HOI延迟对LEO卫星简化动力学POD的影响

通常使用无电离层(IF)线性组合(LC)消除低地球轨道(LEO)卫星简化动力学精密定轨(POD)一阶电离层延迟误差，忽略了高阶电离层(HOI)延迟误差。随着LEO卫星POD技术的发展，计算不同轨道高度的HOI延迟并探索其变化已成为进一步提高POD精度的重要手段。首先，使用国际参考电离层-2016(IRI-2016)和国际地磁参考场第13代(IGRF-13)模型，计算电离层穿刺点(IPP)位置和地磁场强度。其次，使用平滑星载GNSS数据计算电离层斜路径总电子含量(STEC)。然后，分别计算GOCE、GRACE-A和SWARM-A/B卫星的二阶和三阶电离层延迟。最后，评估了HOI延迟对LEO卫星重叠轨道分析、卫星激光测距(SLR)检核和精密科学轨道(PSO)比较结果的影响。实验结果表明：HOI延迟对LEO卫星简化动力学POD的影响大约在毫米至厘米的数量级上；HOI延迟对LEO卫星简化动力学POD外符合精度的影响分别达到0.92,0.22,0.21和0.18 mm;随着LEO卫星轨道高度的增加，HOI延迟对LEO卫星简化动力学POD的影响减小。

Effects of HOI delay on reduced-dynamic POD of LEO satellites

Ionospheric-free(IF) linear combination(LC) is usually used to eliminate the first-order ionospheric delay error of low Earth orbit (LEO) satellite reduced-dynamic precision orbit determination(POD), ignoring the high-order ionospheric(HOI) delay error. With the development of LEO satellite POD technology, calculating the HOI delay at different orbital altitude and exploring its changes has become an important means to further improve POD accuracy. Firstly, using the international reference ionosphere-2016 (IRI-2016) and international geomagnetic reference field: the 13th generation (IGRF-13) models, the ionospheric pierce point (IPP) position and geomagnetic field intensity are calculated. Secondly, the ionospheric slant total electron content (STEC) is calculated using smooth satellite-borne GNSS data. Then, the second-order and third-order ionospheric delay of GOCE, GRACE-A, and SWARM-A/B satellites are calculated, respectively. Finally, the effects of HOI delay on LEO satellite overlapping orbit analysis, satellite laser ranging (SLR) verification, and precision science orbit (PSO) comparison results are evaluated. The experimental results show that the effects of HOI delay on the reduced-dynamic POD of LEO satellites is approximately on the order of millimeters to centimeter level; the effects of HOI delay on the accuracy of reduced-dynamic POD for LEO satellites is 0.92, 0.22, 0.21, and 0.18 mm, respectively; as the orbital altitude of LEO satellites increases, the effects of HOI delay on the reduced-dynamic POD of LEO satellites decreases.