Extensive ionospheric studies were conducted to support the initial phase of system design approval for the existing SLS-4000 GBAS installed at Antonio Carlos Jobim International Airport (formerly Galeão International Airport) (GIG) in Rio de Janeiro, Brazil. This paper focuses on determining the broadcast value of the standard deviation of vertical ionospheric gradients (or ) that is required to bound ionospheric spatial gradients in Brazil under nominal conditions during daytime hours. The time-step method is useful for gaining sufficient samples at distances less than the physical separation distance of ground stations and was utilized to estimate ionospheric spatial gradients. A new method called “geometric similarity” was developed to estimate ionospheric temporal gradients and evaluate the temporal effect added to the bounding values. As a result, a of 13 mm/km, including a temporal gradient contribution of approximately 2 mm/km, is conservative enough to bound ionospheric spatial decorrelation for daytime GBAS operations in Brazil.

中文翻译：

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巴西 GBAS 白天运行的电离层空间去相关评估

进行了广泛的电离层研究，以支持安装在巴西里约热内卢安东尼奥·卡洛斯·乔宾国际机场（前身为加利昂国际机场）（GIG）的现有 SLS-4000 GBAS 系统设计批准的初始阶段。本文重点确定垂直电离层梯度（或) 在白天的名义条件下限制巴西的电离层空间梯度。时间步长方法可用于在小于地面站物理间隔距离的距离处获得足够的样本，并用于估计电离层空间梯度。开发了一种称为“几何相似性”的新方法来估计电离层时间梯度并评估添加到边界值的时间效应。因此，a为 13 毫米/公里，包括大约 2 毫米/公里的时间梯度贡献，足以保守巴西白天 GBAS 操作的电离层空间去相关。