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1. 发明授权

US6160841A Mitigation of multipath effects in global positioning system receivers 失效
标题翻译：在全球定位系统接收机中减轻多径效应
公开(公告)号：US6160841A
公开(公告)日：2000-12-12
申请号：US999553
申请日：1997-11-21
申请人： Thomas Atlee Stansell, Jr. , Jerry Eugene Knight , Richard Gerald Keegan , Charles Robert Cahn
发明人： Thomas Atlee Stansell, Jr. , Jerry Eugene Knight , Richard Gerald Keegan , Charles Robert Cahn
IPC分类号： G01S1/00 , H04B1/7085 , H04B7/005 , H04K1/00
CPC分类号： H04B1/7085 , G01S19/22 , H04B7/005 , H04B2201/70715
摘要： A technique for minimizing or eliminating the effect of multipath signals in a receiver processing pseudorandom (PRN) code signals, such as in a global positioning system (GPS) receiver. The presence of multipath signals adversely affects both code measurements and carrier phase measurements of received PRN signals. One aspect of the invention provides for improved code tracking in the presence of multipath signals, by sampling the received code with a multipath mitigation window (MMW) (FIG. 25D) that results in a code error function (FIG. 25F) that reduces or eliminates the multipath effects. The MMW, which may be any of a number of preferred waveforms (FIGS. 35B-35E), provides a code error function that varies in opposite directions from zero at a desired tracking point (402), but assumes a nearly zero value when the MMW is advanced from the tracking or synchronization point by more than a small fraction of a code chip. Because of this nearly zero code error value on the early side of the desired tracking point, delayed multipath signals will have a corresponding code error function that is nearly zero (FIG. 25F) at the desired tracking point of the directly received signals, and the multipath signals will, therefore, have little or no effect on the desired tracking point and on code synchronization. The effects of multipath signals on carrier phase measurements are minimized by sampling the received signals, together with their possible multipath components, before and immediately after code transitions (vectors A and B, respectively). The vector relationship of the directly received (D) and multipath (M) signals is such that performing a vector average of the two types of samples (A and B) produces the directly received signal (D) and its correct phase, with many, if not all, of the multipath components (M) eliminated.
摘要翻译：一种用于最小化或消除接收机处理伪随机（PRN）码信号中的多径信号对全球定位系统（GPS）接收机的影响的技术。多径信号的存在对接收的PRN信号的码测量和载波相位测量产生不利影响。本发明的一个方面提供了在存在多径信号的情况下通过用多路径减轻窗口（MMW）对接收到的代码进行采样（图25D）来改进代码跟踪，导致代码错误功能（图25F），其减少或消除了多径效应。可以是多个优选波形（图35B-35E）中的任何一个的MMW提供了在期望的跟踪点（402）处与零相反的方向变化的码误差函数，但是当 MMW从跟踪或同步点超过代码芯片的一小部分。由于在期望的跟踪点的早期这个几乎为零的码错误值，延迟的多径信号将具有在直接接收的信号的期望的跟踪点处几乎为零（图25F）的相应的码误差函数，并且因此，多径信号对所需的跟踪点和代码同步几乎没有影响。通过在代码转换之前和之后（分别为向量A和B）对接收到的信号及其可能的多径分量进行采样，使多径信号对载波相位测量的影响最小化。直接接收（D）和多路径（M）信号的向量关系使得执行两种类型的采样（A和B）的矢量平均产生直接接收的信号（D）及其正确的相位，如果不是全部，多路径分量（M）被消除。

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