Alternative positioning methods for advanced geophysical classification in GPS-denied environments

Abstract

This presentation will cover a Pilot Study to develop and apply LiDAR-based Simultaneous Localization and Mapping (SLAM) technology to provide positional data inputs for Geometrics' MetalMapper 2×2 data acquisition software (DAQ) during dynamic and cued advanced geophysical classification (AGC) data collection surveys in GPS-denied environments. In addition to providing positional data for dynamic and cued AGC data collection, the SLAM tool developed for this Pilot Study also allows for field navigation (e.g., returning to a geolocated position) in GPS-denied environments for other aspects of Munitions Response actions. Currently available positional data instruments (e.g., RTK-GPS) preclude the highest quality detection and clearance methods during Munitions Response actions in GPS-denied environments. While optical methods (e.g., Robotic Total Stations) are capable of meeting positional accuracy requirements for AGC data collection in GPS-denied environments, these methods’ inefficiency in field operation often leads to the selection of analog detection methods (i.e., Mag and Dig) to complete subsurface Munitions Response actions with no associated positional data. Tree cover, the most common GPS-denied environment at Munitions Response Sites (MRSs), is variable across time and across a given site, leading to varying levels of quality and efficacy of Munitions Response actions. To address this difference in quality and efficacy, recent developments in SLAM have been adapted to bring AGC-level quality of detection and clearance methods into the GPS-denied environments typically found at MRSs. The Pilot Study includes customizing existing positional data outputs for use within Geometrics’ DAQ; creating a field workflow for georeferenced SLAM positional data acquisition; validating SLAM positional data accuracy using RTK-GPS systems in in open areas (i.e., where GPS coverage exists); and conducting dynamic and cued AGC data collection, processing, and interpretation in both open areas and GPS-denied environments.