GNSS卫星导航信号畸变快速诊断与实时预警建模方法研究

Being the most advanced technology, Global Navigation Satellite System (GNSS) successfully gathers astronomy, physics, space, information, navigation, mapping and other technologies into one coherent system. GNSS can provide global users with accurate position, velocity and timing (PVT) information in real time. It has been widely used in aerospace, marine, search and rescue, transportation, agriculture and other fields. Satellite navigation signal is of vital importance for a GNSS to achieve its high performance, as signal quality will be a direct reflection of the PVT performance and payload status of a GNSS. Although GNSS reliability is highly respected and has attracted considerable attention in the design process, signal distortion is still difficult to be avoided, with severe cases leading to disastrous consequences. Since the project involves many areas of satellite navigation, mathematical analysis, signal processing, astrometry and so on, GNSS signal distortion automatic identification and real time warning mechanisms has not yet be formed both at home and abroad. To fill the gaps in this area, GNSS signal distortion fast identification and real time warning technology is proposed here. In addition, those key technologies are studied in depth to further improve the accuracy and real-time, ensuring efficient and reliable uses of GNSS. The main research contents in this project include: (1) GNSS signal distortion generation mechanism and characteristics; (2) impact of signal distortion on ranging performance; (3) modeling methods of signal distortion automatic identification and its real time warning; (4) model error analysis

全球导航卫星系统（GNSS）是集天文、物理、空间、信息、导航、测绘等技术于一体的现代高新技术，能为全球用户提供实时准确的位置、速度和时间等信息，目前已广泛应用于航空航天、海事、搜救、交通、精细农业等领域。卫星导航信号是GNSS的重要组成部分，导航信号质量的优劣将直接反映GNSS的PVT性能、有效载荷工作状态等。尽管GNSS在设计时非常重视可靠性，但信号畸变问题仍难以避免，严重时可能导致灾难性后果。由于涉及卫星导航、数理分析、信号处理、天体测量等众多领域，目前国内外尚未形成GNSS信号畸变自动识别及预警机制。为填补在该领域研究的空白，项目组提出GNSS信号畸变实时预警技术，并对其关键技术深入研究，以进一步提高预测预警的准确性及实时性，确保GNSS用户的高效可靠使用。研究内容主要有：1.GNSS信号畸变产生机理及特性 2.畸变对用户测距性能影响 3.畸变自动诊断与预警建模方法 4.模型误差分析

项目组严格按照研究计划，紧密围绕卫星导航信号畸变产生机理及特点、信号畸变诊断及预测方法展开深入研究。通过理论建模和仿真，研究并模拟实现了星上主要器件特性及畸变信号产生机理，为导航卫星有效载荷信号生成链路非理想特性及其对导航性能的影响研究提供了重要支撑；深入研究并推导出了信号功率畸变及数模畸变、前端带宽、相关器间隔等因素与伪距精度间的量化关系表达式，并从理论上分析了干扰和多径对信号测距性能的影响，解决了卫星信号畸变对用户影响无法精确定量分析的难题；研究了卫星信号故障诊断及预测预警方法，建立了精确的导航信号传播链路通道模型及误差模型，通道辨识准确率可达99%，研究了下行导航信号特征提取及信号恢复技术，信号恢复准确率可达99.9%，为卫星导航信号性能评估及故障预测提供了一种高效技术途径；利用中国科学院国家授时中心的16米天线信号产生、发射和接收系统，以及昊平观测站40米大口径信号接收系统，项目组搭建了基于MATLAB的仿真验证平台、基于发射接收系统的模拟信号仿真平台以及基于实测卫星导航信号的接收验证平台，并开展大量相关试验验证工作，对提出的算法开展了仿真验证分析，结果满足项目要求。.本项目在国内外重要学术刊物上共资助发表论文13篇（其中SCI一区检索论文2篇，获奖论文2篇，EI收录10篇，核心期刊1篇）；参加国外学术会议5次，策划筹备及参加国内学术会议5次；已受理发明专利2项；获批软件著作权9项；联合培养博士2名，硕士1名，其中有1人荣获国家奖学金。项目直接经费21万元，截至2018年12月底实际支出约16.9264万元，项目支出约占总经费的80.6%，各项支出基本与预算相符。剩余经费4.0736万元计划用于本项目研究相关工作的后续支出。