state of the art concerns the implementation of an “image understanding”, that generally means the automatic retrieve of contextual information from images. This is usually done with the perception of environmental elements and events with respect to time or space, the comprehension of their meaning, and the projection of their status after some variables have changed.

 

The GEOFIT solution

 

GEOFIT features a recently developed compact GPR array solution for real-time 3D mapping of underground utilities. It relies on a massive antenna array with two polarizations, providing a huge amount of data, thus dramatically increasing the detection performance and the level of accuracy of the survey. Combining these data with an accurate positioning measurement device (e.g. GNSS) it can also provide accurate location for underground infrastructures. Basing on these outcomes from recent developments, a first ambition for this section of the project is to realize a step-change in the technology by providing a method for automatically detecting most (ideally all) of the underground assets in the working area.

 

Moreover, the development of purposely-built software interfaces will enable the view of those assets in a cartographic environment and comparing with the information stored into GIS collectors and the Web Map Services (WMS); this platform will allow users to locate, map, update and share subsurface utility information simultaneously. Finally, this information on underground assets will be made available for the integration into the “GEO” domain, thus contributing to the realization of the “GEOBIM”, having BIM data (i.e. detailed data about design and construction) fed with Geo data (i.e. more general data useful for region-scale spatial analyses). On this respect, it is widely acknowledged that the integration of data from both domains is beneficial and is a crucial step forward for future 3D city modelling as well as for facing the multi-disciplinary challenges of our built environment.

 

The GEOFIT contribution

 

Translating this approach for the GPR technology, this will mean to search for meaningful features into the data by varying some parameters and to predict their value in consequence of such change; a possible example concerns the development of a library of patterns of interest and the hunt for the one best fitting in the image produced by the GPR. Thanks to this automatic recognition of objects and patterns a higher level of automation will be achieved. The interface with GIS and WMS is also meant to be used for the purpose of using supplementary sources of data (e.g. recorded position of underground assets) to provide more environmental elements for the image understanding.

 

The third development foreseen in this part of the project is the realization of a “GEOBIM”. In both the Geographic Information (Geo) and Building Information Modelling (BIM) domains, it is widely acknowledged that the integration of data from both domains is beneficial and a crucial step forward for future 3D city modelling as well as for facing the multi-disciplinary challenges of our built environment. In this case, the aim is to integrate models of retrofitted buildings and construction sites (BIM) with models of the underground situation (Geo). Besides, this constitutes a major opportunity for managing and sharing documentation about underground infrastructure; as a matter of fact, right now there is vast duplication of detection because each utility and communication company does its own scanning and potholing and the data collected is rarely shared.

 

Technology readiness level improvement: From TRL5 to TRL7