基于拟合推估的中国区域电离层延迟精确建模方法

摘要

Grid-based ionospheric information with high accuracy is crucial to the Wide Area Augmentation System (WAAS)establishment and operation.With the specialty and complexity of the ionospheric conditions over China region,an approach is proposed to model the Chinese regional ionosphere using collocation after splitting the ionospheric delays into a de-terministic trend together with a stochastic component.The usefulness of the method is validated with GPS measurements col-lected during high-,medium-and low-solar activities over China.It follows from our analyses that,the accuracy of our method resides within 0.4-0.7 m during high-solar activity year,whereas it is reduced to approximately 0.2 m during low-solar activity year.Considering the mid-latitude area of China,the distance between reference stations can maintain about 800 km.For the low-latitude area,however,such a distance should be limited between 350 km and 450 km.%高精度的格网电离层是广域增强系统建设和应用的重要信息之一，针对我国区域电离层复杂多变的特点，本文将电离层延迟变化分为趋势项和随机项两部分，推导了利用拟合推估原理进行中国区域电离层延迟建模的基本方法；在此基础上，利用电离层活动高年、中年和低年的观测数据对方法的精度进行了详细评估。试验结果表明：基于拟合推估的电离层延迟建模方法的修正精度在电离层活动高年约为0．4～0．7 m，在电离层活动低年约为0．2 m；对于我国中纬度地区，基准站间距可适当放大至800 km 左右，而在我国低纬度地区基准站间距应保持在350～450 km 之间。