GNSS动态定位中附有约束条件的整周模糊度解算

发布时间：2018-08-18 11:00

【摘要】：GNSS系统提供的观测值中,伪距观测值无法满足高精度的定位要求,因此研究通过载波观测值快速准确地获得定位信息显得尤为重要。整周模糊度是仅存在于载波观测值中的一个参数,且快速正确的求解出整周模糊度参数是实现高精度定位的关键所在。在模糊度解算时利用已存在的先验信息加以约束可加快模糊度参数的快速分解,为此本文针对GNSS动态定位中考虑附有轨迹约束条件的模糊度分解模型与算法进行了深入的研究。本文的主要研究内容如下:1.本文对GNSS基本观测量和测量原理进行介绍,并详细阐述了GNSS观测方程,观测方程的线性化过程、观测量之间的线性组合以及GNSS相对定位技术。2.概述了基于广播星历计算卫星位置的方法,并以实例分析了广播星历计算卫星坐标的可行性和误差。随后介绍了常用的周跳探测与修复方法,鉴于宽巷相位减窄巷伪距法以及电离层残差法中的不足之处,对两种方法进行了改进,并基于改进后的两种方法提出了一种基于双频非差GNSS相位数据周跳的实时探测与修复方法。通过实测静态数据及动态数据进行实验,验证了该方法可以实时探测并修复观测值中存在的小周跳,大周跳,且在低高度角情况下同样具有良好的效果。3.介绍了整周模糊度解算的理论和方法,并对单历元整周模糊度参数的解算进行主要研究。顾及宽巷组合观测值波长相对更长的优点,本文采用先固定宽巷整周模糊度参数,其次通过宽巷模糊度和1L,2L模糊度之间的关系,进一步求解1L,2L频率整周模糊度的流程进行解算。对于宽巷模糊度的固定,本文提出基于VTV(28)Min准则搜索确定宽巷模糊度参数,通过实测的动态数据验证该方法是可行的。4.针对动态单历元解算时存在浮点解精度差,不易正确确定整周模糊度的问题,提出采用接收机运动轨迹作为约束条件来改善这一问题,以提高解算的成功率。在建立约束条件的过程中,当轨迹信息不明确时,提出根据宽巷相对定位求解接收机坐标,通过改正后的坐标动态建立直线方程作为约束条件进行解算。设计了相关实验,分别采用不引入约束条件、引入已知先验信息建立的约束条件以及引入动态约束条件的实验方案解算整周模糊度,并对模糊度固定结果进行了对比分析,证明了提出方法的可行性及正确性。
[Abstract]:Among the observations provided by GNSS system, pseudo-range observations can not meet the requirements of high precision positioning, so it is very important to study how to obtain the location information quickly and accurately by carrier observations. Integer ambiguity is a parameter that only exists in carrier observations, and the key to achieve high precision location is to solve the integer ambiguity parameter quickly and correctly. The fast decomposition of ambiguity parameters can be accelerated by using prior information in ambiguity resolution. In this paper, the fuzzy decomposition model and algorithm with locus constraints in GNSS dynamic location are studied in depth. The main contents of this paper are as follows: 1. In this paper, the basic observations and measurement principles of GNSS are introduced, and the GNSS observation equation, the linearization process of the observation equation, the linear combination between the observations and the relative positioning technique of GNSS. 2 are described in detail. This paper summarizes the method of calculating satellite position based on broadcast ephemeris, and analyzes the feasibility and error of satellite coordinate calculation by broadcasting ephemeris. Then the common methods of cycle slip detection and repair are introduced. In view of the shortcomings of the method of reducing pseudo-range of wide lane phase and the method of ionospheric residuals, the two methods are improved. Based on the two improved methods, a real-time detection and repair method of cycle slips based on dual-frequency non-differential GNSS phase data is proposed. The experimental results of static and dynamic data show that the proposed method can detect and repair the small cycle slip and large cycle slip in the observed data in real time, and it also has a good effect at low altitude angle. This paper introduces the theory and method of integer ambiguity resolution, and mainly studies the solution of integer ambiguity parameter of single epoch. Considering the advantage that the wavelength of the observation value of the wide roadway combination is relatively long, the whole cycle ambiguity parameter of the wide lane is fixed first, and the process of solving the integer cycle ambiguity of 1L ~ (2) L frequency through the relation between the wide lane ambiguity and the 1L ~ (2) L ambiguity is adopted in this paper. For the fixed ambiguity of wide roadway, this paper presents a method based on VTV (28) Min criterion to determine the ambiguity parameter of wide roadway. The method is proved to be feasible by dynamic data measured. In order to solve the problem that the precision of floating point solution is poor and it is difficult to determine the ambiguity of whole cycle correctly, the problem that the receiver motion trajectory is used as the constraint condition is put forward to improve the success rate of the solution. In the process of establishing the constraint condition, when the track information is not clear, the receiver coordinates are solved according to the relative positioning of the wide lane, and the linear equation is dynamically established by the corrected coordinates as the constraint condition to solve the problem. The relative experiments are designed to calculate the integer ambiguity by using the constraint condition without the constraint condition, the known prior information and the dynamic constraint condition, respectively, and the results of fixed ambiguity are compared and analyzed. The feasibility and correctness of the proposed method are proved.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4

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