GeoGuard: an innovative service for continuous geodetic monitoring by means of single-frequency GNSS receivers

The study of geodynamic processes, as well as the mitigation of natural hazards or those related to structures and infrastructures failure, often require to activate monitoring systems in order to reduce negative effects in terms of economic costs and security for the population and to improve knowledge about the causes and crustal movements.

One of the possible approaches to study such processes consists in the continuous determination of the position (or displacement) of a network of points placed on the surface and integral with the area of interest. In particular, different requirements in terms of temporal resolution (daily, monthly displacement solutions, etc.) or spatial resolution (number of monitored points in the study area), or accuracy of the displacement observation can be defined according to the movements to be monitored.

The use of GPS/GNSS systems to monitor the deformations is now a common practice. It is typically done by installing a network of dual-frequency receivers that provide accuracies of the order of millimeters with a latency of one day. However, the high cost of dual-frequency receivers generally limits the number of monitored points. Moreover, the complexity of a proper processing of GNSS observations requires in general a very specific knowledge which is not of interest for the final user.

In the present work, an innovative end-to-end service for the continuous monitoring of critical infrastructure and natural hazards by means of single-frequency GNSS receiver is presented.

Several pilot tests, performed to monitor both natural hazards and critical structures/infrastructures have shown the possibility to reach daily millimeter accuracy on the final estimated displacement also with low-cost single-frequency receivers.