Bettinger Robert A
Department of Aeronautics & Astronautics, Air Force Institute of Technology, Wright-Patterson AFB, USA.
J Appl Stat. 2021 Dec 7;50(2):434-450. doi: 10.1080/02664763.2021.2008328. eCollection 2023.
Probability distribution functions (PDFs) of atmospheric reentry latitude predictions are shown to be bimodal for spacecraft in low-eccentricity, prograde low Earth orbits at altitudes of 300 km and lower. Using two-line element (TLE) data for initial orbit conditions, coupled with coarse estimates for spacecraft aerodynamic characteristics, parametric simulations produce bimodal distributions that suggest a greater likelihood of reentry near the latitudinal maxima of a given spacecraft's ground track. Various computational measures are used to test for and quantify bimodality in the reentry latitude data sets. Also, a method for approximating bandwidth is introduced for the kernel estimation of reentry latitude probability density. Overall, statistical analysis indicates that actual reentry latitudes are generally within 1-σ of observed hemisphere means as demonstrated by six historical reentry cases.
对于在300公里及以下高度的低偏心率、顺行低地球轨道上的航天器，大气再入纬度预测的概率分布函数显示为双峰分布。利用两行轨道要素（TLE）数据作为初始轨道条件，并结合航天器气动特性的粗略估计，参数模拟产生了双峰分布，这表明在给定航天器地面轨迹的纬度最大值附近再入的可能性更大。使用各种计算方法来测试和量化再入纬度数据集中的双峰性。此外，还引入了一种近似带宽的方法用于再入纬度概率密度的核估计。总体而言，统计分析表明，如六个历史再入案例所示，实际再入纬度通常在观测到的半球平均值的1个标准差范围内。
