Statistical relation of scintillation index S4 with ionospheric irregularity index ROTI over Indian equatorial region
Statistical relation of scintillation index S4 with ionospheric irregularity index ROTI over Indian equatorial region
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DOI：
10.1016/j.asr.2019.05.018
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发表时间：
2019-09-01
影响因子：
2.6
通讯作者：
Majumdar, Saibal
中科院分区：
文献类型：
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作者：
Acharya, Rajat;Majumdar, Saibal
电离层闪烁会使定位性能的准确性下降，从而导致全球导航卫星系统服务的严重退化，特别是在极地和赤道区域。全球导航卫星系统服务的连续性也受到影响，因为严重的闪烁可能导致接收器失锁。在这项工作中，振幅闪烁指数S4的出现概率已统计相关的ROTI的电离层不规则性指数。为此目的，使用了安装在印度各地的GAGAN TEC网络台站同时测量的S4和TEC数据。TEC用于推导ROTI。在ROTI中不同有限范围内观察到的S4分布分别与标准参数模型匹配。这是在平静和扰动地磁条件下进行的。对数正态分布已被发现是大多数情况下的最佳匹配。匹配的对数正态分布的参数被发现系统地变化的范围内的平均ROTI值。因此，根据相应的ROTI值对这些分布参数进行建模。推导出的模型成功地验证了独立的数据和一致性建立使用统计方法。这项工作可能会发现有用的估计可能的闪烁强度S4一旦电离层的不规则性是已知的ROTI。此外，给定ROTI的观测值，如果接收机可以承受的相应阈值S4已知，则可以确定丢失接收机锁定的概率。(C)2019 COSPAR。由爱思唯尔有限公司出版。保留所有权利。
Ionospheric scintillation can cause severe degradation in the GNSS services, particularly at the polar and equatorial regions, by deteriorating the positioning performance in terms of accuracy. The continuity of the GNSS service is also affected as severe scintillation may lead to the loss of lock of the receiver. In this work, the occurrence probability of amplitude scintillation index S4 has been statistically related to the ionospheric irregularity index of ROTI. Simultaneously measured S4 and TEC data from the GAGAN TEC network stations, installed across India, were used for the purpose. TEC is used for the derivation of ROTI. The distribution of the S4 observed over different finite ranges in ROTI was separately matched with standard parametric models. This was done for both quiet and disturbed geomagnetic conditions. Log-normal distribution has been found to be the best match for most of the cases. The parameters for the matched log-normal distributions were found to vary systematically with the mean ROTI values in the range. Therefore, these distribution parameters were modelled in the terms of the corresponding ROTI values. The derived model was successfully validated with independent data and the conformity was established using statistical methods. This work may find usefulness in estimating the probable scintillation strength S4 once the ionospheric irregularity is known in terms of ROTI. Moreover, given an observed value of ROTI, the probability of losing receiver lock can be determined, provided the corresponding threshold S4 that the receiver can withstand is known. (C) 2019 COSPAR. Published by Elsevier Ltd. All rights reserved.