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文中针对极低信噪比条件下的扩频信号处理要求,基于直接扩频(DS)信号相似性和特征分解原理,提出了一种DS伪码序列的估计算法.该算法在未知直扩信号任何信息的情况下,首先通过对该信号的分段处理和平均互相关确定伪码起始码元,然后采用特征分解(EVD)算法准确估计出伪码序列.通过理论推导和证明得到所提算法估计效率和估计误差的两个重要结论.仿真结果表明:在相同信源条件下,该算法较现有算法不仅抗噪声性能提高了2dB以上,而且有效克服了部分反码问题,从而保证极低信噪比条件下DS伪码序列的准确估计.
A DS code sequence estimation algorithm is proposed based on the similarity of DS signals and the principle of feature decomposition for the requirement of spread spectrum signal processing under very low signal to noise ratio In the case of any information, the pseudo-code start symbol is first determined by the segmentation process and the average cross-correlation of the signal, and then the pseudo code sequence is accurately estimated by the characteristic decomposition (EVD) algorithm. By theoretical derivation and proof, The algorithm estimates the efficiency and the estimation error of two important conclusions.The simulation results show that: under the same source conditions, the proposed algorithm not only improves the anti-noise performance more than 2dB, but also effectively overcome some of the anti-code problem, thus ensuring the pole Accurate Estimation of DS Pseudo - Random Code Sequence at Low S / N Ratio.