A preliminary evaluation of the performance of multiple ionospheric models in low- and mid-latitude regions of China in 2010–2011
A preliminary evaluation of the performance of multiple ionospheric models in low- and mid-latitude regions of China in 2010–2011
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DOI：
10.1007/s10291-013-0330-z
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发表时间：
2014-04
期刊：
影响因子：
4.9
通讯作者：
Weihua Luo;Zhizhao Liu;Min Li
中科院分区：
文献类型：
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作者：
Weihua Luo;Zhizhao Liu;Min Li
电离层延迟是全球导航卫星系统（GNSS）的主要误差源。单频GNSS应用需要对地球电离层中的带电粒子引起的信号延迟进行电离层校正。中国北斗系统正在为单频用户开发自己的电离层模型。预计未来几年中国单频GNSS用户和应用数量将快速增长。因此，开发合适的电离层模型对于中国北斗系统和全球单频北斗用户至关重要。本文研究了全球电离层地图（GIM）、国际参考电离层（IRI）、参数化电离层模型（PIM）、Klobuchar和NeQuick五种全球通用电离层模型在中国中低纬地区中太阳活动条件下的性能。一般来说，所有的电离层模式都能再现电离层的日变化趋势。结果表明，所有模式在中纬度地区的预报性能均优于低纬度地区。将所有模型与GIM模型的实测总电子含量（TEC）数据进行比较，IRI模型（2012版）与GIM模型的一致性最好，NeQuick模型的一致性最差。以GIM TEC为参考真值的IRI模式的RMS误差在低纬地区约为3.0 - 10.0 TECU，在中纬地区约为3.0 - 8.0 TECU，在中等太阳活动水平的一年期间观测到。将所有电离层模型引入单频精密单点定位（PPP）中，对GPS观测数据进行电离层延迟改正，结果表明，在我国低、中纬度地区，PIM模型的电离层延迟改正效果最好。在中纬度地区，PIM模式的日单频PPP精度水平约为10 cm，向上约为20 cm。在低纬地区，PIM模式的PPP误差在北10-20 cm，东30-40 cm，上60 cm左右。单频PPP解表明，NeQuick模型在中国低、中纬度地区的精度最低。研究表明，PIM模型可以考虑在中国的单频GNSS用户在低纬度和中纬度地区实现良好的定位精度。
Ionospheric delay is a dominant error source in Global Navigation Satellite System (GNSS). Single-frequency GNSS applications require ionospheric correction of signal delay caused by the charged particles in the earth’s ionosphere. The Chinese Beidou system is developing its own ionospheric model for single-frequency users. The number of single-frequency GNSS users and applications is expected to grow fast in the next years in China. Thus, developing an appropriate ionospheric model is crucially important for the Chinese Beidou system and worldwide single-frequency Beidou users. We study the performance of five globally accessible ionospheric models Global Ionospheric Map (GIM), International Reference Ionosphere (IRI), Parameterized Ionospheric Model (PIM), Klobuchar and NeQuick in low- and mid-latitude regions of China under mid-solar activity condition. Generally, all ionospheric models can reproduce the trend of diurnal ionosphere variations. It is found that all the models have better performances in mid-latitude than in low-latitude regions. When all the models are compared to the observed total electron content (TEC) data derived from GIM model, the IRI model (2012 version) has the best agreement with GIM model and the NeQuick has the poorest agreement. The RMS errors of the IRI model using the GIM TEC as reference truth are about 3.0–10.0 TECU in low-latitude regions and 3.0–8.0 TECU in mid-latitude regions, as observed during a period of 1 year with medium level of solar activity. When all the ionospheric models are ingested into single-frequency precise point positioning (PPP) to correct the ionospheric delays in GPS observations, the PIM model performs the best in both low and mid-latitudes in China. In mid-latitude, the daily single-frequency PPP accuracy using PIM model is ~10 cm in horizontal and ~20 cm in up direction. At low-latitude regions, the PPP error using PIM model is 10–20 cm in north, 30–40 cm in east and ~60 cm in up component. The single-frequency PPP solutions indicate that NeQuick model has the lowest accuracy among all the models in both low- and mid-latitude regions of China. This study suggests that the PIM model may be considered for single-frequency GNSS users in China to achieve a good positioning accuracy in both low- and mid-latitude regions.