GNSS单历元基线解算方法研究

发布时间：2018-08-30 18:27

【摘要】：GNSS单历元定位算法不受周跳的影响,可在卫星失锁后立即重新初始化,在观测环境较恶劣时,单历元相对于多个历元观测数据利用率更高。高精度的实时定位需要模糊度的快速正确固定。虽然双频单历元模糊度固定在实际应用中验证了其高效性和可靠性,但其性能易受到观测环境的影响。单频观测值因受到跟踪卫星数量,基线长度和观测环境的影响,模糊度初始化一般需要几分钟。而多GNSS系统的组合为模糊度的固定提供新的思路和数据支撑。本文针对单历元模糊度固定及其基线解算主要进行以下几方面的研究:1)简要介绍了 GNSS不同系统概况及测量过程中病态问题产生的原因及其解决方法;重点围绕GPS和BDS两系统组合进行分析。2)推导载波双差观测方程的基础上分析单历元模糊度固定中方程出现病态的原因,针对短基线仅采用单频载波相位构建双差载波方程,借助于正则化相关理论解决单历元观测方程的秩亏问题和最小二乘浮点解不可信的问题,提高了单历元整周模糊度固定的成功率。3)对于中长基线单历元模糊度固定率较低的问题,借鉴短基线单历元模糊度固定方法,对中长基线采用两步正则化实现双频单历元模糊度固定,即通过伪距和宽巷载波组合,经过一步正则化实现单历元宽巷模糊度的固定,在此基础上构建无电离层组合,结合已固定的宽巷模糊度,经过第二步正则化实现原始载波模糊度固定。4)针对中长基线模糊度固定后对流层残余误差与高程方向存在相关性问题,文中采用对流层延迟系数构造去相关矩阵,同时考虑对流层参数个数对去相关的影响,分别采用2个系数和1个系数两种方案进行计算,结果表明,考虑一个对流层参数的效果较好,有效地改善了高程方向的定位精度,56 km基线平面和高程的精度均达到毫米级,170 km基线解算精度优于2 cm。
[Abstract]:The GNSS single epoch location algorithm is independent of cycle slip and can be reinitialized immediately after the satellite has lost its lock. When the observation environment is bad, the single epoch data utilization ratio is higher than that of multiple epoch observations. High-precision real-time positioning requires fast and correct fixing of ambiguity. Although the ambiguity of double frequency single epoch is fixed in practical application, its efficiency and reliability are verified, but its performance is easily affected by observation environment. Because the single frequency observations are affected by the number of tracking satellites, the baseline length and the observation environment, the ambiguity initialization usually takes several minutes. The combination of multiple GNSS systems provides new ideas and data support for ambiguity fixation. In this paper, aiming at the fixed ambiguity of single epoch and its baseline solution, the following aspects are mainly studied: 1) the general situation of different GNSS systems and the causes of the pathological problems in the measurement process and their solutions are briefly introduced in this paper. Focusing on the analysis of the combination of GPS and BDS (2) based on the derivation of carrier double difference observation equation, this paper analyzes the pathological reasons of the equation in the fixed ambiguity of single epoch. In view of the short baseline, only single frequency carrier phase is used to construct the double differential carrier equation. By means of regularization correlation theory, the rank deficiency problem and the least square floating point solution of the single epoch observation equation are solved. The success rate of integer ambiguity fixation of single epoch is improved. 3) for the problem of low fixed rate of single epoch ambiguity of medium and long baseline, the short baseline single epoch ambiguity fixation method is used for reference. Two-step regularization is used to realize the fixed ambiguity of double frequency single epoch, that is, through pseudo-range and wide-lane carrier combination, the single-epoch wide-lane ambiguity is fixed by one-step regularization. On this basis, the ionospheric combination is constructed. Combined with the fixed wide lane ambiguity, the original carrier ambiguity is fixed by the second step regularization.) aiming at the correlation between the tropospheric residual error and the elevation direction after the middle and long baseline ambiguity is fixed, In this paper, the delocalization matrix is constructed by the tropospheric delay coefficient, and the influence of the number of tropospheric parameters on the de-correlation is considered. The effect of considering a tropospheric parameter is good, and the positioning accuracy of elevation direction is improved effectively. The accuracy of 56 km baseline plane and elevation reach millimeter level 170 km baseline. The accuracy is better than 2 cm..
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4

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