Effective Approach to Characterization of Prediction Errors for Balloon Ascent Trajectories

摘要

To comply with the objectives of a balloon flight, it is usually necessary to predict, monitor and track the trajectory. Within the framework of the Unmanned Space Vehicles program, the Italian Aerospace Research Center developed several methodologies useful to evaluate balloon mission feasibility, predict balloon trajectory, and assess trajectory prediction errors. These methodologies are based on weather forecast data obtained using the Integrated Forecast System model by the European Center for Medium-Range Weather Forecast and on the use of a proprietary simulation software for the prediction of flight trajectory and thermal behavior of zero-pressure balloons. In this paper, we propose an effective approach for the characterization of trajectory prediction error based on statistical characterization of the forecast error of the Integrated Forecast System atmospheric data (winds, temperature, and pressure), statistical characterization of the error on gas mass due to inflation procedures, and analytical error propagation of these sources of uncertainties on the balloon's velocity vector. The proposed approach allows estimating the actual trajectory dispersion once the predicted trajectory is computed using forecast data. The methodology proposed improves the trajectory prediction methodology that was successfully used during the first Dropped Transonic Flight Test accomplished by Italian Aerospace Research Center.