The convergence period is of critical significance in Precise Point Positioning (PPP) applications. Current criterion for determining PPP convergence period is by comparing the positioning error to the ground truth. This experiment-based criterion can be influenced by many factors like the accuracy of ephemeris and the test area. One can hardly get a consistent result of the convergence period without abundant experiments. Consequently, the criterion is not suitable for global-wide PPP specification determination and relevant GNSS service design. In response, we build a new framework of PPP convergence period evaluation based on statistical analysis, with the definition of an indicator, Sequential Dilution of Precision (SDOP). The SDOP represents the propagation from measurement errors to the filter-derived positioning errors. And the framework is established based on SDOP to connect the measurement error, confidential probability, and PPP convergence period. Furthermore, the impact factors of PPP convergence are classified into three parts, satellite geometry, satellite movement, and un-modeled measurement error, which enables researchers to focus on a specific property for analysis. Specifically, the satellite movement can be described by DOP, and we further define the Speed-Up Ratio (SUR) to represent satellite movement. The SDOP is influenced by both DOP and SUR. The proposed framework and relevant variables are examined with both real data and simulated GNSS and Low Earth Orbit (LEO) data. The results are in good agreement with public recognition. Moreover, as an example usage, the global maps of PPP convergence period are presented using the new framework, which are almost impossible to be given with traditional experiment-based criterion. The variation of PPP convergence period through latitude, longitude, and positioning directions is clearly exhibited. The plots can play a significant part in PPP analysis and GNSS service design.

收敛周期在精确点定位 (PPP) 应用中至关重要。当前确定 PPP 收敛周期的标准是通过将定位误差与地面实况进行比较。这种基于实验的标准会受到许多因素的影响，例如星历的准确性和测试区域。没有大量的实验，很难得到收敛期的一致结果。因此，该标准不适合全球范围的 PPP 规范确定和相关 GNSS 服务设计。对此，我们构建了一个基于统计分析的PPP收敛期评估新框架，并定义了一个指标，即顺序稀释精度（SDOP）。SDOP 表示从测量误差到滤波器导出定位误差的传播。并基于SDOP建立框架，将测量误差、保密概率、PPP收敛期联系起来。此外，PPP收敛的影响因素分为卫星几何、卫星运动和未建模测量误差三部分，使研究人员能够专注于特定属性进行分析。具体来说，卫星运动可以用DOP来描述，我们进一步定义加速比（SUR）来表示卫星运动。SDOP 受 DOP 和 SUR 的影响。提议的框架和相关变量通过真实数据和模拟 GNSS 和低地球轨道 (LEO) 数据进行了检查。结果与公众的认可度非常吻合。此外，作为示例用法，使用新框架呈现 PPP 收敛期的全球地图，这是传统的基于实验的标准几乎不可能给出的。PPP收敛周期随纬度、经度和定位方向的变化被清楚地展示出来。这些图可以在 PPP 分析和 GNSS 服务设计中发挥重要作用。