A study on construction of ionospheric spatial threat model for China SBAS

Abstract

Finite sampling of the ionosphere from the limited number of observations will threat the integrity of SBAS (Space-Based Augmentation System). Ionospheric spatial threat model is introduced to over-bound residual errors in delay estimation for this under-sampled scenario. Ionospheric anomaly existing in low latitude areas exerts considerable influence on threat model realization. Methods are presented to construct spatial threat model for China area with data during periods of severe storms, including the modeling of variogram, selection of disturbance detection threshold and design of data-deprivation strategy. Verification is also conducted to show its applicability in SBAS with GNSS data from China and around areas from typical storm events.