CAJ | 학술논문

根据多径信号的产生机理,在对GPS接收机中的码跟踪环多径信号模型研究的基础上,提出了采用自适应滤波的来消除GPS多径效应的算法.自适应滤波的方法不需要估计模型的系统参数,而直接通过自适应滤波将多径信号滤除.在有噪声的情况下,自适应滤波的RLS算法是最小二乘意义下的最优估计.仿真的结果表明采用自适应滤波算法可以快速的消除多径的影响,修正鉴相函数的过零点偏差,提高码跟踪环的跟踪精度.由于自适应滤波算法是递推算法,易于软、硬件实现.
근거다경신호적산생궤리,재대GPS접수궤중적마근종배다경신호모형연구적기출상,제출료채용자괄응려파적래소제GPS다경효응적산법.자괄응려파적방법불수요고계모형적계통삼수,이직접통과자괄응려파장다경신호려제.재유조성적정황하,자괄응려파적RLS산법시최소이승의의하적최우고계.방진적결과표명채용자괄응려파산법가이쾌속적소제다경적영향,수정감상함수적과영점편차,제고마근종배적근종정도.유우자괄응려파산법시체추산법,역우연、경건실현.
Multipath not only degrades the sensitivity of a GPS receiver,but also becomes the dominant error resource in GPSpositioning systems. Multipath mitigation algorithm is the most significant in high sensitive and high accuracy GPS receivers. In this paper,multipath signal model in code tracking loop is studied first and a novel method for mitigation of multipath is presented which employs adaptive filtering recursive least square (RLS) algorithm. The system parameters need not be estimated in adaptive filtering algorithm and multipath signal can be filtered out directly. Under noisy scenario,the RLS algorithm is the best estimate for the filter weights with minimum least-squares errors. Simulation results show that the proposed method can reduce multipath error envelope effectively. The crossing-zero bias of the discriminator can be corrected which enhances the accuracy of code tracking in GPS receiver's delay-locked loop (DLL). The most importance is that the RLS algorithm is recursive and convenient to implement both in hardware and software.