Precise measurements of signal phase are essential for Global Navigation Satellite System (GNSS) position estimates. However, propagation through the earth's ionosphere imposes frequency‐dependent phase errors. The frequency dependence is exploited to correct phase errors proportional to total electron content (TEC) divided by frequency. Scintillation causes additional stochastic errors, which can become the largest phase error contribution. Both geometry‐free (GFCs) and ionosphere‐free (IFCs) frequency combinations are subject to such uncorrectable but generally small phase scintillation errors. A recent published study compared GPS TEC estimates derived from nominally identical L1‐L2 and L1‐L5 GFCs. The TEC errors establish an upper bound on uncorrelated single‐frequency scintillation error contributions. The measured TEC errors were verified with phase‐screen simulations. However, a known but largely overlooked phase unwrapping error affects the extraction of signal phase from phase‐screen complex signal realizations. This paper demonstrates a procedure for detecting and correcting phase‐unwrapping errors and discusses their ramifications.

中文翻译：

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GNSS信号相位，TEC和相位解缠误差

信号相位的精确测量对于全球导航卫星系统（GNSS）位置估计至关重要。但是，通过地球电离层的传播会产生与频率有关的相位误差。利用频率依赖性来校正与总电子含量（TEC）除以频率成比例的相位误差。闪烁会导致其他随机误差，这可能会成为最大的相位误差贡献。无几何形状（GFC）和无电离层（IFC）频率组合均会受到这种无法校正但通常较小的相位闪烁的影响错误。最近发表的一项研究比较了从名义上相同的L1-L2和L1-L5 GFC导出的GPS TEC估算值。TEC误差确定了不相关的单频闪烁误差贡献的上限。所测量的TEC误差已通过相位屏蔽仿真进行了验证。然而，一个已知但被忽视的相位解开误差会影响从相位屏蔽复杂信号实现中提取信号相位。本文演示了一种检测和纠正相位展开错误的过程，并讨论了其后果。