Networked quantum sensor for geolocation of anomalous underground ferrous sources

OUSD (R&E) MODERNIZATION PRIORITY: Quantum Science TECHNOLOGY AREA(S): Sensors, Electronics and Electronic Warfare OBJECTIVE: Detect and geo-locate subterranean tunneling activities by using a quantum networked magnetometer. DESCRIPTION: In challenging environments, the DoD needs the capability to distinguish hidden threats in subsurface environments. These threats manifest as hidden, dynamic, and ferrous materials violating the perimeters of sovereignty. Quantum magnetic sensors have surpassed conventional sensors in demonstrating higher sensitivity and lower SWaP. However, these sensors have yet to convincingly demonstrate a relevant DoD mission in terms of geolocation and detection at a judicious range. The DoD recognizes that one stand-alone sensor is not adequate to detect these anomalies, but rather an array of sensors working in unison is required. Therefore, DoD seeks networked sensors with algorithms and signal-processing techniques demonstrating real-time geolocation, identification, and dynamic tracking of threats. Of particular interest is harbor defense, FOB protection, and border security. This effort is not intended to fund magnetometer development but rather experimental demonstrations that isolate signals of interest from noise to ascertain geolocation from the surface within 10% error underground and/or undersea. Furthermore, limits of range of detection given configuration of an array is of high interest to the DoD. Pathway towards further development to a much bigger network of sensors globally should be addressed at the conclusion of this work. PHASE I: To qualify for Direct to Phase II, sufficient evidence of a previous externally funded effort that specifically addresses detection of underground activities is needed. Any final reports, findings, publications must be included in the proposal. PHASE II: In order for this project to be successful, detected signals from tool movement inside a tunnel must be processed and adapted to the inverse propagation model with accurate geo-location. This effort does not repeat sensor development, but rather focuses on algorithm development and system integration to increase the technology readiness level (TRL). To accommodate algorithm development, it is desirable to set up a prototype system at a remote tunnel site for continual collection of data to verify and fine tune the physics model for geo-location. Although the geo-location algorithms worked in previous testing for simple sources with predictable magnetic fields, geo-location of hand tools was not as successful. The Phase II effort should significantly extend the system's ability to detect the use of hand tools in a subterranean environment. We are also looking to find ways to minimize sensor deployment but maximize detection range. PHASE III DUAL USE APPLICATIONS: If the project is successful, Phase III can be extended to undersea for port surveillance, PBIED detection, and border protection for illegal drug movement underground (between US/Mexico border etc.) REFERENCES: L. G. Stolarczyka, R. Troublefielda, J. Battis. Detection of Underground Tunnels with a Synchronized Electromagnetic Wave Gradiometer , Proceedings of SPIE Vol. 5778, doi: 10.1117/12.609623. L. Chen, Y. Feng, P. Wu, W. Zhu and G. Fang, "An Innovative Magnetic Anomaly Detection Algorithm Based on Signal Modulation," in IEEE Transactions on Magnetics, vol. 56, no. 9, pp. 1-9, Sept. 2020, Art no. 6200609, doi: 10.1109/TMAG.2020.3005896. KEYWORDS: quantum sensor; atomic magnetometer; tunnel detection; networked quantum sensor