卫星导航系统单频定位技术研究

发布时间：2018-03-29 04:27

本文选题：单频　切入点：多径　出处：《国防科学技术大学》2013年硕士论文

【摘要】：BDS目前只公布了B1频点数据,因此民用BDS接收机均是单频接收机,GPS民用接收机也以单频接收机为主。单频接收机在定位精度、稳定度等方面很难与双频甚至三频接收机相比,为提高定位精度,需要对单频接收机定位精度提高办法进行研究。本文首先分析了伪距观测值误差特性及误差抑制方法,然后从提高观测值精度和优化定位算法两个方面研究了提高单频定位精度的方法。本文主要内容包括三个方面:第一,伪距观测值误差特性及误差抑制方法。与GPS系统星座不同,我国BDS系统星座为GEO,MEO,IGSO三种卫星组成的混合星座。针对BDS的这一特性,利用实测数据分析了不同类型卫星的观测值误差特点,着重研究了伪距多径误差特性,实测数据表明:IGSO与MEO伪距观测值多径误差表现出相近特性,GEO卫星伪距观测值多径误差表现出慢变特性。第二,穿刺点周围格网点部分不可用时的电离层延迟修正方法。格网电离层修正是一种精度较高的单频电离层延迟修正方法,广泛应用于广域差分系统。由于通信故障、误码等原因导致接收机接收的部分格网信息不可用,传统垂直电离层延迟的计算方法在电离层发生剧烈变化时会引入较大误差。针对这一问题,提出了基于部分格网信息不可用时的电离层修正方法,并在实测数据基础上进行仿真,仿真结果表明,该方法提高了穿刺点周围格网点信息部分不可用时的电离层延迟修正精度。最后,利用实测数据对基于格网电离层延迟修正的广域差分定位性能进行评估,并与不使用广域差分信息且利用模型法修正电离层延迟定位结果进行比较,结果表明:基于格网电离层延迟修正的广域差分定位定位结果明显优于其它几组定位结果。第三,基于观测数据融合的抗差卡尔曼滤波定位技术。伪距观测值误差较大,且受到干扰时可能含有较大粗差,容易导致卡尔曼滤波定位结果发散。针对这一问题,提出基于载波平滑伪距的卡尔曼滤波技术。实测数据表明,该方法可以增加卡尔曼滤波对误差(尤其是伪距粗差)的抑制能力,抑制卡尔曼滤波发散;为充分利用单频接收机观测数据,提高定位精度,对经典卡尔曼滤波观测方程进行改进,提出了基于数据融合的滤波解算技术,实测数据表明:该方法提高了单频接收机数据利用率,提高了非急转弯情况下滤波解算定位精度。
[Abstract]:At present, BDS only publishes B1 frequency data, so civil BDS receivers are mainly single-frequency receivers. It is difficult for single-frequency receivers to compare with dual-frequency or even three-frequency receivers in positioning accuracy and stability. In order to improve the positioning accuracy, it is necessary to study the method of improving the positioning accuracy of single frequency receiver. Firstly, the error characteristics of pseudo-range observation value and the method of error suppression are analyzed in this paper. Then, the methods of improving the accuracy of single frequency location are studied from two aspects: improving the precision of observation value and optimizing the localization algorithm. The main contents of this paper include three aspects: first, Error characteristics of pseudo-range observations and error suppression methods. Unlike GPS system constellations, China's BDS system constellations are mixed constellations composed of three kinds of satellites, GEOMEOOIGSO. In view of this characteristic of BDS, The characteristics of observation errors of different types of satellites are analyzed by using the measured data, and the characteristics of pseudo-range multipath errors are emphatically studied. The measured data show that the multipath error of the pseudo-range observation value of MEO and that of the MEO pseudo-range shows similar characteristics. The multipath error of the pseudo-range observation value of GEO satellite shows the characteristic of slow variation. The correction method of ionospheric delay is a high precision single frequency ionospheric delay correction method, which is widely used in wide area differential system. Because of error code and other reasons, some grid information received by receiver is not available. The traditional calculation method of vertical ionospheric delay will introduce large error when the ionosphere changes dramatically. An ionospheric correction method based on the non-availability of partial grid information is proposed and simulated on the basis of measured data. The simulation results show that, This method improves the accuracy of ionospheric delay correction when the information of the grid dot around the puncture point is not available. Finally, the wide area differential location performance based on the grid ionospheric delay correction is evaluated by using the measured data. The results are compared with the results of correction of ionospheric delay location using model method without using wide area differential information. The results show that the results of wide area differential positioning based on grid ionospheric delay correction are obviously superior to those of other groups. Third, Robust Kalman filter location technology based on observation data fusion. The error of pseudo-range observation value is large, and there may be a large gross error when it is disturbed, which can easily lead to the divergence of Kalman filter location results. The Kalman filtering technique based on carrier smoothing pseudo-range is proposed. The measured data show that the proposed method can increase the ability of Kalman filtering to suppress the error (especially the gross error of pseudo-range) and restrain the divergence of Kalman filter. In order to make full use of the observation data of single frequency receiver and improve the positioning accuracy, the classical Kalman filter observation equation is improved, and the filtering solution technology based on data fusion is proposed. The measured data show that this method can improve the data utilization ratio of single frequency receiver and improve the accuracy of filtering and positioning in the case of non-sharp turning.
【学位授予单位】：国防科学技术大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P228.4

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