An unwritten rule to resolve GNSS ambiguities in precise point positioning (PPP-AR) is that users should follow faithfully the frequency choices and observable combinations mandated by satellite clock and phase bias providers. Switching to other frequencies of measurements requires that the satellite clocks be converted, albeit in a roundabout way, to agree with the new frequencies of code biases. Satellite phase biases, on the other hand, are prescribed conventionally as wide-lane and narrow-lane combinations, which prevents users from resolving other phase combinations in the case of multi-frequency observables. We therefore develop an approach to compute observable-specific phase biases (phase OSBs) in concert with the legacy, but ambiguity-fixed, satellite clocks to enable PPP-AR over any frequency choices and observable combinations at the user end, i.e., all-frequency PPP-AR. In particular, the phase OSBs on the baseline frequencies (e.g., L1/L2 for GPS and E1/E5a for Galileo) are estimated by decoupling the code OSBs pre-aligned with the satellite clocks; then satellite clocks are re-estimated by holding pre-resolved undifferenced ambiguities and phase OSBs on the baseline frequencies; finally, all third-frequency phase OSBs are determined by introducing the ambiguity-fixed satellite clocks above. We used a global network of multi-frequency GPS/Galileo data over a month to verify this approach. In dual-frequency PPP-AR using GPS L1/L2, L1/L5, Galileo E1/E5a, E1/E5b, E1/E5 and E1/E6 signals, over 95% of wide-lane and narrow-lane ambiguity residuals were within ±0.25 and ±0.15 cycles, respectively, after the code and phase OSB corrections on raw GNSS measurements. As a result, the ambiguity fixing rates reached around 95% in all PPP-AR tests, though it was only the satellite clocks aligned with the GPS L1/L2 and Galileo E1/E5a pseudorange that were applied throughout. We stress that the key to computing such phase OSBs for all-frequency PPP-AR is that the code OSBs have the same bias datum as that of the satellite clocks.

解决精确点定位 (PPP-AR) 中 GNSS 模糊性的一条不成文规则是，用户应忠实地遵循卫星时钟和相位偏差提供者要求的频率选择和可观测组合。切换到其他测量频率需要转换卫星时钟，尽管是以迂回的方式，以与新的代码偏差频率一致。另一方面，卫星相位偏差通常被规定为宽通道和窄通道组合，这会阻止用户在多频可观测的情况下解析其他相位组合。因此，我们开发了一种方法来计算可观察到的特定相位偏差（相位 OSB），与传统相一致，但模糊性固定，即全频PPP-AR。特别是，基线频率上的相位 OSB（例如, L1/L2 用于 GPS 和 E1/E5a 用于伽利略）是通过解耦与卫星时钟预先对齐的代码 OSB 来估计的；然后通过在基线频率上保持预先解决的无差歧义和相位 OSB 来重新估计卫星时钟；最后，通过引入上面的模糊度固定卫星时钟来确定所有第三频率相位 OSB。我们使用了一个多频 GPS/Galileo 数据的全球网络超过一个月来验证这种方法。在使用 GPS L1/L2、L1/L5、Galileo E1/E5a、E1/E5b、E1/E5 和 E1/E6 信号的双频 PPP-AR 中，超过 95% 的宽车道和窄车道模糊残差在在对原始 GNSS 测量进行代码和相位 OSB 校正后，分别为 ±0.25 和 ±0.15 个周期。结果，在所有 PPP-AR 测试中，歧义固定率达到了 95% 左右，尽管只有与 GPS L1/L2 和 Galileo E1/E5a 伪距对齐的卫星时钟始终被应用。我们强调，为全频 PPP-AR 计算此类相位 OSB 的关键是代码 OSB 具有与卫星时钟相同的偏置数据。