摘要
针对卫星通信侦察与对抗,提出了一种DS-SS通信信号的伪码序列盲估计算法。首先采用循环自相关方法估计信号载频,对截获的中频信号进行解调,得到基带信号,再采用循环自相关估计PN码周期。然后利用分段互相关方法估计信息码与PN码同步调制起始点。在此基础上,完成对伪码码序列的识别。仿真实验结果表明,该方法在极低信噪比条件下可以得到准确的伪码序列估计。
Focused on satellite countermeasure and reconnaissance, a blind estimation algorithm for direct sequence spread spectrum （DS-SS） signals was proposed and analyzed. First, the carrier frequen- cy was estimated by cyclic autocorrelation. Then the intermediate frequency signal was demodulated to baseband. A method based on the second order cyclic autocorrelation was used to estimate the period of PN sequence of the baseband signal. After this, the synchronous start bit between the information sym- bols and the PN codes were estimated with the average of subsection cross correlation. Finally, the period of PN sequence was identified. Experimental simulations show that the method can work well on signals at low signal noise ratio （SNR）.
出处
《现代防御技术》
北大核心
2009年第3期85-88,130,共5页
Modern Defence Technology
关键词
循环自相关
直扩信号
伪码序列估计
通信侦察
cyclic-autocorrelation
DS - SS signal
PN sequence estimation
signal reconnaissance
