Single-frequency precise point positioning (SF-PPP) has attracted increasing attention due to its high precision and cost effectiveness. With various strategies to handle the dominant error, i.e., ionosphere delay, the ionosphere-float (IF), ionosphere-free-half (IFH), ionosphere-corrected (IC), and ionosphere-weighted (IW) SF-PPP models are certain to possess different characteristics and performance levels. This study is dedicated to assessing and comparing the four models from model characteristics, positioning performance, and atmosphere delay retrieval. The model comparison shows that IC and IW models are full-rank while IF and IFH models have a rank deficiency of size one that will result in biased estimations, which means the better solvability of IC and IW models. The experiments are carried out based on the 7-day Global Positioning System (GPS) observations collected at 57 global Multi-GNSS Experiment (MGEX) stations and Global Ionosphere Map (GIM) products. The results indicate that the IW model can accelerate SF-PPP convergence and achieve higher positioning accuracy compared to the other three SF-PPP models, especially in kinematic mode. With convergence criteria of 0.25 m in horizontal and 0.5 m in vertical, the east/north/up convergence times of IW model are 0.5/15.0/25.0 min and 0.5/16.0/36.5 min for static and kinematic modes, respectively. The IW model is able to achieve an instantaneous positioning accuracy of 0.28/0.35/0.75 m. In addition, a real kinematic test also demonstrates the best positioning solutions of IW model. Regarding troposphere delay retrieval, the IF, IFH, and IW models obtain a comparable daily accuracy of 3.0 cm on average, while the IC model achieves the worst accuracy of 8.0 cm. For precise ionosphere delay estimation, IW model only needs an average initialization time of 34.3 min, but a longer initialization time of 51.6 min is required for IF model. The daily precision of ionosphere delay estimation for IW model can reach up to 10.8 cm. At the present accuracy of GIM products, it is suggested that the IW model should be adopted for SF-PPP first due to its superior performance in positioning and atmosphere delay retrieval.

单频精确点定位（SF-PPP）由于其高精度和高性价比而受到越来越多的关注。采用各种策略来处理主要误差，即电离层延迟，电离层浮动（IF），无电离半边（IFH），电离层校正（IC）和电离层加权（IW）SF-PPP模型肯定具有不同的特性和性能水平。这项研究致力于从模型特征，定位性能和大气延迟检索中评估和比较这四个模型。模型比较表明，IC和IW模型是满秩的，而IF和IFH模型的秩为1，这将导致估计偏差，这意味着IC和IW模型具有更好的可解性。实验是根据在57个全球Multi-GNSS实验（MGEX）站和全球电离层地图（GIM）产品上收集的7天全球定位系统（GPS）观测值进行的。结果表明，与其他三个SF-PPP模型相比，IW模型可以加快SF-PPP收敛并实现更高的定位精度，尤其是在运动学模式下。在水平方向上为0.25 m且垂直方向上为0.5 m的收敛准则下，IW模型的静态/运动模式的东/北/上收敛时间分别为0.5 / 15.0 / 25.0 min和0.5 / 16.0 / 36.5 min。IW模型能够实现0.28 / 0.35 / 0.75 m的瞬时定位精度。此外，真实的运动学测试还展示了IW模型的最佳定位解决方案。关于对流层延迟检索，IF，IFH，IW模型和IW模型的平均日精度可比为3.0 cm，而IC模型的最差精度为8.0 cm。对于精确的电离层延迟估计，IW模型仅需要34.3分钟的平均初始化时间，而IF模型则需要51.6分钟的更长的初始化时间。IW模型电离层延迟估计的每日精度可以达到10.8 cm。在目前的GIM产品精度的情况下，建议先将IW模型用于SF-PPP，因为它在定位和大气延迟检索方面具有出色的性能。IF模型需要6分钟。IW模型电离层延迟估计的每日精度可以达到10.8 cm。在目前的GIM产品精度下，建议先将IW模型用于SF-PPP，因为它在定位和大气延迟检索方面具有出色的性能。IF模型需要6分钟。IW模型电离层延迟估计的每日精度可以达到10.8 cm。在目前的GIM产品精度的情况下，建议先将IW模型用于SF-PPP，因为它在定位和大气延迟检索方面具有出色的性能。