Spatial Characteristics Analysis of Higher-Order Terms in the Ionosphere Based on Optimization Method

The paper delves into the investigation of the patterns and optimization algorithms for the correction of higher-order terms in the ionosphere. By analyzing the influence of varying geographical latitudes and hemispheric differences (north versus south) on the delays caused by higher-order ionospheric terms, it is revealed that the lower the latitude, the more pronounced the effect of these higher-order terms becomes. Furthermore, an optimization algorithm based on Slant Total Electron Content (STEC) is proposed in this study. This algorithm leverages high-precision STEC data sources to directly calculate the higher-order ionospheric terms, thereby significantly enhancing the computational accuracy. Experimental results demonstrate that this optimized algorithm is capable of capturing finer details in the variations of higher-order ionospheric effects, validating its effectiveness and reliability. This research holds significant importance for enhancing the accuracy of high-precision GNSS positioning and navigation, particularly in fields requiring stringent precision such as earthquake disaster prediction and plate tectonic movement monitoring, where it presents broad application prospects.