【作者】 汤勇刚；

【导师】 沈林成；

【作者基本信息】 国防科学技术大学 ， 控制科学与工程， 2007， 博士

【摘要】 “北斗一号”导航系统是我国目前唯一拥有完全自主知识产权的卫星导航系统,但是从目前的系统总体架构、定位体制和应用范围来看,该系统与GPS还有较大差距。面对国防和经济建设的需求,迫切需要大力发展基于北斗导航系统的应用技术。论文以地面车辆和水面舰艇等中低动态载体的导航为背景,以北斗卫星导航系统和激光陀螺捷联惯导系统构成的组合导航系统为研究对象,针对“北斗一号”系统定位时延大、隐蔽性差、用户数目受限的缺点,提出利用载波相位时间差分建立北斗/捷联惯导组合导航系统,并对主要理论问题和方法进行了研究。论文主要完成了以下研究工作:（1）根据载波相位测量模型和在对主要误差源时空相关特性分析的基础上,建立了载波相位时间差分的数学模型,讨论了载波相位时间差分/惯导组合导航的基本原理。根据整周模糊度在不发生周跳的情况下是常数的性质,以及主要误差具有较强的时空相关性的特点,载波相位时间差分通过历元间求差避免了解算、检验整周模糊度和修复周跳等一系列繁琐的运算,基本上抵消了共模误差,能够精确地反映用户的位置变化信息。因此,利用载波相位时间差分与惯导组合,能够估计并修正惯导系统的误差,有效地抑制导航误差的积累。（2）根据卫星导航/惯导组合导航系统的非线性模型,利用新近提出的从基本定义出发的全局可观性分析方法,对考虑杆臂不确定性条件下的卫星导航/捷联惯导组合导航系统全局可观性进行了研究,给出了全局可观性充分条件,并通过仿真和实验进行了验证。全局可观性分析方法避免了传统方法中繁琐的矩阵求秩运算,分析过程简洁、直观,不需要使用近似的线性系统模型（线性时变模型或分段线性定常模型）来代替准确的非线性系统模型,更全面、更深刻地揭示了状态估计与载体运动之间的关系,为杆臂标定和组合导航算法设计提供了理论基础和数学工具。（3）根据全局可观性分析方法和全局可观充分条件,对载波相位时间差分/捷联惯导组合导航系统的可观性进行了分析,证明对于一般的卫星导航系统,以载波相位时间差分为观测量,如果能够观察到4颗以上的卫星,在一般的机动条件下,除位置以外系统各状态均可观;对于目前只有3颗卫星可供观测的“北斗一号”系统,如载体为受顶向（或天向）速度约束的地面车辆和水面舰艇,在一般的机动条件下,除位置以外系统各状态可观。在可观性分析的基础上,建立了滤波器模型,完成了组合导航算法设计,并研究和解决了若干关键问题,包括滤波器的降阶、周跳的影响及检测、非完整约束的应用等。通过静态实验、跑车实验和水面舰艇实验,对理论分析的结果、数学模型和算法进行了实验研究和验证。实验结果表明:利用载波相位时间差分与捷联惯导组合,能够准确地估计惯导系统的误差,从而有效地抑制导航误差的积累。因此,北斗载波相位时间差分/捷联惯导组合导航技术可应用于地面车辆和水面舰艇的导航,能够在不对外发射信号、不受用户数目限制的前提下,在较长的时间保持较高的导航精度。（4）研究了利用载波相位时间差分测量速度的方法。主要工作包括:对载波相位时间差分速度估计算法的研究、速度估计精度及其误差分析、对利用非线性跟踪—微分器提取载波相位率和时滞补偿算法的研究、实验和仿真验证。实验结果表明,利用载波相位时间差分可以获得精确的速度信息;非线性跟踪—微分器及时滞补偿算法的使用在基本消除时滞的基础上有效地减弱了对噪声的放大作用;在一般观测条件下（6颗星,速度几何误差因子3～4）,用单GPS接收机,静态条件下测速精度可达到10^-3m/s的水平,动态条件下与差分GPS的精度水平相当;北斗系统卫星数目少,并受几何构形的限制,在天向运动约束的辅助下,北向精度达到10^-1m/s的水平,东向速度估计的精度达到10^-2m/s的水平。对几何精度因子的分析及北斗与GPS实验结果的比较说明:如果卫星分布的几何构形得到改善,北斗载波相位时间差分速度估计的精度还可以进一步提高。更多还原

【Abstract】 Beidou-Ⅰsatellite navigation system is the only Chinese satellite navigation system with full independent intellectual property.However,Beidou-Ⅰis inferior to GPS in system structure,positioning mechanism and range of application.To fulfill the requirements of national defense and economic development,there are urgent needs to develop applied technologies based on Beidou system.To overcome the shortcomings of Beidou-Ⅰ,e.g.,large time delay,weak secrecy and limited capacity in active positioning,this thesis proposes a Beidou/SINS integrated navigation technology using time differenced carrier phase,and researches on major theoretic problems and related key technologies.The main works of this thesis are:（1） The mathematic model of time differenced carrier phase is established based on the model of carrier phase and the analyses of temporal/spatial correlation characters of main error sources in carrier phase measurements.The basic principle of time differenced carrier phase/INS integration is presented.It is argued that time differenced carrier phase is an accurate measurement of delta range without ambiguity,because the ambiguity,which is constant unless cycle slips take place,and the common mode errors that are strongly correlated in space and time both are canceled out by time difference. The time differenced carrier phase,which is a function of user’s position changes,can be used to damp the accumulation of navigation errors of INS,obtaining satisfactory navigation accuracy in a relatively long time span.（2） A newly proposed nonlinear global observability analysis approach starting directly from basic concept of observability is introduced to analyze the observability of nonlinear satellite navigation system/INS integrated navigation system.Sufficient conditions for global observability of satellite navigation system/INS integrated navigation system considering the uncertainty of lever arm are presented.The analysis results are supported and validated by simulations and vehicular tests.The global observability analysis approach is straightforward and intuitive,avoiding cumbersome rank evaluation in traditional methods.Because there is no need to approximate the original nonlinear system by a linear models（linear time-varying models or piecewise linear constant models）,the analysis reveals more comprehensively and profoundly the relationship between the system’s observability and the carrier’s movements.The global observability analysis provides the theoretic foundation and a mathematic tool to aid the design of the filter for integrated navigation and online lever arm calibration.（3） By utilizing the approach of global observability analysis and the sufficient conditions,the observability of time differenced carrier phase/SINS system is investigated.It is indicated that for a general navigation satellite system all the states of satellite navigation system/INS integration system except position are observable in normal conditions,if more than 4 satellites are observed.For Beidou I system all the states except position are observable in normal conditions,if the carrier is a land vehicle or a ship,of which the motion is limited in the up direction.Under the guidance of global observability analysis,the filtering models and integrated navigation algorithms are designed.Several key problems of the integrated navigation system,e.g.,reduced order filter,the effect and detection of cycle slips and the application of nonholonomic constrains are studied.The models and algorithms are validated by experiments, including static tests,land vehicle tests and ship tests.The resultes show that the time differenced carrier phase/SINS integration can estimate the errors of SINS precisely, and helps attenuate the accumulation of navigation errors effectively.The Beidou time differenced carrier phase/SINS integrated navigation system can be applied to land vehicles and ships,and has the ability to keep adequate accuracy for a relatively long time without sending out signals and limitations on capacity of users.（4） The problem of velocity determination using time differenced carrier phase is investigated.The research is mainly concentrated on:algorithms of velocity determination,analyses about the precision of velocity estimation and main factors affecting the accuracy,algorithms for deriving carrier phase rate using nonlinear tracking-differentiator and method of time delay compensation.Simulations and vehicular tests are performed to support and validate the theoretic analyses and the algorithms.Simulations and tests show that the user’s velocity can be determined precisely by using time differenced carrier phase.The use of nonlinear tracking-differentiator can weaken the noise amplification and minimize the time delay in differentiation.Under normal observation conditions（6 satellites with velocity geometric dilution of precision at 3-4）,and using single GPS receiver,the velocity accuracy reaches 10^-3 m/s level in static cases,and is comparable to that of DGPS in dynamic cases.But for Beidou system,the accuracy is limited by the number and the geometry of satellites.Under the aid of up-direction constraint,the velocity accuracy reaches 10^-1 m/s in north and 10^-2m/s in east.By analyzing the accuracy of velocity estimation the inner relationship between position accuracy of Beidou time differenced carrier phase/SINS integrated navigation system and the geometry of satellites is explained.Through the analyses of velocity geometric dilution of precision and the comparision of GPS and Beidou system,it is shown that the velocity accuracy could be upgraded if the geometry of Beidou satellites was improved.With the evolution of Beidou system there are great potentials in improving the performance of time differenced carrier phase/SINS integrated navigation system and velocity determination using carrier phase of Beidou system.更多还原