The United States Navy has been developing passive magnetic gradiometers for use in underwater mine hunting for decades, including sensor hardware, vehicle integration and detection algorithm development. Currently, analyzing the data from these systems has been the purview of a small number of analysts, making the dissemination of data collected from munitions response sites problematic. This project sought to create a toolbox within Geosoft’s Oasis montaj software package that would allow import of raw data from these gradiometers as well as access to the robust detection algorithms developed and being used by the Navy. This will increase usability of these sensors and data products, as well as developing trust in the results being presented and provided to remedial program managers.

The Laser Scalar Gradiometer (LSG) is a prototype passive magnetic gradiometer designed for underwater mine countermeasures surveys, built by Polatomic Inc. in collaboration with the US Navy. This system and its successors, mounted on unmanned underwater vehicles, are capable of detecting ferrous targets such as mines and discarded munitions. Oasis montaj is the industry standard software package for analyzing magnetic survey data and the new toolbox designed specifically for this sensor will make future analysis open to a wider audience.

Comparing the original algorithm implementation to the Oasis montaj toolbox has shown that they both yield quantitatively very similar results, which is the primary metric of success. These new software tools will be available to the community, similar to other unexploded ordnance tools created in partnership with the Department of Defense, so software costs will be low. The cost of sensor and vehicle hardware is high, but comparable to other survey equipment already in use.

The only implementation issues for this technology pair are acquiring the hardware and software required. It is likely that an organization interested in using magnetic sensors to survey for unexploded ordnance will already be using Geosoft’s Oasis montaj and should thus have access to the software tools developed here. The remaining concern will be in acquiring an appropriate magnetic gradiometer and unmanned underwater vehicle or data from one already being used. A related concern would be any raw data formatting and/or sensor geometry differences between platforms between software upgrades within Geosoft Oasis montaj.