AltBOC无模糊双重估计跟踪环路设计

Unambiguous dual estimate tracking loops design for AltBOC

针对在交替二进制偏移载波(AltBOC)调制方式中,由于自相关函数存在多个相关峰值,会导致接收机在码同步过程中产生跟踪模糊,造成很大的跟踪误差的问题,提出了一种基于双重估计技术的AltBOC无模糊跟踪方法.该方法使用双跟踪环路结构,并采用易于硬件实现的组合伪随机扩频码和余弦信号来设计双跟踪环路.推导出了AltBOC二维相关函数,并根据相关函数得到了信号延时的估计值.仿真结果表明:该方法能够实现AltBOC的无模糊跟踪,相对于传统的AltBOC无模糊跟踪方法,该方法具有更好的抗噪声和抗多径性能.

As the multiple side-peaks exist in the alternative binary offset carrier（AltBOC） autocorrelation function,the ambiguous tracking would take place in the synchronous process of receivers.So an unambiguous tracking method for AltBOC modulated signals based on dual estimate tracking method was proposed.The dual tracking loops structure was used,and a combined PRN code and a pure cosine signal which can be easily implemented in the hardware receivers were employed.The two-dimensional correlation function for AltBOC was derived and unambiguous signal delay estimation was deduced according to it.Simulation results indicate that compared with other traditional AltBOC unambiguous tracking methods,the proposed method can track AltBOC signals unambiguously,showing better performance in tracking accuracy and multipath mitigation.