GPS多频精密单点定位中时变性偏差估计与应用

Aiming at the existence of the time-variation bias in the GPS multi-frequency precise point positioning (PPP) and its effect on data processing and service of PPP. In this project, the estimation model of the time-variation inter-frequency satellite clock bias for the single frequency is constructed and the estimation theory and method are established. According to the time-variation features of the inter-frequency satellite clock bias, the recovering algorithm of the multi-frequency GPS satellite clock errors is implemented to improve the estimation and service of the GPS satellite clock. Based on the closed characterization of the GPS multi-observation and estimated parameters, the computing methods for the inter-wide-lane UPD bias in the multi-frequency GPS and time-variation UPD of narrow lane are studied to improve the quality of the ambiguity and realize the unification of the ambiguity parameters; The estimation model and method for the time-variation biases in the pseudorange observation are studied and computed to improve accuracy of the pseudorange observation and provide the premise for the rapid PPP convergence. Using the time-variation bias results and combining time-space state, their physical properties are analyzed and studied to strengthen understanding and mastering of the multi-frequency GPS and their biases. Based on the understanding and mastering, the simply and rapid service strategy and application in the PPP of the new time-variation bias also are studied to give full play to the advantage of the multi-frequency GPS in PPP.

针对GPS多频精密单点定位（PPP）中时变性偏差的存在及对PPP数据处理和服务的影响，本项目拟建立多频GPS单个频点间时变性卫星钟差偏差估计模型，构建其估计理论与方法；根据多频GPS时变性频间卫星钟差偏差特征，研究多频GPS卫星钟差恢复算法，完善GPS卫星钟差解算与服务策略。依据多频GPS观测和解算参数的可闭合性，研究多频GPS宽巷UPD之间偏差和时变性窄巷UPD解算模型与方法，提高模糊度参数质量和实现模糊度参数统一；探索多频GPS伪距观测中时变性偏差估计模型与方法，提高伪距观测精度，为PPP参数快速收敛提供技术支撑。采用多频GPS时变性偏差结果，结合卫星时空状态，进行其物理特性分析与研究，增强对多频GPS系统和信号的认识与掌握；基于对多频GPS时变性偏差认识，研究其简单、快捷的服务策略和在PPP中的应用理论与算法，充分发挥多频GPS观测在PPP中的优势。

GPS精密单点定位（Precise Point Positioning, PPP）数据处理中，需要详细地考虑各类误差对解算参数精度和收敛时间的影响，并采取措施以消除、高精度改正或补偿。受卫星、接收机硬件和空间环境等影响，GPS多频PPP数据处理中存在一些新的时变性偏差。针对多频GPS中时变性偏差存在及其对PPP数据处理的影响，系统、全面地进行其估计理论与分析研究。分析了GPS卫星钟差频间偏差（Inter-Frequency Clock Bias，IFCB）的时变性特点，提出了采用GPS伪距观测进行IFCB估计的方法。推导了相位、伪距观测对应IFCB解算结果的组成，即伪距观测对应IFCB是DCB（Differential Code Bias）的组合，相位观测对应IFCB是UPD（Uncalibrated Phase Delay）的组合。采用大量的GPS观测数据解算结果分析了GPS中组合的伪距偏差DCB（P1-P2）、DCB（P1-P5）的时变性、周期性特征，并应用于GPS PPP中，提高了定位精度。针对GPS伪距观测C1、P1间偏差的时变性，提出了DCB（C1-P1）的解算方法，并分析得到DCB（C1-P1）具有明显的周期性。基于发现的周期性特性，进行DCB(C1-P1)序列模型化，提高了时变性DCB(C1-P1)的服务能力和其在定位中的作用。根据GPS观测中时变性偏差的存在，发展了多频GPS卫星钟差估计、服务理论与方法，为多频GNSS卫星钟差估计与服务提供理论支撑。提出了GPS伪距观测精度的评估算法，基于评估结果，构建了新的GPS PPP随机模型。新构建的随机模型应用于GPS数据处理中获得了较好的效果。分析了GPS卫星钟差的周期性变化特点，根据得到的周期性特征，进行了GPS卫星钟差模型化研究，以简化和提升GPS PPP服务能力。