Extending NCAR's Graphical Turbulence Guidance (GTG) to unmanned aircraft systems (UASes) at Army test ranges

This presentation will describe how the Research Applications Laboratory (RAL) at the National Center for Atmospheric Research (NCAR) is modifying their Graphical Turbulence Guidance (GTG) so it can be applied to flights of unmanned aircraft systems (UASes) at ranges of the U. S. Army Test and Evaluation Command (ATEC).

GTG was originally developed under funding from the Federal Aviation Administration (FAA) to help plan routes for commercial aviation. Accordingly, the system's diagnostic algorithms have traditionally been optimized for numerical weather prediction models with national coverage and grid intervals of order 10 km. For most UAS flights, the relevant domains and grid intervals are at least an order of magnitude smaller, and the relevant altitudes are lower.

The first version of GTG for UASes uses gridded output from the Four-Dimensional Weather System (4DWX) developed by NCAR's RAL and deployed at eight Army test ranges around the country. GTG's diagnostic algorithms have been newly tuned for 4DWX's high horizontal resolution and its combination of physical parameterizations. Although more research is required to understand better how UASes respond to turbulence, the modified GTG is nevertheless demonstrating benefit in early testing.