【作者】 郑利龙；

【导师】 曹志刚；

【作者基本信息】 清华大学 ， 信息与通信工程， 2004， 博士

【摘要】 本文对复杂环境下GPS信号参数估计与定位方法进行了研究,完成了GPS信号伪码延时估计、GPS信号接收的抗多径及抗干扰技术、GPS组合定位方法的有关理论分析与应用方法分析,提出了载波辅助的伪距时延估计算法、提出智能天线在消除GPS多径效应的应用和其抗干扰方法并研究GPS/DR组合定位的数据融合算法。论文的主要工作包括下述几个方面:在研究高动态环境中多普勒频率对伪码延时测量精度的影响的基础上,使用扩展卡尔曼滤波方法进行载波相位和频率的估计,并利用载波辅助技术由载波相位的变化来校正伪码延时环,降低多普勒频移对伪码延时环的直接影响,从而得到准确的伪码延时估计,提高了伪码延时环的动态性能。在详细分析多径信号特点的基础上,对多径信号引入的接收机的伪距测量误差和载波相位跟踪误差进行了深入分析,给出了减小多径误差的方法,提出了消除多径效应的接收机天线在GPS抗干扰方面的应用。同时,针对GPS信号传播环境的复杂性和由此引发的干扰的多样性,对GPS信号接收的抗干扰方法进行了深入研究,提出了基于现代智能天线技术的抗干扰方法,实验结果证明方法的有效性。 给出了车载GPS/DR组合导航系统的结构,建立了该导航系统的数学模型。然后针对一般组合滤波算法中,由于DR系统误差的引入,导致滤波效果不好的问题,提出了一种组合导航系统的数据融合算法和进行了实际跑车数据的处理。针对GPS应用技术、产品相对成熟的现状和GLONASS与GPS的相似性,探讨利用GPS技术实现GLONASS接收机的可能性,设计了以GPS芯片组为核心的GLONASS C/A码接收机方案。同时,对组合定位中的若干算法进行了研究,包括组合定位模型及其求解方法,几何精度因子的计算和选星算法,电离层延迟的补偿方法等。针对香港的交通环境特点,给出了改进的地图匹配代价函数的定义,采用模糊综合评判的方法进一步给出了地图匹配可信度的概念。在此基础上给出了GPS和地图匹配的融合定位方法,该方法只在软件上加以改进,不需要增加额外的定位传感器,因此系统的成本和复杂度较低。同时不存在DR系统的误差积累<WP=5>问题,因此对数据融合算法的要求较低,但是对地图的精度要求较高。实验结果证明方法的有效性。超宽带和GPS融合定位不仅提高定位的精度而且适应多种场合。比如室内。本章在详细介绍UWB原理的基础上,论述了GPS和UWB组合定位的原理,给出GPS和UWB组合定位的模型和误差分析。更多还原

【Abstract】 This dissertation is going to study the GPS signal parameter estimation and positioning methodologies. We have fulfilled the studies of the pseudo-code delay estimation, the anti-multipath technique of the GPS signals and the GPS positioning fusion method. The pseudo-range delay estimation with the assistance of the carrier signal of the GPS is proposed. The making use of smart antenna to cope with multipath effect is investigated and the GPS/DR combination and the data fusion algorithm have been studied. GPS/MM technique providing better positioning performances has shown. GPS/UWB combined postioning system is discussed as well. The major works of this thesis are as follows:The effect of the Doppler frequency precision measurement of the pseudo-code delay in high dynamic circumstance is studied. The usage of the extended-Kalman-filter (EKF) method in estimation of the carrier phase and the receiving signal frequency are being investigated. Also making use of the carrier-assisted technology, we can calibrate the pseudo-code delay loop through carrier-phase deviations. Such that we can obtain the accurate pseudo-code delay estimation and improve the dynamic performance of the pseudocode delay loop.After careful analysis of the characteristics of the multipath signals, for those measurement pseudo-range errors and carrier-phase tracking errors which introduced by the mutlipath effect have a thorough study. The reduction of multipath effect by introduction of anti-multipath smart antenna is discussed. In a complicated environment, the performance of GPS is dependidng on the interference of the environment. A study on the anti-multipath effect is carried out and the smart antenna is used to tackle this problem and the anti-RF interference technologies are considered in this section. Besides, the structure of the vehicle integrated system with GPS/DR is given and the mathematical model of this system is established. Errors caused by the DR give poor signal performances. We proposed a data fusion algorithm for this <WP=7>integrated navigation system and the algorithm has improved the accuracy of the GPS and this is tested by actual vehicle data.The GPS and GLONASS receivers have quite similarity structures. With the maturity of the GPS technology and products, we would like to investigate the possibility of using GPS technology to develop the GLONASS receivers. The GLONASS C/A code receiver design is based on the GPS chip sets. Also the algorithm for the combined GLONASS/GPS including the combined positioning model and its calculating method are studied. The methods for calculating the GDOP, the satellite selection and ionospheric delay compensation are also discussed.Base on the complicated traffic environment of Hong Kong, the electronic map information is used to improve the accuracy of the positioning information of the vehicle obtained from the GPS signals. Also a modified map matching algorithm is introduced. The advantage of this method is that no additional hardwares or sensors are needed and the improvement of the positioning accuracy is based on the software and the proposed algorithm. Finally, we would like to investigate the navigation system reliability and robustness with the help of the GPS and UWB technologies.更多还原