The Electric Propulsion Electrostatic Analyzer Experiment (ÈPÈE) is a compact ion energy bandpass filter deployed on the International Space Station (ISS) in March 2023 and providing continuous measurements through April 2024. This period coincides with the Solar Cycle 25 maximum, capturing unique observations of solar activity extremes in the mid- to low-latitude regions of the topside ionosphere. From these in situ spectra we derive plasma parameters that inform space-weather impacts on satellite navigation and radio communication. We present a statistical processing pipeline for ÈPÈE that (i) estimates the instrument noise floor, (ii) accounts for irregular temporal sampling, and (iii) extracts ionospheric signals. Rather than discarding noisy data, the method learns a baseline noise model and fits the measurement surface using a scaled Vecchia Gaussian process approximation, recovering values typically rejected by thresholding. The resulting products increase data coverage and enable noise-assisted monitoring of ionospheric variability.

翻译：电推进静电分析仪实验（ÈPÈE）是一种紧凑型离子能量带通滤波器，于2023年3月部署在国际空间站（ISS）上，持续测量至2024年4月。该时段正值太阳周期25活动峰年，在顶部电离层中低纬度区域捕获了太阳活动极端事件的独特观测数据。我们从这些原位能谱中推导出等离子体参数，用于揭示空间天气对卫星导航与无线电通信的影响。本文提出针对ÈPÈE数据的统计处理流程，该流程具备以下功能：（i）估计仪器本底噪声，（ii）处理非均匀时间采样数据，（iii）提取电离层信号。该方法并非直接剔除噪声数据，而是通过建立基线噪声模型，采用缩放版Vecchia高斯过程近似对测量曲面进行拟合，从而恢复通常被阈值过滤所剔除的有效数值。最终生成的数据产品不仅提升了数据覆盖率，更实现了基于噪声辅助的电离层变异性监测。