Cycle slip determination plays an important role in continuous real-time kinematic (RTK) positioning. Since cycle slips should be processed at each epoch, a fast determination method is needed for high-speed RTK applications, such as autopilot and airborne positioning, in which case high-sampling-rate GNSS data (such as 50 HZ) are required to be processed in real time. The geometry-free (GF) phase combination is one of the most commonly used combinations to deal with the cycle slips. However, the GF phase combination cannot distinguish the frequency on which cycle slips occur. Therefore, other methods, such as the Hatch–Melbourne–Wübbena (HMW) combination, are usually adopted to determine the frequency and the size of the cycle slips. Since noisy code pseudorange measurements are introduced, it is difficult to identify the small cycle slips, especially when cycle slips occur in multiple satellites and multiple frequencies simultaneously. In this contribution, a modified geometry-free (MGF) phase-only linear combination is proposed to quickly determine cycle slips for high-sampling-rate multi-GNSS RTK. The MGF algorithm utilizes the decimal part of the time difference GF phase combination to determine cycle slips satellite by satellite. It can directly estimate the cycle slips on a specific frequency, rather than a combined cycle slip as in the GF combination. The MGF method is tested against airborne and other kinematic situations. The results show that the MGF method can quickly determine the small cycle slips on each frequency even when all carrier phases suffer from cycle slips simultaneously. Compared with the combined method of GF and HMW and using a 24-h 1-Hz GPS/BDS dataset, the MGF method is 144 times faster and reduces the number of incorrectly repaired cycle slips from 4005 to 141.

中文翻译：

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使用改进的无几何相位组合快速确定高倍数GNSS RTK的周跳

循环滑移确定在连续实时运动学（RTK）定位中起着重要作用。由于应在每个时期处理周跳，因此对于高速RTK应用（如自动驾驶仪和机载定位）需要一种快速确定方法，在这种情况下，需要使用高采样率的GNSS数据（例如50 HZ）实时处理。无几何形状（GF）相组合是处理循环滑移的最常用组合之一。但是，GF相组合不能区分发生周跳的频率。因此，通常采用其他方法，例如Hatch-Melbourne-Wübbena（HMW）组合来确定周期转差的频率和大小。由于引入了噪声代码伪距测量，因此很难识别出较小的周跳，特别是在多个卫星和多个频率同时发生周跳时。在此贡献中，提出了一种改进的无几何形状（MGF）仅相位线性组合，以快速确定高采样率多GNSS RTK的周跳。MGF算法利用时间差GF相位组合的小数部分来逐个卫星确定周跳。它可以直接估计特定频率上的周跳，而不是GF组合中的组合周跳。MGF方法针对空中和其他运动情况进行了测试。结果表明，即使所有载波相位同时遭受周期滑动，MGF方法仍可以快速确定每个频率上的小周期滑动。与GF和HMW的组合方法相比，并使用24小时1 Hz GPS / BDS数据集，