多径环境下TDDM-BOC信号伪码周期估计

Period Estimation of PN Sequence for TDDM-BOC Signal in Multipath Environment

针对低信噪比下存在多径效应的时分数据调制二进制偏移载波(TDDM-BOC)调制信号的伪码周期估计难题,提出了一种基于二次谱的TDDM-BOC信号伪码周期估计算法。该算法首先推导出多径环境下TDDM-BOC信号模型,然后求出多径TDDM-BOC信号的功率谱,再求其二次谱,最后通过检测二次谱的尖峰脉冲间的间距得到多径环境下TDDM-BOC信号的伪码周期。实验过程中采用累加平均的方法可以达到降噪和精确估计的目的。仿真结果表明:该算法能够在多径环境下对TDDM-BOC信号伪码周期进行有效估计,且估计性能与多径环境有密切关系,这为今后我国"北斗"导航接收设备的开发提供了一定的理论参考。

For the problem set Cartier（TDDM-BOC） of estimating pseudo-code period of Time signal Division Data Modulation-Binary Off- with muhipath effect under low signal-to-noise ratio（ SNR）, an algorithm based on quadratic spectrum is proposed to estimate the pseudo-code period of TDDM-BOC signal. First- ly,the TDDM-BOC signal model in muhipath environment is derived. Then the power spectrum of the muhipath TDDM-BOC signal is found ,its secondary spectrum can be obtained by using Fourier transform of the power spectrum. Finally,the pseudo-code period of TDDM-BOC signal in muhipath environment can be got by detecting spacing between peak pulses. The method of accumulative average is adopted to a- chieve the purpose of noise reduction and accurate estimation. Simulation results show that the pseudo- code period of TDDM-BOC signal in multipath environment is effectively estimated by using the algorithm and its performance closely relates with the multipath environment. It has a certain reference value for Bei- dou navigation receiver design.