Characterization and mitigation of multipath fading on multi-frequency GNSS signals in urban environment
Characterization and mitigation of multipath fading on multi-frequency GNSS signals in urban environment
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DOI：
10.1007/s42401-020-00068-5
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发表时间：
2020-10
影响因子：
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通讯作者：
Rong Yang;X. Zhan;Jihong Huang
中科院分区：
文献类型：
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作者：
Rong Yang;X. Zhan;Jihong Huang
全球导航卫星系统(GNSS)接收器在室内和城市峡谷环境中存在多径干扰时，性能可能会下降。将有多个反射信号从关于附近建筑物的不同位置的不同路径和方向到达接收器天线，导致直接信号的幅度和相位的显著波动和失真。这就是所谓的多径衰落效应，通常表现出跨越信号频带的时间、空间和频率分集的随机特征。为了更好地了解多径衰落效应，在上海陆家嘴中心商务区附近进行了现场测试。对采集的数据进行处理，以表征多频GNSS信号的信号衰减和相位起伏，包括趋势码延迟、载波相位和导航误码。可以计算得到的关于幅度、码延迟和载波相位的闪烁指数，例如S4。基于这些多径特性，在多频跟踪环路的设计中，将采用频率间辅助策略进行多径抑制。实验结果验证了多频跟踪算法在城市环境中的有效性。
The global navigation satellite systems (GNSS) receiver is likely to experience performance degradation in the presence of multipath interferences in indoor and urban canyon environments. There will be multiple reflected signals arriving at the receiver antenna from different paths and directions regarding the different locations of the nearby constructions, causing significant fluctuations and distortions on the amplitude and phase of the direct signals. This is the so-called multipath fading effects and usually exhibit with the random features of temporal, spatial, and frequency diversity across the signal bands. To have a better understanding of the multipath fading effects, a live test was conducted near Lujiazui CBD area in Shanghai. The collected data were processed to characterize the signal attenuations and phase fluctuations on multi-frequency GNSS signals via the detrend code delay, carrier phase, and navigation bit errors. The resulting scintillation index on amplitude, code delay, and carrier phase, e.g.,S4,andcan be calculated. Based on these multipath features, the inter-frequency aiding strategy will be utilized for the multipath mitigations in the multi-frequency tracking loop design. The results demonstrate the effectiveness of the multi-frequency tracking algorithm in the urban environment.