Impact of anomalous ionospheric gradients on GBAS in the low-latitude region of China
Impact of anomalous ionospheric gradients on GBAS in the low-latitude region of China
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DOI：
10.1007/s10291-020-01038-2
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发表时间：
2020-10
期刊：
影响因子：
4.9
通讯作者：
Zhipeng Wang;Tinglin Li;Qiang Li;Kun Fang
中科院分区：
文献类型：
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作者：
Zhipeng Wang;Tinglin Li;Qiang Li;Kun Fang
空间去相关引起的电离层梯度是影响地基增强系统(GBAS)完整性的重要因素。采用电离层长期异常监测方法，对中国地壳运动观测网络2008-2018年的GPS数据进行了处理，并对一次典型的异常事件进行了分析验证。与楔形相比，低纬区域的等离子体气泡更能用梯形来描述。中国最大探测到的异常梯度为196亿毫米/公里，并确定异常梯度的保守上限为300亿毫米/公里。采用楔形和梯形两种方法建立了中国的GBAS威胁模型。基于这些威胁模型，我们分析了电离层梯度异常对中国低纬地区大气边界层强度的影响。结果表明，采用楔形板时，电离层异常监测仪的性能满足GBAS接近D型服务的要求。然而，对于以下情况，性能不能满足梯形情况下的要求：当飞机的速度和方向与斜率较窄的威胁模型相似时，飞机在GBAS设施受到影响之前就受到异常的影响；此外，监视性能急剧下降，可能会出现较大的差动距离误差。最后，对高危进场条件进行了详细分析，并对在低纬地区进行飞机进场提出了建议。
The ionospheric gradient caused by spatial decorrelation is a crucial factor affecting the integrity of a ground-based augmentation system (GBAS). We processed GPS data from the Crustal Movement Observation Network of China from 2008 to 2018 with the long-term ionospheric anomaly monitoring method and then analyzed and verified a typical anomalous event. Compared with the wedge, plasma bubbles in the low-latitude region can be better described by the trapezoid. The largest detected anomalous gradient in China was 196 mm/km, and the conservative upper bound of anomalous gradients was determined to be 300 mm/km. Wedge and trapezoid were applied to establish GBAS threat models for China. Based on these threat models, we analyzed the impact of anomalous ionospheric gradients on GBAS in the low-latitude region of China. The results show that the performances of ionospheric anomaly monitors satisfy the requirements of GBAS approach service type D when the wedge is applied. However, the performances do not satisfy the requirements under the trapezoid for the following scenarios: When the speed and direction of the aircraft are similar to the threat model with a narrower slope width, the aircraft is affected by anomalies before the time that the GBAS facilities are affected; moreover, the monitor performance decreases sharply, and large differential range errors may occur. Finally, the high-risk approach conditions were analyzed in detail, and we provided recommendations for conducting aircraft approaches at low latitudes.