The resolution of ambiguity (AR) is of paramount importance for the precise point positioning (PPP) technique, as it enables the reduction of convergence duration and the improvement of positioning accuracy. Uncalibrated phase delay (UPD) is a key factor in ambiguity fixation. We investigate the difference between different scale UPD estimates which are obtained from MGEX and YNCORS stations in PPP-AR performance during quiet and geomagnetic storm periods. The conclusion is supported by two sets of experiments which indicate that regional UPD estimates offer higher stability and accuracy. In the quiet period, the average time to first fix (TTFF) of the regional UPD-based PPP-AR is enhanced by 35.75% compared with the global UPD-based PPP-AR, the N-direction accuracy is enhanced by 60.32%, the E-direction accuracy is decreased by 6.36%, the U-direction accuracy is decreased by 56.14%, and the convergence rate is enhanced by 7.5% to reach 100%. During the period of geomagnetic storm, the average initialization time of regional UPD-based PPP-AR is 32.05% faster than the average initialization time of global UPD-based PPP-AR. the N-direction accuracy is enhanced by 90.32%, the E-direction accuracy is decreased by 61.11%, the U-direction accuracy is enhanced by 55.18%, and the convergence rate is enhanced by 6.67%. Additionally, the TTFF of PPP-AR based on regional UPD is significantly shorter and more stable. The difference may be due to the regional UPD absorbing part of the common error caused by the geomagnetic storm, which results in a greater enhancement in the accuracy and stability of the regional UPD product during the storm.

中文翻译：

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在安静和地磁暴期间低纬度地区 BDS/GNSS PPP-AR 的全球和区域 UPD 评估


模糊度分辨率 （AR） 对于精确点定位 （PPP） 技术至关重要，因为它可以减少收敛持续时间并提高定位精度。未校准的相位延迟 （UPD） 是模糊固定的一个关键因素。我们研究了从 MGEX 和 YNCORS 站获得的不同比例 UPD 估计值在安静和地磁暴期间 PPP-AR 性能的差异。该结论得到了两组实验的支持，这些实验表明区域 UPD 估计提供了更高的稳定性和准确性。在静默期内，区域基于 UPD 的 PPP-AR 的平均首次定位时间 （TTFF） 与全球基于 UPD 的 PPP-AR 相比提高了 35.75%，N 方向精度提高了 60.32%，E 方向精度降低了 6.36%，U 方向精度降低了 56.14%，收敛率提高了 7.5%，达到 100%。在地磁暴期间，区域性基于UPD的PPP-AR的平均初始化时间比全球基于UPD的PPP-AR的平均初始化时间快32.05%。N 方向精度提高了 90.32%，E 方向精度降低了 61.11%，U 方向精度提高了 55.18%，收敛率提高了 6.67%。此外，基于区域 UPD 的 PPP-AR 的 TTFF 明显更短且更稳定。这种差异可能是由于区域 UPD 吸收了地磁暴引起的常见误差的一部分，导致区域 UPD 产品在风暴期间的准确性和稳定性得到了更大的增强。