北斗载波信号在传播和接收过程中都会耦合噪声, 这些噪声直接影响北斗定位等有效数据的处理。在EEMD算法的基础上, 针对IMF重构分量数人为设定影响降噪精度的问题, 综合考虑了信号的形状细节、SNR、相关系数R等衡量降噪效果的参数, 设计了EEMD分解重构分量数的寻优指标, 并基于此提出了一种自适应指标寻优的EEMD算法(AIO-EEMD)。使用该算法对实测北斗载波信号进行了降噪实验, 并分析了实验效果, 结果证明, 所设计的AIO-EEMD算法能够有效地对北斗载波信号进行降噪, 提高其信噪比。

The Beidou carrier signal is coupled into a certain noise during propagation and reception, which directly affect the processing of effective data such as Beidou positioning. Based on the ensemble empirical mode decomposition (EEMD) algorithm, aiming at the problem that the intrinsic mode function (IMF) reconstruction number is artificially set so that the noise reduction accuracy may be affected and considering the parameters such as the shape details, signal to noise ratio (SNR) and correlation coefficient R of the signal, the optimization index of EEMD decomposition and reconstruction component number has been designed and then an adaptive index optimizing EEMD algorithm has been proposed. The algorithm has been used to denoise the real Beidou carrier signals, and the experimental results have been analyzed. It proves that the designed AIO-EEMD algorithm can effectively reduce the noise of the Beidou carrier signal and improve its SNR.