2022 Volume 65 Issue 6 Pages 244-252
In this study, the landing point ellipse predicted using the Earth GRAM atmosphere model and the pinpointed landing point predicted using NCEP GFS forecast data are validated using flight data for a low-ballistic-coefficient flight vehicle with a deployable aeroshell. The equations of motion in the Earth-centered Earth-fixed (ECEF) coordinate system are used for the atmospheric re-entry trajectory calculation, combined with the atmospheric model or the forecast data. The flight data of the RATS, which was launched by the S-520-31 sounding rocket, is used for validation. It was confirmed that the actual landing point is located within the 1σ landing error ellipse calculated using Monte Carlo simulation with Earth GRAM. It was found that the closer the forecast data was to the flight data, the more accurate the forecast became, and the smaller the change in the landing point for each forecast update. The maximum likelihood trajectory using the NCEP GFS forecast data available immediately before the flight is similar in shape to the actual flight trajectory, and the difference in the landing point is approximately 1 km.
