基带信号码元同步抽取是目前星载AIS(Automatic Identification System)信号处理中的一个难点问题,针对过零检测和迟门早门等现有算法存在的不足,提出了基于能量度量的基带信号自适应码元同步抽取算法.将基带信号根据采样率和码速率的比值分割成相同的段的组合,之后分别计算每个段内相应样点的能量度量,最后选择使能量度量最大时的样点集作为最优同步抽取样点,该样点集具有最大信噪比.仿真结果验证了该算法误码率优于过零检测和迟门早门算法.%The arithmetic of decimation and synchronisation of Base-band signal is a key problem in space-based AIS( Automatic Identification System) processing. Aiming at the defect of the Detection of Striding across Zero and the Early-late Gate, a method to decimate and synchronise the base-band signal based on energy measurement was proposed. We divided the base-band signal into segments with the same length according the rate of sampling and the rate of code, and then we calculated the measurement of corresponding sampling point of every segment. Finally we chose the sequence number of the maximum energy measurement as the best decimation and synchronisation sampling point, which has the character of maximum SNR. Numerical performance of the proposed methods performs better than the existing ones.
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