Georadar (ground penetrating radar) survey is a special diagnostic technique based on electromagnetic waves: they are sent on to the surfaces to be monitored and they are received back with different reflection due to the dielectric characteristics of the elements they went trough. Resolution and depth of the survey depend on the type of ground to be analysed and on the frequency of the impulse sent. This method is of use for locating and determining depth of claddings, caves, cracks, metallic elements and any other objects with a sensible dielectric contrast. In addition, this type of equipment, is specially used in archaeological surveys, for foundations and underground structures survey, for mapping technological urban plants (and to detect any pit and foreign material in them), as well as for monitoring humidity in walls and other materials.

Any preservation and restoration design of an historical building may not avoid the analysis and monitoring of the structure shifts, either during the restoration works, either after the works are over. The instruments used for this task allow to make computer checks (also from distant central stations) of: horizontal shifts, settlings, gradients, rotations, bending, stress, pressure, temperature and levels. Moreover these instruments of special accuracy and sensors may be applied for monitoring structures like dikes, bridges and large structures.