一种改进的变步长LMS算法在天线失配通道校正中的应用

摘要

天线阵列通道之间幅相特性的不一致会对天线阵列的性能有很大影响,故在其工作前要对其各通道的幅度和相位特性进行校正.本文针对天线阵列通道之间与频率无关的恒定通道失配问题,考虑到天线阵列常常工作在干扰噪声比较严重的低信噪比环境下,提出了一种改进的变步长LMS算法对失配通道的幅度和相位进行校正.仿真结果表明,采用误差自相关和遗忘累加均值调节步长的本文算法,可以很好地校正与频率无关的通道失配,与变步长LMS算法相比,在低信噪比环境下所能校正的幅度和相位精度更高,具有收敛速度更快、稳态误差更小、抗干扰能力较强的特点,且易于工程实现.%The performance of antenna array is affected significantly by the mismatch of amplitude and phase among antenna array channels , so the mismatch must be calibrated before the antenna array func-tions.Given that the antenna array usually functions in low signal-to-noise ratio ( SNR) environment with strong interference noise , a calibration technique based on modified variable step size LMS algorithm is proposed to calibrate the mismatch of amplitude and phase among antenna array channels .The modified algorithm uses autocorrelation error and residual accumulation average to adjust step size .Simulation re-sults show that , compared with variable step size LMS algorithm , the modified variable step size LMS al-gorithm can calibrate the mismatch of amplitude and phase more accurately in low SNR environment , ac-complish faster convergence , have less steady-state offset noise and stronger capability of anti-interfer-ence , and is easy to be implemented .