Development of a Coupled Dropsonde-Autonomous Descent Vehicle System

Abstract

This paper describes the benefits of using a dropsonde to automatically provide real time wind data to an autonomous descent vehicle (ADV). Two major sources of wind error are identified: wind errors resulting from large scale temporal and/or spatial differences between forecast and actual wind columns (Type A), and small scale wind fluctuations and/or measurement inaccuracies typically in the form of measurement noise (Type B). An autonomously coupled dropsonde-ADV system was developed in which a dropsonde is released preceding the descent vehicle, with enough lead time to descend to the ground prior to release of the ADV, and automatically telemeters wind data to the ADV, minimizing the more severe Type A wind errors. Simulations of the descent vehicle’s path (computed using actual wind data) are presented to compare the coupled dropsonde-ADV system to other ADV deployment scenarios. The simulations show that the use of a dropsonde to collect wind data can significantly reduce errors in the landing location of the ADV (89% in our simulations) as compared to an ADV that uses only forecasted wind data from prior to the descent. These results quantify the value of using spatiallyand temporallyrelevant wind data, and the potential benefits that can result from incorporating a coupled dropsonde-ADV system.