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针对全球导航卫星系统中的多径干扰抑制问题,提出了一种有效的低复杂度多径干扰抑制算法,在直达信号和多径干扰来向角(DOA)未知的情况下,利用RELAX算法,通过反复迭代的思想逐一估计出直达信号和多径干扰的DOA和幅度,进而识别多径干扰,利用线性约束最小方差无畸变波束形成技术,在直达信号方向形成增益与在多径干扰方向形成零陷而抑制多径干扰,并进行了仿真试验。分析结果表明:当多径干扰部分相干时,RELAX算法估计的DOA均方根误差比MUSIC算法低了约12dB;当多径干扰完全相干时,RELAX算法估计的DOA均方根误差比MUSIC算法低了约25dB;所提算法能够准确估计出直达信号和多径干扰的DOA,保证通过波束形成零陷空域多径干扰,使得进入跟踪环路的信号非常洁净,处理后的码相位跟踪误差接近于0。
Aiming at the problem of multipath interference suppression in global navigation satellite system, an effective and low complexity multipath interference suppression algorithm is proposed. With the DOA of direct signal and multipath interference unknown, The DOA and amplitude of the direct signal and the multipath interference are estimated one by one through repeated iterations, and multipath interference is further identified. With the linear constrained minimum variance undistorted beamforming technique, the gain in the direct signal direction and the zero Trap and inhibit multipath interference, and conducted a simulation test. The analysis results show that when the multipath interference is partially coherent, the RELA algorithm estimates the DOA root mean square error of the DOA less than MUSIC by about 12dB. When the multipath interference is completely coherent, the RELA algorithm estimates the DOA root mean square error less than the MUSIC algorithm About 25dB. The proposed algorithm can accurately estimate the DOA of direct signal and multipath interference, and ensure the multipath interference of zonal spatiotemporal beamforming. The signal entering the tracking loop is very clean and the tracking error of the processed code phase is close to 0.