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针对传统假设检验帧同步算法阈值选取单一造成的错同步与漏同步概率较高的情况，提出了一种改进的大气激光通信帧同步实现算法，称之为二次筛选算法。针对 OOK 调制的大气激光通信链路，提出了大假设检验值计算公式，通过修改假设检验中阈值的选取原则，实现对接收信息序列的快速搜索，并对可能存在的帧同步位置建立相应地位置集合；利用最大似然准则，通过二次筛选，实现了最终的帧同步。仿真结果表明，所提算法可以在保持低错同步概率的前提下有效提高帧同步探测概率:当信道信噪比不低于2.7d B 时，帧同步错同步概率不高于310?，且同步探测率达到 90%以上。同时，二次筛选算法中阈值范围边界的选择对算法影响较大，应根据具体的系统要求来选择。
Aiming at the problem that the traditional assumption of frame synchronization algorithm detects the single error caused by the single threshold selection, we propose an improved frame synchronization algorithm for atmosphere laser communication, which is called as secondary filtering algorithm. Aiming at the OOK modulated atmospheric laser communication link, a formula for calculating large hypothesis test value is proposed. By modifying the selection principle of threshold in hypothesis testing, a fast search of the received information sequence is achieved and a corresponding position of the frame synchronization position is established The final frame synchronization is achieved by using the maximum likelihood criterion through secondary filtering. The simulation results show that the proposed algorithm can effectively improve the detection probability of frame synchronization while keeping the probability of low error synchronization: when the signal to noise ratio of the channel is not less than 2.7d B, the synchronization probability of frame synchronization error is not higher than 310?, And the synchronization Detection rate of 90% or more. At the same time, the selection of the threshold range boundary in the secondary screening algorithm has a great influence on the algorithm, and should be selected according to the specific system requirements.