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针对低信噪比高动态信号的载波频偏捕获提出了一种新的算法即谱线平移算法。首先,介绍了现有的大载波频偏捕获技术,分析了其不能适应高动态信号捕获的原因;其次,分析了载波频偏及其变化率对载波频偏捕获的影响,主要考虑多普勒频移变化率对信号捕获的影响,它将严重限制低信噪比情况下对载波频偏估计时非相干累加的次数,在此基础上,提出并研究了适应低信噪比高动态信号大载波频偏捕获的谱线平移算法,并对算法进行了性能仿真,表明其具有2~3dB的改善增益,与最大似然算法相比具有绝对优势。
Aiming at the carrier frequency offset acquisition of high dynamic signal with low signal-to-noise ratio (SNR), a new algorithm called spectral line shift algorithm is proposed. Firstly, the existing acquisition techniques of large carrier frequency offset are introduced, and the reasons why it can not adapt to high dynamic signal acquisition are analyzed. Secondly, the influence of carrier frequency offset and its rate of change on the acquisition of carrier frequency offset is analyzed. The main consideration is Doppler It will severely limit the number of non-coherent accumulation of carrier frequency offset estimation under low signal-to-noise ratio. On the basis of this, it is proposed and adapted to adapt to low signal-to-noise ratio high dynamic signal large The algorithm of spectral line shift captured by the carrier frequency offset and the performance simulation of the algorithm show that it has an improved gain of 2 ~ 3dB, which has an absolute advantage over the maximum likelihood algorithm.