Herbicide Ballistic Technology: Spatial Tracking Analysis of Operations Characterizing Performance of Target Treatment

Abstract. Since 2012, the Herbicide Ballistic Technology (HBT) platform has been deployed in helicopter operations with a mission to eliminate nascent populations of the invasive plant species Miconia (Miconia calvescens DC) spreading across the East Maui Watershed (Hawaii, USA). The HBT platform is a refined pesticide application system that pneumatically delivers encapsulated, herbicide projectiles (i.e., paintballs) from long range (up to ~30m) and varying attitude. This onboard system provides accurate, effective treatment of individual plant targets occupying remote, inaccessible portions of the forested landscape. Statistics in operational performance are accomplished through GIS analyses of recorded GPS data assigned to treated plant targets. Recently, we have developed a telemetry system for HBT applications (HBT-TS) to enhance the attribute data of a target treatment. The HBT-TS integrates a hardware sensor device with the electro-pneumatic marker that is actuated by the trigger to generate time stamped, geo-referenced attribute data including, (i) target assignment, (ii) azimuth, (iii) tilt and (iv) range determined from the applicator position, for every projectile discharged. With target assignments, the HBT-TS records the exact dose applied to each target. Furthermore, the timestamps show that actual time to administer projectiles (i.e., target treatment) is a minor component of the total time on target. By tracking the orientation and distance of the discharged projectile, we are able to calculate a precise offset target location relative to the applicator position and provide a high-resolution interpretation of herbicide use rate (grams acid equivalents ha^-1) based on the known amount of herbicide contained in each projectile and the final placement on the landscape. We acknowledge the challenges of GPS inaccuracies while recording in a dynamic environment (i.e., a moving platform in extreme topography), albeit with increased precision. Regardless, the current state of the HBT-TS technology enhances operational intelligence relevant to landscape scale invasive species management.