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在基于统一载波体制的深空测控通信中,为了有效消除大调制度下的多普勒频偏,提出一种利用频谱对称性、基于圆自卷积的主载波捕获新算法。首先对已下变频的采样信号做FFT变换计算出信号频谱;然后利用圆自卷积法计算出频谱的对称点,即为主载波频率。仿真分析和FPGA验证表明,该算法能够实现各种调制度下的主载波捕获,解决了深空测控通信中大调制度下的多普勒频偏问题。
In the deep space observation and control communication based on unified carrier system, in order to effectively eliminate the Doppler frequency offset in the large-scale system, a new algorithm of primary carrier capture using spectral symmetry and circular self-convolution is proposed. First of all, the down-converted sampling signal is subjected to FFT transform to calculate the signal spectrum; and then the circular convolution method is used to calculate the symmetry point of the spectrum, which is the main carrier frequency. Simulation and FPGA verification show that this algorithm can achieve the main carrier capture under various modulation degrees, and solve the Doppler frequency offset problem under the major modulation in deep space monitoring and control communication.