GPS信号可用性评价及定位精度改善方法研究

发布时间：2018-08-13 13:03

【摘要】：GPS从最初的军事上的应用到现在被广泛应用到各个领域，已经得到了长足的发展，与人们的生活密不可分。并且技术上较早期的GPS系统也有了很大的进步，无论是授时还是定位导航，在理想条件下其精度都可以满足人们的需要。但是在实际条件下，尤其是在高楼林立的城市中，存在着各种遮挡，包括较高的楼层、高架桥、路旁的大树、以及GPS信号的多径效应等，造成GPS信号并不是实时的可用，定位的精度也受到了较大的影响。本文主要是对GPS信号的可用性评价与改善GPS定位精度两个方面进行了研究。首先，介绍了与GPS信号可用性有关的几点因素，包括GPS定位的精度因子、多径效应的影响等。并在实测试验中，以NI公司的labview为平台，通过编写的GPS信号接收与处理软件，对GPS信号的可用性进行了分析。采集了一段时间内部分区域实验数据，计算了的GPS信号的可用性，并观察了GPS信号的可用性与精度因子、可见卫星数量等的关系。其次，由于现实环境下GPS信号偶尔会被遮挡和干扰，其定位的精度受到了一定的影响。消除GPS随机误差的重要方法是对其进行动态滤波。文中将扩展卡尔曼滤波应用到GPS定位系统中去。建立了GPS定位系统的数学模型，，将选取的状态量的真实值从随机干扰中最优估计出来。在实测实验中，将GPS信号接收与处理软件与所建立的扩展卡尔曼滤波模型结合起来，并用matlab对滤波过程进行实现。结果表明所建立的GPS定位系统模型准确，对GPS定位精度起到了一定的改善作用。总之，本文通过对GPS可用性评价的研究和将扩展卡尔曼滤波的方法应用到GPS定位系统，研究了影响GPS信号可用性的因素，应用扩展卡尔曼滤波算法改善了GPS接收机的定位精度，在涉及到导航定位的应用领域有一定的借鉴和参考价值。
[Abstract]:GPS has been widely used in various fields from the initial military application to the present. It has made great progress and is closely related to people's life. And the early GPS system has also made great progress in technology, whether it is timing or positioning navigation, in ideal conditions, its accuracy can meet the needs of people. But in the actual condition, especially in the city with high buildings, there are many kinds of occlusion, including the higher floor, the viaduct, the big tree beside the road, and the multipath effect of GPS signal, so the GPS signal is not available in real time. Positioning accuracy is also greatly affected. In this paper, the usability evaluation of GPS signal and the improvement of GPS positioning accuracy are studied. Firstly, several factors related to the availability of GPS signal are introduced, including the accuracy factor of GPS location and the influence of multipath effect. The usability of GPS signal is analyzed by using GPS signal receiving and processing software written on the platform of labview of NI company. Some regional experimental data are collected for a period of time, and the availability of GPS signal is calculated. The relationship between the availability of GPS signal and the accuracy factor, the number of satellites and so on is observed. Secondly, the positioning accuracy of GPS signal is affected by the occasional occlusion and interference in real environment. Dynamic filtering is an important method to eliminate the random error of GPS. In this paper, extended Kalman filter is applied to GPS positioning system. The mathematical model of GPS positioning system is established, and the real value of the selected state is estimated from the random disturbance. In the experiment, the GPS signal receiving and processing software is combined with the extended Kalman filter model, and the filtering process is realized by matlab. The results show that the established GPS positioning system model is accurate, and it can improve the positioning accuracy of GPS. In a word, through the research of GPS usability evaluation and the application of extended Kalman filter to GPS positioning system, the factors that affect the availability of GPS signal are studied, and the location accuracy of GPS receiver is improved by using extended Kalman filter algorithm. It has some reference value in the application field of navigation and positioning.
【学位授予单位】：沈阳航空航天大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：P228.4

【参考文献】