中文摘要：

讨论了真三频信号的特征及其模拟方法。研宄了采用三频信号实现PPP的关键问题，及三频PPP的特性。讨论了三频信号的周跳探测方法、频问钟差偏差的改正和观测模型。通过对模拟的三频数据的解算，研究了三频PPP的特性。结果表明，可以采用不同的观测、观测组合、观测组合组进行PPP数据处理。双频无电离层延迟组合（L3，P3和L6，P6）和双频非组合（L1＋L2，P1＋P2和L1＋L5，P1＋P5）对应的参数收敛时间、解算精度几乎相当。三频观测对于长时间观测结果精度的改善不明显，但对于短时间观测结果的精度与参数收敛时间都有一定的改善效果。数据质量不稳定时，三频观测可以减少定位中初始化的次数。

英文摘要：

The simulation method of the triple-frequency signals is presented based on the characterization of real triple-frequency signals. The key issues and performances of triple-frequency precise point positioning （PPP） are studied. The methods of triple-frequency cycle slip detection, correctionof the inter-frequency clock bias and observation model are discussed. To study the performance of triple-frequency PPP, the simulated triple-frequency data is processed. The results show that PPP can be realized based on the different observations, observation combinations and groups of observation combinations. The results indicate that the convergence time and positioning accuracy of the double-frequency ionosphere-free combinations （L3, P3 and L6, P6）and uncombined observations （L1 ＋ L2, P1 ＋ P2 and L1 ＋ L5, P1 ＋ P5） are almost equally. Although the triple-frequency observa-tions cannot improve positioning accuracy of the long time observation, it is resultful for improving the convergence time and positioning accuracy of short time observation. When the data quality of the triple-frequency observations is unstable, it can reduce the times of initialization.