双模式卫星导航定位技术研究

发布时间：2018-06-28 15:50

  本文选题：低轨卫星 + Doppler定位　； 参考：《电子科技大学》2014年硕士论文

【摘要】：随着人们对定位服务需求的激增,全球导航定位系统以及其它电磁波定位技术研究工作方兴未艾。全球导航定位系统虽然具有全天候、高精度等诸多优势并且已在众多领域中发挥着关键作用,但是传统卫星导航系统抗干扰能力弱以及普通用户无法使用被严格保密的用于高精度定位的扩频序列。为了提高某些关键领域中卫星定位服务的独立性和安全性,本文研究一种融合了低轨卫星和全球导航定位系统的双模式卫星导航系统。双模式卫星导航系统利用低轨卫星自身的高动态特性产生的Doppler频偏作为测量目标进行定位解算。本文首先阐述Doppler定位解算原理并详细推导如何利用Doppler频率观测值通过最小二乘法和Kalman滤波法来求解用户位置。接着简要分析Doppler测量过程中的误差来源和卫星几何分布对定位精度的影响。同时介绍常见干扰对定位的危害性以及怎样衡量干扰的大小,并对两类Doppler测量值平滑方法的性能进行比较。分别使用仿真的低轨卫星数据和实际GPS数据对两种Doppler定位解算算法进行实验测试,实验结果表明双模式卫星导航系统中采用的Doppler定位方法可使用户获得十到几百米范围的定位精度。本文重点研究了适合于双模式卫星导航系统的Doppler接收机跟踪环路设计方法,旨在使新设计的接收机跟踪环路既能够在低轨卫星高动态条件下顺利工作同时还能有效减少初始捕获单元的计算量。文章首先介绍了一种新型频率鉴别器,然后给出了传统基于Kalman滤波的锁相环的带宽和频率估计误差计算公式,并分析其性能。最后使用新型频率鉴别器改进传统自适应两阶段Kalman滤波环路,提出了一种锁频环辅助的Kalman滤波跟踪环路设计方案。利用实际采集的GPS数据和模拟低轨卫星数据对新型跟踪环路的仿真测试结果表明此方法不仅能够在高动态环境中正常工作,而且还能够容忍更大的初始频率偏差从而大幅度降低捕获的精度要求。
[Abstract]:With the rapid increase in demand for positioning services, the research of global navigation and positioning system and other electromagnetic wave positioning technology is in the ascendant. Although the Global Navigation and Positioning system has many advantages, such as all-weather, high-precision and so on, it has played a key role in many fields. But the traditional satellite navigation system has weak anti-jamming ability and ordinary users can not use the strictly secret spread spectrum sequence for high-precision positioning. In order to improve the independence and security of satellite positioning service in some key fields, this paper studies a dual-mode satellite navigation system which combines Leo satellite and global navigation positioning system. The dual-mode satellite navigation system uses the Doppler frequency offset generated by the high dynamic characteristics of the Leo satellite as the target to locate and calculate. In this paper, the principle of Doppler location solution is introduced, and how to use Doppler frequency observations to solve user's position by least square method and Kalman filter method is deduced in detail. Then, the error sources and the influence of satellite geometry distribution on the positioning accuracy are analyzed briefly. At the same time, the harmfulness of common interference to localization and how to measure the magnitude of interference are introduced, and the performance of two kinds of Doppler measurement smoothing methods are compared. Using simulated Leo satellite data and actual GPS data, two Doppler positioning solution methods are tested. The experimental results show that the Doppler localization method used in the dual-mode satellite navigation system can achieve the positioning accuracy in the range of 10 to several hundred meters. This paper focuses on the design method of Doppler receiver tracking loop suitable for dual-mode satellite navigation system. The new designed receiver tracking loop can not only work smoothly under the high dynamic condition of Leo satellite, but also reduce the computation of the initial acquisition unit effectively. In this paper, a new frequency discriminator is introduced, then the calculation formulas of bandwidth and frequency estimation error of traditional phase-locked loop based on Kalman filter are given, and its performance is analyzed. Finally, a new frequency discriminator is used to improve the traditional adaptive two-stage Kalman filter loop, and a design scheme of the frequency-locked loop aided Kalman filter tracking loop is proposed. The simulation results of GPS data and simulated Leo satellite data show that this method can not only work normally in high dynamic environment, but also in high dynamic environment. Moreover, it can tolerate larger initial frequency deviation and greatly reduce the precision requirement of capture.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN967.1
，

本文编号：2078527