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针对航天测控系统中CCSDS推荐的连续相位调制(Continuous phase modulation,CPM)信号载波相位难以恢复的问题,文中提出了一种简化非相干检测算法。首先依据最大似然比准则,推导出信号的最优非相干检测算法,然后将基于Laurent分解的CPM信号的线性模型引入,简化非相干接收机结构。同时考虑到信号相位间的连续性,每次分支度量通过处理多个符号时间的接收信号来提高检测性能。简化的接收机由几个前端滤波器和紧随其后的维特比运算部件构成,文中最后给出了L=4的高斯最小频移键控(Guassian minimum shift keying,GMSK)信号的接收性能,结果表明在误码率同为1×10-4的条件下,观察窗口为8个码元长度时,简化非相干检测比起最优相干检测算法只有1.2 dB的性能损失。
Aiming at the problem of CCSDS continuous phase modulation (CPM) signal carrier phase recovery difficult to recover in the space measurement and control system, a simplified non-coherent detection algorithm is proposed in this paper. First, according to the maximum likelihood ratio criterion, the optimal incoherent detection algorithm of signal is deduced. Then the linear model of CPM signal based on Laurent decomposition is introduced to simplify the structure of incoherent receiver. Taking into account the continuity between the signal phases, each branch metric improves the detection performance by processing received signals at multiple symbol times. The simplified receiver is composed of several front-end filters and the following Viterbi components. Finally, the receiving performance of GMSK signal with L = 4 is given. The results show that the simplified non-coherent detection has a performance loss of only 1.2 dB compared with the optimal coherence detection algorithm when the observation window is 8 symbol lengths under the same bit error rate of 1 × 10-4.