我国中纬地区卫星信号失锁现象初步研究

Preliminary study on loss of lock of satellite signal at the mid-latitude region in China

利用山东威海槎山站(122.296°E,36.866°N)地面GNSS电离层电子总含量(total electron content,TEC)与闪烁接收机2018—2019年的观测数据,初步探索了我国中纬度地区卫星信号失锁现象及其可能的成因。依据定义的卫星信号失锁判定标准,结合全球电离层TEC数据,展示了典型的信号失锁现象并进一步开展事件分析及初步统计研究。结果表明:在太阳活动低年,我国中纬地区地面接收机捕获到卫星信号失锁现象,其持续时间从1 min到10 min多不等;信号失锁前经常出现信噪比下降、闪烁强度增强等现象。结合相应区域的Madrigal TEC数据,初步推断电离层的等离子体密度或TEC在时间和空间上的较快减少可导致信号失锁。本文研究揭示了我国中纬度地区卫星信号失锁现象的特点及可能的形成原因,具有一定的科学意义和应用价值。

The phenomenon of loss of lock of satellite signal at the middle latitude region is firstly presented by using a ground-based GNSS ionospheric TEC and scintillation receiver(Weihai, China) 122.296°E, 36.866°N, during a period of 2018-2019. Based on our proposed criterion to filtering out loss of lock of satellite signal, a couple of classical loss of lock events have been shown. Moreover, the possible reasons to inducing them are then analyzed by using the global TEC data obtained from the madrigal database. The preliminary results suggest that the loss of lock phenomenon obtained by the ground-based receiver can still happen even during periods of low solar activities at middle latitudes of China. Furthermore, the duration of loss of lock cases varies from 1 minute to more than 10 minutes.Additionally, before and after the event of loss of lock, the signal-to-noise ratio(SNR) and scintillation indices are often strongly fluctuating. Regarding the possible generation reason, the rapid decrease of plasma density(or TEC) of the ionosphere are possibly associated with the loss of lock. Consequently, this study firstly investigates the loss of lock at middle-latitude regions in China through a ground-based GNSS receiver, extending our knowledge on this harmful phenomenon and suggesting the potential application value.