An accurate modeling method of global ionospheric TEC based on SHPTS method was constructed. This method systematically integrates related models and algorithms such as "inter-station zoning method", "spherical harmonic ionospheric model", "generalized trigonometric series ionospheric model" and "ionospheric TEC negative value processing strategy", which not only improves the accuracy and reliability of global ionospheric TEC grid in areas covered by observed data (such as land and offshore air, etc.). In addition, relatively good estimation results are guaranteed in areas not covered by observation data (such as the ocean and over the poles, etc.), thus significantly improving the overall performance of the global ionospheric TEC grid. CAS Fast Ionospheric products provide global high precision vertical ionospheric TEC information with a temporal resolution of 1 hour, a spatial resolution of 2.5° zonal and 5° longitude, a thin ionospheric height of 450km, expressed in TECu (1 TECu corresponds to 16.2 cm pseudo-distance delay on L1 frequency), and a time delay of 2 days.
Product Standard
| Specification | Description |
|---|---|
| Provider | Chinese Academy of Sciences(CAS) |
| Data Input | IGS global GNSS reference station data |
| Data Processin | Global ionospheric TEC modeling based on SHPTS method |
| System Frequency | BDS B1/B3, GPS L1/L2, GAL E1/E5 |
| Coverage Area | -90°N – 90°N, 180°W – 180°E |
| Thin Layer Height | 450Km |
| Spatial Resolution | 2.5° Lat x 5° Lon |
| Temporal Resolution | 30 minutes |
| Data Format | IONEX |
| Data Download | ftp://ftp.gipp.org.cn/product/ionex/ |
| Reference | Li et al. 2014； Li et al. 2017 |