Analysis and Correction of Atmospheric Refraction Effects on MLAT

The non-uniformity of the atmospheric medium induces the refraction effect in signal propagation, causing the bending of propagation paths and a propagation velocity slower than the speed of light. Consequently, it affects the time of arrival and, in turn, influences the performance of Multilateration systems(MLAT). This research analyze the influencing factors of atmospheric refraction and employs Innsbruck sounding data to fit a refractive index profile. The proposed model demonstrates superior performance in predicting the refractive index for the Innsbruck region compared to the three traditional models: the three-segment model, the exponential model, and the double exponential model. Furthermore, this study unveils the impact of atmospheric refraction on time difference observations and the mechanism leading to positioning errors. To address this, a novel atmospheric refraction correction algorithm based on the Taylor method is introduced and its effectiveness is verified.