论文部分内容阅读
针对非协作卫星通信场合中同调制参数的MSK单通道混合信号的载波频偏估计问题进行研究,推导了卫星信道条件下MSK混合信号的循环谱表达式。通过搜索零频率处循环频率轴上的大强度谱线进行混合信号频偏估计,并针对谱线选择时存在的模糊问题,利用循环谱快速算法中的泄漏谱线包络辅助进行模糊消除。仿真结果表明在信噪比大于-20 dB时,对混合信号载波频偏估计较为准确。该方法对混合信号载波初相和时延等未知参数影响不敏感,并且不需要任何先验信息,其估计精度能够满足后续信号处理的需要。
The carrier frequency offset estimation of MSK single-channel mixed signal with same modulation parameters in non-cooperative satellite communication is studied. The cyclic spectrum expression of MSK mixed signal in satellite channel is derived. The frequency offset estimation of the mixed signal is carried out by searching for the high-intensity spectral lines on the frequency axis of the zero-frequency cycle. Aiming at the problem of fuzzy selection in the spectral line selection, the envelope of the leakage spectrum in the fast cyclic algorithm is used to assist in the fuzzy elimination. The simulation results show that the frequency offset estimation of the mixed signal carrier is more accurate when the SNR is greater than -20 dB. The proposed method is insensitive to unknown parameters such as initial phase and delay of mixed-signal carrier, and does not require any prior information. Its estimation accuracy can meet the needs of subsequent signal processing.