FIQUgS Innovations in Quantum Gravity Sensing: Data Processing for an Archeological Case Study

The FIQUgS project represents a transformative step forward in geophysical research, combining cutting-edge quantum gravity sensing technology with advanced software tools to enhance subsurface exploration. A landmark demonstration of these capabilities occurred in October 2024 in Lisbon, Portugal, during a collaborative archaeological study with the Centro de Arqueologia de Lisboa. This case study aimed to detect and characterize shallow tunnels and cavities from the Roman era beneath Lisbon’s historic center, leveraging the Differential Quantum Gravimeter (DQG) and a suite of sophisticated data processing software.  The work presented here aims to enter into the details of data processing from the preliminary stage of survey planning to the post processing inversion and interpretation of data.

Central to this first real outdoor application of the DQG, was the FIQUgS survey planning tool, which used statistical inference to optimize survey paths and observation point spacing. This tool minimized data acquisition efforts while maximizing the sensitivity of detection capabilities. Post-survey, the collected data underwent extensive processing using FIQUgS-developed algorithms designed to refine gravity anomaly and vertical gravity gradient measurements. The vertical gravity gradient measurements proved particularly advantageous, significantly reducing the impact of distant mass effects and environmental noise, thereby enhancing the clarity of subsurface features.  

An integral part of the data analysis was the automated inversion module, which used the processed measurements to reconstruct the geometry of subsurface structures. The module successfully identified and modeled a Roman-era tunnel with an estimated cross-sectional area of approximately 5 square meters. By integrating additional geophysical data, such as digital terrain models, the inversion tool further improved the accuracy of the subsurface density distribution.  

This case study highlights the practical value of FIQUgS software innovations in real-world applications. The seamless integration of advanced survey planning, data processing, and inversion tools allowed for a comprehensive analysis of complex subsurface conditions. The success of the Lisbon study underscores the potential of quantum gravity sensors and associated software to address long-standing challenges in geophysical research and archaeological exploration. As the FIQUgS project continues to develop, these technologies promise broader applicability in areas such as mineral exploration, groundwater management, and structural monitoring.  

This achievement demonstrates the synergy between hardware and software in advancing geophysical methodologies, paving the way for more efficient and precise subsurface investigations across diverse scientific and industrial domains.