【摘要】 通过对窄带干扰(NBI)条件下低信噪比直接序列扩频(DS-SS)信号的细微特征分析,得到了NBI特征波形和DS-SS扩频伪码(PN)的盲估计。首先按PN码周期和码速率(假设已获知)对接收DS-SS信号进行取样预处理形成观察向量集,接着用细微特征分析方法对该集合进行处理,最后可以估计出信号所夹杂的NBI特征波形和信号的PN码序列。为了减少所估计PN码的相位模糊性,本文在取样预处理时将取样时间窗口增大到PN码周期的二倍,结果使所估计的PN码或是原码或是反码,从而提高了估计准确性。同时利用所估计的NBI特征波形可消除原始信号所夹杂的NBI,而利用所估计的PN码序列则可以对DS-SS信号实施盲解扩处理。理论分析和数值结果表明,该方法有效,并能工作在较低的输入信噪比和信号干扰比环境下。更多还原

【Abstract】 A modified approach based on eigen-analysis of direct sequence spread spectrum (DS-SS) signals under narrow band interferences(NBIs) is proposed.It can estimate the eigen-waveforms of NBIs and pseudo noise(PN) sequence of DS-SS signals blindly on the low signal noise ratio(SNR) and signal interference ratio(SIR) DS-SS signals.Some parameters,such as period and chip interval of the PN sequence,need to be known.Firstly,the received signal is divided into non-overlapping temporal vectors according to two times of the period of the PN sequence,then the approach based on eigen-analysis is used to process the vectors one by one.Finally,the NBI eigen-waveforms and the PN sequences of the signals can be blindly estimated.Based on the estimated NBI eigen-waveforms and the PN sequences,NBIs can be rejected,and the DS-SS signals despreading without the PN code can be realized too.Theoretical analysis and experimental results show that the approach is effective and works well in the lower SNR and SIR ambient.更多还原