【作者】 李源；

【导师】 战兴群； 张欣；

【作者基本信息】 上海交通大学 ， 航空宇航科学与技术， 2018， 硕士

【摘要】 全球导航卫星系统GNSS(Global Navigation Satellite System)是一种空基无线电导航定位系统。在地球上的任何时刻和地点,只要用户接收机能够正常捕获跟踪至少4颗GNSS卫星信号,就能获得自身的准确位置。但是,信号在传播过程中的衰减效应是无线电系统的天然缺陷,也就意味着当导航卫星信号受到遮挡的场景下,例如用户接收机处于城市峡谷、隧道、建筑物内或者地下矿区等区域时,卫星导航信号几乎完全消失,从而无法提供有效的导航定位服务,这一定程度上说明了卫星导航技术应用范围的局限性,而伪卫星地基导航技术为其提供了一种有效的解决方案。伪卫星协同定位通过增加可观测导航卫星的数量,优化GNSS观测定位星座的几何分布和构型,进而提高卫星导航系统的精确性、连续性、完好性和可靠性,实现对卫星导航系统的增强效果。甚至在GNSS信号无法到达的区域,伪卫星定位组网可独立提供导航定位服务,从而增加了卫星导航的应用覆盖范围。因此,伪卫星技术具有很重要的应用研究价值。但是,现阶段伪卫星技术中还面临诸多需要解决的技术难题,例如系统时间同步、信号远近效应和多路径效应等。本文针对这些技术难题,分析其机理并给出了相应的解决方案,将伪卫星布置于室外环境下,开展协同北斗导航卫星定位实验探究,并基于室外伪卫星建立导航定位星座的能力,创新性地将伪卫星应用于室内组合导航半物理仿真测试环境中,构建室内GNSS信号链路,从而开展室内伪卫星协同惯性导航定位实验探究。本文主要的研究内容与结果如下:首先,分析了伪卫星信号结构和功率等特性,研究了采用码分多址CDMA+时分多址TDMA的信号模式应对“远近效应”问题,进而给出了接收机端近乎无感知型伪卫星信号体制的设计方案。在信号研究的基础上,考虑到伪卫星组网和GPS标准时高精度时间同步的需求,设计实现了带授时模块的收发一体硬件平台,并通过信号发射试验验证其设计的正确性,说明所设计的单体伪卫星达到量产的标准。其次,针对伪卫星协同定位系统中的关键技术开展研究,提出了伪卫星组网时间同步校准技术方案,创新型的提出了基于灰色粒子群的伪卫星钟差监测与自适应预报算法;推导了伪卫星载波相位双差定位算法模型,并进一步提出了基于载体姿态的整周模糊度快速求解算法;研究了多路径效应的缓解算法,推导了基于CNMC模型的实时多路径延时估计方法,并通过将其应用到伪卫星钟差监测实验中,验证了算法的有效性和准确性;从避免相邻伪卫星信号功率相互干扰的角度出发,研究了伪卫星选址问题,从而指导伪卫星组网的布局。最后,通过开展室外和室内伪卫星实验,验证本文所提出的伪卫星协同定位系统的技术方案。针对室外伪卫星协同定位系统,阐述了系统的结构和组成要素,开发了伪卫星协同定位系统的后台运行控制软件,描述了跑车试验地部署情况,通过对伪卫星协同导航卫星定位和导航卫星独立定位的误差比较分析,验证了室外伪卫星协同定位系统的有效性和完好性;针对室内伪卫星信号环境实验,首先提出了一种伪卫星组网协同惯性导航的半物理仿真测试技术方案,并依据设计方案搭建了组合导航仿真测试环境演示系统,选择超紧组合导航软件接收机作为测试对象,由伪卫星室内组网提供GNSS导航卫星信号环境,完成了超紧组合导航软件接收机半物理仿真测试实验,实验结果论证了测试系统的有效性和可靠性。更多还原

【Abstract】 Global Navigation Satellite System GNSS(Global Navigation Satellite System)is a space radio navigation system.At any moment and place on Earth,the user’s receiver can get its exact location as long as the receiver can normally capture and track at least 4 GNSS satellite signals.However,the attenuation effect of the signal in the propagation process is a natural defect of the radio system,which means that when the navigation satellite signal is blocked,for example,when the user receiver is in an urban canyon,a tunnel,a building,or an underground mining area,Satellite navigation signals almost completely disappear,which cannot provide effective navigation and positioning services,which explains the limitations of the application scope of satellite navigation technology to a certain extent.Pseudo-satellite ground-based navigation technology provides an effective solution.Pseudolite collaboration positioning improves the accuracy,continuity,integrity and reliability of satellite navigation systems by increasing the number of observable navigation satellites,optimizing the geometry distribution and configuration of GNSS observing positioning constellations,and enhancing the satellite navigation system effect.Even in the areas where GNSS signals cannot be reached,the Positioning Satellite Network can independently provide navigation and positioning services,thereby increasing the coverage of satellite navigation applications.Therefore,pseudolite technology has very important application research value.However,there are still many technical problems to be solved in pseudolite technology at this stage,such as system time synchronization,signal distance effect and multi-path effect.In view of these technical problems,this paper analyzes the mechanism and presents the corresponding solutions.Pseudolites are deployed in outdoor environment to explore collaborative Beidou navigation satellite positioning experiments.Based on the ability of outdoor pseudolites to establish navigation and positioning constellations,innovative Pseudo-satellites are used in indoor integrated navigation and semi-physical simulation test environment to build indoor GNSS signal links,so as to carry out indoor pseudo-satellite coordinated inertial navigation and positioning experiments.The main contents and results of this paper are as follows:First of all,the architecture and power characteristics of pseudolite signals are analyzed.The problem of "near-far effect" is solved by adopting the signal mode of CDMA + TDMA,and then the near-unaware pseudolite signal system Design.On the basis of the signal research,taking into account the requirements of high-precision time synchronization of the pseudolite network and GPS standard,a transceiver hardware platform with a timing module is designed,and the overall architecture of the hardware and the design scheme of each sub-module are given.The signal transmission test verifies the validity and correctness of the design.It shows that the designed single pseudolite has reached the standard of mass production.Secondly,based on the research of the key technologies in pseudolites cooperative positioning system,a scheme of time synchronization calibration for pseudolites’ network is put forward,and an innovative algorithm based on gray particle swarm is proposed to detect and adaptively predict the satellite clock errors.Pseudolite carrier phase double-difference positioning algorithm model,and further put forward a solution based on carrier attitude of the whole week ambiguity fast;study the mitigation effect of multi-path effects,derived based on CNMC model of real-time multi-path delay estimation method The validity and accuracy of the proposed algorithm are verified by applying it to the satellite clock error monitoring experiment.From the perspective of avoiding the mutual interference of the power of adjacent pseudolite signals,the problem of the location of the pseudolite is studied,Network layout.Finally,through the experiment of outdoor and indoor pseudo-satellites,the technical scheme of the pseudo-satellite collaboration positioning system proposed in this paper is validated.For the outdoor pseudolite satellite positioning system,the architecture and components of the system are described.The background operation and control software of the pseudolite positioning system is developed.The deployment of the road bike test site is described.By analyzing the relationship between the pseudolite satellite navigation satellite positioning and navigation satellite independence In order to verify the validity and integrity of the outdoor Pseudolite collaborative positioning system,aiming at indoor pseudolite signal environment experiment,a semi-physical simulation test technology scheme of Pseudolite networking collaborative inertial navigation is firstly proposed.And based on the design scheme,a demonstration system of integrated navigation simulation test environment was set up.The receiver of ultra-tight integrated navigation software was selected as the test object,and the GNSS navigation satellite signal environment was provided by the pseudolite indoor network.Based on a set of ultra-tight integrated navigation software receiver semi-physical simulation test experiment,and the experimental results demonstrate the validity and reliability of the test system.更多还原