空间信号非理想特性及其对导航性能的影响研究

GNSS Signal-in-space (SIS) performance is key to positioning accuracy and integrity. The nominal SIS signal deformations impact the receiving performance and channel applicability of the signal, whereas the evil waveform (EWF) induced by the satellite signal generation hardware failure poses a threat to the Safety-of-life (SOL) service for air navigation. Among previous studies about SIS non-idealities and their impacts on navigation performance, the well-established ICAO 2OS EWF threat model cannot fit into nominal signal deformations, nor can it characterize the signal deformation for new signal structures effectively. There is also some argument about other related models and performance indexes. Considering the characteristics of navigation applications with new signal structures, this project will accurately model and analyze the non-idealities of main components in the payload signal generation link and the corresponding signal distortions, aided by the integrated end-to-end simulation and experimental validation. The signal distortion model applicable to new signal structures will be proposed. Next, the index system for SIS signal quality evaluation will be elaborated clearly. Then the impacts of SIS signal distortions on signal performance will be revealed analytically. In addition, the SIS signal quality assessment methods will be investigated. And the efficient pre-distortion algorithms will be explored. The study will provide basic theories, supporting methods and reference experiments for the optimization of navigation signal structures and payload signal generation system as well as the establishment of their quality indexes.

高精度和高完好性的GNSS应用对卫星播发的空间信号性能提出了要求。标称空间信号的失真影响信号的接收性能和对信道的适应能力，而卫星信号生成链路故障引起的有害波形则对航空导航等服务构成威胁。现有关于空间信号非理想特性及其对导航性能影响的研究中，广获应用的ICAO 2OS EWF模型并不适用于标称信号失真，也不能阐明新体制信号的畸变机理；其他模型和有关指标也尚存争议。本项目将针对新信号体制下导航应用的特点，对卫星信号生成链路主要组件的非理想性及其引起的信号失真进行精确建模和深入分析，辅以集成化端到端仿真和试验验证，提出适用于新体制信号的失真模型，建立清晰完整的空间信号质量指标体系，揭示空间信号失真对信号导航性能的影响机制，研究空间信号质量监测评估方法，并探索高效的星上预失真方法，从而为导航信号体制和有效载荷信号生成链路的优化设计及其质量指标的确立提供理论基础、方法支撑和和试验参考。

高精度和高完好性的GNSS应用对卫星播发的空间信号质量提出了要求。卫星信号生成/传播链路的非理想性不可避免地引入不同类型或特性的标称信号失真以至更严重的信号畸变/有害波形，不仅影响信号的接收性能和对信道的适应能力，而且对航空导航等生命安全服务构成威胁。现有关于空间信号非理想性及其对导航性能影响的研究中，广获应用的ICAO 2OS EWF模型并不能全面有效地描述标称信号失真及新体制信号的畸变，其他模型和有关指标也尚存争议。本项目针对新信号体制下导航应用的特点，首先对卫星信号生成链路主要组件的非理想性及其引起的信号失真进行深入的建模分析，辅以集成化端到端仿真和试验验证，在此基础上提出具有多体制和多应用普适性的空间信号标称失真模型，精确描述空间信号失真对导航信号性能的影响，进一步建立清晰完整的空间信号质量评估指标体系，提供高效高精度的空间信号质量监测评估方法，并探索星上数字预失真补偿的新思路，从而为导航信号体制和有效载荷信号生成链路的优化设计及其质量指标的确立提供理论基础、方法支撑和试验参考。