网络RTK电离层完备性监测
发布时间：2018-09-18 16:32
【摘要】：完备性是指系统在导航系统有任何故障或误差超限不能应用于导航和定位服务时向用户发送警告信息的能力。本文通过理论分析和实验验证质量控制和完备性问题,保证实时网络RTK的成功运行。由于电离层变化非常复杂,并且难于建模,电离层延迟是影响网络RTK定位的主要无差源。使用NRTK系统可以对电离层误差的大部分(低阶项)进行建模和消除。然而,在太阳或地磁风暴或电离层扰动期间,存在较大的电离层残差,影响了相位模糊度的确定和网络RTK的性能。因此,完备性需要通过电离层完备性监测来监测和控制电离层残余无差,以保证流动站定位的可靠性和可用性。网络RTK的电离层完备性监测包括以下四方面。第一,估计和分析电离层延迟;第二,构建了电离层插值模型;第三,计算电离层残差完备性监测指标(IRIM);第四,计算电离层残插值不确定度(IRIU)。本文实验采用了广东省CORS站2015年9月11日和9月22日两天的两个子网数据,采样间隔1秒。基线长度对模糊度的正确固定有重要的影响。基线长度越短,双差的残余误差越小。通常双差电离层延迟在分米到厘米级别,当基线的长度较长时,它会变大。因此,双差电离层延迟在很大程度上取决于基线长度。由于电离层活动的特点及其在空间中的弥散特性,利用区域误差模型预测流动站处的改正数是一种常用方法。在这些模型中,Wanninger(1995)提出的线性插值法(LIM)是典型的且最常用的获取流动站误差预测值的插值方法。对不同时段和测站网的电离层改正残差的分析表明了改正精度的变化及其对电离层条件的依赖性。的双差电离层延迟真值和双差电离层残差会受太阳辐射的影响,特别是在下午和傍晚时,双差电离层延迟及其残差会很大。电离层活动的变化取决于太阳辐射量。由于电离层残差的线性部分通常已经通过插值方法剔除,残留在网中的主要是非线性部分,该部分无法通过插值来建模。因此,电离层的线性度可以为网内的电离层插值误差和电离层残余误差提供一个好的估值。在计算得到了基线的双差电离层延迟并建立了插值模型后,可以利用电离层残余完备性监测(IRIM)和电离层残余完备性不确定性(IRIU)来监测剩余残差。完备性监测指标IRIM和IRIU的对应值与电离层残差的变化相似。IRIM和IRIU都反映了电离层残差的情况。
[Abstract]:Completeness refers to the ability of the system to send warning information to the user when there is any fault in the navigation system or when the error exceeds the limit and cannot be applied to the navigation and positioning service. In this paper, the quality control and completeness problem are verified by theoretical analysis and experiment to ensure the successful operation of RTK in real time network. Because of the complexity of ionospheric variation and the difficulty in modeling, ionospheric delay is the main non-differential source of network RTK location. Most of the ionospheric errors (low order terms) can be modeled and eliminated by using NRTK system. However, during solar or geomagnetic storms or ionospheric disturbances, there are large ionospheric residuals, which affect the determination of phase ambiguity and the performance of network RTK. Therefore, the completeness needs to monitor and control the ionospheric residual error through ionospheric completeness monitoring to ensure the reliability and availability of mobile station location. The ionospheric completeness monitoring of the network RTK consists of the following four aspects. First, estimate and analyze ionospheric delay; second, construct ionospheric interpolation model; third, calculate ionospheric residual completeness monitoring index (IRIM); fourth, calculate ionospheric residual interpolation uncertainty (IRIU). In this paper, two subnet data from CORS station in Guangdong province, September 11, 2015, and September 22, 2015, are used. The sampling interval is 1 second. Baseline length has an important effect on the correct fixation of ambiguity. The shorter the baseline length, the smaller the residual error of double difference. Usually the double-difference ionospheric delay is in the decimeter to centimeter level, when the baseline length is longer, it will become larger. Therefore, the double difference ionospheric delay depends to a large extent on the baseline length. Because of the characteristics of ionospheric activity and its dispersion in space, it is a common method to predict the corrections at mobile stations by using the regional error model. In these models, (LIM), a linear interpolation method proposed by Wanninger (1995), is a typical and most commonly used interpolation method to obtain the error prediction value of mobile station. The analysis of ionospheric correction residuals in different periods and stations shows the variation of correction accuracy and its dependence on ionospheric conditions. The true values of the double difference ionospheric delay and the double difference ionospheric residuals will be affected by solar radiation, especially in the afternoon and evening, the double difference ionospheric delay and its residuals will be very large. Changes in ionospheric activity depend on the amount of solar radiation. Because the linear part of the ionospheric residuals is usually eliminated by interpolation, the residual part in the network is mainly nonlinear, which cannot be modeled by interpolation. Therefore, the ionospheric linearity can provide a good estimate for the ionospheric interpolation error and the ionospheric residual error in the network. After the double difference ionospheric delay of the baseline is calculated and the interpolation model is established, the residual (IRIM) can be monitored by using the ionospheric residual completeness and the ionospheric residual completeness uncertainty (IRIU) can be used to monitor the residual error. The corresponding values of IRIM and IRIU are similar to the variation of ionospheric residuals. IRIM and IRIU both reflect the ionospheric residuals.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4;P352.7
[Abstract]:Completeness refers to the ability of the system to send warning information to the user when there is any fault in the navigation system or when the error exceeds the limit and cannot be applied to the navigation and positioning service. In this paper, the quality control and completeness problem are verified by theoretical analysis and experiment to ensure the successful operation of RTK in real time network. Because of the complexity of ionospheric variation and the difficulty in modeling, ionospheric delay is the main non-differential source of network RTK location. Most of the ionospheric errors (low order terms) can be modeled and eliminated by using NRTK system. However, during solar or geomagnetic storms or ionospheric disturbances, there are large ionospheric residuals, which affect the determination of phase ambiguity and the performance of network RTK. Therefore, the completeness needs to monitor and control the ionospheric residual error through ionospheric completeness monitoring to ensure the reliability and availability of mobile station location. The ionospheric completeness monitoring of the network RTK consists of the following four aspects. First, estimate and analyze ionospheric delay; second, construct ionospheric interpolation model; third, calculate ionospheric residual completeness monitoring index (IRIM); fourth, calculate ionospheric residual interpolation uncertainty (IRIU). In this paper, two subnet data from CORS station in Guangdong province, September 11, 2015, and September 22, 2015, are used. The sampling interval is 1 second. Baseline length has an important effect on the correct fixation of ambiguity. The shorter the baseline length, the smaller the residual error of double difference. Usually the double-difference ionospheric delay is in the decimeter to centimeter level, when the baseline length is longer, it will become larger. Therefore, the double difference ionospheric delay depends to a large extent on the baseline length. Because of the characteristics of ionospheric activity and its dispersion in space, it is a common method to predict the corrections at mobile stations by using the regional error model. In these models, (LIM), a linear interpolation method proposed by Wanninger (1995), is a typical and most commonly used interpolation method to obtain the error prediction value of mobile station. The analysis of ionospheric correction residuals in different periods and stations shows the variation of correction accuracy and its dependence on ionospheric conditions. The true values of the double difference ionospheric delay and the double difference ionospheric residuals will be affected by solar radiation, especially in the afternoon and evening, the double difference ionospheric delay and its residuals will be very large. Changes in ionospheric activity depend on the amount of solar radiation. Because the linear part of the ionospheric residuals is usually eliminated by interpolation, the residual part in the network is mainly nonlinear, which cannot be modeled by interpolation. Therefore, the ionospheric linearity can provide a good estimate for the ionospheric interpolation error and the ionospheric residual error in the network. After the double difference ionospheric delay of the baseline is calculated and the interpolation model is established, the residual (IRIM) can be monitored by using the ionospheric residual completeness and the ionospheric residual completeness uncertainty (IRIU) can be used to monitor the residual error. The corresponding values of IRIM and IRIU are similar to the variation of ionospheric residuals. IRIM and IRIU both reflect the ionospheric residuals.
【学位授予单位】：武汉大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P228.4;P352.7
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