LIAO Siming, postgraduate, majors in satellite navigation and positioning, and differential code bias estimation, E-mail: 2216063152@qq.com
The presence of differential code bias(DCB) can affect the accuracy of total electron content(TEC) calculations and pseudorange observations, thereby impacting navigation, positioning, timing, and meteorological research results.In order to accurately estimate DCB, this paper analyzes the temporal variations of GPS inter-frequency DCB data provided by the Chinese Academy of Sciences(CAS) from 2021 to 2022 and proposes an LR-KF-LSTM combined model for precise prediction and analysis of DCB. Experimental results indicate that the average absolute percentage error of this method is less than 1.9%, the average absolute error is less than 0.03 ns, and the root mean square error is less than 0.04 ns.Compared with the LSTM model, BP neural network model, and the DCB values from the CAS product, the combined model shows better prediction performance under different solar activity and geomagnetic conditions. This combined network model can effectively predict satellite DCB and also provides a reference for addressing the issue of single-day or multi-day missing data in the DCB data CAS products.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |