Abstract Doppler, which is an instantaneous GNSS observable signal, has been proven effective in determining velocity and acceleration due to its high availability and accuracy. We propose a real-time triple-frequency cycle slip correction (CSC) method based on Doppler-aided signals because Doppler shift is time-independent and immune to cycle slips. When the sampling interval is less than 1 second, cycle slips on triple-frequency can be detected and repaired using pure Doppler data with high reliability; however, this method cannot be used when the sampling interval exceeds 1 second because the integral cumulative error of Doppler increases significantly. For such cases, a modified triple-frequency CSC approach has been developed based on the raw phase and smoothed code data that was refined using the Doppler signal. To suppress the effect of the integral Doppler error, a balance factor is introduced to adjust the contributions of the raw code and Doppler observables. After the refinement of the GNSS data, three independent combinations need be selected to detect and repair cycle slips with triple-frequency observations. Four constrained criteria have been proposed to select optimal combinations that can reduce the residual ionospheric delay (RID) and measurement noise to a low level. Finally, experiments were carried out to test the performance of the new method using real triple-frequency BDS observations (GPST: 3:15:00-5:55:00, March 23, 2018). The results show that pure Doppler can detect and repair cycle slips effectively with small intervals, and modified Hatch-Melbourne-Wubbena (HMW) method based on Doppler-aided signals can achieve 99.7% success rate in cycle slip correction with large intervals (up to 30 s).

中文翻译：

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一种改进的基于多普勒辅助信号的北斗三频测量实时周跳校正算法

摘要 多普勒是一种瞬时 GNSS 可观测信号，由于其高可用性和准确性，已被证明在确定速度和加速度方面是有效的。我们提出了一种基于多普勒辅助信号的实时三频周跳校正 (CSC) 方法，因为多普勒频移与时间无关且不受周跳影响。当采样间隔小于1秒时，可利用纯多普勒数据检测和修复三频周跳，可靠性高；但是这种方法在采样间隔超过1秒时不能使用，因为多普勒积分累积误差显着增加。对于这种情况，基于原始相位和使用多普勒信号细化的平滑代码数据开发了一种改进的三频 CSC 方法。为了抑制积分多普勒误差的影响，引入了一个平衡因子来调整原始代码和多普勒观测值的贡献。在对 GNSS 数据进行细化后，需要选择三个独立的组合来检测和修复具有三频观测的周跳。已经提出了四个约束标准来选择可以将残余电离层延迟 (RID) 和测量噪声降低到低水平的最佳组合。最后，使用真实的三频北斗观测（GPST：3:15:00-5:55:00，2018年3月23日）进行了实验以测试新方法的性能。结果表明，纯多普勒可以有效地检测和修复小间隔周跳，基于多普勒辅助信号的改进Hatch-Melbourne-Wubbena（HMW）方法可以达到99。